@article{maurer_seminoff_reiskind_stapleton_2024, title={Diverse migratory strategies for a hawksbill sea turtle population}, volume={1}, ISSN={["1099-0755"]}, url={http://dx.doi.org/10.1002/aqc.4080}, DOI={10.1002/aqc.4080}, abstractNote={

Outside of short, infrequent visits to reproductive habitats, sea turtle lifespans are largely spent in foraging areas. Supporting imperilled populations in an era of biodiversity declines and environmental change requires improvements in the understanding of foraging distributions, plus the migratory corridors that connect foraging and reproductive habitats.
This study evaluates the migratory strategies and foraging geography of hawksbill sea turtles (Eretmochelys imbricata) in the Western Atlantic. The post‐nesting migrations of 22 females were tracked via satellite telemetry from Long Island, Antigua, during 2016–2019, and a state‐space model was utilized to estimate true turtle locations from Argos satellite fixes. Model output was used to characterize migratory routes and home ranges occupied during non‐migratory inter‐nesting and foraging periods.
Hawksbill migrations (N = 19) resulted in displacements to foraging areas ranging 7–2300 km. Foraging geography varied considerably—whereas eight turtles remained in the immediate vicinity of Antigua and Barbuda (<30 km), there were also longer‐distance migrations (>470 km) to locations such as The Bahamas and Nicaragua. Inter‐nesting core home ranges (50% utilization distributions) ranged from 7 to 72 km2, while foraging core areas ranged from 7 to 46 km2.
These results add to evidence suggesting that, broadly, post‐nesting hawksbills forage in neritic habitats throughout the Wider Caribbean, including several high‐use areas. Short displacements to foraging habitats relatively nearby to nesting beaches appear to be the most common migratory behaviour, but individuals in a single population may exhibit various migratory strategies, resulting in basin‐wide connectivity between nesting and foraging sites. Given that a single individual or nesting population may inhabit several management jurisdictions, an idealized scenario for regional hawksbill conservation would entail data sharing between managers at linked nesting areas, foraging habitats and migratory corridors such that policies to protect key habitats and mitigate human impacts are designed and evaluated based on best‐available science.
}, journal={AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS}, author={Maurer, Andrew S. and Seminoff, Jeffrey A. and Reiskind, Martha O. Burford and Stapleton, Seth P.}, year={2024}, month={Jan} }
 @article{maurer_gross_stapleton_2022, title={Beached Sargassum alters sand thermal environments: Implications for incubating sea turtle eggs}, volume={546}, ISSN={["1879-1697"]}, DOI={10.1016/j.jembe.2021.151650}, abstractNote={Global environmental change has featured a rise in macroalgae blooms. These events generate immense amounts of biomass that can subsequently arrive on shorelines. Such a scenario has been playing out since 2011 in the tropical and subtropical Atlantic, where Sargassum spp. have been causing periodic ‘golden tides’ in coastal habitats. Here we describe impacts on sea turtle nesting ecology, with a focus on the below-ground thermal environment for incubating eggs. Sargassum may blanket the surface of beaches due to natural wave or wind energy and can be redistributed via anthropogenic beach cleaning. When it covers egg clutches, it may alter incubation temperatures and therefore affect both embryonic survival and primary sex ratios. To evaluate the thermal impacts of Sargassum, we measured sand temperatures with data loggers buried under Sargassum cover treatments on a beach in Antigua, West Indies. Our split-plot experiment also tested for effects from shade, season (summer versus autumn), and high rainfall events. We modeled temperatures with a mixed-effects model and, surprisingly, our most compelling finding suggested that Sargassum's effects on below-ground temperatures were contingent on season. Greater Sargassum cover was associated with a cooling effect in the summer but warming in the autumn. We assume that the model term for season integrates several climate-related factors that vary seasonally in the Eastern Caribbean and modulate Sargassum's impact, including windspeeds. Comparing estimated marginal means for the high-cover treatments versus the controls, Sargassum cover led to a 0.21 °C increase in the autumn and a 0.17 °C decrease in the summer; these thermal changes can significantly impact developmental outcomes for sea turtle embryos. Atlantic nesting beach managers should monitor this macroalgal phenomenon and can use these data to begin to infer impacts on sea turtle populations and develop potential management strategies.}, journal={JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY}, author={Maurer, Andrew S. and Gross, Kevin and Stapleton, Seth P.}, year={2022}, month={Jan} }
 @article{maurer_v. cove_siegal_lashley_2022, title={Urbanization affects the behavior of a predator-free ungulate in protected lands}, volume={222}, ISSN={["1872-6062"]}, DOI={10.1016/j.landurbplan.2022.104391}, abstractNote={Natural habitats have been converted to urban areas across the globe such that many landscapes now represent matrices of developed and protected lands. As urbanization continues to expand, associated pressures on wildlife will increase, including effects on animals in adjacent protected habitats. For prey species (e.g., ungulates), an understanding of the ecological impacts of urbanization is typically confounded by coincident effects from co-occurring predators. Yet, understanding how urbanization affects prey behaviors in the absence of predators is becoming increasingly relevant as many top predators face extirpation. We placed camera traps at varying distances from urban areas within protected areas in the Florida Keys, USA, to evaluate the influence of urbanization on the behavior of the key deer (Odocoileus virginianus clavium), an endangered species that has been without non-human mammalian predators for ∼ 4000 years. We predicted that as distance to urban areas decreased, key deer would use sites at the same rate, exhibit bigger group sizes, and shift activity patterns to be more nocturnal. Our results indicate that intensity of site use decreased with proximity to urban areas, potentially reflecting human avoidance. Group size increased closer to urban areas, consistent with other studies relating this behavior to anthropogenic subsidies and vigilance for humans. Activity patterns changed but did not become more nocturnal near urban areas as predicted by global analyses relating human disturbance to wildlife nocturnality. Our results have important implications for ungulate behavioral ecology and, taken together, suggest that influences on protected species from adjacent land uses are an important consideration when planning land use and designing protected areas.}, journal={LANDSCAPE AND URBAN PLANNING}, author={Maurer, Andrew S. and V. Cove, Michael and Siegal, Olivia M. and Lashley, Marcus A.}, year={2022}, month={Jun} }
 @article{maurer_seminoff_layman_stapleton_godfrey_reiskind_2021, title={Population Viability of Sea Turtles in the Context of Global Warming}, volume={71}, ISSN={["1525-3244"]}, DOI={10.1093/biosci/biab028}, abstractNote={
 Sea turtles present a model for the potential impacts of climate change on imperiled species, with projected warming generating concern about their persistence. Various sea turtle life-history traits are affected by temperature; most strikingly, warmer egg incubation temperatures cause female-biased sex ratios and higher embryo mortality. Predictions of sea turtle resilience to climate change are often focused on how resulting male limitation or reduced offspring production may affect populations. In the present article, by reviewing research on sea turtles, we provide an overview of how temperature impacts on incubating eggs may cascade through life history to ultimately affect population viability. We explore how sex-specific patterns in survival and breeding periodicity determine the differences among offspring, adult, and operational sex ratios. We then discuss the implications of skewed sex ratios for male-limited reproduction, consider the negative correlation between sex ratio skew and genetic diversity, and examine consequences for adaptive potential. Our synthesis underscores the importance of considering the effects of climate throughout the life history of any species. Lethal effects (e.g., embryo mortality) are relatively direct impacts, but sublethal effects at immature life-history stages may not alter population growth rates until cohorts reach reproductive maturity. This leaves a lag during which some species transition through several stages subject to distinct biological circumstances and climate impacts. These perspectives will help managers conceptualize the drivers of emergent population dynamics and identify existing knowledge gaps under different scenarios of predicted environmental change.}, number={8}, journal={BIOSCIENCE}, author={Maurer, Andrew S. and Seminoff, Jeffrey A. and Layman, Craig A. and Stapleton, Seth P. and Godfrey, Matthew H. and Reiskind, Martha O. Burford}, year={2021}, month={Aug}, pages={790–804} }
 @article{cove_maurer_2019, title={Home decorating by an endangered ecosystem engineer}, volume={17}, ISSN={["1540-9309"]}, DOI={10.1002/fee.2040}, abstractNote={The endangered Key Largo woodrat (Neotoma floridana smalli) is a packrat. Nights are spent making round trips between nests and distant foraging sites to gather sticks, seeds, and other decorative items to place inside or atop their nests. Interestingly, this stick-nest building behavior appears to be plastic (flexible). Surveys conducted as recently as 2008 suggested the behavior had largely disappeared, but “stick stacking” reappeared around the same time as recent establishment of supplemental nests (Cove et al. 2017) and predator removal efforts (eg domestic cats). We placed painted sticks with unique triplet color combinations in spatial arrays to quantify the distance woodrats travel for home decorating materials. Woodrats appeared to preferentially select these colorful sticks (left). We documented straight-line foraging distances as far as 54 m, despite the presence of unpainted sticks near the nest. It's a dangerous world for a rodent dragging cumbersome sticks; we observed several tailless woodrats (right), which likely had narrow escapes from predators. This strategy therefore poses an ecological puzzle – why transport inedible colorful sticks and ornaments like skulls (left, inset)? It doesn't follow the bowerbird model of sexual selection, wherein males beautify nests to attract mates, because it is primarily female woodrats that build elaborate nests. Because woodrats are exposing themselves to increased predation risk during travel and may be attracting predators to nests via stick stacking, we wonder if this is a maladaptive behavior in the presence of exotic predators. Given that the behavior appears plastic, though, why has it reappeared if it is maladaptive? Do the benefits of protective shelter in the nest interior outweigh travel-associated predation costs, now that exotic predators have been suppressed below some threshold? Is this an ecological catch-22, where stick-stacking behavior simultaneously protects the nest interior but increases predation risk outside?}, number={4}, journal={FRONTIERS IN ECOLOGY AND THE ENVIRONMENT}, author={Cove, Michael V. and Maurer, Andrew S.}, year={2019}, month={May}, pages={231–231} }
 @article{maurer_johnson_2017, title={Loggerhead Nesting in the Northern Gulf of Mexico: Importance of Beach Slope to Nest Site Selection in the Mississippi Barrier Islands}, volume={16}, ISSN={["1943-3956"]}, DOI={10.2744/ccb-1256.1}, abstractNote={Abstract Here we describe the effects of beach morphological features on loggerhead (Caretta caretta) nesting behavior on the barrier islands of the north-central Gulf of Mexico. Our results show that loggerhead crawl length decreases as beach slope increases, and our data comparing nest crawls (resulting in egg laying) versus false crawls (emergence onto the beach without laying eggs) suggest that beach slope and crawl length differ between the crawl types but elevation does not. We infer that loggerheads cue in to beach slope to reach a perceived elevation with reduced risk of inundation, crawling longer distances on flatter slopes compared with shorter distances on steep slopes, but that after this elevation is reached, other environmental variables may ultimately factor into the decision to lay eggs.}, number={2}, journal={CHELONIAN CONSERVATION AND BIOLOGY}, author={Maurer, Andrew S. and Johnson, Matthew W.}, year={2017}, month={Dec}, pages={250–254} }
 @article{cove_simons_gardner_maurer_o'connell_2016, title={Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys}, volume={25}, ISSN={1061-2971}, url={http://dx.doi.org/10.1111/rec.12418}, DOI={10.1111/rec.12418}, abstractNote={The Key Largo woodrat (Neotoma floridana smalli) and Key Largo cotton mouse (Peromyscus gossypinus allapaticola) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co‐occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free‐ranging domestic cat (Felis catus) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick‐stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.}, number={2}, journal={Restoration Ecology}, publisher={Wiley}, author={Cove, Michael V. and Simons, Theodore R. and Gardner, Beth and Maurer, Andrew S. and O'Connell, Allan F.}, year={2016}, month={Aug}, pages={253–260} }
 @article{maurer_de neef_stapleton_2015, title={Sargassum accumulation may spell trouble for nesting sea turtles}, volume={13}, DOI={10.1890/1540-9295-13.7.394}, abstractNote={Thigh-high mounds of sargassum seaweed line the northern section of a beach on Long Island, Antigua –an island in the West Indies – that hosts nesting hawksbill sea turtles (Eretmochelys imbricata) every summer. A meter offshore – although it is difficult to tell where the shore begins and the sea ends – the seaweed is crisp, even crunchy underfoot. We plod through it to skirt a mangrove tree during nightly patrols for nesting hawksbills, but the thick seaweed soup makes wading slow and difficult. The mass of seaweed varies with the prevailing winds and currents but often stretches over 10 m into the water. Closer to shore, it is a warm, fly-infested mush in various states of stinking decay. It collects on the beach to form a low but substantial wall, at times approaching 1 m in height and well over 2 m in width (Figure 1). And the sargassum keeps coming. Unfortunately, this image of sargassum is becoming widespread across much of the Caribbean region. Immense quantities of sargassum have been washing ashore on Long Island, around Antigua, and across the Caribbean in waves over the past 5 years. Sargassum, a genus of macroalgae that has garnered much research attention in recent years, has been dubbed the “floating rainforest” of the sea (Laffoley et al. 2011). The primary reason for this attention and the nickname lies in the middle of the North Atlantic Subtropical Gyre: the Sargasso Sea, where predominant ocean currents create a vortex that amasses huge quantities of the seaweed. This unique habitat is essential for a diverse array of fauna (Laffoley et al. 2011); for instance, open-ocean sargassum mats provide important nurseries for sea turtles such as loggerheads (Caretta caretta; Mansfield et al. 2014). But, over the past half-decade, sargassum has been proliferating in unprecedented quantities and is affecting areas far from the Sargasso Sea. Massive amounts have appeared on coasts from Florida to South America, even reaching western Africa. As a result, sargassum is generating substantial interest among the travel and tourism sectors, commercial enterprises seeking to harvest the seaweed, and conservation organizations (Smetacek and Zingone 2013). There is some speculation as to the source of all of this biomass, but evidence from a peak year in 2011 points to a possible origin off the coast of Brazil, north of the Amazon River mouth (Gower et al. 2013). This coastal influx begs the question: what does all this seaweed mean for the region's populations of nesting sea turtles? Although sargassum in the open sea is a critical nursery ground, how will coastal accumulation affect Caribbean nesting beaches? The wider Caribbean region hosts numerous nesting sites for six of the seven extant marine turtle species (Dow et al. 2007); globally, these six species are categorized from Vulnerable to Critically Endangered by the International Union for Conservation of Nature (IUCN 2015). The benefits of sargassum are largely recognized among members of the conservation community. As mentioned, oceanic sargassum is a key habitat for neonatal and juvenile sea turtles (Mansfield et al. 2014), and increased prevalence may improve prospects of survival for these age classes. When washed onto nesting beaches, seaweed may serve to stabilize against erosion. It also represents a mechanism for the transport of marine nutrients to terrestrial ecosystems (Polis and Hurd 1996), which further enhances stabilization by promoting the growth of sand-holding plants. These are important functions, given that healthy nesting beaches are critical components of population recovery efforts, and especially considering that only an estimated 1 in 1000 sea turtle eggs hatch and survive the decade or more required to reach maturity (Frazer 1986). Based on recent experiences at our study site on Long Island, Antigua, however, we suspect that sargassum may pose an emerging threat on some nesting beaches, where it can act as a barrier. Crescent-shaped Pasture Bay, the primary nesting beach on Long Island, is windward facing (in contrast to many other hawksbill beaches) and oriented north–northeast. This positioning makes it an ideal area for accrual of sand and a choice landing spot for female hawksbills seeking a nesting site. Unfortunately, the geography and the typical prevailing currents also mean it is a perfect sargassum trap. Nearly 90 individual hawksbills laid eggs at >310 nests on Long Island in 2014, with the majority deposited along the 650-m-long Pasture Bay. Such high nesting densities make every section of suitable habitat valuable, and over the past three decades, the northern portion of Pasture Bay has been among the sites most intensively used by hawksbills. During 2015, however, in those north stretches where massive amounts of sargassum have accumulated (~10% of Pasture Bay's shoreline), there has been virtually no nesting activity. We have recorded little nesting activity in sections with more variable presence of sargassum (an additional 10–15% of the Bay's coastline). These findings suggest that dense sargassum can hinder or altogether preclude access to preferred nesting locations, effectively shrinking the primary nesting beach by as much as 25%. If the sargassum persists, already high nesting densities will climb higher in those areas unaffected by sargassum, increasing the chances of nesting hawksbills digging into previously laid nests. Such destruction of in situ clutches has been observed here for more than a decade, even without the sargassum further concentrating nests. Impeded access to nesting sites is not the only potential problem for sea turtles. We hypothesize that seaweed that is pushed over incubating nests by waves on particularly narrow beaches (such as northern Pasture Bay) or by beach cleaners may create an anoxic and contaminated incubation environment when it decomposes, and may alter thermal conditions (our preliminary data suggest a cooling effect, which could result in the production of more male hatchlings since gender is temperature-dependent in this taxon). Hatchlings that successfully emerge from nests along sargassum-affected stretches of shoreline will face further obstructions both on land and at sea (Figure 2), and their use of wave direction to navigate during the initial offshore migration (Salmon and Lohmann 1989) may be compromised. These factors, in turn, may increase mortality through hyperthermia, exhaustion, drowning, and vulnerability to predation. Hatchlings, such as this neonatal hawksbill turtle that succumbed in the nearshore waters of eastern Antigua, may struggle through the dense mats of sargassum as they attempt to begin offshore migrations. Sea turtles face a multitude of threats, including harvesting, degradation of key foraging and nesting sites, and bycatch in the fisheries industries (Lutcavage et al. 1997; Brautigam and Eckert 2006). Although most threats are well understood, mass seaweed stranding is a new phenomenon, especially in the eastern Caribbean, and its direct impacts on sea turtle nesting remain largely unexplored. While sargassum may enhance beach stability, we do not view widespread coastal accumulation as an overwhelming ecological positive. Indeed, the direct consequences of sargassum accumulation on beaches may be a detriment to nesting sea turtles and their offspring in some areas. Sea turtles are ancient relics that have withstood the test of time, and their high reproductive output can buffer against the occasional poor nesting season. Nevertheless, new and sustained threats can have severe consequences for populations that are already imperiled. On Long Island, we have borne witness to a nearly threefold increase in nesting numbers since the inception of our monitoring program in 1987. This is encouraging news for a critically endangered species (Mortimer and Donnelly 2008). However, the altered nesting behavior we have observed and the postulated impacts of sargassum on nests and hatchlings are concerning. Unanswered questions about the current sargassum strandings make for an unpredictable future. Sargassum may wash out with storms, and the rafts of seaweed may cease to appear in nearshore waters, providing a respite to the region's beaches and sea turtles. Yet, any reprieve may be short-lived; some scientists suggest that sargassum influxes may reflect larger-scale climatic changes, so high concentrations of seaweed may be a new reality that the Caribbean region will have to contend with in the years to come. The Jumby Bay Hawksbill Project is generously supported by the Jumby Bay Island Company and is a member of the Wider Caribbean Sea Turtle Conservation Network. J Horrocks provided useful comments on an earlier version of this text. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.}, number={7}, journal={Frontiers in Ecology and the Environment}, author={Maurer, A. S. and De Neef, E. and Stapleton, S.}, year={2015}, pages={394–395} }