@article{kelly_freeman_gutierrez-fonseca_gomez_perez_victoria-lacy_ramirez_pringle_2024, title={Decomposition rates appear stable despite elevated shrimp abundances following hurricanes in montane streams, Puerto Rico}, volume={1}, ISSN={["1573-5117"]}, url={https://doi.org/10.1007/s10750-023-05458-2}, DOI={10.1007/s10750-023-05458-2}, journal={HYDROBIOLOGIA}, author={Kelly, Max and Freeman, Mary and Gutierrez-Fonseca, Pablo E. and Gomez, Jesus E. and Perez, Rafael and Victoria-Lacy, Lulu and Ramirez, Alonso and Pringle, Catherine}, year={2024}, month={Jan} }
 @article{alves-martins_stropp_juen_ladle_lobo_martinez-arribas_de marco junior_brasil_ferreira_bastos_et al._2024, title={Sampling completeness changes perceptions of continental scale climate-species richness relationships in odonates}, volume={2}, ISSN={["1365-2699"]}, DOI={10.1111/jbi.14810}, abstractNote={Abstract}, journal={JOURNAL OF BIOGEOGRAPHY}, author={Alves-Martins, Fernanda and Stropp, Juliana and Juen, Leandro and Ladle, Richard J. and Lobo, Jorge M. and Martinez-Arribas, Javier and De Marco Junior, Paulo and Brasil, Leandro Schlemmer and Ferreira, Victor Rennan Santos and Bastos, Rafael Costa and et al.}, year={2024}, month={Feb} }
 @article{ardon_clark_marzolf_ramirez_pringle_2023, title={Can we see the nitrate from the trees? Long-term linkages between tropical forest productivity and stream nitrogen concentrations}, volume={2}, ISSN={["1573-515X"]}, DOI={10.1007/s10533-023-01030-1}, journal={BIOGEOCHEMISTRY}, author={Ardon, Marcelo and Clark, Deborah A. and Marzolf, Nicholas S. and Ramirez, Alonso and Pringle, Catherine M.}, year={2023}, month={Feb} }
 @article{gutierrez-fonseca_pringle_ramirez_gomez_garcia_2023, title={Hurricane disturbance drives trophic changes in neotropical mountain stream food webs}, volume={11}, ISSN={["1939-9170"]}, url={https://doi.org/10.1002/ecy.4202}, DOI={10.1002/ecy.4202}, abstractNote={Abstract}, journal={ECOLOGY}, author={Gutierrez-Fonseca, Pablo E. and Pringle, Catherine M. and Ramirez, Alonso and Gomez, Jesus E. and Garcia, Pavel}, year={2023}, month={Nov} }
 @article{vazquez_ramirez_favila_alvarado-barrientos_2023, title={Land use scenarios, seasonality, and stream identity determine the water physicochemistry of tropical cloud forest streams}, volume={11}, ISSN={["2167-8359"]}, url={https://doi.org/10.7717/peerj.15487}, DOI={10.7717/peerj.15487}, abstractNote={
Background
Land use is a major factor determining stream water physicochemistry. However, most streams move from one land use type to another as they drain their watersheds. Here, we studied three land use scenarios in a tropical cloud forest zone in Mexico. We addressed three main goals, to: (1) assess how land use scenarios generate different patterns in stream physicochemical characteristics; (2) explore how seasonality (i.e., dry, dry-to-wet transition, and wet seasons) might result in changes to those patterns over the year; and (3) explore whether physicochemical patterns in different scenarios resulted in effects on biotic components (e.g., algal biomass).
}, journal={PEERJ}, author={Vazquez, Gabriela and Ramirez, Alonso and Favila, Mario E. and Alvarado-Barrientos, M. Susana}, year={2023}, month={Jun} }
 @article{santiago-vera_ramirez_2023, title={MEIOFAUNA IN TROPICAL MONTANE STREAMS: BIOTIC AND ABIOTIC FACTORS REGULATING COMMUNITIES}, volume={28}, ISSN={["1900-1649"]}, url={https://doi.org/10.15446/abc.v28n2.103379}, DOI={10.15446/abc.v28n2.103379}, abstractNote={Meiofauna is a group of heterotrophic organisms smaller than macroinvertebrates but larger than microfauna and characterized by groups such as testate amoebae, ciliates, and nematodes. They are a link between bacteria and resources and macroinvertebrates. However, tropical meiofauna is poorly studied; thus, our goal was to characterize meiofaunal community composition and abundance and assess potential environmental variables controlling these community dynamics. Monthly samplings of meiofauna were conducted for eight months in Quebrada Prieta, El Yunque National Forest, Puerto Rico. Sampling was made in 12 pools, and data on discharge, sediment characteristics, and biotic variables were also collected. A total of 62 meiofaunal morphospecies were identified, with nematodes dominating the community, followed by testate amoebae. Bacterivores and detritivores taxa dominated the community. Meiofaunal abundance was negatively related to discharge and positively to the percentage of coarse sand, nitrate, and macroinvertebrate abundance. The composition of meiofauna in Quebrada Prieta is like the composition reported for temperate streams, at least in major meiofaunal groups present. However, the community in Quebrada Prieta was dominated by testate amoebae. In contrast, temperate streams are often dominated by rotifers and nematodes. Both abiotic and biotic variables are important for meiofaunal communities in the headwater streams in Puerto Rico.}, number={2}, journal={ACTA BIOLOGICA COLOMBIANA}, author={Santiago-Vera, Josue and Ramirez, Alonso}, year={2023} }
 @article{ramirez_vazquez_sosa_garcia_castillo_garcia-franco_martinez_mehltreter_pineda_alvarado-barrientos_et al._2023, title={Stream food webs in tropical mountains rely on allochthonous carbon regardless of land use}, volume={18}, ISSN={["1932-6203"]}, url={https://doi.org/10.1371/journal.pone.0295738}, DOI={10.1371/journal.pone.0295738}, abstractNote={The relative importance of allochthonous and autochthonous carbon (C) as sources of energy for tropical stream food webs remains an open question. Allochthonous C might be the main energy source for small and shaded forest streams, while autochthonous C is more likely to fuel food webs draining land uses with less dense vegetation. We studied food webs in cloud forest streams draining watersheds with forests, coffee plantations, and pastures. Our goal was to assess the effects of those land uses on the C source and structure of stream food webs. The study took place in tropical montane streams in La Antigua Watershed, in eastern Mexico. We selected three streams per land use and sampled biofilm and leaf litter as the main food resources, and macroinvertebrates and aquatic vertebrates from different trophic guilds. Samples were analyzed for δ13C and δ15N isotopes. Using a Bayesian mixing model, we estimated the proportional assimilation of autochthonous and allochthonous carbon by each guild. We found that consumers were mostly using allochthonous C in all streams, regardless of watershed land use. Our findings indicate that montane cloud forest streams are dominated by allochthony even in watersheds dominated by pastures. Abundant precipitation in this life zone might facilitate the movement of allochthonous C into streams. While food webs of streams from coffee plantations and pastures also rely on allochthonous resources, other impacts do result in important changes in stream functioning.}, number={12}, journal={PLOS ONE}, author={Ramirez, Alonso and Vazquez, Gabriela and Sosa, Vinicio and Garcia, Pavel and Castillo, Gonzalo and Garcia-Franco, Jose and Martinez, Ma. Luisa and Mehltreter, Klaus and Pineda, Eduardo and Alvarado-Barrientos, M. Susana and et al.}, editor={Masese, Frank O.Editor}, year={2023}, month={Dec} }
 @article{babbington_engman_clark_ramirez_2023, title={The trophic ecology of an invasive predator in a novel ecosystem: Green sunfish Lepomis cyanellus in a restored urban stream}, volume={36}, ISSN={["2352-2496"]}, DOI={10.1016/j.fooweb.2023.e00292}, abstractNote={Rapid urbanization will increase the number of novel stream ecosystems in the Southeastern United States. The green sunfish (Lepomis cyanellus) is a globally widespread, invasive species that is particularly well-adapted to urban stream conditions. The trophic ecology of green sunfish is understudied, especially in the novel ecosystems where they appear to thrive. We assessed predation by green sunfish in the food web of a heavily engineered and restored urban stream in Raleigh, North Carolina. We sampled fish species composition, size structure, abundance, the benthic macroinvertebrate assemblage, and fish diets during two seasons. Green sunfish was the sole species inhabiting the study stream, with the exception of a single goldfish. The population size structure indicated potential overcrowding in our study ecosystem. Chironomidae was the most common taxa in both the benthic macroinvertebrate assemblage and in fish diets during the summer. We observed a seasonal shift in diets to lesser prey-specific abundance of Chironomidae and a greater overall abundance of terrestrial prey from summer to winter. Green sunfish can persist in small restored urban streams of the Southeast US where virtually no other fish occur, and they utilize benthic invertebrates and terrestrial prey as resources.}, journal={FOOD WEBS}, author={Babbington, Brittany A. and Engman, Augustin C. and Clark, Z. Winston and Ramirez, Alonso}, year={2023}, month={Sep} }
 @article{marzolf_baca_bruce_vega-gomez_watson_ganong_ramirez_pringle_ardon_2022, title={Do experimental pH increases alter the structure and function of a lowland tropical stream?}, volume={13}, ISSN={["2150-8925"]}, url={https://doi.org/10.1002/ecs2.4097}, DOI={10.1002/ecs2.4097}, abstractNote={Abstract}, number={7}, journal={ECOSPHERE}, publisher={Wiley}, author={Marzolf, Nicholas S. and Baca, Dominic M. and Bruce, Terrius K. and Vega-Gomez, Mariely and Watson, Christopher D. and Ganong, Carissa N. and Ramirez, Alonso and Pringle, Catherine M. and Ardon, Marcelo}, year={2022}, month={Jul} }
 @article{maldonado-benítez_mariani-ríos_ramírez_2022, title={Effects of urbanization on Odonata assemblages in tropical island streams in San Juan, Puerto Rico}, url={https://doi.org/10.48156/1388.2022.1917163}, DOI={10.48156/1388.2022.1917163}, abstractNote={Urbanization has considerable impacts on stream ecosystems. Streams in urban settings are affected by multiple stressors such as flow modifications and loss of riparian vegetation. The richness and abundance of aquatic insects, such as odonates, directly reflect these alterations and can be used to assess urban impacts on streams. The effects of urbanization on odonate richness and abundance on tropical islands is as yet poorly understood. The objective of this study is to identify the effects of urbanization on stream habitat quality and associated odonate assemblages in Puerto Rico. We sampled 16 streams along a rural to urban gradient in the San Juan Metropolitan Area, where each stream was characterized using the Stream Visual Assessment Protocol (SVAP) for Puerto Rico and by analyzing their surrounding land cover. A 100-m segment of each stream was surveyed to assess adult odonate richness and abundance during the rainy and dry seasons. Adults were identified visually, and their abundance was recorded. Favorable local scale factors, like improved habitat quality, as measured with the SVAP, resulted in higher abundances of odonates. However, regional factors such as percent urban cover did not appear to significantly affect richness and abundances of odonates. Overall, our study indicates that odonate assemblages are affected by the loss of habitat integrity, and conservation of tropical odonates may benefit from focusing on local scale factors.}, journal={International Journal of Odonatology}, author={Maldonado-Benítez, Norman and Mariani-Ríos, Ashley and Ramírez, Alonso}, year={2022}, month={Feb} }
 @article{mariani-rios_maldonado-benitez_ramirez_2022, title={Natural history of Odonata assemblages in tropical streams in Puerto Rico}, volume={8}, ISSN={["2376-6808"]}, url={https://doi.org/10.1080/23766808.2022.2043699}, DOI={10.1080/23766808.2022.2043699}, abstractNote={ABSTRACT Freshwater macroinvertebrates play an important role in maintaining stream food webs. Odonata (dragonflies and damselflies) are important top predators in these communities and serve as indicators of stream health. Our understanding of odonate assemblages is limited in the Caribbean and the natural history of most odonate species in the region remains unknown. The focus of this research is to study the natural history of odonate species in headwater montane streams following major hurricane impacts in Puerto Rico. We monitored assemblages from August 2018 to July 2019 in two headwater streams within El Yunque National Forest, Puerto Rico. The study streams drain a protected forest, with aseasonal precipitation patterns, relatively constant water temperature, and flashy hydrographs that quickly respond to rain events. We sampled 226 adults and 550 larvae, dominated by three Caribbean endemics: Scapanea frontalis, Macrothemis celeno, and Telebasis vulnerata. Only S. frontalis and M. celeno were abundant enough to assess the temporal patterns and their natural history. Larval density fluctuated throughout the year with short peaks in abundance during different times of the year, according to the species. Small individuals (≤10 mm body length) were more abundant than the large ones. However, all size classes were present during the year. The dominant species, S. frontalis and M. celeno, had continuous development patterns, without identifiable size classes and multiple overlapping generations. The exception was the last stadium that formed a separate group in the body length vs head width plots. Species had clear habitat preferences; S. frontalis was abundant in riffles and preferred areas with high amounts of cobble. Macrothemis celeno prefers pool habitats with fine substrates. While we found trends for negative relations between abundance and discharge, canopy cover, water temperature, and rainfall, none was statistically significant. Observed patterns suggest a lack of strong temporal seasonality in the natural history of Odonata, which coincides with the aseasonal environment of streams draining our study area. Overall, our study is the first to assess temporal variability of Odonata assemblages in montane streams of Puerto Rico and provides information on Caribbean endemic species.}, number={1}, journal={NEOTROPICAL BIODIVERSITY}, author={Mariani-Rios, Ashley and Maldonado-Benitez, Norman and Ramirez, Alonso}, year={2022}, month={Dec}, pages={112–123} }
 @article{marzolf_small_oviedo-vargas_ganong_duff_ramirez_pringle_genereux_ardon_2022, title={Partitioning inorganic carbon fluxes from paired O-2-CO2 gas measurements in a Neotropical headwater stream, Costa Rica}, volume={7}, ISSN={["1573-515X"]}, url={https://doi.org/10.1007/s10533-022-00954-4}, DOI={10.1007/s10533-022-00954-4}, abstractNote={The role of streams and rivers in the global carbon (C) cycle remains unconstrained, especially in headwater streams where CO2 evasion (FCO2) to the atmosphere is high. Stream C cycling is understudied in the tropics compared to temperate streams, and tropical streams may have among the highest FCO2 due to higher temperatures, continuous organic matter inputs, and high respiration rates both in-stream and in surrounding soils. In this paper, we present paired in-stream O2 and CO2 sensor data from a headwater stream in a lowland rainforest in Costa Rica to explore temporal variability in gas concentrations and ecosystem processes. Further, we estimate groundwater CO2 inputs (GWCO2) from riparian well CO2 measurements. Paired O2–CO2 data reveal stream CO2 supersaturation driven by groundwater CO2 inputs and large in-stream production of CO2. At short time scales, CO2 was diluted during storm events, but increased at longer seasonal scales. Areal fluxes in our study reach show that FCO2 is supported by greater in-stream metabolism compared to GWCO2. Our results underscore the importance of tropical headwater streams as large contributors of carbon dioxide to the atmosphere and show evaded C can be derived from both in-stream and terrestrial sources.}, journal={BIOGEOCHEMISTRY}, publisher={Springer Science and Business Media LLC}, author={Marzolf, Nicholas S. and Small, Gaston E. and Oviedo-Vargas, Diana and Ganong, Carissa N. and Duff, John H. and Ramirez, Alonso and Pringle, Catherine M. and Genereux, David P. and Ardon, Marcelo}, year={2022}, month={Jul} }
 @article{maasri_jaehnig_adamescu_adrian_baigun_baird_batista-morales_bonada_brown_cai_et al._2021, title={A global agenda for advancing freshwater biodiversity research}, volume={12}, ISSN={["1461-0248"]}, DOI={10.1111/ele.13931}, abstractNote={Abstract}, journal={ECOLOGY LETTERS}, author={Maasri, Alain and Jaehnig, Sonja C. and Adamescu, Mihai C. and Adrian, Rita and Baigun, Claudio and Baird, Donald J. and Batista-Morales, Angelica and Bonada, Nuria and Brown, Lee E. and Cai, Qinghua and et al.}, year={2021}, month={Dec} }
 @article{zimmerman_wood_gonzalez_ramirez_silver_uriarte_willig_waide_lugo_2021, title={Disturbance and resilience in the Luquillo Experimental Forest}, volume={253}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2020.108891}, abstractNote={The Luquillo Experimental Forest (LEF) has a long history of research on tropical forestry, ecology, and conservation, dating as far back as the early 19th Century. Scientific surveys conducted by early explorers of Puerto Rico, followed by United States institutions contributed early understanding of biogeography, species endemism, and tropical soil characteristics. Research in the second half of the 1900s established the LEF as an exemplar of forest management and restoration research in the tropics. Research conducted as part of a radiation experiment funded by the Atomic Energy Commission in the 1960s on forest metabolism established the field of ecosystem ecology in the tropics. Subsequent research has built on these early advances to develop new theories on ecosystem response to disturbance regimes and the role of the biota in ecosystem resilience. Recent and current research in the LEF has advanced understanding of resilience to hurricane disturbances, human land use, gamma irradiation, landslides, drought, and warming, showing that even following the most severe disturbances (e.g., landslides, agriculture) forests reestablish within 60 years. Work in the LEF has reversed the paradigm that tropical ecosystems are fragile, but instead exhibit remarkable resilience to many forms of disturbance present at multiple spatial and temporal scales. Current research is already advancing understanding of how climate change and attendant effects on the disturbance regime might affect the composition, structure, and function of tropical forest ecosystems.}, journal={BIOLOGICAL CONSERVATION}, author={Zimmerman, Jess K. and Wood, Tana E. and Gonzalez, Grizelle and Ramirez, Alonso and Silver, Whendee L. and Uriarte, Maria and Willig, Michael R. and Waide, Robert B. and Lugo, Ariel E.}, year={2021}, month={Jan} }
 @article{boyero_lopez-rojo_tonin_perez_correa-araneda_pearson_bosch_albarino_anbalagan_barmuta_et al._2021, title={Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics}, volume={12}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-021-23930-2}, abstractNote={Abstract}, number={1}, journal={NATURE COMMUNICATIONS}, author={Boyero, Luz and Lopez-Rojo, Naiara and Tonin, Alan M. and Perez, Javier and Correa-Araneda, Francisco and Pearson, Richard G. and Bosch, Jaime and Albarino, Ricardo J. and Anbalagan, Sankarappan and Barmuta, Leon A. and et al.}, year={2021}, month={Jun} }
 @article{boyero_perez_lopez-rojo_tonin_correa-araneda_pearson_bosch_albarino_anbalagan_barmuta_et al._2021, title={Latitude dictates plant diversity effects on instream decomposition}, volume={7}, ISSN={["2375-2548"]}, DOI={10.1126/sciadv.abe7860}, abstractNote={Plant litter functional diversity effects on instream decomposition change across latitudes.}, number={13}, journal={SCIENCE ADVANCES}, author={Boyero, Luz and Perez, Javier and Lopez-Rojo, Naiara and Tonin, Alan M. and Correa-Araneda, Francisco and Pearson, Richard G. and Bosch, Jaime and Albarino, Ricardo J. and Anbalagan, Sankarappan and Barmuta, Leon A. and et al.}, year={2021}, month={Mar} }
 @article{reyes-maldonado_marie_ramirez_2021, title={Rearing methods and life cycle characteristics of Chironomus sp. Florida (Chironomidae: Diptera): A rapid-developing species for laboratory studies}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0247382}, abstractNote={The species Chironomus sp. “Florida” has several qualities that make it a potential aquatic laboratory model to be used in Puerto Rico. Its use as such, however, requires a rearing protocol and life cycle description not previously reported. The present study addresses this lack of information by first describing a rearing method obtained through three years of observations. Next we describe and discuss the life cycle and the effects of temperature and feeding on development. The species has a short life cycle (typically 11 days) and larval stages easily identified using body measurements. Temperature affects the duration of the life cycle, with warm temperatures producing faster development than cold temperatures. The effects of different food concentrations vary: in large water volumes, concentrations of 2 mg/larva/day produce faster developmental times, but at low water volumes, small food concentrations of 0.5 mg/larva/day produce faster developmental times. The rearing protocol and life cycle parameters presented in this study are intended to promote the use of this species as a laboratory model. The fast development of Chironomus sp. “Florida” makes it ideal for toxicological studies.}, number={2}, journal={PLOS ONE}, author={Reyes-Maldonado, Roberto and Marie, Bruno and Ramirez, Alonso}, year={2021}, month={Feb} }
 @article{ramirez_maldonado-benitez_mariani-rios_figueroa-santiago_2020, title={Dragonflies and damselflies (Odonata) from Puerto Rico: a checklist with notes on distribution and habitat}, volume={8}, ISSN={["2167-8359"]}, DOI={10.7717/peerj.9711}, abstractNote={BackgroundConservation of tropical freshwater fauna requires a solid understanding of species biodiversity patterns. We provide an up to date annotated list of Odonata of Puerto Rico, which is based on current reports. The list is complemented with notes on the geographic and altitudinal distribution of this order on the island. We also compare current composition relative to early reports conducted when Puerto Rico was mostly an agricultural region.}, journal={PEERJ}, author={Ramirez, Alonso and Maldonado-Benitez, Norman and Mariani-Rios, Ashley and Figueroa-Santiago, Javier}, year={2020}, month={Oct} }
 @article{gutierrez-fonseca_ramirez_2020, title={Mayfly emergence production and body length response to hydrology in a tropical lowland stream}, volume={8}, ISSN={["2167-8359"]}, url={https://doi.org/10.7717/peerj.9883}, DOI={10.7717/peerj.9883}, abstractNote={
Background
Hydrological impacts on aquatic biota have been assessed in numerous empirical studies. Aquatic insects are severely affected by population declines and consequent diversity loss. However, many uncertainties remain regarding the effects of hydrology on insect production and the consequences of energy transfer to the terrestrial ecosystem. Likewise, sublethal effects on insect morphology remain poorly quantified in highly variable environments. Here, we characterized monthly fluctuation in benthic and emerged biomass of Ephemeroptera in a tropical lowland stream. We quantified the proportion of mayfly production that emerges into the riparian forest. We also examined the potential morphological changes in Farrodes caribbianus (the most abundant mayfly in our samples) due to environmental stress.
}, journal={PEERJ}, author={Gutierrez-Fonseca, Pablo E. and Ramirez, Alonso}, year={2020}, month={Sep} }
 @article{ramirez_caballero_vazquez_colon-gaud_2020, title={Preface: Recent advances in tropical lake research}, volume={847}, ISSN={["1573-5117"]}, DOI={10.1007/s10750-020-04443-3}, number={20}, journal={HYDROBIOLOGIA}, author={Ramirez, Alonso and Caballero, Margarita and Vazquez, Gabriela and Colon-Gaud, Checo}, year={2020}, month={Nov}, pages={4143–4144} }
 @article{rosas_colon-gaud_ramirez_2020, title={Trophic basis of production in tropical headwater streams, Puerto Rico: an assessment of the importance of allochthonous resources in fueling food webs}, volume={847}, ISSN={["1573-5117"]}, url={https://doi.org/10.1007/s10750-020-04224-y}, DOI={10.1007/s10750-020-04224-y}, number={8}, journal={HYDROBIOLOGIA}, publisher={Springer Science and Business Media LLC}, author={Rosas, Keysa G. and Colon-Gaud, Checo and Ramirez, Alonso}, year={2020}, month={May}, pages={1961–1975} }
 @article{van beusekom_gonzalez_stankavich_zimmerman_ramirez_2020, title={Understanding tropical forest abiotic response to hurricanes using experimental manipulations, field observations, and satellite data}, volume={17}, ISSN={["1726-4189"]}, DOI={10.5194/bg-17-3149-2020}, abstractNote={Abstract. With projected increasing intensity of hurricanes and large
uncertainty in the path of forest recovery from hurricanes, studies are
needed to understand the fundamental response of forests to canopy opening
and debris deposition: the response of the abiotic factors underneath the
canopy. Through two manipulative experiments and instrumenting prior to
Hurricane Maria (2017) in the Luquillo Experimental Forest (LEF) of
Puerto Rico, this study found a long recovery time of primary abiotic
factors (beneath canopy light, throughfall, and temperature) influenced by
the disturbance of canopy opening, as well as complex responses by the secondary
abiotic factors (relative humidity, soil moisture, and leaf saturation)
influenced by the disturbance of the primary factors. Recovery took 4–5 years for beneath canopy light, while throughfall recovery took 4–9 years
and neither had recovered when Hurricane Maria passed 3 years after the
second experiment. Air and soil temperature seemingly recovered quickly from
each disturbance (<2.5 years in two experiments for ∼+1 ∘C of change); however, temperature was the most important
modulator of secondary factors, which followed the long-term patterns of the
throughfall. While the soil remained wetter and relative humidity in the air
stayed lower until recovery, leaves in the litter and canopy were wetter and
drier, with evidence that leaves dry out faster in low rainfall and saturate
faster in high rainfall after disturbance. Comparison of satellite and field
data before and after the 2017 hurricanes showed the utility of satellites
in expanding the data coverage, but the muted response of the satellite data
suggests they measure dense forest as well as thin forest that is not as
disturbed by hurricanes. Thus, quick recovery times recorded by satellites
should not be assumed representative of all the forest. Data records
spanning the multiple manipulative experiments followed by Hurricane
Maria in the LEF provide evidence that intermediate hurricane frequency
has the most extreme abiotic response (with evidence on almost all abiotic
factors tested) versus infrequent or frequent hurricanes.
                    }, number={12}, journal={BIOGEOSCIENCES}, author={Van Beusekom, Ashley E. and Gonzalez, Grizelle and Stankavich, Sarah and Zimmerman, Jess K. and Ramirez, Alonso}, year={2020}, month={Jun}, pages={3149–3163} }
 @article{gutierrez-fonseca_ramirez_pringle_torres_mcdowell_covich_crowl_perez-reyes_2020, title={When the rainforest dries: Drought effects on a montane tropical stream ecosystem in Puerto Rico}, volume={39}, ISSN={["2161-9565"]}, DOI={10.1086/708808}, abstractNote={Global climate change predictions include decreased precipitation and more frequent droughts in many world regions. In the aseasonal wet tropics, predicting potential impacts is particularly challenging because droughts are rare and therefore poorly understood. In 2015, the Caribbean islands experienced the most severe drought within the past 5 decades. Here, we use this extreme event as an opportunity to assess how tropical stream ecosystems draining the Luquillo Experimental Forest (LEF) in Puerto Rico respond to severe drought. During 2015, precipitation was 45% lower than the long-term (1975–2016) average for the LEF, resulting in a 54% reduction in stream discharge. After 5 mo of declining discharge (April–August 2015), one branch of our focal study stream system became a series of isolated pools and a few riffle-type runs, while the other branch had greatly reduced flow between its pools. Concentrated biotic activity within pools resulted in elevated and highly-variable nutrient (5.1–12.1 µg PO43−-P/L; 12.9–57.2 µg NH4+-N/L; 80.0–160.0 µg NO3−-N/L) and specific conductance (95–114 µS/cm) levels among pools. However, the algal standing crop was 14× lower than the previous 15-y average despite increases in nutrient levels, reflecting intense grazing pressure of insect and shrimp consumers, potentially due to decreased pool volume. Higher nutrient levels in stream pools did increase biofilm productivity, and at the peak of the drought daily fluctuations in dissolved oxygen ranged from ∼1.0 to 6.5 mg/L. Significantly-higher riparian inputs of organic matter (7.6× the long-term average) occurred during a 15-d period in May. The drought caused a general increase in macroinvertebrate density, with collector–gatherers and some grazer taxa increasing significantly at the peak of the drought, but taxonomic richness did not change. Omnivorous shrimp abundance increased slightly in response to decreased stream flow in one branch of our focal stream. Our study highlights the marked effects of severe droughts on neotropical streams in the wet tropics, with large effects on basal resources and consequent changes in trophic dynamics. Ultimately, our findings underline the need for a whole-ecosystem perspective to understand how streams respond to increased frequencies of extreme events associated with climate change.}, number={2}, journal={FRESHWATER SCIENCE}, author={Gutierrez-Fonseca, Pablo E. and Ramirez, Alonso and Pringle, Catherine M. and Torres, Pedro J. and McDowell, William H. and Covich, Alan and Crowl, Todd A. and Perez-Reyes, Omar}, year={2020}, month={Jun}, pages={197–212} }
 @article{classen-rodriguez_gutierrez-fonseca_ramirez_2019, title={Leaf litter decomposition and macroinvertebrate assemblages along an urban stream gradient in Puerto Rico}, volume={51}, ISSN={["1744-7429"]}, url={https://doi.org/10.1111/btp.12685}, DOI={10.1111/btp.12685}, abstractNote={Abstract}, number={5}, journal={BIOTROPICA}, author={Classen-Rodriguez, Leticia and Gutierrez-Fonseca, Pablo E. and Ramirez, Alonso}, year={2019}, month={Sep}, pages={641–651} }
 @inbook{ríos-touma_ramírez_2019, title={Multiple Stressors in the Neotropical Region: Environmental Impacts in Biodiversity Hotspots}, ISBN={9780128117132}, url={http://dx.doi.org/10.1016/b978-0-12-811713-2.00012-1}, DOI={10.1016/b978-0-12-811713-2.00012-1}, abstractNote={The Neotropical Region is highly diverse geographically, climatically, and biologically. Freshwater ecosystems are impacted by many stressors with impacts that remain poorly understood. While we know the status and the effects of some stressors on certain fish and invertebrate species, whole ecosystem effects are yet to be understood. We describe the status and general trends of 10 stressors: variation in rainfall due to climate change; changes in forest cover (e.g., logging, deforestation, and afforestation); agriculture and livestock; impervious cover (e.g., urban areas); mining operations; flow regulation; loss of riparian zones and floodplains; overfishing; and the introduction of exotic species. Agriculture, mining, and increase in impervious cover due to urbanization are the major stressors for neotropical freshwater ecosystems. Although information is limited the local extinctions of freshwater populations and the loss of ecosystem functions and services are common and likely to increase given the limited conservation measures applied in the region.}, booktitle={Multiple Stressors in River Ecosystems}, publisher={Elsevier}, author={Ríos-Touma, Blanca and Ramírez, Alonso}, year={2019}, pages={205–220} }
 @article{mcdowell_mcdowell_potter_ramirez_2019, title={Nutrient export and elemental stoichiometry in an urban tropical river}, volume={29}, ISSN={["1939-5582"]}, url={https://doi.org/10.1002/eap.1839}, DOI={10.1002/eap.1839}, abstractNote={Abstract}, number={2}, journal={ECOLOGICAL APPLICATIONS}, author={McDowell, William H. and McDowell, William G. and Potter, Jody D. and Ramirez, Alonso}, year={2019}, month={Mar} }
 @article{kelly_cuevas_ramírez_2019, title={Urbanization increases the proportion of aquatic insects in the diets of riparian spiders}, volume={38}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/703442}, DOI={10.1086/703442}, abstractNote={The exchange of nutrients and organic material that occurs along the riparian zones of stream ecosystems is vital to providing energetic subsidies for both aquatic and terrestrial food webs. Orb-weaver spiders are major consumers of emerging aquatic insects, so impacts to the stream ecosystem and the riparian zone around it can have significant effects on riparian spider assemblages. Aquatic insects can represent anywhere from ∼50–100% of the diet of riparian orb-weavers, generally depending on factors such as spider taxa and prey diversity. However, most of the studies that examine riparian orb-weaver diets have been done in non-urban areas. Thus, little is known about how urbanization affects the transfer of energy and nutrients between aquatic and terrestrial ecosystems. The objective of our study was to determine if the proportion of aquatic insects in the diets of riparian orb-weaver spiders is altered by urbanization. We used stable isotope analyses and Bayesian mixing models to assess trophic transfers between primary energy sources, insects, and orb-weaver spiders along the riparian zone of an urban gradient in San Juan, Puerto Rico. We found that both δ13C and δ15N values varied with the amount of urbanization in aquatic insects, terrestrial insects, and 2 genera of riparian orb-weaver spiders. Spiders closely reflected changes in the isotopic values observed in aquatic insects along the urban gradient, with a noticeable decrease in δ15N values at the most urbanized sites. In addition, we found that the proportion of aquatic insects in the diets of the orb-weavers was ∼30% greater in heavily urbanized areas than non-urbanized areas. This study represents one of the few efforts to determine how urbanization can significantly alter riparian food webs and influence the exchange of subsidies between aquatic and terrestrial ecosystems.}, number={2}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Kelly, Sean P. and Cuevas, Elvira and Ramírez, Alonso}, year={2019}, month={Jun}, pages={379–390} }
 @article{reyes-maldonado_sánchez-ruiz_ramírez_kelly_2018, title={Comunidades de arañas ribereñas como indicadores de la condición de los ecosistemas fluviales en la cuenca del Río Piedras de Puerto Rico.}, volume={39}, ISSN={0304-3584 2145-7166}, url={http://dx.doi.org/10.17533/udea.acbi.v39n107a07}, DOI={10.17533/udea.acbi.v39n107a07}, abstractNote={La degradacion de los sistemas riberenos, por causa de las actividades humanas, ha permitido el desarrollo de numerosos metodos que evaluan la severidad de los impactos antropogenicos. Los protocolos de biomonitoreo, empleando macroinvertebrados acuaticos, son usados mundialmente en estas evaluaciones. No obstante, estos metodos tienen la desventaja que solo evaluan el canal del rio, ignorando la zona riberena adyacente. Otros metodos consideran, en su evaluacion, las caracteristicas fisicas de ambas zonas, pero ignoran la biota del lugar. Las aranas riberenas se han discutido como potenciales bioindicadores dado que podrian proveer una alternativa mas holistica para evaluar los sistemas riberenos. Nuestro objetivo fue determinar si los cambios en las comunidades de aranas riberenas podrian utilizarse para separar lugares con diferentes niveles de impacto. Se correlaciono el porcentaje de cobertura vegetal y diferentes protocolos de biomonitoreo, con metricas de riqueza y abundancia de aranas a lo largo de un gradiente urbano. Se encontraron diferencias en la composicion de la comunidad de aranas entre lugares, con una tendencia general de menor riqueza y menor abundancia en los sitios mas impactados. La abundancia de las aranas se correlaciono significativamente con el porcentaje de cobertura vegetal y la riqueza de familias se correlaciono con dos de los protocolos de monitoreo usados. Estos hallazgos respaldan la utilizacion de las comunidades de aranas como indicadoras de disturbio en los ecosistemas riberenos de Puerto Rico. Sugerimos incorporar las comunidades de aranas riberenas en futuros protocolos de biomonitoreo para asegurar una vision mas holistica de las condiciones de los lugares evaluados.}, number={107}, journal={Actualidades Biológicas}, publisher={Universidad de Antioquia}, author={Reyes-Maldonado, Roberto and Sánchez-Ruiz, José A. and Ramírez, Alonso and Kelly, Sean P.}, year={2018}, pages={1–23} }
 @article{ramírez_gutiérrez-fonseca_kelly_engman_wagner_rosas_rodríguez_2018, title={Drought Facilitates Species Invasions in an Urban Stream: Results From a Long-Term Study of Tropical Island Fish Assemblage Structure}, volume={6}, ISSN={2296-701X}, url={http://dx.doi.org/10.3389/fevo.2018.00115}, DOI={10.3389/fevo.2018.00115}, abstractNote={The natural flow regime is a key regulator of the dynamics of stream communities and ecosystem processes. Native fish assemblages are evolutionarily adapted to their local flow regime. In the Caribbean, streams are vulnerable to changes in climate that will alter their flow regimes. We assessed long-term patterns in fish assemblages (2008-2016) in an urban stream in San Juan, Puerto Rico. We hypothesized that drought periods would result in negative effects on native fish species and positive effects on introduced species. Fish assemblages were sampled annually from 2008 to 2016 by backpack electrofishing, with additional sampling during 2015, which was a drought year. Cumulative dry season discharge was consistently over 300 m3/s from 2008 to 2013, except from 2014 to 2016 when it dropped below 170 m3/s. Thirteen species were found, including most native species reported for Puerto Rico and introduced species (e.g., Cichlids, Poeciliids, and Loracariids). Native species were dominant in abundance during most years, except during drought and post-drought sampling events when introduced species became dominant. Introduced species increased in richness with time from less than two species between 2008 and 2013 to seven in 2015. The increase in introduced species was mostly attributed to the appearance of several species of cichlids towards the end of the study. Cluster analysis divided the data set in two groups: drought and non-drought sampling events. Introduced cichlids and the native A. monticola accounted for more than 60% of assemblage dissimilarity. Fish assemblage abundance and richness were negatively related to several components of stream hydrology (e.g., cumulative daily stream discharge, the number of major floods). A significant change in size over time was found for the native A. monticola, which decreased in size during the drought period. Overall, our study documents drought-facilitated invasions by several aggressive and highly ecologically competitive species, highlights the importance of the natural flow regime as a source of environmental resilience to invasions in tropical island streams, and provides an example of how climate change has and will likely continue to alter Caribbean stream fish assemblages.}, number={AUG}, journal={Frontiers in Ecology and Evolution}, publisher={Frontiers Media SA}, author={Ramírez, Alonso and Gutiérrez-Fonseca, Pablo E. and Kelly, Sean P. and Engman, Augustin C. and Wagner, Karleen and Rosas, Keysa G. and Rodríguez, Natalia}, year={2018}, month={Aug} }
 @article{reyes-torres_ramírez_2018, title={Effects of experimental pool level reduction on Phylloicus pulchrus (Trichoptera: Calamoceratidae) feeding and conspecific behavior from a tropical rainforest stream}, volume={3}, ISSN={2389-7864 1794-161X}, url={http://dx.doi.org/10.21676/23897864.2352}, DOI={10.21676/23897864.2352}, abstractNote={ 
Aumentos en la ocurrencia y persistencia de sequías alrededor del mundo estimulan el entendimiento de sus efectos en las poblaciones naturales y funcionamiento del ecosistema. El principal resultado de las sequías en los ríos es la fragmentación del ecosistema riverino en pozas aisladas a medida que el flujo y la profundidad del agua disminuyen. Hay estudios limitados sobre la respuesta de los tricópteros a reducciones en niveles de agua y su efecto en el funcionamiento del ecosistema. El objetivo de este estudio fue evaluar como reducciones en niveles del agua, similar a las asociadas con sequías, influencian la alimentación y comportamiento conspecífico de Phylloicus pulchrus. Reducciones de pozas en laboratorio simulando condiciones naturales fueron empleadas por dos semanas. Cuatro acuarios plásticos rectangulares fueron llenados a una tercera parte con agua aereada de la quebrada. Dentro de cada acuario se colocaron diez cámaras plásticas circulares (con aperturas de malla) con hojas senescentes de Guarea guidonea. Se simularon dos niveles de pozas (normal y bajo) con dos tratamientos (experimental y control).  Las cámaras experimentales (n=20) contenían larvas del cuarto estadío (n=80, 40=normal, 40=bajo) mientras que las del control (n=20) no. Se evaluó el efecto de la reducción de pozas en la pérdida de masa de las hojas, interacciones agresivas (>25 % de su envoltura removida) y mortalidad larval. La reducción en el nivel de las pozas aumentó la pérdida de masa de las hojas (ANOVA: F=5.17, p=0.03), interacciones agresivas (Chi cuadrado: x2=6.24, n=80, p= 0.01), y mortalidad larval (Chi square: x2=4.51, n=80, p= 0.03). Este estudio muestra la respuesta temprana de un tricóptero tropical a una señal abiótica de un cambio ambiental drástico. Esta investigación contribuye al escaso conocimiento sobre el comportamiento de procesamiento de hojarasca en larvas de tricópteros durante etapas tempranas de reducciones de flujo, como las causadas por sequías.}, journal={Intropica}, publisher={Universidad del Magdalena}, author={Reyes-Torres, Limarie J. and Ramírez, Alonso}, year={2018}, month={Mar}, pages={13} }
 @article{gutiérrez-fonseca_ramírez_pringle_2018, title={Large-scale climatic phenomena drive fluctuations in macroinvertebrate assemblages in lowland tropical streams, Costa Rica: The importance of ENSO events in determining long-term (15y) patterns}, volume={13}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0191781}, DOI={10.1371/journal.pone.0191781}, abstractNote={Understanding how environmental variables influence the distribution and density of organisms over relatively long temporal scales is a central question in ecology given increased climatic variability (e.g., precipitation, ENSO events). The primary goal of our study was to evaluate long-term (15y time span) patterns of climate, as well as environmental parameters in two Neotropical streams in lowland Costa Rica, to assess potential effects on aquatic macroinvertebrates. We also examined the relative effects of an 8y whole-stream P-enrichment experiment on macroinvertebrate assemblages against the backdrop of this long-term study. Climate, environmental variables and macroinvertebrate samples were measured monthly for 7y and then quarterly for an additional 8y in each stream. Temporal patterns in climatic and environmental variables showed high variability over time, without clear inter-annual or intra-annual patterns. Macroinvertebrate richness and abundance decreased with increasing discharge and was positively related to the number of days since the last high discharge event. Findings show that fluctuations in stream physicochemistry and macroinvertebrate assemblage structure are ultimately the result of large-scale climatic phenomena, such as ENSO events, while the 8y P-enrichment did not appear to affect macroinvertebrates. Our study demonstrates that Neotropical lowland streams are highly dynamic and not as stable as is commonly presumed, with high intra- and inter-annual variability in environmental parameters that change the structure and composition of freshwater macroinvertebrate assemblages.}, number={2}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Gutiérrez-Fonseca, Pablo E. and Ramírez, Alonso and Pringle, Catherine M.}, editor={Cañedo-Argüelles, MiguelEditor}, year={2018}, month={Feb}, pages={e0191781} }
 @article{reyes-torres_ramírez_2018, title={Life history and phenology of Phylloicus pulchrus  (Trichoptera: Calamoceratidae) in a tropical rainforest  stream of Puerto Rico}, volume={66}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v66i2.33411}, DOI={10.15517/rbt.v66i2.33411}, abstractNote={Caddisflies are abundant, diverse, and important insects in freshwater ecosystems.  However our knowledge on their life history is incomplete, in particular for the Neotropics. The objectives of this study were to describe the life history and phenology of Phylloicus pulchrus in the Luquillo Experimental Forest, Puerto Rico. Eggs and larvae were reared to determine the species lifespan and time in each instar. Larval instars were determined based on a head width vs. pronotal suture length correlation (N= 120). Larvae and benthic leaf litter were sampled monthly at a headwater stream for a year; all specimens were classified into instars based on their case size. Adult P. pulchrus were sampled monthly for a year with a light trap and at various times with a Malaise trap. Monthly environmental variables were related to species and sex abundance. There was a gradient of egg development where eggs (within compound masses) closest to the water were more developed. There were five larval instars and reared larvae showed longer development times and more variable body measurements in later instars. The best correlation for larval instar determination was case length-head width (Pearson= 0.90, P= 2.2e-16, N= 120). Phylloicus pulchrus has a multivoltine life cycle, with asynchronous larval development. Adult abundance was low. First to third instar larvae were influenced significantly by rainfall and rainfall seasonality had a negative significant effect on second instar larval abundance (ANOVA= 7.45, P= 0.02).Compound egg masses were probably oviposited by different females that gathered for oviposition. Phylloicus pulchrus follows the predominant developmental characteristic of Trichoptera of having five larval stages. Development times were longer than expected (longest times for a Phylloicus species) and may be an effect of laboratory rearing. The influence of rainfall (and seasonality) on different larval instars highlights the importance of this variable on early larval development. The cause of low adult abundance remains unclear, but may be related to low emergence rates and trap efficiency. Rev. Biol. Trop. 66(2): 814-825. Epub 2018 June 01. }, number={2}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Reyes-Torres, Limarie J. and Ramírez, Alonso}, year={2018}, month={May}, pages={814} }
 @inbook{novelo-gutiérrez_ramírez_gonzález-soriano_2018, title={Superfamily Gomphoidea}, ISBN={9780128042236}, url={http://dx.doi.org/10.1016/b978-0-12-804223-6.00016-0}, DOI={10.1016/b978-0-12-804223-6.00016-0}, abstractNote={An illustrated key to the larvae of 27 out of 29 genera of Gomphidae of the Neotropical region is provided. Additional information on microhabitats and notes on the larval habits is also included. Larvae of Brasiliogomphus and Cyanogomphus are still unknown, and larva of Diaphlebia is keyed by supposition. Gomphidae represents between 34-35% of all known Neotropical anisopterans. Most Gomphidae species inhabit running waters and many of their larvae behave as shallow burrowers. Larvae of Gomphidae are characterized manily by body abundantly setose; antennae 4-articulated with the third antennal article the largest, and the fourth segment minute or vestigial; prementum flat, ligula without median cleft, apical margin with piliform setae; molar crest of mandible movable; legs scarcely opposable, short, and setose, and female larva gonapophyses rudimentary or vestigial.}, booktitle={Thorp and Covich's Freshwater Invertebrates}, publisher={Elsevier}, author={Novelo-Gutiérrez, Rodolfo and Ramírez, Alonso and González-Soriano, Enrique}, year={2018}, pages={377–397} }
 @article{román-heracleo_springer_ramírez_2018, title={The larva of Perissolestes remotus (Williamson & Williamson, 1924) (Zygoptera: Perilestidae)}, volume={21}, ISSN={1388-7890 2159-6719}, url={http://dx.doi.org/10.1080/13887890.2018.1511481}, DOI={10.1080/13887890.2018.1511481}, abstractNote={The larva of Perissolestes remotus is described for the first time based on Costa Rican specimens collected in forested streams with abundant organic matter. It is characterized by a slender, elongated body, with lateral keels on abdominal segments 1–9, and a middorsal row of spines on segments 4–10. We also provide additional notes on the larvae of P. magdalenae using material from Panama. The larva is similar to the only other species of Perissolestes present in Mexico and Central America, P. magdalenae, but can be separated by the articulation of the prementum-postmentum reaching the metacoxa (reaching the mesocoxa in P. magdalenae) and the female gonapophyses exceeding past the posterior margin of S10 (just reaching posterior margin in P. magdalenae). At the generic level, Perissolestes can be differentiated from Perilestes by the presence of abdominal keels on segments 1–9 (from 4–9 in Perilestes) and by having caudal gills with small spines along the medial trachea (spines absent in Perilestes).}, number={3-4}, journal={International Journal of Odonatology}, publisher={Informa UK Limited}, author={Román-Heracleo, Jareth and Springer, Monika and Ramírez, Alonso}, year={2018}, month={Jul}, pages={173–179} }
 @inbook{pringle_anderson_ardón_bixby_connelly_duff_jackman_paaby_ramírez_small_et al._2017, place={Chicago, IL}, title={18. Rivers of Costa Rica}, ISBN={9780226278933 9780226121505 9780226121642}, url={http://dx.doi.org/10.7208/chicago/9780226121642.003.0018}, DOI={10.7208/chicago/9780226121642.003.0018}, booktitle={Costa Rican Ecosystems}, publisher={University of Chicago Press}, author={Pringle, Catherine M. and Anderson, Elizabeth P. and Ardón, Marcelo and Bixby, Rebecca J. and Connelly, Scott and Duff, John H. and Jackman, Alan P. and Paaby, Pia and Ramírez, Alonso and Small, Gaston E. and et al.}, editor={Kappelle, M.Editor}, year={2017}, month={Feb}, pages={621–655} }
 @article{sanchez-ruiz_ramírez_kelly_2017, title={Decreases in the size of riparian orb webs along an urbanization gradient}, volume={45}, ISSN={0161-8202 1937-2396}, url={http://dx.doi.org/10.1636/joa-s-16-076.1}, DOI={10.1636/joa-s-16-076.1}, abstractNote={Abstract Urbanization is associated with a variety of anthropogenic impacts that alter aquatic ecosystems and could affect riparian web-spinning spiders. The objective of this study was to evaluate how changes in web structural features and body condition of a horizontal orb-weaver are associated with surrounding levels of urbanization. Along an urban watershed in Puerto Rico, we found a significant negative relationship between the capture area of webs and in the body condition of spiders with increasing levels of surrounding impervious surface. We propose that these changes in web structure and body condition are associated with variations in the diversity and quality of prey, as well as the loss of riparian substrate in more heavily urban areas.}, number={2}, journal={Journal of Arachnology}, publisher={American Arachnological Society}, author={Sanchez-Ruiz, José A. and Ramírez, Alonso and Kelly, Sean P.}, year={2017}, month={Aug}, pages={248–252} }
 @article{forero céspedes_gutiérrez fonseca_ramírez_2017, title={Facilitation between shrimps and mayflies in montane stream ecosystems, Puerto Rico}, volume={1}, url={https://www.revistaaccb.org/r/index.php/accb/article/view/136/131}, number={29}, journal={Revista de la Asociación Colombiana de Ciencias Biológicas}, author={Forero Céspedes, A.M. and Gutiérrez Fonseca, P.E. and Ramírez, A.}, year={2017}, pages={15–20} }
 @article{boyero_graça_tonin_pérez_j. swafford_ferreira_landeira-dabarca_a. alexandrou_gessner_mckie_et al._2017, title={Riparian plant litter quality increases with latitude}, volume={7}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-017-10640-3}, DOI={10.1038/s41598-017-10640-3}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Boyero, Luz and Graça, Manuel A. S. and Tonin, Alan M. and Pérez, Javier and J. Swafford, Andrew and Ferreira, Verónica and Landeira-Dabarca, Andrea and A. Alexandrou, Markos and Gessner, Mark O. and McKie, Brendan G. and et al.}, year={2017}, month={Sep} }
 @article{garcía_novelo-gutiérrez_vázquez_ramírez_2016, title={Allochthonous vs. autochthonous energy resources for aquatic insects in cloud forest streams, Veracruz, Mexico}, volume={26}, ISSN={0188-8897 2448-7333}, url={http://dx.doi.org/10.24275/uam/izt/dcbs/hidro/2016v26n3/garcia}, DOI={10.24275/uam/izt/dcbs/hidro/2016v26n3/garcia}, abstractNote={Background. Recent tropical studies question the assumption that forested headwater streams rely on allochthonous resources as their main energy source, suggesting that autochthonous resources are more important. Goals. Here, we characterized the energy base, as gut contents, of cloud forest streams with contrasting riparian vegetation cover in Veracruz, Mexico, during dry, rainy and “nortes” (e.g., less dry and cold) seasons. Methods. Two first-order streams were selected for the study - one flowing through forest and the other through pasture with sparse riparian vegetation. Gut content analyses showed aquatic insect diets composed of diatoms, green algae, fungi, plant tissue, and amorphous detritus. Results. The forest stream had taxa with gut contents composed of 31 to 99% allochthonous material, while the pasture stream reached a maximum of 82% during “nortes”. Diatoms accounted for most of the autochthonous material in guts, especially in the pasture stream during the dry season. A significant proportion of ingested allochthonous material was fungi, mainly in the forest stream during the rainy season. Conclusions. Overall, our study supports the view that in forested tropical streams autochthonous material is an important food resource. However, allochthonous material was found to be an important food item, even in pasture streams with limited riparian cover.}, number={3}, journal={Hidrobiológica}, publisher={Universidad Autonoma Metropolitana}, author={García, P. and Novelo-Gutiérrez, R. and Vázquez, G. and Ramírez, A.}, year={2016}, month={Dec}, pages={483–496} }
 @article{boyero_pearson_hui_gessner_pérez_alexandrou_graça_cardinale_albariño_arunachalam_et al._2016, title={Biotic and abiotic variables influencing plant litter breakdown in streams: a global study}, volume={283}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2015.2664}, DOI={10.1098/rspb.2015.2664}, abstractNote={
            Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (
            Alnus glutinosa
            ) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons.
          }, number={1829}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Boyero, Luz and Pearson, Richard G. and Hui, Cang and Gessner, Mark O. and Pérez, Javier and Alexandrou, Markos A. and Graça, Manuel A. S. and Cardinale, Bradley J. and Albariño, Ricardo J. and Arunachalam, Muthukumarasamy and et al.}, year={2016}, month={Apr}, pages={20152664} }
 @article{gutiérrez-fonseca_ramírez_2016, title={Ecological evaluation of streams in Puerto Rico: Major threats and evaluation tools,Evaluación de la calidad ecológica de los ríos en Puerto Rico: Principales amenazas y herramientas de evaluación}, volume={26}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85022327391&partnerID=MN8TOARS}, number={3}, journal={Hidrobiologica}, author={Gutiérrez-Fonseca, P.E. and Ramírez, A.}, year={2016}, pages={433–441} }
 @article{gutiérrez fonseca_ramírez_2016, title={Evaluación de la calidad ecológica de los ríos en Puerto Rico: principales amenazas y herramientas de evaluación}, volume={26}, number={3}, journal={Hidrobiológica}, author={Gutiérrez Fonseca, PE and Ramírez, A.}, year={2016}, pages={433–441} }
 @inbook{wehrtmann_ramírez_pérez-reyes_2016, title={Freshwater Decapod Diversity and Conservation in Central America and the Caribbean}, ISBN={9783319425252 9783319425276}, url={http://dx.doi.org/10.1007/978-3-319-42527-6_9}, DOI={10.1007/978-3-319-42527-6_9}, booktitle={A Global Overview of the Conservation of Freshwater Decapod Crustaceans}, publisher={Springer International Publishing}, author={Wehrtmann, Ingo S. and Ramírez, Alonso and Pérez-Reyes, Omar}, year={2016}, pages={267–301} }
 @article{reyes-torres_meléndez-torres_ramírez_2016, title={Ocurrencia de nemátodos en ninfas de Ephemeroptera en una quebrada de bosque tropical lluvioso}, volume={11}, ISSN={2389-7864 1794-161X}, url={http://dx.doi.org/10.21676/23897864.1863}, DOI={10.21676/23897864.1863}, abstractNote={Nematodes are common symbionts of aquatic insects. Here, we assessed the presence of nematodes in mayfly nymphs (Ephemeroptera), evaluated their prevalence in the population, and determined factors associated with nematode presence. Mayflies were collected (n = 130) from three stream habitats (riffles, pools, and boulders) using a D net, in Prieta stream, El Verde Field Station, Puerto Rico. Mayflies were dissected and nematode presence was determined under a light microscope (4 x and 10 x). Nematode prevalence was 50 %. Nematodes were not identified beyond Phylum level, but we were able to eliminate various groups as infective agents (Nematoda: Mermithidae and Nematomorpha: Gordiida). They were mostly found in the abdomen, head or thorax of mayflies. There were differences in infection among taxa, Neohagenulus was the group with the highest proportion of infection. Mayfly body shape, feeding strategy, or activity potentially explain differences in infection among taxa. There were no differences in infection among habitats, but mayflies were less abundant in riffles; and there was no relation between mayfly body length and the number of nematodes present. To our knowledge, this is the first report of a nematode present in mayfly nymphs in Puerto Rico.}, journal={Intropica}, publisher={Universidad del Magdalena}, author={Reyes-Torres, Limarie Judith and Meléndez-Torres, Yazminne and Ramírez, Alonso}, year={2016}, month={Dec}, pages={67} }
 @article{small_ardón_duff_jackman_ramírez_triska_pringle_2016, title={Phosphorus retention in a lowland Neotropical stream following an eight-year enrichment experiment}, volume={35}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/684491}, DOI={10.1086/684491}, abstractNote={Human alteration of the global P cycle has led to widespread P loading in freshwater ecosystems. Much research has been devoted to the capacity of wetlands and lakes to serve as long-term sinks for P inputs from the watershed, but we know much less about the potential of headwater streams to serve in this role. We assessed storage and retention of P in biotic and abiotic compartments after an 8-y experimental P addition to a 1st-order stream in a Neotropical wet forest. Sediment P extractions indicated that nearly all P storage was in the form of Fe- and Al-bound P (∼700 μg P/g dry sediment), similar to nearby naturally high-P streams. At the end of the enrichment, ∼25% of the total P added over the 8-y study was still present in sediments within 200 m of the injection site, consistent with water-column measurements showing sustained levels of high net P uptake throughout the experiment. Sediment P declined to baseline levels (∼100 μg P/g dry sediment) over 4 y after the enrichment ended. Leaf-litter P content increased nearly 2× over background levels during P enrichment and was associated with a 3× increase in microbial respiration rates, although these biotic responses were low compared to nearby naturally high-P streams. Biotic storage accounted for <0.03% of retention of the added P. Our results suggest that the high sorption capacity of these sediments dampened the biotic effects of P loading and altered the timing and quantity of P exported downstream.}, number={1}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Small, Gaston E. and Ardón, Marcelo and Duff, John H. and Jackman, Alan P. and Ramírez, Alonso and Triska, Frank J. and Pringle, Catherine M.}, year={2016}, month={Mar}, pages={1–11} }
 @article{capps_bentsen_ramírez_2016, title={Poverty, urbanization, and environmental degradation: urban streams in the developing world}, volume={35}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/684945}, DOI={10.1086/684945}, abstractNote={Urbanization is occurring at a rapid pace in developing countries. The urban stream syndrome has been well documented in higher-income countries, but in lower-income, developing countries, resources often are unavailable for quantifying how urbanization affects streams. Basic infrastructure to support water supply and wastewater treatment frequently is lacking in lower-income countries, and this situation has repercussions for human health and for ecosystem structure and function. The interaction of environmental, social, and economic factors may produce differences in the expression of the urban stream syndrome in lower-income countries relative to in high-income countries. We address how patterns of economic development and urbanization can influence the quality of freshwater resources, and we discuss some of the relationships between urban watersheds and marginalized human populations in lower-income countries. We argue that sustainable management of urban watersheds and the provisioning of drinking water and sanitation services require integration of innovative technology and financing schemes into ecosystem-based management. We must develop new and enhance existing uses for sewage and other wastewater to support ecologically functional urban watersheds. Furthermore, managers of freshwater resources in lower-income countries require more data on which to base decisions. Acquisition of these data will necessitate the creation of interdisciplinary research teams with representatives from national and international development organizations to address stakeholder-driven research questions.}, number={1}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Capps, Krista A. and Bentsen, Catherine N. and Ramírez, Alonso}, year={2016}, month={Mar}, pages={429–435} }
 @article{cardona-rivera_ramírez_2016, title={Predation of Telebasis vulnerata (Odonata: Coenagrionidae) eggs by detritivorous caddisfly larva, Phylloicus pulchrus (Trichoptera: Calamoceratidae)}, volume={19}, ISSN={1388-7890 2159-6719}, url={http://dx.doi.org/10.1080/13887890.2016.1258372}, DOI={10.1080/13887890.2016.1258372}, abstractNote={After observing the presence of Phylloicus pulchrus (Trichoptera: Calamoceratidae) and tadpoles of Leptodactylus albilabris (Anura: Leptodactylidae) on submerged leaves with recently laid eggs of Telebasis vulnerata (Odonata: Coenagrionidae), we set up an experiment to determine if they were consuming Odonata eggs. We collected leaves from the stream, where consumers were positioned over egg masses, and designed an experiment to expose T. vulnerata eggs for two days to consumers. Observations indicated that tadpoles did not harm T. vulnerata eggs. In contrast, P. pulchrus completely scraped eggs from leaves, with little damage to the leaf tissue itself. P. pulchrus is detritivorous insect that consume leaf tissue, but it is capable of consuming T. vulnerata eggs, potentially as a supplementary food resource.}, number={4}, journal={International Journal of Odonatology}, publisher={Informa UK Limited}, author={Cardona-Rivera, Gabriela A. and Ramírez, Alonso}, year={2016}, month={Oct}, pages={253–256} }
 @inbook{pringle_anderson_ardón_bixby_connelly_duff_jackman_paaby_ramírez_small_et al._2016, place={Chicago, Illinois}, title={Rivers of Costa Rica}, DOI={10.7208/9780226121642-023}, booktitle={Costa Rican Ecosystems}, publisher={The University of Chicago Press}, author={Pringle, C.M. and Anderson, E.P. and Ardón, M. and Bixby, R.J. and Connelly, S. and Duff, J.H. and Jackman, A.P. and Paaby, P. and Ramírez, A. and Small, G.E. and et al.}, editor={Kappelle, M.Editor}, year={2016}, pages={621–655} }
 @article{ramirez_gutiérrez fonseca_2016, title={Sobre ensambles y ensamblajes ecológicos - respuesta a Monge-Nájera}, volume={64}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v64i2.21232}, DOI={10.15517/rbt.v64i2.21232}, abstractNote={Critical evaluation of terminology use in ecology is important to avoid using jargon that helps little to facilitate communication. Here we reply to Monge-Najera’s comment on the use of the terms ensemble and assemblage, we argue for the use of the words ensamble and ensamblaje in Spanish. In addition, both terms have a proper place in ecology and we provide a case for their use in proper ecological context.}, number={2}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Ramirez, Alonso and Gutiérrez Fonseca, Pablo E.}, year={2016}, month={May}, pages={817} }
 @article{novelo-gutiérrez_ramírez_delgado_2016, title={The larvae of Epigomphus jannyae Belle, 1993 and E. tumefactus Calvert, 1903 (Insecta: Odonata: Gomphidae)}, volume={4}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.2338}, DOI={10.7717/peerj.2338}, abstractNote={The taxonomic knowledge about immature stages of the insect order Odonata (dragonflies and damselflies) is rather limited in tropical America. Here, the larvae ofEpigomphus jannyaeBelle, 1993 andE. tumefactusCalvert, 1903 are described, figured, and compared with other described congeners.E. jannyaelarva is characterized by 3rd antennomere 1.6 times longer than its widest part; ligula very poorly developed, with ten short, truncate teeth on middle; apical lobe of labial palp rounded and smooth. Lateral margins on abdominal segments (S5–9) serrated, lateral spines on S6–9 small and divergent; male epiproct with a pair of dorsal tubercles at basal 0.66; tips of cerci and paraprocts strongly divergent. The larva ofE. tumefactusis characterized by 3rd antennomere 2.3 times longer than its widest part, ligula with 6–7 truncate teeth, apical lobe of labial palp acute and finely serrate. Lateral margins of S6–9 serrate, lateral spines on S7–9; male epiproct with a pair of dorsal tubercles at basal 0.50. Differences with other species were found in 3rd antennomere, lateral spines of S7–9, and the caudal appendages.Epigomphuslarvae inhabit small, shallow creeks (1st order streams) where they live in fine benthic sediments. When mature, the larva leaves the water in shady places, climbing small rocks at the water’s edge and metamorphosing horizontally on flat rocks. These new descriptions bring the total number ofEpigomphusspecies with known larval stages to eight; only 28% of the species in this genus are known as larva.}, number={8}, journal={PeerJ}, publisher={PeerJ}, author={Novelo-Gutiérrez, Rodolfo and Ramírez, Alonso and Delgado, Débora}, year={2016}, month={Aug}, pages={e2338} }
 @article{roy_capps_el-sabaawi_jones_parr_ramírez_smith_walsh_wenger_2016, title={Urbanization and stream ecology: diverse mechanisms of change}, volume={35}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/685097}, DOI={10.1086/685097}, abstractNote={The field of urban stream ecology has evolved rapidly in the last 3 decades, and it now includes natural scientists from numerous disciplines working with social scientists, landscape planners and designers, and land and water managers to address complex, socioecological problems that have manifested in urban landscapes. Over the last decade, stream ecologists have met 3 times at the Symposium on Urbanization and Stream Ecology (SUSE) to discuss current research, identify knowledge gaps, and promote future research collaborations. The papers in this special series on urbanization and stream ecology include both primary research studies and conceptual synthesis papers spurred from discussions at SUSE in May 2014. The themes of the meeting are reflected in the papers in this series emphasizing global differences in mechanisms and responses of stream ecosystems to urbanization and management solutions in diverse urban streams. Our hope is that this series will encourage continued interdisciplinary and collaborative research to increase the global understanding of urban stream ecology toward stream protection and restoration in urban landscapes.}, number={1}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Roy, Allison H. and Capps, Krista A. and El-Sabaawi, Rana W. and Jones, Krista L. and Parr, Thomas B. and Ramírez, Alonso and Smith, Robert F. and Walsh, Christopher J. and Wenger, Seth J.}, year={2016}, month={Mar}, pages={272–277} }
 @inbook{ramirez - babativa_vazquez_ramirez_caballero_2015, place={Mexico}, title={Dinámica metabólica del periliton de ríos de la cuenca alta del río La Antigua, Veracruz, México}, booktitle={Tendencias de investigación en Limnología tropical: Perspectivas universitarias en Latinoamérica}, publisher={Asociación Mexicana de Limnología, A.C., Instituto de Ciencias del Mar y Limnología, UNAM, y Consejo Nacional de Ciencia y Tecnología.}, author={Ramirez - Babativa, D and Vazquez, G and Ramirez, A and Caballero, M}, editor={Alcocer, J. and Merino-Ibarra, M. and Escobar-Briones, E.Editors}, year={2015}, month={Sep}, pages={155–164} }
 @article{boyero_pearson_gessner_dudgeon_ramírez_yule_callisto_pringle_encalada_arunachalam_et al._2015, title={Leaf-litter breakdown in tropical streams: is variability the norm?}, volume={34}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/681093}, DOI={10.1086/681093}, abstractNote={Many forested headwater streams are heterotrophic ecosystems in which allochthonous inputs of plant litter are a major source of energy. Leaves of riparian vegetation entering the stream are broken down by a combination of biotic and abiotic processes and, in most temperate and boreal streams, provide food and habitat for dense populations of detritivorous invertebrates. However, tropical streams in different parts of the world show substantial variability in the number and diversity of leaf-shredding detritivores (hereafter detritivores). We used data obtained with standardized methods from multiple streams in Africa, the Americas, Asia, and Australia to test the hypothesis that this variability would lead to differences in the relative role of detritivores and microorganisms in the breakdown process. We also tested the hypotheses that variability in litter breakdown rates changes with litter type (native litter mixtures vs nonnative alder [Alnus glutinosa]) and is higher across regions within than outside the tropics. We found that litter breakdown rates were highly variable across sites, with no consistent pattern within geographic areas, although litter consumption by detritivores was negligible at several sites, all in America. Geographic patterns of litter breakdown also varied between litter types, with higher breakdown rates for alder than for native litter in most but not all regions. When litter breakdown rates at the tropical sites were compared to previously reported values from temperate and boreal regions, we found that differences in variability between tropical and temperate sites were inconsistent, with great differences among studies. Further global-scale studies will be needed to assess the extent to which latitudinal changes in the diversity and composition of microbial and detritivore assemblages contribute to variability in litter breakdown rates.}, number={2}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Boyero, Luz and Pearson, Richard G. and Gessner, Mark O. and Dudgeon, David and Ramírez, Alonso and Yule, Catherine M. and Callisto, Marcos and Pringle, Catherine M. and Encalada, Andrea C. and Arunachalam, Muthukumarasamy and et al.}, year={2015}, month={Jun}, pages={759–769} }
 @article{gutiérrez fonseca_alonso rodríguez_cornejo_bailey_maes_ramírez_2015, title={New records of Anacroneuria Klapálek, 1909 (Plecoptera: Perlidae) for Central America}, volume={3994}, ISSN={1175-5334 1175-5326}, url={http://dx.doi.org/10.11646/zootaxa.3994.3.9}, DOI={10.11646/zootaxa.3994.3.9}, abstractNote={The perlid genus Anacroneuria is the most widely distributed stonefly occurring in the Neotropics. Regional studies of this genus were made early in the last century, whereas local taxonomic and distributional studies have recently increased. In this study, we provide new Central American records for four species of Anacroneuria. Anacroneuria choco Stark & Bersosa 2006, A. costana (Navás 1924), A. hacha Stark 1998, and A. laru Gutiérrez-Fonseca 2015 are newly reported including new range extensions. }, number={3}, journal={Zootaxa}, publisher={Magnolia Press}, author={Gutiérrez Fonseca, Pablo E. and Alonso Rodríguez, Aura M. and Cornejo, Aydeé and Bailey, Anna Cristina and Maes, Jean Michel and Ramírez, Alonso}, year={2015}, month={Aug}, pages={445} }
 @article{astudillo_novelo-gutiérrez_vázquez_garcía-franco_ramírez_2015, title={Relationships between land cover, riparian vegetation, stream characteristics, and aquatic insects in cloud forest streams, Mexico}, volume={768}, ISSN={0018-8158 1573-5117}, url={http://dx.doi.org/10.1007/s10750-015-2545-1}, DOI={10.1007/s10750-015-2545-1}, number={1}, journal={Hydrobiologia}, publisher={Springer Science and Business Media LLC}, author={Astudillo, Manuel R. and Novelo-Gutiérrez, Rodolfo and Vázquez, Gabriela and García-Franco, José G. and Ramírez, Alonso}, year={2015}, month={Oct}, pages={167–181} }
 @article{kelly_cuevas_ramírez_2015, title={Stable isotope analyses of web-spinning spider assemblages along a headwater stream in Puerto Rico}, volume={3}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.1324}, DOI={10.7717/peerj.1324}, abstractNote={Web-spinning spiders that inhabit stream channels are considered specialists of aquatic ecosystems and are major consumers of emerging aquatic insects, while other spider taxa are more commonly found in riparian forests and as a result may consume more terrestrial insects. To determine if there was a difference in spider taxa abundance between riverine web-spinning spider assemblages within the stream channel and the assemblages 10 m into the riparian forest, we compared abundances for all web-spinning spiders along a headwater stream in El Yunque National Forest in northeast Puerto Rico. By using a nonmetric dimensional scaling (NMDS) abundance analysis we were able to see a clear separation of the two spider assemblages. The second objective of the study was to determine if aquatic insects contributed more to the diet of the spider assemblages closest to the stream channel and therefore stable isotope analyses ofδ15N andδ13C for web-spinning spiders along with their possible prey were utilized. The results of the Bayesian mixing model (SIAR) however showed little difference in the diets of riverine (0 m), riparian (10 m) and upland (25 m) spiders. We found that aquatic insects made up ∼50% of the diet for web-spinning spiders collected at 0 m, 10 m, and 25 m from the stream. This study highlights the importance of aquatic insects as a food source for web-spinning spiders despite the taxonomic differences in assemblages at different distances from the stream.}, number={10}, journal={PeerJ}, publisher={PeerJ}, author={Kelly, Sean P. and Cuevas, Elvira and Ramírez, Alonso}, year={2015}, month={Oct}, pages={e1324} }
 @article{ramírez_ardón_m. douglas_a. s. graça_2015, title={Tropical freshwater sciences: an overview of ongoing tropical research}, volume={34}, ISSN={2161-9549 2161-9565}, url={http://dx.doi.org/10.1086/681257}, DOI={10.1086/681257}, abstractNote={Alonso Ramirez, Marcelo Ardon, Michael Douglas, and Manuel Graca Department of Environmental Science, University of Puerto Rico, Rio Piedras campus, San Juan, Puerto Rico 00919 USA Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, North Carolina 27858 USA Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territories 0909 Australia MARE – Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Largo Marques de Pombal, Coimbra, Portugal}, number={2}, journal={Freshwater Science}, publisher={University of Chicago Press}, author={Ramírez, Alonso and Ardón, Marcelo and M. Douglas, Michael and A. S. Graça, Manuel}, year={2015}, month={Jun}, pages={606–608} }
 @article{astudillo_ramírez_novelo-gutiérrez_vázquez_2014, title={Descomposición de hojarasca en seis arroyos de Bosque Mesófilo de Montaña en la cuenca alta del río La Antigua, Veracruz, México}, volume={62}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v62i0.15782}, DOI={10.15517/rbt.v62i0.15782}, abstractNote={Leaf litter decomposition in six Cloud Forest streams of the upper La Antigua watershed, Veracruz, Mexico. Leaf litter decomposition is an important stream ecosystem process. To understand factors controlling leaf decomposition in cloud forest in Mexico, we incubated leaf packs in different streams along a land use cover gradient for 35 days during the dry and wet seasons. We assessed relations between leaf decom- position rates (k), stream physicochemistry, and macroinvertebrates colonizing leaf packs. Physicochemical parameters showed a clear seasonal difference at all study streams. Leaves were colonized by collector-gatherer insects, followed by shredders. Assessment of factors related to k indicated that only forest cover was negatively related to leaf decomposition rates. Thus stream physicochemistry and seasonality had no impact on decompo- sition rates. We concluded that leaf litter decomposition at our study streams is a stable process over the year. However, it is possible that this stability is the result of factors regulating decomposition during the different seasons and streams. Rev. Biol. Trop. 62 (Suppl. 2): 111-127. Epub 2014 April 01.}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Astudillo, Manuel R. and Ramírez, Alonso and Novelo-Gutiérrez, Rodolfo and Vázquez, Gabriela}, year={2014}, month={Apr}, pages={111} }
 @article{burgos-caraballo_cantrell_ramírez_2014, title={Diversity of Benthic Biofilms Along a Land Use Gradient in Tropical Headwater Streams, Puerto Rico}, volume={68}, ISSN={0095-3628 1432-184X}, url={http://dx.doi.org/10.1007/s00248-014-0401-x}, DOI={10.1007/s00248-014-0401-x}, abstractNote={The properties of freshwater ecosystems can be altered, directly or indirectly, by different land uses (e.g., urbanization and agriculture). Streams heavily influenced by high nutrient concentrations associated with agriculture or urbanization may present conditions that can be intolerable for many aquatic species such as macroinvertebrates and fishes. However, information with respect to how benthic microbial communities may respond to changes in stream ecosystem properties in relation to agricultural or urban land uses is limited, in particular for tropical ecosystems. In this study, diversity of benthic biofilms was evaluated in 16 streams along a gradient of land use at the Turabo watershed in Puerto Rico using terminal restriction fragment length polymorphism. Diversity indices and community structure descriptors (species richness, Shannon diversity, dominance and evenness) were calculated for both bacteria and eukaryotes for each stream. Diversity of both groups, bacteria and eukaryotes, did not show a consistent pattern with land use, since it could be high or low at streams dominated by different land uses. This suggests that diversity of biofilms may be more related to site-specific conditions rather than watershed scale factors. To assess this contention, the relationship between biofilm diversity and reach-scale parameters (i.e., nutrient concentrations, canopy cover, conductivity, and dissolved oxygen) was determined using the Akaike Information Criterion (AIC(c)) for small sample size. Results indicated that nitrate was the variable that best explained variations in biofilm diversity. Since nitrate concentrations tend to increase with urban land use, our results suggest that urbanization may indeed increase microbial diversity indirectly by increasing nutrients in stream water.}, number={1}, journal={Microbial Ecology}, publisher={Springer Science and Business Media LLC}, author={Burgos-Caraballo, Sofía and Cantrell, Sharon A. and Ramírez, Alonso}, year={2014}, month={Mar}, pages={47–59} }
 @article{macias_colón-gaud_duggins_ramírez_2014, title={Do omnivorous shrimp influence mayfly nymph life history traits in a tropical island stream?}, volume={62}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v62i0.15777}, DOI={10.15517/rbt.v62i0.15777}, abstractNote={Interspecific interactions can play an important role in determining habitat selection and resource use between competing species. We examined interactions between an omnivorous shrimp and a grazing mayfly, two co-dominant taxa found in Puerto Rican headwater streams, to assess how predator presence may influence mayfly resource use and instantaneous growth in a tropical rainforest ecosystem. We conducted a series of behavioral and growth experiments to determine the effects of the freshwater shrimp, Xiphocaris elongata, on the growth rate and resource selection of mayfly nymphs in the family Leptophlebiidae. For resource choice assessments, we conducted a series of five day laboratory experiments where mayflies were given access to two resource substrate choices (cobble vs. leaves) in the presence or absence of shrimp. To assess for the effects of shrimp on mayfly fitness, we measured mayfly growth in laboratory aquaria after five days using four treatments (cobble, leaves, cobble + leaves, no resource) in the presence or absence of shrimp. In resource choice experiments, mayflies showed preference for cobble over leaf substrata (p < 0.05) regardless of the presence of shrimps, however, the preference for cobble was significantly greater when shrimp were present in the leaf habitat. In growth experiments, there were no statistical differences in mayfly growth in the presence or absence of shrimp (p = 0.07). However, we measured increased mayfly nymph growth in the absence of predators and when both cobble and leaves were available. Our results suggest that interspecific interactions between these taxa could potentially influence organic matter resource dynamics (e.g., leaf litter processing and export) in Puerto Rican streams.}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Macias, Nicholas A. and Colón-Gaud, Checo and Duggins, Jonathan W. and Ramírez, Alonso}, year={2014}, month={Apr}, pages={41} }
 @article{ramírez_gutiérrez-fonseca_2014, title={Estudios sobre macroinvertebrados acuáticos en América Latina: avances recientes y direcciones futuras}, volume={62}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v62i0.15775}, DOI={10.15517/rbt.v62i0.15775}, abstractNote={Studies on Latin American freshwater macroinvertebrates: recent advances and future direc- tions. Latin America is an active scientific research area, in particular with respect to the study of freshwater macroinvertebrates. The present serves as an introduction to a special issue that highlights recent research projects on macroinvertebrates in Latin America. As part of this introduction, we conducted a literature analy- sis of the last 14 years of publications from the region that highlights the steady increase in publications on macroinvertebrates. Most studies from 2000-2013 were conducted in Brazil, Colombia, Argentina, and Costa Rica, and were focused on taxonomy and different issues related to biodiversity and distribution. There was a tendency for the use of local low-impact journals, but high impact publications were also found. This special issue contributes with 18 studies conducted in eight different countries. Two major topics are covered in the special issue, the ecology and natural history of aquatic macroinvertebrates and their use in the evaluation of anthropogenic impacts to aquatic ecosystems. Based on the literature review and contributions included in the issue, we discuss research needs for the region. Identified needs include: (1) to continue emphasizing taxonomic research, (2) assess mechanisms responsible for changes in biodiversity, (3) assess the role of macroinvertebrates in ecosystem processes and function, (4) improve biomonitoring efforts beyond unimetric indices, (5) the need for an ecosystem perspective, and (6) establishing long-term studies. This special issue is an initial effort to advance our knowledge on freshwater macroinvertebrates in Latin America. Rev. Biol. Trop. 62 (Suppl. 2): 9-20. Epub 2014 April 01.}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Ramírez, Alonso and Gutiérrez-Fonseca, Pablo E.}, year={2014}, month={Apr}, pages={9} }
 @article{ramírez_gutiérrez-fonseca_2014, title={Functional feeding groups of aquatic insect families in Latin America: a critical analysis and review of existing literature}, volume={62}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v62i0.15785}, DOI={10.15517/rbt.v62i0.15785}, abstractNote={Aquatic macroinvertebrates are involved in numerous processes within aquatic ecosystems. They often have important effects on ecosystem processes such as primary production (via grazing), detritus breakdown, and nutrient mineralization and downstream spiraling. The functional feeding groups (FFG) classification was developed as a tool to facilitate the incorporation of macroinvertebrates in studies of aquatic ecosystems. This classification has the advantage of combining morphological characteristics (e.g., mouth part specialization) and behavioral mechanisms (e.g., way of feeding) used by macroinvertebrates when consuming resources. Although recent efforts have greatly advanced our ability to identify aquatic macroinvertebrates, there is limited information on FFG assignment. Furthermore, there has been some variation in the use of the FFG classification, in part due to an emphasis on using gut content analysis to assign FFG, which is more appropriate for assigning trophic guilds. Thus, the main goals of this study are to (1) provide an overview of the value of using the FFG classification, (2) make an initial attempt to summarize available information on FFG for aquatic insects in Latin America, and (3) provide general guidelines on how to assign organisms to their FFGs. FFGs are intended to reflect the potential effects of organisms in their ecosystems and the way they consume resources. Groups include scrapers that consume resources that grow attached to the substrate by removing them with their mouth parts; shredders that cut or chew pieces of living or dead plant material, including all plant parts like leaves and wood; collectors-gatherers that use modified mouth parts to sieve or collect small particles (< 1 mm) accumulated on the stream bottom; filterers that have special adaptations to remove particles directly from the water column; and predators that consume other organisms using different strategies to capture them. In addition, we provide details on piercers that feed on vascular plants by cutting or piercing the tissue using sharp or chewing mouth parts and consume plant liquids. We also provide a list of families of aquatic insects in Latin America, with an initial assignment to FFGs. We recommended caution when assigning FFGs based on gut contents, as it can provide misleading information. Overall, FFG is a very useful tool to understand the role of aquatic macroinvertebrates in stream ecosystems and comparisons among studies will benefit from consistency in their use.}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Ramírez, Alonso and Gutiérrez-Fonseca, Pablo E.}, year={2014}, month={Apr}, pages={155} }
 @article{munoz-erickson_lugo_melendez-ackerman_santiago-acevedo_seguinot-barbosa_mendez-lazaro_hall_quintero_ramirez_garcia-montiel_et al._2014, title={Knowledge to Serve the City: Insights from an Emerging Knowledge-Action Network to Address Vulnerability and Sustainability in San Juan, Puerto Rico}, volume={7}, url={http://digitalcommons.lmu.edu/cate/vol7/iss1/5}, number={1}, journal={Cities and the Environment (CATE)}, author={Munoz-Erickson, TA and Lugo, AE and Melendez-Ackerman, E and Santiago-Acevedo, LE and Seguinot-Barbosa, J and Mendez-Lazaro, P and Hall, M and Quintero, Braulio and Ramirez, A and Garcia-Montiel, D and et al.}, year={2014}, pages={5} }
 @article{torres_ramírez_2014, title={Land use effects on leaf litter breakdown in low-order streams draining a rapidly developing tropical watershed in Puerto Rico}, volume={62}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v62i0.15783}, DOI={10.15517/rbt.v62i0.15783}, abstractNote={Land use has an important role influencing stream ecosystem processes, such as leaf litter breakdown. Here, we assessed rates of leaf litter breakdown in low-order tropical streams draining forest, agriculture, and urban land uses in Puerto Rico. To measure leaf breakdown rates, we placed litter bags made of coarse mesh in nine streams, three for each land use type. At each stream, we measured changes in leaf mass over time, leaf breakdown rates, macroinvertebrate assemblages, and stream physicochemistry. Streams differed in their water physicochemistry, with urban streams showing high values for most variables. Stream physical habitat was evaluated using a visual assessment protocol, which indicated that agricultural and urban streams were more degraded than forested streams. Leaf breakdown rates were fast in all streams (k values ranging 0.006-0.024). Breakdown rates were significantly related to the physical conditions of the stream channel (e.g., visual protocol scores), with fastest rates in forested streams. Invertebrates colonizing leaves were mainly mayflies (Leptophlebiidae, Baetidae, and Caenidae), dipterans (Chironomidae), caddisflies (Polycentropodidae), and beetles (Elmidae and Gyrinidae). Our streams lacked large decapod populations, contrasting with other Puerto Rican streams. We found little evidence for an insect effect on leaf breakdown. Results suggest that land use is an important factor affecting leaf litter processing in streams. In contrast to studies in temperate regions, we found little evidence for a positive nutrient related effect of agricultural land use on decomposition rates. Changes in the physical characteristics of streams appear to be the main drivers behind observed decomposition patterns.}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Torres, Pedro J. and Ramírez, Alonso}, year={2014}, month={Apr}, pages={129} }
 @article{astudillo_ramírez_novelo-gutiérrez_vázquez_2014, title={Leaf litter decomposition in six cloud forest streams of the upper La Antigua watershed, Veracruz, Mexico,Descomposición de hojarasca en seis arroyos de Bosque Mesófilo de Montaña en la cuenca alta del río La Antigua, Veracruz, México}, volume={62}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84907386204&partnerID=MN8TOARS}, journal={Revista de Biologia Tropical}, author={Astudillo, M.R. and Ramírez, A. and Novelo-Gutiérrez, R. and Vázquez, G.}, year={2014}, pages={111–127} }
 @book{rodriguez_ramirez_2014, place={Rio Piedras, Puerto Rico}, title={Protocolo de evaluación visual de quebradas para Puerto Rico.}, institution={Universidad de Puerto Rico, recinto de Río Piedras}, author={Rodriguez, N and Ramirez, A}, year={2014}, month={May} }
 @inbook{ramírez_gutiérrez-fonseca_2014, place={Jiutepec, Morelos, México}, title={Puerto Rico}, booktitle={Diversidad, conservación y uso de los macroinvertebrados dulceacuícolas de México, Centroamérica, Colombia, Cuba y Puerto Rico}, publisher={Instituto Mexicano de Tecnología del Agua}, author={Ramírez, A. and Gutiérrez-Fonseca, P.E.}, editor={Alonso-EguíaLis, P. and Mora, J.M. and Campbell, B. and Springer, M.Editors}, year={2014} }
 @article{ramírez_rosas_lugo_ramos-gonzález_2014, title={Spatio-temporal variation in stream water chemistry in a tropical urban watershed}, volume={19}, ISSN={1708-3087}, url={http://dx.doi.org/10.5751/es-06481-190245}, DOI={10.5751/es-06481-190245}, abstractNote={Urban activities and related infrastructure alter the natural patterns of stream physical and chemical conditions. According to the Urban Stream Syndrome, streams draining urban landscapes are characterized by high concentrations of nutrients and ions, and might have elevated water temperatures and variable oxygen concentrations. Here, we report temporal and spatial variability in stream physicochemistry in a highly urbanized watershed in Puerto Rico. The main objective of the study was to describe stream physicochemical characteristics and relate them to urban intensity, e.g., percent impervious surface cover, and watershed infrastructure, e.g., road and pipe densities. The Rio Piedras Watershed in the San Juan Metropolitan Area, Puerto Rico, is one of the most urbanized regions on the island. The Rio Piedras presented high solute concentrations that were related to watershed factors, such as percent impervious cover. Temporal variability in ion concentrations lacked seasonality, as did all other parameters measured except water temperature, which was lower during winter and highest during summer, as expected based on latitude. Spatially, stream physicochemistry was strongly related to watershed percent impervious cover and also to the density of urban infrastructure, e.g., roads, pipe, and building densities. Although the watershed is serviced by a sewage collection system, illegal discharges and leaky infrastructure are probably responsible for the elevated ion concentration found. Overall, the Rio Piedras is an example of the response of a tropical urban watershed after major sewage inputs are removed, thus highlighting the importance of proper infrastructure maintenance and management of runoff to control ion concentrations in tropical streams.}, number={2}, journal={Ecology and Society}, publisher={Resilience Alliance, Inc.}, author={Ramírez, Alonso and Rosas, Keysa G. and Lugo, Ariel E. and Ramos-González, Olga M.}, year={2014} }
 @article{studies on latin american freshwater macroinvertebrates: recent advances and future directions,estudios sobre macroinvertebrados acuáticos en américa latina: avances recientes y direcciones futuras_2014, volume={62}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84907410779&partnerID=MN8TOARS}, journal={Revista de Biologia Tropical}, year={2014}, pages={9–20} }
 @article{gómez-anaya_novelo-gutiérrez_ramírez_arce-pérez_2014, title={Using empirical field data of aquatic insects to infer a cut-off slope value in asymptotic models to assess inventories completeness}, volume={85}, ISSN={1870-3453}, url={http://dx.doi.org/10.7550/rmb.36978}, DOI={10.7550/rmb.36978}, abstractNote={The selection of the most appropriate model is essential to predict the potential species richness of a siteor landscape. Species accumulation curves have been used as a basic tool for comparing richness when differentsampling protocols have been applied. Among the parameters generated by these models the slope has been cited asan indicator of completeness without regard to a defined cut-off value. In this work, we fit 12 field data sets of aquaticColeoptera (Hidalgo) and Odonata larvae (Michoacan) to 2 asymptotic models (Clench and Linear Dependence) inorder to calculate the slopes at the maximum effort and relate them with efficiency. Then, the theoretical effort neededto achieve the 95% of the lists was calculated for each data set in order to get the theoretical slopes. The averageslope value found was 0.01 with a variance of <0.001, so we propose this value as indicative of a list reaching 95% ofcompleteness for data obtained from similar sampling protocols.}, number={1}, journal={Revista Mexicana de Biodiversidad}, publisher={Universidad Nacional Autonoma de Mexico}, author={Gómez-Anaya, José Antonio and Novelo-Gutiérrez, Rodolfo and Ramírez, Alonso and Arce-Pérez, Roberto}, year={2014}, month={Mar}, pages={218–227} }
 @article{gutiérrez-fonseca_rosas_ramírez_2013, title={Aquatic insects of Puerto Rico: a list of families}, volume={20}, number={2}, journal={Dugesiana}, author={Gutiérrez-Fonseca, P.E. and Rosas, K.G. and Ramírez, A.}, year={2013}, month={Dec}, pages={215–219} }
 @article{ardón_duff_ramírez_small_jackman_triska_pringle_2013, title={Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift}, volume={443}, ISSN={0048-9697}, url={http://dx.doi.org/10.1016/j.scitotenv.2012.10.068}, DOI={10.1016/j.scitotenv.2012.10.068}, abstractNote={Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (~6) than streams that do not receive IGF (pH ~5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO(3)(-)) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO(3)(-) was an important buffering mechanism in both streams. Base cation, Fe(2+), and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low-solute poorly buffered streams might be particularly vulnerable to episodic acidification.}, journal={Science of The Total Environment}, publisher={Elsevier BV}, author={Ardón, Marcelo and Duff, John H. and Ramírez, Alonso and Small, Gaston E. and Jackman, Alan P. and Triska, Frank J. and Pringle, Catherine M.}, year={2013}, month={Jan}, pages={267–277} }
 @article{novelo-gutiérrez_ramírez_2013, title={First record of Telebasis filiola Perty (Odonata: Coenagrionidae) preying on small web-building spiders (Arachnida: Tetragnathidae)}, volume={16}, ISSN={1388-7890 2159-6719}, url={http://dx.doi.org/10.1080/13887890.2013.830992}, DOI={10.1080/13887890.2013.830992}, abstractNote={At a wetland in southeastern Mexico a female of Telebasis filiola was observed and photographed preying on a small web-building spider of the genus Leucauge. This is the first record of gleaning by a representative of the genus Telebasis. A brief discussion on this subject in other odonates is provided.}, number={4}, journal={International Journal of Odonatology}, publisher={Informa UK Limited}, author={Novelo-Gutiérrez, Rodolfo and Ramírez, Alonso}, year={2013}, month={Dec}, pages={289–292} }
 @article{gutiérrez-fonseca_ramírez_umaña_springer_2013, title={Freshwater macroinvertebrates from Cocos Island, Costa Rica: Species and comparison with other islands of the Eastern Tropical Pacific,Macroinvertebrados dulceacuícolas de la Isla del Coco, Costa Rica: Especies y comparación con otras islas del Pacífico Tropical Oriental}, volume={61}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84877281220&partnerID=MN8TOARS}, number={2}, journal={Revista de Biologia Tropical}, author={Gutiérrez-Fonseca, P.E. and Ramírez, A. and Umaña, G. and Springer, M.}, year={2013}, pages={657–668} }
 @article{gutiérrez fonseca_ramírez_umaña_springer_2013, title={Macroinvertebrados dulceacuícolas de la Isla del Coco, Costa Rica: especies y comparación con otras islas del Pacífico Tropical Oriental}, volume={61}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v61i2.11166}, DOI={10.15517/rbt.v61i2.11166}, abstractNote={Freshwater macroinvertebrates from Cocos Island, Costa Rica: species and comparison with other islands of the Eastern Tropical Pacific. Cocos Island is an oceanic island in the Eastern Pacific, at 496km from Cabo Blanco, Costa Rica. This 24 km2 island is surrounded by a protected marine area of 9640 km2. it was declared National Park in 1978 and a World Heritage by UNESCO in 1997. Freshwater macroinvertebrate fauna was collected in 20 sites covering three rivers (Genio, Chatam and Sucio) and two creeks (Minuto and an unnamed creek behind the park rangers' house). Tank bromeliads or phytotelmata were also examined for aquatic macroinvertebrates. Physicochemical parameters were determined in 13 study sites. Additionally, a comparison with other islands in the Eastern Tropical Pacific was conducted to determine the most important factors controlling the diversity in Tropical Pacific islands. A total of 455 individuals were collected belonging to 20 taxa (mostly identified to genus level) from 15 families of aquatic insects. Other macroinvertebrates such as Palaemonid shrimps, Hidrachnida and Oligochaeta were also collected. The family Staphylinidae (Coleoptera) was the most abundant, followed by Chironomidae (Diptera). Diptera was the order of insects with the highest taxonomic richness. A relationship between distance and the number of families was observed supporting the premises of the Theory of island Biogeography. This relationship was improved by correcting area by island elevation, indicating that mountainous islands had the richest faunas, potentially due to high cloud interception that feeds freshwater environments favoring the establishment of aquatic fauna. Physicochemical variables were similar in all sites, possibly due to the geology and the absence of significant sources of pollution on the island.}, number={2}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Gutiérrez Fonseca, Pablo E. and Ramírez, Alonso and Umaña, Gerardo and Springer, Monika}, year={2013}, month={Jul}, pages={657–668} }
 @article{gómez-anaya_novelo-gutiérrez_ramírez_2013, title={Temporal variation on Odonata larval assemblage diversity in a lowland stream in western Mexico}, volume={42}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84890475933&partnerID=MN8TOARS}, number={4}, journal={Odonatologica}, author={Gómez-Anaya, J.A. and Novelo-Gutiérrez, R. and Ramírez, A.}, year={2013}, pages={309–323} }
 @article{ramírez_gutiérrez fonseca_2013, title={The larvae of <em>Heteragrion majus}, volume={3609}, ISSN={1175-5334 1175-5326}, url={http://dx.doi.org/10.11646/zootaxa.3609.1.8}, DOI={10.11646/zootaxa.3609.1.8}, abstractNote={The final larval stadium of Heteragrion majus Selys, 1886 and H. atrolineatum Donnelly, 1992 are described and illus-trated for the first time, using reared material from Costa Rica, and compared with other species of the genus known from the country. All species were very similar as larvae, but they can be separated by the presence and distribution of antennal setae, spines on the posterior margin of the abdominal segments, and size. A key to separate all five species known for Costa Rica is provided. }, number={1}, journal={Zootaxa}, publisher={Magnolia Press}, author={Ramírez, Alonso and Gutiérrez Fonseca, Pablo E.}, year={2013}, month={Jan}, pages={96–100} }
 @article{engman_ramírez_2012, title={Fish assemblage structure in urban streams of Puerto Rico: the importance of reach- and catchment-scale abiotic factors}, volume={693}, ISSN={0018-8158 1573-5117}, url={http://dx.doi.org/10.1007/s10750-012-1100-6}, DOI={10.1007/s10750-012-1100-6}, number={1}, journal={Hydrobiologia}, publisher={Springer Science and Business Media LLC}, author={Engman, Augustin C. and Ramírez, Alonso}, year={2012}, month={Apr}, pages={141–155} }
 @article{small_ardón_jackman_duff_triska_ramírez_snyder_pringle_2012, title={Rainfall-Driven Amplification of Seasonal Acidification in Poorly Buffered Tropical Streams}, volume={15}, ISSN={1432-9840 1435-0629}, url={http://dx.doi.org/10.1007/s10021-012-9559-6}, DOI={10.1007/s10021-012-9559-6}, number={6}, journal={Ecosystems}, publisher={Springer Science and Business Media LLC}, author={Small, Gaston E. and Ardón, Marcelo and Jackman, Alan P. and Duff, John H. and Triska, Frank J. and Ramírez, Alonso and Snyder, Marcía and Pringle, Catherine M.}, year={2012}, month={Jun}, pages={974–985} }
 @article{boyero_pearson_gessner_barmuta_ferreira_graça_dudgeon_boulton_callisto_chauvet_et al._2011, title={A global experiment suggests climate warming will not accelerate litter decomposition in streams but might reduce carbon sequestration}, volume={14}, ISSN={1461-023X}, url={http://dx.doi.org/10.1111/j.1461-0248.2010.01578.x}, DOI={10.1111/j.1461-0248.2010.01578.x}, abstractNote={The decomposition of plant litter is one of the most important ecosystem processes in the biosphere and is particularly sensitive to climate warming. Aquatic ecosystems are well suited to studying warming effects on decomposition because the otherwise confounding influence of moisture is constant. By using a latitudinal temperature gradient in an unprecedented global experiment in streams, we found that climate warming will likely hasten microbial litter decomposition and produce an equivalent decline in detritivore-mediated decomposition rates. As a result, overall decomposition rates should remain unchanged. Nevertheless, the process would be profoundly altered, because the shift in importance from detritivores to microbes in warm climates would likely increase CO(2) production and decrease the generation and sequestration of recalcitrant organic particles. In view of recent estimates showing that inland waters are a significant component of the global carbon cycle, this implies consequences for global biogeochemistry and a possible positive climate feedback.}, number={3}, journal={Ecology Letters}, publisher={Wiley}, author={Boyero, Luz and Pearson, Richard G. and Gessner, Mark O. and Barmuta, Leon A. and Ferreira, Verónica and Graça, Manuel A. S. and Dudgeon, David and Boulton, Andrew J. and Callisto, Marcos and Chauvet, Eric and et al.}, year={2011}, month={Feb}, pages={289–294} }
 @article{jesús-crespo_ramírez_2011, title={Effects of urbanization on stream physicochemistry and macroinvertebrate assemblages in a tropical urban watershed in Puerto Rico}, volume={30}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.1899/10-081.1}, DOI={10.1899/10-081.1}, abstractNote={Abstract Urbanization is degrading stream ecosystems worldwide. Tropical island streams may respond to urbanization differently than temperate streams because of their overall climate differences, and they may respond differently than continental tropical urban streams because of their reduced biological diversity and short drainages. We characterized the physicochemistry, physical habitat, and macroinvertebrate assemblages of 16 stream tributaries in the Rio Piedras Watershed (San Juan, Puerto Rico). We also described landuse patterns upstream from each sampling site for the entire subwatershed and for riparian buffers of 5- and 100-m width. Urbanization had a negative effect on the physicochemical and biological condition of the Rio Piedras. Streams were distributed in ordination space along a strong physicochemical gradient that was related to concentrations of K+, Mg2+, dissolved O2 (DO), and PO43−. Along this gradient, DO and Mg2+ decreased and PO43− and K+ increased with higher % urban cover in the subwatershed. Macroinvertebrate assemblages also were related to urbanization, and more macroinvertebrate families and pollution-sensitive taxa were found at sites where physicochemistry reflected less urban cover. Family richness and pollution-sensitive taxa were positively associated with greater % forest cover in the 5-m riparian buffer zone, a result that supports the use of riparian buffers to ameliorate the effects of urbanization on stream biointegrity in the Rio Piedras. Our results are similar to findings in urban streams in temperate zones and in tropical continental streams. Therefore, despite island characteristics, tropical island stream physicochemistry and macroinvertebrate assemblages responded to urbanization in ways that are in general agreement with the predictions of the Urban Stream Syndrome.}, number={3}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Jesús-Crespo and Ramírez, Alonso}, year={2011}, month={Sep}, pages={739–750} }
 @article{boyero_pearson_dudgeon_graça_gessner_albariño_ferreira_yule_boulton_arunachalam_et al._2011, title={Global distribution of a key trophic guild contrasts with common latitudinal diversity patterns}, volume={92}, ISSN={0012-9658}, url={http://dx.doi.org/10.1890/10-2244.1}, DOI={10.1890/10-2244.1}, abstractNote={Most hypotheses explaining the general gradient of higher diversity toward the equator are implicit or explicit about greater species packing in the tropics. However, global patterns of diversity within guilds, including trophic guilds (i.e., groups of organisms that use similar food resources), are poorly known. We explored global diversity patterns of a key trophic guild in stream ecosystems, the detritivore shredders. This was motivated by the fundamental ecological role of shredders as decomposers of leaf litter and by some records pointing to low shredder diversity and abundance in the tropics, which contrasts with diversity patterns of most major taxa for which broad-scale latitudinal patterns haven been examined. Given this evidence, we hypothesized that shredders are more abundant and diverse in temperate than in tropical streams, and that this pattern is related to the higher temperatures and lower availability of high-quality leaf litter in the tropics. Our comprehensive global survey (129 stream sites from 14 regions on six continents) corroborated the expected latitudinal pattern and showed that shredder distribution (abundance, diversity and assemblage composition) was explained by a combination of factors, including water temperature (some taxa were restricted to cool waters) and biogeography (some taxa were more diverse in particular biogeographic realms). In contrast to our hypothesis, shredder diversity was unrelated to leaf toughness, but it was inversely related to litter diversity. Our findings markedly contrast with global trends of diversity for most taxa, and with the general rule of higher consumer diversity at higher levels of resource diversity. Moreover, they highlight the emerging role of temperature in understanding global patterns of diversity, which is of great relevance in the face of projected global warming.}, number={9}, journal={Ecology}, publisher={Wiley}, author={Boyero, Luz and Pearson, Richard G and Dudgeon, David and Graça, Manuel A. S and Gessner, Mark O and Albariño, Ricardo J and Ferreira, Verónica and Yule, Catherine M and Boulton, Andrew J and Arunachalam, Muthukumarasamy and et al.}, year={2011}, month={Sep}, pages={1839–1848} }
 @article{boyero_pearson_dudgeon_ferreira_graça_gessner_boulton_chauvet_yule_albariño_et al._2011, title={Global patterns of stream detritivore distribution: implications for biodiversity loss in changing climates}, volume={21}, ISSN={1466-822X}, url={http://dx.doi.org/10.1111/j.1466-8238.2011.00673.x}, DOI={10.1111/j.1466-8238.2011.00673.x}, abstractNote={ABSTRACT}, number={2}, journal={Global Ecology and Biogeography}, publisher={Wiley}, author={Boyero, Luz and Pearson, Richard G. and Dudgeon, David and Ferreira, Verónica and Graça, Manuel A. S. and Gessner, Mark O. and Boulton, Andrew J. and Chauvet, Eric and Yule, Catherine M. and Albariño, Ricardo J. and et al.}, year={2011}, month={May}, pages={134–141} }
 @article{ramírez_altamiranda-saavedra_gutiérrez-fonseca_springer_2011, title={The neotropical damselfly genus Cora: new larval descriptions and a comparative analysis of larvae of known species (Odonata: Polythoridae)}, volume={14}, ISSN={1388-7890 2159-6719}, url={http://dx.doi.org/10.1080/13887890.2011.616992}, DOI={10.1080/13887890.2011.616992}, abstractNote={The final larval stadium of four species of Cora are described and compared with known species in the genus. Cora skinneri Calvert, 1907, C. semiopaca Selys, 1878 and C. lugubris Navás, 1934 are described and illustrated for the first time using material from Costa Rica for the first two and from Colombia for the latter. A redescription of C. marina Selys, 1868 from specimens collected in Costa Rica is also included for comparison. Although all species are very similar as larvae, two major groups can be differentiated based on the shape of the caudal gills. The three species here described for the first time are very similar, but can be separated from each other using a combination of characters. Se describen los estadios finales de las larvas de tres especies de Cora y se comparan con las especies conocidas en el género. Cora skinneri Calvert, 1907, C. semiopaca Selys, 1878 y C. lugubris Navás, 1934 son descritas e ilustradas por primera vez usando material de Costa Rica para las dos primeras y de Colombia para la última especie. Se incluye además la descripción de la larva de C. marina Selys, 1868 de especímenes recolectados en Costa Rica para propósitos comparativos. Las especies de Cora son muy similares como larvas, pero se pueden diferenciar dos grandes grupos basado en la forma de las branquias caudales. Las tres especies que se describen pertenecen al mismo grupo y se pueden separar entre ellas usando una variedad de caracteres.}, number={3}, journal={International Journal of Odonatology}, publisher={Informa UK Limited}, author={Ramírez, Alonso and Altamiranda-Saavedra, Mariano and Gutiérrez-Fonseca, Pablo and Springer, Monika}, year={2011}, month={Sep}, pages={249–256} }
 @article{de jesús-crespo_ramirez_2011, title={The use of a Stream Visual Assessment Protocol to determine ecosystem integrity in an urban watershed in Puerto Rico}, volume={36}, ISSN={1474-7065}, url={http://dx.doi.org/10.1016/j.pce.2010.11.007}, DOI={10.1016/j.pce.2010.11.007}, abstractNote={The growing need to protect stream ecosystems in Puerto Rico requires the development of monitoring procedures that help determine management priorities. Physical habitat assessments have been used to make quick evaluations that are cost efficient and easy conduct, yet they need to be studied further to understand their accuracy at predicting stream health. This study evaluated the efficiency of the Hawaii Stream Visual Assessment Protocol (HSVAP) at determining integrity of streams within the highly urbanized Rio Piedras watershed in Puerto Rico. To validate the protocol we compared results from HSVAP assessments conducted at 16 reaches with water quality and macroinvertebrate data collected at the same sites. Results from linear regressions between the water quality measures and HSVAP scores showed that there was no significant relationships (R2 = 0.48; p = 0.08). This implies that the protocol is not supported by the water quality data. However, results from regressions between macroinvertebrate diversity and the number of families per site showed a significant positive relation with HSVAP scores (R2 = 0.30; p = 0.02; R2 = 0.24; p = 0.05). In addition, a significant negative relation was observed between HSVAP scores and the Family Biotic Index (FBI) (R2 = 0.32; p = 0.02). Comparisons between ratings obtained from the FBI and HSVAP scores suggest that the HSVAP classified sites as having higher quality than the biological metric. Based on these results, it can be concluded that the HSVAP is a good tool for a general assessment of the physical characteristics of a stream, but it needs modifications to accurately assess ecological quality of streams in Puerto Rico.}, number={12}, journal={Physics and Chemistry of the Earth, Parts A/B/C}, publisher={Elsevier BV}, author={de Jesús-Crespo, Rebeca and Ramirez, Alonso}, year={2011}, month={Jan}, pages={560–566} }
 @article{ramírez_engman_rosas_perez-reyes_martinó-cardona_2011, title={Urban impacts on tropical island streams: Some key aspects influencing ecosystem response}, volume={15}, ISSN={1083-8155 1573-1642}, url={http://dx.doi.org/10.1007/s11252-011-0214-3}, DOI={10.1007/s11252-011-0214-3}, number={2}, journal={Urban Ecosystems}, publisher={Springer Science and Business Media LLC}, author={Ramírez, Alonso and Engman, Augustin and Rosas, Keysa G. and Perez-Reyes, Omar and Martinó-Cardona, Diana M.}, year={2011}, month={Nov}, pages={315–325} }
 @article{benstead_cross_march_mcdowell_ramírez_covich_2010, title={Biotic and abiotic controls on the ecosystem significance of consumer excretion in two contrasting tropical streams}, volume={55}, ISSN={0046-5070}, url={http://dx.doi.org/10.1111/j.1365-2427.2010.02461.x}, DOI={10.1111/j.1365-2427.2010.02461.x}, abstractNote={Summary}, number={10}, journal={Freshwater Biology}, publisher={Wiley}, author={Benstead, Jonathan P. and Cross, Wyatt F. and March, James G. and McDOWELL, WILLIAM H. and Ramírez, Alonso and Covich, Alan P.}, year={2010}, month={Jun}, pages={2047–2061} }
 @article{hanson_springer_ramirez_2010, title={Chapter 1. Introduction to the groups of aquatic macroinvertebrates,Capítulo 1. Introducción a los grupos de macroinvertebrados acuáticos}, volume={58}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-81255211463&partnerID=MN8TOARS}, number={SUPPL. 4}, journal={Revista de Biologia Tropical}, author={Hanson, P. and Springer, M. and Ramirez, A.}, year={2010}, pages={3–37} }
 @article{ramírez_2010, title={Chapter 2. Recollection methods,Capítulo 2. Métodos de recolección}, volume={58}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-81255197707&partnerID=MN8TOARS}, number={SUPPL. 4}, journal={Revista de Biologia Tropical}, author={Ramírez, A.}, year={2010}, pages={41–50} }
 @article{ramírez_2010, title={Chapter 5. Odonata,Capítulo 5. Odonata}, volume={58}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-81255146513&partnerID=MN8TOARS}, number={SUPPL. 4}, journal={Revista de Biologia Tropical}, author={Ramírez, A.}, year={2010}, pages={97–136} }
 @article{hanson_springer_ramirez_2010, title={Introducción a los grupos de macroinvertebrados acuáticos}, volume={58}, ISSN={2215-2075 0034-7744}, url={http://dx.doi.org/10.15517/rbt.v58i4.20080}, DOI={10.15517/rbt.v58i4.20080}, number={Suppl. 4}, journal={Revista de Biología Tropical}, publisher={Universidad de Costa Rica}, author={Hanson, Paul and Springer, Monica and Ramirez, Alonso}, year={2010}, month={Dec}, pages={3–37} }
 @article{ramírez_2010, title={Métodos de recolección}, volume={58}, number={Suppl. 4}, journal={Revista de Biologia Tropical}, author={Ramírez, A.}, year={2010}, pages={41–50} }
 @article{ramírez_2010, title={Odonata}, volume={58}, number={Suppl. 4}, journal={Revista de Biologia Tropical}, author={Ramírez, A.}, year={2010}, pages={97–136} }
 @article{springer_ramirez_hanson_2010, title={[Fresh water macroinvertebrates of Costa Rica I].,Macroinvertebrados de agua dulce de Costa Rica I.}, volume={58 Suppl 4}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84856623971&partnerID=MN8TOARS}, journal={Revista de biología tropical}, author={Springer, M. and Ramirez, A. and Hanson, P.}, year={2010} }
 @article{boyero_ramírez_dudgeon_pearson_2009, title={Are tropical streams really different?}, volume={28}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.1899/08-146.1}, DOI={10.1899/08-146.1}, abstractNote={Stream shredders have been reported as scarce in several tropical areas. This pattern is in contrast to observations in temperate streams, which support an abundant and diverse shredder fauna. Two possible explanations for this pattern are that most shredders are adapted to cool conditions and that temperate riparian vegetation often produces more palatable and more nutritious leaves than do the more diverse, tropical rainforests. In peninsular Malaysia, most streams flow through lowland dipterocarp forests that are characterized by strikingly high tree diversity and by many species with tough leathery leaves that are high in lignin and toxic secondary compounds and low in protein. In contrast, highland streams flow through montane rain forests and are more similar to temperate streams. We hypothesized that shredder fauna would be distributed along an altitudinal gradient, with more abundant and diverse assemblages in highland streams. We sampled leaf litter in 12 sites at altitudes from 55 to 1560 m above sea level. As expected, highland sites supported higher abundance and diversity of shredders (9–15 species per site) than did lowland sites (3–8 species per site). Shredder densities were similar among lowland sites, but species composition was variable. Large snails (Brotia spp.) were the dominant shredders in nonacidic streams in Taman Negara, but they were absent from acidic streams and from streams elsewhere in peninsular Malaysia. Shredder biomass was generally high because of the large body size of most species (e.g., crabs, snails, semiaquatic cockroaches, calamoceratids, and tipulids). Large mouthparts might allow these species to shred tough leaves efficiently, and large body size might enable them to tolerate a wide variety of toxic secondary compounds. Our results suggest that shredder diversity might depend on elevation, water temperature, characteristics of the riparian vegetation along altitudinal gradients, and variation in water chemistry at local scales.}, number={2}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Boyero, Luz and Ramírez, Alonso and Dudgeon, David and Pearson, Richard G.}, year={2009}, month={Jun}, pages={397–403} }
 @article{blanco_ramírez_scatena_2009, title={The streams of Gorgona Natural National Park within the global context: An introduction to the special issue}, volume={31}, number={91}, journal={Actualidades Biologicas}, author={Blanco, J.F. and Ramírez, A. and Scatena, F.N.}, year={2009}, pages={105–110} }
 @article{wenger_roy_jackson_bernhardt_carter_filoso_gibson_hession_kaushal_martí_et al._2009, title={Twenty-six key research questions in urban stream ecology: an assessment of the state of the science}, volume={28}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.1899/08-186.1}, DOI={10.1899/08-186.1}, abstractNote={Abstract Urban streams have been the focus of much research in recent years, but many questions about the mechanisms driving the urban stream syndrome remain unanswered. Identification of key research questions is an important step toward effective, efficient management of urban streams to meet societal goals. We developed a list of priority research questions by: 1) soliciting input from interested scientists via a listserv and online survey, 2) holding an open discussion on the questions at the Second Symposium on Urbanization and Stream Ecology, and 3) reviewing the literature in the preparation of this paper. We present the resulting list of 26 questions in the context of a review and summary of the present understanding of urban effects on streams. The key questions address major gaps in our understanding of ecosystem structure and function responses (e.g., what are the sublethal impacts of urbanization on biota?), characteristics of urban stream stressors (e.g., can we identify clusters of covarying stressors?), and management strategies (e.g., what are appropriate indicators of ecosystem structure and function to use as management targets?). The identified research needs highlight our limited understanding of mechanisms driving the urban stream syndrome and the variability in characteristics of the effects of urbanization across different biogeoclimatic conditions, stages of development, government policies, and cultural norms. We discuss how to proceed with appropriate management activities given our current incomplete understanding of the urban stream syndrome.}, number={4}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Wenger, Seth J. and Roy, Allison H. and Jackson, C. Rhett and Bernhardt, Emily S. and Carter, Timothy L. and Filoso, Solange and Gibson, Catherine A. and Hession, W. Cully and Kaushal, Sujay S. and Martí, Eugenia and et al.}, year={2009}, month={Dec}, pages={1080–1098} }
 @article{ramírez_de jesús-crespo_martinó-cardona_martínez-rivera_burgos-caraballo_2009, title={Urban streams in Puerto Rico: what can we learn from the tropics?}, volume={28}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.1899/08-165.1}, DOI={10.1899/08-165.1}, abstractNote={Abstract Urbanization is increasing rapidly in tropical regions. Information on the response of tropical streams to urbanization is critically needed, but this information is limited. Here we summarize our current understanding of urban stream ecosystems in Puerto Rico, a tropical island with a high level of industrialization and large urban areas. We focused on 16 tributaries of the Rio Piedras watershed, which drains the San Juan metropolitan area, and 16 tributaries of the Turabo watershed, a rapidly developing suburban area. Urban effects on nutrients and aquatic macroinvertebrates were similar to those described for other geographic regions. PO4, K, and Mg concentrations increased considerably with urbanization, PO4-P ranged from <5 µg/L in streams draining forested watersheds to >500 µg/L in heavily urbanized streams. Macroinvertebrate assemblage composition changed to dominance by tolerant taxa (e.g., snails, Chironomidae) as the proportion of urban land increased in the subwatershed. In contrast, other factors did not follow expected responses to urbanization. Stream hydrology was equally flashy in streams draining forested and urbanized watersheds. Urban streams were commonly channelized, but in contrast to studies done elsewhere, channel incision was not greater in urban than in forested streams. Degree of urbanization was not related to the integrity of the fish assemblages. River connectivity seems to be more important than urbanization in determining fish assemblage composition in Puerto Rican streams because all native species are migratory (i.e., diadromous). Urbanization increased water temperature and microbial activity. Overall, urban streams in Puerto Rico presented some unexpected responses to urbanization that seem to be the result of its island or coastal characteristics. Examples from Puerto Rico provide information on how tropical streams might respond to the impacts of urbanization.}, number={4}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Ramírez, Alonso and De Jesús-Crespo, Rebeca and Martinó-Cardona, Diana M. and Martínez-Rivera, Noraida and Burgos-Caraballo, Sofía}, year={2009}, month={Dec}, pages={1070–1079} }
 @article{cross_covich_crowl_benstead_ramírez_2008, title={Secondary production, longevity and resource consumption rates of freshwater shrimps in two tropical streams with contrasting geomorphology and food web structure}, volume={53}, ISSN={0046-5070 1365-2427}, url={http://dx.doi.org/10.1111/j.1365-2427.2008.02078.x}, DOI={10.1111/j.1365-2427.2008.02078.x}, abstractNote={Summary}, number={12}, journal={Freshwater Biology}, publisher={Wiley}, author={Cross, Wyatt F. and Covich, Alan P. and Crowl, Todd A. and Benstead, Jonathan P. and Ramírez, Alonso}, year={2008}, month={Dec}, pages={2504–2519} }
 @article{small_pringle_triska_duff_jackman_hidalgo_ramírez_ardón_2008, title={The dynamics of phosphorus retention during an eight-year P-addition in a Neotropical headwater stream}, volume={30}, ISSN={0368-0770}, url={http://dx.doi.org/10.1080/03680770.2008.11902187}, DOI={10.1080/03680770.2008.11902187}, abstractNote={Understanding the capacity of stream ecosystems to retain nutrients through physical-chemical processes and biotic assimilation has been a central goal of stream ecologists for decades. Currently, most of our understanding of nutrient saturation is based on short-term (<1 day) nutrient addition experiments, while predicting total stream ecosystem response to long-term anthropogenic nutrient loading requires considering the stream’s capacity to remove nutrients over extended periods. Dissolved phosphorus (P) retention results from a combination of biotic and abiotic mechanisms, which could follow different trajectories through time. Short-term biotic P uptake by algae and heterotrophic microbes typically involves direct assimilation from the water column and is saturated at low background soluble reactive phosphorus (SRP) levels (MULHOLLAND et al. 1990). However, during long-term P-loading, the biotic community could also respond by increasing biomass (PETERSON et al. 1985, SLAVIK et al. 2004, but see GREENWOOD & ROSEMOND 2005), temporarily increasing the community’s P-retention capacity. Abiotic P-sorption is an equilibrium process controlled by the relative concentrations of sorbed-P and dissolved-P, although it also depends on sediment size, iron, aluminum, organic content, and pH (MEYER 1979). During long-term P-loading, sediment should become increasingly P-saturated, decreasing abiotic retention. Because biotic and abiotic P-uptake mechanisms could have opposite responses to long-term Ploading, the relative importance of each mechanism will control a stream’s retention capacity over time. Specifically, where P-uptake is dominated by biotic pathways, streams could become temporarily more efficient at removing dissolved-P, whereas where P-uptake is primarily abiotic, streams potentially become less efficient. Here we present data from an 8-year experimental P-addition in a first-order stream, the Carapa, at La Selva Biological Station, Costa Rica. Previous experiments of P-dynamics in the Rio Salto at La Selva indicate that most uptake of P due to the input of naturally P-enriched regional groundwater is due to abiotic sorption (TRISKA et al. 2006). Biweekly measurements of dissolved P concentration upstream and at 3 downstream stations during the long-term P-injection in the Carapa allowed us to calculate P-uptake rates over the 8-year study. Assuming a dominance of abiotic control, we predicted that sediments would become saturated over time, decreasing Puptake efficiency.}, number={4}, journal={SIL Proceedings, 1922-2010}, publisher={Informa UK Limited}, author={Small, Gaston E. and Pringle, Catherine M. and Triska, Frank J. and Duff, John H. and Jackman, Alan P. and Hidalgo, Minor and Ramírez, Alonso and Ardón, Marcelo}, year={2008}, month={Jan}, pages={551–554} }
 @article{cross_ramírez_santana_santiago_2008, title={Toward Quantifying the Relative Importance of Invertebrate Consumption and Bioturbation in Puerto Rican Streams}, volume={40}, ISSN={0006-3606}, url={http://dx.doi.org/10.1111/j.1744-7429.2007.00388.x}, DOI={10.1111/j.1744-7429.2007.00388.x}, abstractNote={ABSTRACT}, number={4}, journal={Biotropica}, publisher={Wiley}, author={Cross, Wyatt. F. and Ramírez, A. and Santana, A. and Santiago, L. Silvestrini}, year={2008}, month={Jan}, pages={477–484} }
 @inbook{ramírez_pringle_wantzen_2008, place={New York}, title={Tropical Stream Conservation}, ISBN={9780120884490}, url={http://dx.doi.org/10.1016/b978-012088449-0.50012-1}, DOI={10.1016/b978-012088449-0.50012-1}, abstractNote={This chapter focuses on the conservation issues that are relevant to most tropical regions and stream types. It also reviews the major factors impacting tropical streams. Conservation issues affecting tropical streams are complex and result from particular combinations of socio-economic factors and ecological responses. It reveals that the major factors impacting tropical streams are mainly over-fishing, deforestation, and water abstraction for irrigation and human consumption, pollution, and alterations in riverine connectivity. Most tropical regions have annual population growth rates of nearly 3% and this rapid pace of growth is commonly followed by over-exploitation of natural resources. The problem of over-exploitation of natural resources by developing countries is exacerbated by over-consumption in developed nations. On the other hand, the ecological factors include the increased rate of erosion of land after clearance for agriculture. Tropical streams located in coastal areas and island streams tend to be dominated by migratory fishes and shrimps that must pass their immature stages in estuaries or coastal waters. Deforestation is a major environmental problem in tropical regions, where rates of tropical forest loss currently exceed 1.25×105 km2 yr-1. Removal of catchment vegetation, in particular riparian vegetation, alters water movement from land to stream, resulting in increases in erosion and sedimentation in the channel. Loss of longitudinal and lateral riverine connectivity is one of the main results of river regulation, damming, and water abstraction. The case study shows that the abandonment of agriculture in Puerto Rico has had a positive effect on water quality, as chemically loaded runoff into streams has decreased.}, booktitle={Tropical Stream Ecology}, publisher={Elsevier}, author={Ramírez, Alonso and Pringle, Catherine M. and Wantzen, Karl M.}, editor={Dudgeon, DavidEditor}, year={2008}, pages={285–304} }
 @inbook{ramírez_2007, place={Jiutepec}, title={Biodiversidad de insectos acuáticos y el funcionamiento de los ecosistemas}, ISBN={978–968–5536–89–9}, booktitle={Entomología Acuática Mexicana: estado actual de conocimiento y aplicación.}, publisher={Instituto Mexicano de Tecnologia del Agua, Sociedad Mexicana de Entommologia}, author={Ramírez, A.}, editor={Gutierrez, Rodolfo Novelo and Alonso-Equia-Lis, Perla EdithEditors}, year={2007}, pages={39–49} }
 @article{bobeldyk_ramírez_2007, title={Leaf Breakdown in a Tropical Headwater Stream (Puerto Rico): The role of Freshwater Shrimps and Detritivorous Insects}, volume={22}, ISSN={0270-5060 2156-6941}, url={http://dx.doi.org/10.1080/02705060.2007.9664819}, DOI={10.1080/02705060.2007.9664819}, abstractNote={ABSTRACT Current ecological theory suggests that some organisms have overlapping roles, such that species loss may not disrupt ecosystem processes. In a tropical headwater stream, we hypothesized that the loss of major shredders (two species of shrimps) would decrease leaf breakdown rates. We tested our hypothesis by conducting a leaf breakdown experiment using Cecropia schreberiana leaves under the following treatments: (1) shrimp exclusion, (2) invertebrate exclusion (i.e., shrimp and insect), and (3) control, where all groups had access to leaves. Treatments were replicated in three pools in Quebrada Prieta, Luquillo Experimental Forest, Puerto Rico. Leaf packs were collected from each treatment on days 1, 3, 6, 13, 25, and 35. We found that breakdown rates between the control and shrimp exclusion treatments were not significantly different, whereas the total invertebrate exclusion treatment broke down the slowest. However, ash-free dry mass remaining at day 35 was significantly different among all treatments; control treatments (with shrimps) had the lowest mass remaining and the total invertebrate exclusion had the largest mass remaining. Our study demonstrated that even in a tropical island stream dominated by large populations of decapods, there was a significant degree of leaf breakdown by small, less abundant groups of detritivorous insects. In the long-term, however, shrimps may have a crucial role in the ecosystem process of leaf breakdown by maintaining faster rates of organic matter recycling.}, number={4}, journal={Journal of Freshwater Ecology}, publisher={Informa UK Limited}, author={Bobeldyk, Angela M. and Ramírez, Alonso}, year={2007}, month={Dec}, pages={581–590} }
 @article{ramírez_pringle_2006, title={Fast growth and turnover of chironomid assemblages in response to stream phosphorus levels in a tropical lowland landscape}, volume={51}, ISSN={0024-3590}, url={http://dx.doi.org/10.4319/lo.2006.51.1.0189}, DOI={10.4319/lo.2006.51.1.0189}, abstractNote={We studied the response of a dominant primary consumer, larval Chironomidae (Diptera), to phosphorus (via a microbial response) across eight detritus‐based streams spanning a gradient in soluble reactive phosphorus (range 0.2–8.6 µmol L−1) in a tropical landscape in Central America. We predicted that phosphorus would enhance food resources for larval Chironomidae and positively affect their production. A low‐phosphorus stream was also experimentally enriched to isolate effects of phosphorus from other solutes present. We found considerable variation in daily growth rates (range 0.09–0.57 mg mg−1 d−1) and annual biomass turnover rates (range 66–126 mg mg−1 yr−1) among streams, both positively related to phosphorus levels. Larval biomass was replaced every 5 d under low‐phosphorus and every 3.5 d under high‐phosphorus conditions (including the experimentally phosphorus‐enriched stream). Annual secondary production (range 793–9,346 mg m−2 yr−1) was variable among streams and negatively related to benthic organic matter, potentially because of low dissolved oxygen. The increase in larval biomass turnover along the phosphorus gradient indicates that a gradient of increasing energy flow exists from detrital‐based resources (e.g., fungi) to primary consumers. Larval chironomids matured more rapidly under high phosphorus conditions; this strategy results in (1) similar larval biomass among streams and (2) a potential gradient of increasing energy flow from primary consumers to upper trophic levels as phosphorus increases. Nutrientenhanced turnover rate of primary consumers can occur without increases in secondary production in stream ecosystems.}, number={1}, journal={Limnology and Oceanography}, publisher={Wiley}, author={Ramírez, Alonso and Pringle, Catherine M.}, year={2006}, month={Jan}, pages={189–196} }
 @article{wantzen_ramírez_winemiller_2006, title={New vistas in Neotropical stream ecology—Preface}, volume={25}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.1899/0887-3593(2006)25[61:nvinse]2.0.co;2}, DOI={10.1899/0887-3593(2006)25[61:nvinse]2.0.co;2}, abstractNote={Most of our current models for stream nutrient dynamics, decomposition, and regulation of community structure have been derived from extensive and detailed research on lotic systems in the temperate zone. We have scarcely researched even a small fraction of the extensive aquatic ecosystems in the tropics. The vast Neotropical region contains the greatest concentration of biodiversity (species) on planet Earth. Streams and rivers of tropical South America, Central America, and the Caribbean Islands encompass varied landscapes and biogeographic regions. Most streams in South America are part of large drainage basins, the largest being the Amazon, Parana ´, and Orinoco. Streams draining Central America and the Caribbean islands have small drainage basins, generally steep gradients, and close proximity to the ocean. Regional environmental heterogeneity in the tropics is particularly influenced by patterns of precipitation (seasonal vs aseasonal, mesic vs arid) and soils/geology (e.g., acidic blackwaters vs neutral whitewaters). Neotropical streams may be nearly as environmentally diverse as the rich faunas and floras that they support.}, number={1}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Wantzen, Karl M. and Ramírez, Alonso and Winemiller, Kirk O.}, year={2006}, month={Mar}, pages={61–65} }
 @article{triska_pringle_duff_avanzino_ramirez_ardon_jackman_2006, title={Soluble Reactive Phosphorus Transport and Retention in Tropical, Rainforest Streams Draining a Volcanic and Geothermally Active Landscape in Costa Rica. : Long-Term Concentration Patterns, Pore Water Environment and Response to ENSO Events}, volume={81}, ISSN={0168-2563 1573-515X}, url={http://dx.doi.org/10.1007/s10533-006-9026-6}, DOI={10.1007/s10533-006-9026-6}, number={2}, journal={Biogeochemistry}, publisher={Springer Science and Business Media LLC}, author={Triska, Frank J. and Pringle, Catherine M. and Duff, John H. and Avanzino, Ronald J. and Ramirez, Alonso and Ardon, Marcelo and Jackman, Alan P.}, year={2006}, month={Jun}, pages={131–143} }
 @article{ramírez_pringle_douglas_2006, title={Temporal and spatial patterns in stream physicochemistry and insect assemblages in tropical lowland streams}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33645656031&partnerID=MN8TOARS}, DOI={10.1899/0887-3593(2006)25[108:TASPIS]2.0.CO;2}, abstractNote={Abstract Stream physicochemistry and insect assemblages were studied in lowland tropical streams in Costa Rica to determine physicochemical variables explaining temporal and spatial variations in insect density and biomass. Streams drained a tropical wet forest landscape and had similar geomorphology, but differed in their water chemistry because of differential inputs of solute-rich (i.e., P, Cl–, and Mg) geothermally modified groundwater. We hypothesized that, within a stream, physical factors, such as discharge, would result in temporal variation in insect assemblages, whereas interstream differences in solute composition would result in differences in insect assemblages among streams. Insect density, biomass, richness, and stream physicochemistry were measured monthly for 1 y in 6 streams. Insect samples were collected with a core sampler in runs where leaf litter overlying fine sediments was the main substrate. Streams with high inputs of geothermally modified groundwater had high conductivity and high concentrations of soluble reactive P (SRP). Annual temporal patterns in stream physicochemistry were related either to rainfall, with subsequent changes in discharge, or to the % geothermally modified groundwater entering streams. Streamwater pH decreased throughout the year, and unbuffered, nongeothermally modified streams changed from near neutral (pH >6) to near acidic (pH <4.5). In all streams, insect density and biomass were highest during the dry season and lowest during the wet season. Insect density and biomass were related positively to pH and to the number of days since the last storm. Insect taxonomic composition was similar among streams. Moreover, interstream variation in insect assemblages was small, and insect density and biomass were not related to any of the measured physicochemical variables, including SRP, which ranged from <5 to 267 μg/L. Overall, the physicochemical characteristics of the study streams were related mainly to geothermally modified groundwater inputs and seasonal patterns in rainfall. Streams with geothermally modified groundwater inputs were better buffered against pH changes than the other streams. Insect assemblages reflected fluctuations in stream physicochemistry during the year and were associated with 2 main factors: floods and pH. Physicochemical characteristics were very different among streams, but insect assemblages were not related to them. We hypothesize that the heterogeneous nature of benthic substrata in the streams resulted in high variation in density and biomass of insects, potentially obscuring differences in insect assemblages among streams.}, number={1}, journal={Journal of North American Benthological Society}, author={Ramírez, A. and Pringle, C.M. and Douglas, M.}, year={2006}, pages={108–125} }
 @article{ramirez_hernandez-cruz_2004, title={Aquatic Insect Assemblages in Shrimp-dominated Tropical Streams, Puerto Rico}, volume={36}, ISSN={0006-3606 1744-7429}, url={http://dx.doi.org/10.1111/j.1744-7429.2004.tb00317.x}, DOI={10.1111/j.1744-7429.2004.tb00317.x}, abstractNote={ABSTRACTWe examined the effects of shrimp on insects in Puerto Rico by assessing insect assemblages in streams relative to varying shrimp densities and also by manipulating shrimp presence. Insect assemblages were typical of tropical island streams and insects were found in all stream habitats. Shrimp impacted insects directly via predation and competition and indirectly through removing particles from the water column. Variation in shrimp distribution is likely to be an important factor determining insect‐assemblage structure in tropical streams.}, number={2}, journal={Biotropica}, publisher={Wiley}, author={Ramirez, Alonso and Hernandez-Cruz, Luz Raquel}, year={2004}, month={Jun}, pages={259–266} }
 @article{ramírez_pringle_2004, title={Do macroconsumers affect insect responses to a natural stream phosphorus gradient?}, volume={515}, ISSN={0018-8158}, url={http://dx.doi.org/10.1023/b:hydr.0000027298.65920.96}, DOI={10.1023/b:hydr.0000027298.65920.96}, number={1-3}, journal={Hydrobiologia}, publisher={Springer Science and Business Media LLC}, author={Ramírez, A. and Pringle, Catherine M.}, year={2004}, month={Mar}, pages={235–246} }
 @article{ramírez_2004, title={Ecological Research and the Costa Rican Park System}, volume={14}, ISSN={1051-0761}, url={http://dx.doi.org/10.1890/03-5086}, DOI={10.1890/03-5086}, abstractNote={Ecological ApplicationsVolume 14, Issue 1 p. 25-27 Forum ECOLOGICAL RESEARCH AND THE COSTA RICAN PARK SYSTEM Alonso RamÍrez, Alonso RamÍrez Institute for Tropical Ecosystem Studies, University of Puerto Rico, P.O. Box 23341, San Juan, Puerto Rico 00931-3341 E-mail: aramirez@sunites.upr.clu.eduSearch for more papers by this author Alonso RamÍrez, Alonso RamÍrez Institute for Tropical Ecosystem Studies, University of Puerto Rico, P.O. Box 23341, San Juan, Puerto Rico 00931-3341 E-mail: aramirez@sunites.upr.clu.eduSearch for more papers by this author First published: 01 January 2004 https://doi.org/10.1890/03-5086Citations: 2 Corresponding Editor: J. S. Baron Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume14, Issue1January 2004Pages 25-27 RelatedInformation}, number={1}, journal={Ecological Applications}, publisher={Wiley}, author={RamÍrez, Alonso}, year={2004}, month={Jan}, pages={25–27} }
 @article{ramirez_pringle_molina_2003, title={Effects of stream phosphorus levels on microbial respiration}, volume={48}, ISSN={0046-5070 1365-2427}, url={http://dx.doi.org/10.1046/j.1365-2427.2003.00973.x}, DOI={10.1046/j.1365-2427.2003.00973.x}, abstractNote={SUMMARY 1. We examined microbial respiration among streams in lowland Costa Rica comprising a natural phosphorus gradient (5–350 μg SRP L−1) resulting from variable inputs of solute‐rich (e.g. P, SO4 and Cl) groundwater.}, number={1}, journal={Freshwater Biology}, publisher={Wiley}, author={Ramirez, Alonso and Pringle, Catherine M. and Molina, Luisenrique}, year={2003}, month={Jan}, pages={88–97} }
 @article{rosemond_pringle_ramírez_paul_meyer_2002, title={Landscape variation in phosphorus concentration and effects on detritus-based tropical streams}, volume={47}, ISSN={0024-3590}, url={http://dx.doi.org/10.4319/lo.2002.47.1.0278}, DOI={10.4319/lo.2002.47.1.0278}, abstractNote={Landscape‐scale variation in streamwater phosphorus (P) concentration can affect aquatic food webs. Such variation occurs naturally in streams at La Selva Biological Station in Costa Rica due to spatially variable inputs of geothermally modified groundwater. We examined effects of this gradient on detrital food web components at 16 stream sites. The Michaelis‐Menten model provided a good fit of the relationship between soluble reactive phosphorus (SRP) and leaf decay rate, fungal biomass, and invertebrate biomass, indicating that these variables were controlled by P concentration and that half‐saturation constants were relatively low (7—13 µg L−21 SRP). In a subsequent short‐term (3 week) whole‐stream P enrichment study, we found no effect of P addition on leaf decay rate or on biomass or density of invertebrates. However, laboratory tests of P, N, and Ca concentrations on mass loss of leaves showed detectable stimulation by both N and P after 3 weeks. A fourth study assessed the relative contribution of invertebrate consumption versus P concentration in determining decay rates among streams. The majority of variation was due to P concentration (71%), compared to effects of invertebrates (3%) or invertebrate × P interactions (14%). Overall, we found that a landscape‐scale natural gradient in P concentration influenced decay rates of organic matter and biomass of consumers, providing evidence that benthic detrital food webs can be limited from the bottom up by nutrients. Microbial processes appeared to be most important in driving differences in organic matter decay among sites, but invertebrates also contributed to elevated decay rates at high‐P sites.}, number={1}, journal={Limnology and Oceanography}, publisher={Wiley}, author={Rosemond, Amy D. and Pringle, Catherine M. and Ramírez, Alonso and Paul, Michael J. and Meyer, Judy L.}, year={2002}, month={Jan}, pages={278–289} }
 @article{rosemond_pringle_ramírez_paul_2001, title={A Test of Top-Down and Bottom-up Control in a Detritus-based food web}, volume={82}, ISSN={0012-9658}, url={http://dx.doi.org/10.1890/0012-9658(2001)082[2279:atotda]2.0.co;2}, DOI={10.1890/0012-9658(2001)082[2279:atotda]2.0.co;2}, abstractNote={In food webs based on primary production, biomass of organisms within trophic levels can be simultaneously controlled by resources (bottom-up) and consumers (top-down). In contrast, very little is known about top-down and bottom-up control in detritus-based food webs. Here, we tested whether exclusion of macroconsumers (fishes and shrimps) and/or phosphorus (P) addition affected insect detritivore biomass and decay rate and quality of leaf detritus in a tropical stream. Four treatments were established in a third-order stream in Costa Rica: (1) macroconsumers present, ambient P; (2) macrocon- sumers excluded, ambient P; (3) macroconsumers present, P added; (4) macroconsumers excluded, P added. Biomass of insect larvae inhabiting leaf packs and mass loss of leaves were measured after 7 and 10 d in situ. After 10 d, biomass and density of insect larvae increased as a result of both P addition and exclusion of macroconsumers. Chironomids (Diptera, Chironominae) were the dominant detritivores in leaf packs, comprising 51-80% of total invertebrate biomass and were responsible for the observed treatment effects. Mass loss rates of leaf packs were accelerated by the presence of macroconsumers but not by P addition. Positive effects of P on insects presumably occurred through increased microbial carbon relative to leaf carbon. However, percentage nitrogen (N), C:N, and fungal biomass of leaves were not affected by either experimental treatment. Laboratory growth studies corroborated positive effects of P on chironomids: growth rates were higher in high-P treatments (high-P stream water and low-P stream water with P added) vs. low-P stream water. However, no differences in the in situ growth rates were observed between a high- and a low-P stream. The relative importance of top-down and bottom-up effects was evaluated using several indices. Loss rates of organic matter were affected more by top-down effects of macro- consumers than by bottom-up effects of P. Macroconsumers had negative effects on two trophic levels, contrary to food-web theory predicting alternating negative and positive effects. Positive bottom-up effects of P on insect biomass were greater than negative top- down effects of macroconsumers. In addition, P effects on invertebrates were similar in direction but greater in magnitude than previously published effects of nutrients on con- sumers in food webs based on primary producers. These results suggest that the impacts of nutrient enrichment on detritivores may be as great or greater than those previously observed on herbivores.}, number={8}, journal={Ecology}, publisher={Wiley}, author={Rosemond, Amy D. and Pringle, Catherine M. and Ramírez, Alonso and Paul, Michael J.}, year={2001}, month={Aug}, pages={2279–2293} }
 @article{ramírez_pringle_2001, title={Spatial and temporal patterns of invertebrate drift in streams draining a Neotropical landscape}, volume={46}, ISSN={0046-5070 1365-2427}, url={http://dx.doi.org/10.1111/j.1365-2427.2001.00636.x}, DOI={10.1111/j.1365-2427.2001.00636.x}, abstractNote={1. Invertebrate drift in streams draining a tropical landscape in Costa Rica was studied to assess differences in assemblage composition above and below a major gradient break in geomorphic landform and to assess temporal patterns of drift in lowland reaches below the gradient break. The gradient break (∼50 m a.s.l.) is the point at which the foothills of the Costa Rican Cordillera Central (piedmont) merge with the Caribbean coastal plain (lowlands). 
2. Spatial patterns were assessed along two streams by sampling drift over 24 h once a month for 3 months in both the piedmont (90 m a.s.l.) and lowlands (30 m a.s.l.). Temporal patterns of drift were assessed through monthly diel sampling of three lowland sites over 8–10 months, encompassing both ‘dry’ (<400 mm precipitation per month, November to May) and wet (July to October) seasons. 
3. Drift composition was insect dominated in piedmont sites and larval shrimp dominated in the lowlands. Percent similarity of assemblages between piedmont and lowland sites was low (range 26–43%) because of high larval shrimp densities in lowland versus piedmont sites. 
4. Drift densities were higher during night than day, with peaks at sunset on all dates and at all sites. Diel patterns in drift agree with previous observations for the study area and support the ‘risk of predation’ hypothesis. 
5. Analysis of monthly patterns in lowland sites showed high variability in drift densities; however, all major taxa were found every month. Overall, there was a trend for high invertebrate densities during the ‘dry’ season, but these trends were not significant. 
6. Observed changes in drift composition support the concept of river zonation, which predicts a change in community composition along the stream continuum due to geomorphic features. Drift at lowland sites below the gradient break was dominated by shrimps, which are linked to marine environments via their migratory behaviour.}, number={1}, journal={Freshwater Biology}, publisher={Wiley}, author={Ramírez, Alonso and Pringle, Catherine M.}, year={2001}, month={Jan}, pages={47–62} }
 @inbook{ramírez_2000, place={New York}, title={Dragonflies and damselflies of Costa Rican Cloud Forests}, booktitle={Monteverde: Ecology and Conservation of a Tropical Cloud Forest}, publisher={Oxford University Press}, author={Ramírez, A.}, editor={Nadkarni, N. and Wheelwright, N.T.Editors}, year={2000}, pages={97} }
 @article{ramírez_paulson_esquivel_2000, title={Odonata of Costa Rica: Diversity and checklist of species}, volume={48}, number={1}, journal={Revista de Biología Tropical}, author={Ramírez, A. and Paulson, D.R. and Esquivel, C.}, year={2000}, pages={245–252} }
 @article{ramírez_novelo-gutiérrez_1999, title={The Neotropical Dragonfly Genus Macrothemis: New Larval Descriptions and an Evaluation of Its Generic Status Based on Larval Stages (Odonata:Libellulidae)}, volume={18}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.2307/1468009}, DOI={10.2307/1468009}, abstractNote={The larvae of Macrothemis aurimaculata and M. inequiunguis are described and illustrated. A redescription of M. celeno is also provided. Macrothemis aurimaculata can be separated from other species in the genus because it has reduced or vestigial dorsal protuberances on abdominal segments VII-IX. Macrothemis inequiunguis can be differentiated by the presence of 7 setae on the labial palp, in contrast to ≤6 in other species. Both species inhabit streams in areas with slow-moving water. Macrothemis celeno closely resembles M. inacuta and M. pseudimitans. Some features to separate larvae of Macrothemis from its close relative Brechmorhoga are given. A key for identification of all the described larvae of Macrothemis is provided.}, number={1}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Ramírez, Alonso and Novelo-Gutiérrez, Rodolfo}, year={1999}, month={Mar}, pages={67–73} }
 @article{ramírez_paaby_pringle_agüero_1998, title={Effect of habitat type on benthic macroinvertebrates in two tropical lowland streams, Costa Rica}, volume={46}, number={Suppl.6}, journal={Revista de Biología Tropical}, author={Ramírez, A. and Paaby, P. and Pringle, C.M. and Agüero, G.}, year={1998}, pages={201–213} }
 @article{ramírez_pringle_1998, title={Invertebrate drift and benthic community dynamics in a lowland neotropical stream, Costa Rica}, volume={386}, ISSN={0018-8158}, url={http://dx.doi.org/10.1023/a:1003409927131}, DOI={10.1023/a:1003409927131}, number={1/3}, journal={Hydrobiologia}, publisher={Springer Science and Business Media LLC}, author={Ramírez, Alonso and Pringle, Catherine M.}, year={1998}, pages={19–26} }
 @article{rosemond_pringle_ramírez_1998, title={Macroconsumer effects on insect detritivores and detritus processing in a tropical stream}, volume={39}, ISSN={0046-5070 1365-2427}, url={http://dx.doi.org/10.1046/j.1365-2427.1998.00301.x}, DOI={10.1046/j.1365-2427.1998.00301.x}, abstractNote={1. Few studies have assessed the effects of macroconsumers, such as fishes and shrimps, on detritus and detritivores.}, number={3}, journal={Freshwater Biology}, publisher={Wiley}, author={Rosemond, Amy D. and Pringle, Catherine M. and Ramírez, Alonso}, year={1998}, month={May}, pages={515–523} }
 @article{ramírez_pringle_1998, title={Structure and Production of a Benthic Insect Assemblage in a Neotropical Stream}, volume={17}, ISSN={0887-3593 1937-237X}, url={http://dx.doi.org/10.2307/1468365}, DOI={10.2307/1468365}, abstractNote={The structure and production of a benthic insect assemblage were assessed over a 12-mo period in a neotropical stream draining the Caribbean slope of Costa Rica. Two stream habitats, riffles and pools, were sampled monthly. Benthic assemblage composition was similar to that reported for other areas in Central America and was dominated by the orders Ephemeroptera (Tricorythodes, Leptohyphes, Thraulodes, Baetis?), Coleoptera (Elmidae), and Diptera (mainly Chironomidae). Collector-gatherers were the dominant functional-feeding group and very few shredders were found. Annual habitat-weighted secondary production was highest for Tricorythodes (87.07 mg ash-free dry mass [AFDM] m<sup>-2</sup> y<sup>-1</sup>) and Chironomidae (74.47 mg AFDM m<sup>-2</sup> y<sup>-1</sup>). Total habitat-weighted secondary production was 363.65 mg AFDM m<sup>-2</sup> y<sup>-1</sup>. Riffles supported the highest abundance, biomass, and secondary production of benthic insects. This study provides the 1st estimates of secondary production for a neotropical stream. Abundance, biomass, and secondary production in the study stream were low in comparison to results obtained in subtropical and temperate regions. However, annual production to biomass (P/B) ratios were high (range 5-103), indicating rapid population turnover. Monthly assessment of assemblage structure showed that benthic abundance increased with the number of days since the last large rainstorm (>50 mm/24 h). In addition, habitat-weighted abundance was negatively correlated with stream discharge. The abundance of macroconsumers (e.g., fishes and benthic shrimps) that potentially reduce food resources and prey upon insects might in part be responsible for the low abundance, production, and proportion of insect shredders in the study stream. Results suggest that other organisms (i.e., macroconsumers, microbes) are filling the functional roles that are normally assumed by benthic insects in temperate regions. Therefore, energy is potentially flowing through pathways other than insects from primary producers and detritus to upper trophic levels. In addition, precipitation and subsequent high discharge are major factors determining the structure of benthic communities in the study stream. Our results support the hypothesis that the structure and production of the benthic insect assemblage in this neotropical stream are the result of interactions between the physical environment (e.g., discharge and habitat type) and macroconsumers.}, number={4}, journal={Journal of the North American Benthological Society}, publisher={University of Chicago Press}, author={Ramírez, Alonso and Pringle, Catherine M.}, year={1998}, month={Dec}, pages={443–463} }
 @article{paaby_ramírez_pringle_1998, title={The benthic macroinvertebrate community in Caribbean Costa Rican streams and the effect of sampling methods}, volume={46}, number={Suppl. 6}, journal={Revista de Biología Tropical}, author={Paaby, P. and Ramírez, A. and Pringle, C.M.}, year={1998}, pages={185–199} }
 @article{novelo-gutierrez_ramirez_1998, title={The larva of Macrothemisinacuta (Odonata: Libellulidae)}, volume={109}, number={5}, journal={Entomological News}, author={Novelo-Gutierrez, Rodolfo and Ramirez, Alonso}, year={1998}, pages={301–306} }
 @article{pringle_ramírez_1998, title={Use of both benthic and drift sampling techniques to assess tropical stream invertebrate communities along an altitudinal gradient, Costa Rica}, volume={39}, ISSN={0046-5070 1365-2427}, url={http://dx.doi.org/10.1046/j.1365-2427.1998.00311.x}, DOI={10.1046/j.1365-2427.1998.00311.x}, abstractNote={1. Two sampling techniques were used to characterize invertebrate communities in eight, low‐order streams along an altitudinal gradient in Costa Rica that represents the last continuous tract of primary forest spanning such extremes in elevation (i.e. near sea level to 2900 m a.s.l.) along the Caribbean Slope of Central America. A standard Surber sampler was used to sample invertebrates on the stream bottom, and drift sampling nets were used to sample invertebrates drifting in the stream flow.}, number={2}, journal={Freshwater Biology}, publisher={Wiley}, author={Pringle, Catherine M. and Ramírez, Alonso}, year={1998}, month={Mar}, pages={359–373} }
 @article{ramírez_1997, title={Description and natural history of the Costa Rican Odonata larvae. V: Megaloprepus caerulatus (Drury, 1782) (Zygoptera, Pseudostigmatidae).}, volume={26}, number={1}, journal={Odonatologica}, author={Ramírez, A.}, year={1997}, pages={75–81} }
 @article{ramírez_1997, title={Lista de especies costarricenses del orden Odonata (Insecta) de las que se conoce la náyade}, volume={44/45}, number={3/1}, journal={Revista de Biología Tropical}, author={Ramírez, A.}, year={1997}, pages={225–232} }
 @article{ramírez_1996, title={Six new dragonfly larvae of the family Gomphidae in Costa Rica, with a key to the Central American genera (Anisoptera)}, volume={25}, number={2}, journal={Odonatologica}, author={Ramírez, A.}, year={1996}, pages={143–156} }
 @article{de la rosa_ramírez_1995, title={A note on phototactic behavior and on phoretic associations in larvae of Mecistogaster ornata Rambur from northern Costa Rica (Zygoptera: Pseudostigmatidae)}, volume={24}, number={2}, journal={Odonatologica}, author={De la Rosa, C and Ramírez, A.}, year={1995}, pages={219–224} }
 @article{ramírez_1995, title={Descripción e historia natural de las larvas de odonatos de Costa Rica. IV: Mecistogaster ornata (Rambur, 1842) (Zygoptera, Pseudostigmatidae).}, volume={3}, journal={Bulletin of American Odonatology}, author={Ramírez, A.}, year={1995}, pages={43–47} }
 @article{novelo-gutierrez_ramirez_1995, title={The larvae of Neocordulia batesi longipollex Calvert, 1909 (Odonata: Cordulidae)}, volume={103}, number={2}, journal={Journal of the New York Entomological Society}, author={Novelo-Gutierrez, R and Ramirez, A}, year={1995}, pages={180–184} }
 @article{ramírez_1994, title={Descripción e historia natural de las larvas de odonatos de Costa Rica. III: Gynacantha tibiata (Karsch, 1891) (Anisoptera Aeshnidae).}, volume={2}, journal={Bulletin of American Odonatology}, author={Ramírez, A.}, year={1994}, pages={9–14} }
 @article{ramírez_1994, title={Descripción e historia natural de las náyades de odonatos de Costa Rica. II: Archilestes neblina (Garrison,1982) (Odonata, Lestidae), con una clave para las especies del género en Costa Rica}, volume={90}, journal={Folia Entomológica Mexicana}, author={Ramírez, A.}, year={1994}, pages={9–16} }
 @article{ramírez-ulate_novelo-gutiérrez_1994, title={Megapodagrionidae (Odonata, Zygoptera) de Mexico y Centro América I: Las náyades de Philogenia carrillica, P. peacocki y P. terraba.}, volume={63}, DOI={10.21829/azm.1994.63631946}, abstractNote={So describen e ilustran las náyades de tres especies del género Philogenia que habitan en Costa Rica, proporcionando una clave para ¡a separación de éstas. De las 35 especies conocidas actualmente de este género, sólo la náyade de P. cassandra ha sido descrita, P. peacocki se asemeja a P. cainitica en Id proporción de los antenómeros y en la forma de la lígula; y a P. ferraba en el tipo de branquias; la primera de estas tres especies es la de mayor tamaño y la última la más pequeña. las náyades de Philogenia habitan debajo de las rocas, en arroyos con segmentos de fuerte corriente, y cubiertos por bosque primario.}, journal={Acta Zoológica Mexicana}, author={Ramírez-Ulate, A. and Novelo-Gutiérrez, R.}, year={1994}, pages={61–73} }
 @article{ramírez_1992, title={Description and natural history of Costa Rican dragonfly larvae. I: Heteragrion erythrogastrum Selys, 1886 (Zygoptera: Megapodagrionidae)}, volume={21}, number={3}, journal={Odonatologica}, author={Ramírez, A.}, year={1992}, pages={361–365} }