TY - JOUR TI - Using economic instruments to develop effective management of invasive species: insights from a bioeconomic model AU - McDermott, Shana M. AU - Irwin, Rebecca E. AU - Taylor, Brad W. T2 - Ecological Applications AB - Economic growth is recognized as an important factor associated with species invasions. Consequently, there is increasing need to develop solutions that combine economics and ecology to inform invasive species management. We developed a model combining economic, ecological, and sociological factors to assess the degree to which economic policies can be used to control invasive plants. Because invasive plants often spread across numerous properties, we explored whether property owners should manage invaders cooperatively as a group by incorporating the negative effects of invader spread in management decisions (collective management) or independently, whereby the negative effects of invasive plant spread are ignored (independent management). Our modeling approach used a dynamic optimization framework, and we applied the model to invader spread using Linaria vulgaris . Model simulations allowed us to determine the optimal management strategy based on net benefits for a range of invader densities. We found that optimal management strategies varied as a function of initial plant densities. At low densities, net benefits were high for both collective and independent management to eradicate the invader, suggesting the importance of early detection and eradication. At moderate densities, collective management led to faster and more frequent invader eradication compared to independent management. When we used a financial penalty to ensure that independent properties were managed collectively, we found that the penalty would be most feasible when levied on a property's perimeter boundary to control spread among properties. At the highest densities, the optimal management strategy was “do nothing” because the economic costs of removal were too high relative to the benefits of removal. Spatial variation in L. vulgaris densities resulted in different optimal management strategies for neighboring properties, making a formal economic policy to encourage invasive species removal critical. To accomplish the management and enforcement of these economic policies, we discuss modification of existing agencies and infrastructure. Finally, a sensitivity analysis revealed that lowering the economic cost of invader removal would strongly increase the probability of invader eradication. Taken together, our results provide quantitative insight into management decisions and economic policy instruments that can encourage invasive species removal across a social landscape. DA - 2013/7// PY - 2013/7// DO - 10.1890/12-0649.1 VL - 23 IS - 5 SP - 1086-1100 J2 - Ecological Applications LA - en OP - SN - 1051-0761 1939-5582 UR - http://dx.doi.org/10.1890/12-0649.1 DB - Crossref ER - TY - JOUR TI - Dose‐dependent effects of nectar alkaloids in a montane plant–pollinator community AU - Manson, Jessamyn S. AU - Cook, Daniel AU - Gardner, Dale R. AU - Irwin, Rebecca E. T2 - Journal of Ecology AB - Summary Although secondary metabolites are prevalent in floral nectar, the ecological consequences for pollinators and pollination remain relatively unexplored. While often deterrent to pollinators at high concentrations, secondary metabolite concentrations in nectar tend to be much lower than secondary metabolite concentrations in leaves and flowers; yet, they may still affect the maintenance of pollination mutualisms. Delphinium barbeyi , a common montane herb, contains norditerpene alkaloids in its nectar but at concentrations that are substantially lower than those found in its leaves or flowers. By manipulating nectar alkaloid concentrations in the field and laboratory, we assessed the degree to which varying concentrations of alkaloids in nectar influenced pollinator behaviour and activity and plant reproduction. In the field, nectar alkaloids significantly reduced both the number of flower visits and the time spent per flower by free‐flying bumblebee pollinators, but we only observed effects at alkaloid concentrations 50 times that of natural nectar. When we supplemented D . barbeyi nectar with alkaloids at concentrations almost 15 times that of natural nectar, we found no evidence for direct or pollinator‐mediated indirect effects on female plant reproduction. In the laboratory, the direct consumptive effects of nectar alkaloids on bumblebee pollinators were also concentration dependent. Bumblebees exhibited reduced mobility and vigour but only at alkaloid concentrations more than 25 times higher than those found in natural nectar. Synthesis . We found that nectar alkaloids have dose‐dependent effects on pollinator behaviour and activity. While concentrations of nectar alkaloids rivalling those found in leaves would negatively affect pollinator behaviour and pollination services, the natural concentrations of nectar alkaloids in D. barbeyi have no negative direct or pollinator‐mediated indirect effects on plant reproduction. These results provide experimental insight into the dose‐dependent ecological consequences of nectar secondary metabolites for pollinators and pollination, suggesting that low nectar alkaloid concentrations incurred no ecological costs for D . barbeyi . DA - 2013/8/29/ PY - 2013/8/29/ DO - 10.1111/1365-2745.12144 VL - 101 IS - 6 SP - 1604-1612 J2 - Journal of Ecology LA - en OP - SN - 0022-0477 1365-2745 UR - http://dx.doi.org/10.1111/1365-2745.12144 DB - Crossref ER - TY - JOUR TI - Norditerpene alkaloid concentrations in tissues and floral rewards of larkspurs and impacts on pollinators AU - Cook, Daniel AU - Manson, Jessamyn S. AU - Gardner, Dale R. AU - Welch, Kevin D. AU - Irwin, Rebecca E. T2 - Biochemical Systematics and Ecology AB - Plant secondary compounds mediate interactions with insects and other animals. The norditerpene alkaloids are significant secondary compounds in Delphinium (larkspur) species which are divided into two classes: the 7, 8-methylenedioxylycoctonine (MDL-type) and N-(methylsuccinimido) anthranoyllycoctonine (MSAL-type), and are known to be toxic to herbivorous insects and livestock. Alkaloid concentrations were measured in a whole plant context in vegetative and floral tissues as well as rewards (pollen and nectar) in Delphinium barbeyi and Delphinium nuttallianum. Alkaloid concentrations differed between vegetative tissues, floral tissues and floral rewards. Alkaloid concentrations in floral parts were consistent with optimal defense theory, with tissues more closely tied to plant fitness, such as fruits, being more heavily defended than foliage. However, alkaloid concentrations were significantly lower in nectar compared to other tissues. The norditerpene alkaloids influenced the activity of bumble bees, the dominant pollinator of larkspur, but the effects were concentration dependent. Alkaloids in nectar are found at concentrations that have no effect on bee activity; however, if alkaloid concentrations in nectar were similar to those in foliage bee activity would be reduced significantly. These results suggest that nectar with low alkaloid concentrations may be beneficial to plant fitness by limiting adverse effects on pollinator activity. DA - 2013/6// PY - 2013/6// DO - 10.1016/j.bse.2012.11.015 VL - 48 SP - 123-131 J2 - Biochemical Systematics and Ecology LA - en OP - SN - 0305-1978 UR - http://dx.doi.org/10.1016/j.bse.2012.11.015 DB - Crossref KW - Larkspur KW - Delphinium KW - Norditerpene alkaloids KW - Plant parts KW - Pollen KW - Nectar ER - TY - JOUR TI - Nutrient supply from fishes facilitates macroalgae and suppresses corals in a Caribbean coral reef ecosystem AU - Burkepile, Deron E. AU - Allgeier, Jacob E. AU - Shantz, Andrew A. AU - Pritchard, Catharine E. AU - Lemoine, Nathan P. AU - Bhatti, Laura H. AU - Layman, Craig A. T2 - Scientific Reports AB - On coral reefs, fishes can facilitate coral growth via nutrient excretion; however, as coral abundance declines, these nutrients may help facilitate increases in macroalgae. By combining surveys of reef communities with bioenergetics modeling, we showed that fish excretion supplied 25 times more nitrogen to forereefs in the Florida Keys, USA, than all other biotic and abiotic sources combined. One apparent result was a positive relationship between fish excretion and macroalgal cover on these reefs. Herbivore biomass also showed a negative relationship with macroalgal cover, suggesting strong interactions of top-down and bottom-up forcing. Nutrient supply by fishes also showed a negative correlation with juvenile coral density, likely mediated by competition between macroalgae and corals, suggesting that fish excretion may hinder coral recovery following large-scale coral loss. Thus, the impact of nutrient supply by fishes may be context-dependent and reinforce either coral-dominant or coral-depauperate reef communities depending on initial community states. DA - 2013/3/20/ PY - 2013/3/20/ DO - 10.1038/SREP01493 VL - 3 IS - 1 J2 - Sci Rep LA - en OP - SN - 2045-2322 UR - http://dx.doi.org/10.1038/SREP01493 DB - Crossref ER - TY - JOUR TI - The relative contribution of terrain, land cover, and vegetation structure indices to species distribution models AU - Wilson, John W. AU - Sexton, Joseph O. AU - Jobe, R. Todd AU - Haddad, Nick M. T2 - BIOLOGICAL CONSERVATION AB - Habitat assessments for biodiversity conservation are often complicated by the lack of detailed knowledge of a study species’ distribution. As an alternative to resource-intensive field-based methods to obtain such information, remotely sensed products can be utilized in species distribution models to infer a species’ distribution and ecological needs. Here we demonstrate how to arbitrate among a variety of remotely sensed predictor variables to estimate the distribution and ecological needs of an endangered butterfly species occurring mainly in inaccessible areas. We classified 19 continuous environmental predictor variables into three conceptually independent predictor classes, terrain, land cover, and vertical vegetation structure, and compared the accuracy of competing Maxent habitat models consisting of different combinations of each class. Each class contributed, though disproportionately, to our most reliable model that considered all 19 variables. We confirm that variables obtained from remote sensors can effectively estimate the distribution and ecological needs of a relatively unknown imperiled species occurring in inaccessible locations. Importantly, increasing the variety of predictor classes through multi-sensor fusion resulted in greater model accuracy than increasing the absolute number of predictor variables. DA - 2013/8// PY - 2013/8// DO - 10.1016/j.biocon.2013.04.021 VL - 164 SP - 170-176 SN - 1873-2917 KW - Butterflies KW - Distributions KW - Habitat assessment KW - Niche models KW - Remote sensing KW - Threatened species ER - TY - JOUR TI - Royal Manas National Park, Bhutan: a hot spot for wild felids AU - Tempa, Tshering AU - Hebblewhite, Mark AU - Mills, L. Scott AU - Wangchuk, Tshewang R. AU - Norbu, Nawang AU - Wangchuk, Tenzin AU - Nidup, Tshering AU - Dendup, Pema AU - Wangchuk, Dorji AU - Wangdi, Yeshi AU - Dorji, Tshering T2 - ORYX AB - Abstract The non-uniformity of the distribution of biodiversity makes allocation of the limited resources available for conservation of biodiversity a difficult task. Approaches such as biodiversity hotspot identification, endemic bird areas, crisis ecoregions, global 200 ecoregions, and the Last of the Wild are used by scientists and international conservation agencies to prioritize conservation efforts. As part of the biodiverse Eastern Himalayan region, Bhutan has been identified as a conservation priority area by all these different approaches, yet data validating these assessments are limited. To examine whether Bhutan is a biodiversity hot spot for a key taxonomic group, we conducted camera trapping in the lower foothills of Bhutan, in Royal Manas National Park, from November 2010 to February 2011. We recorded six species of wild felids of which five are listed on the IUCN Red List: tiger Panthera tigris , golden cat Pardofelis temminckii , marbled cat Pardofelis marmorata , leopard cat Prionailurus bengalensis , clouded leopard Neofelis nebulosa and common leopard Panthera pardus . Our study area of 74 km 2 has c. 16% of felid species, confirming Bhutan as a biodiversity hot spot for this group. DA - 2013/4// PY - 2013/4// DO - 10.1017/s0030605312001317 VL - 47 IS - 2 SP - 207-210 SN - 1365-3008 KW - Bhutan KW - biodiversity KW - camera trap KW - eastern Himalayas KW - felid diversity KW - hotspot KW - Manas KW - tiger ER - TY - JOUR TI - Predator effects on faunal community composition in shallow seagrass beds of The Bahamas AU - Hammerschlag-Peyer, Caroline M. AU - Allgeier, Jacob E. AU - Layman, Craig A. T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Much emphasis has been placed on predator effects that cascade through food webs. Such top-down effects seem to be most common in systems with relatively simple food chains, and rarer in species-rich systems where numerous weak interactions among species can buffer strong top-down effects. Seagrass ecosystems are typically species-rich and characterized by complex food webs, but evidence of top-down effects in these systems has been mixed. We examined effects of predatory fishes on the species richness, biomass, density, and composition of the epifaunal community in a shallow seagrass ecosystem of The Bahamas. We used exclusion experiments at two different spatial scales, and applied mesh sizes that excluded different-sized predator individuals. We found some evidence of species-level top-down effects (i.e., strong interactions within a subset of the community), driving higher biomass in at least one decapod mesopredator. In contrast, community-level predator effects were rather weak, with predator size and spatial scale of experiments displaying no detectable impact on the overall epifaunal community. Multiple factors may have contributed to these patterns, including high species richness, relatively shallow water depth, small-scale spatial variation in habitat features, and the size and abundance of predators. Because of the rapid global decline of seagrasses and their associated fauna, increased knowledge of predator effects on faunal communities of seagrass beds is critical for long-term conservation efforts. DA - 2013/8// PY - 2013/8// DO - 10.1016/j.jembe.2013.06.002 VL - 446 SP - 282-290 SN - 0022-0981 KW - Exclusion experiment KW - Food web KW - Interaction strength KW - Predator prey interaction KW - Top-down effect KW - Trophic cascade ER - TY - JOUR TI - Human-caused mortality influences spatial population dynamics: Pumas in landscapes with varying mortality risks AU - Newby, Jesse R. AU - Mills, L. Scott AU - Ruth, Toni K. AU - Pletscher, Daniel H. AU - Mitchell, Michael S. AU - Quigley, Howard B. AU - Murphy, Kerry M. AU - DeSimone, Rich T2 - BIOLOGICAL CONSERVATION AB - An understanding of how stressors affect dispersal attributes and the contribution of local populations to multi-population dynamics are of immediate value to basic and applied ecology. Puma (Puma concolor) populations are expected to be influenced by inter-population movements and susceptible to human-induced source–sink dynamics. Using long-term datasets we quantified the contribution of two puma populations to operationally define them as sources or sinks. The puma population in the Northern Greater Yellowstone Ecosystem (NGYE) was largely insulated from human-induced mortality by Yellowstone National Park. Pumas in the western Montana Garnet Mountain system were exposed to greater human-induced mortality, which changed over the study due to the closure of a 915 km2 area to hunting. The NGYE’s population growth depended on inter-population movements, as did its ability to act as a source to the larger region. The heavily hunted Garnet area was a sink with a declining population until the hunting closure, after which it became a source with positive intrinsic growth and a 16× increase in emigration. We also examined the spatial and temporal characteristics of individual dispersal attributes (emigration, dispersal distance, establishment success) of subadult pumas (N = 126). Human-caused mortality was found to negatively impact all three dispersal components. Our results demonstrate the influence of human-induced mortality on not only within population vital rates, but also inter-population vital rates, affecting the magnitude and mechanisms of local population’s contribution to the larger metapopulation. DA - 2013/3// PY - 2013/3// DO - 10.1016/j.biocon.2012.10.018 VL - 159 SP - 230-239 SN - 1873-2917 KW - Dispersal KW - Population contribution KW - Puma concolor KW - Source-sink KW - Spatially structured populations ER - TY - JOUR TI - Disproportionate predation on endemic marmots by invasive coyotes AU - Witczuk, Julia AU - Pagacz, Stanislaw AU - Mills, L. Scott T2 - JOURNAL OF MAMMALOGY AB - We investigated predation by normative coyotes (Canis latrans) on endemic Olympic marmots (Marmota olympus) in Olympic National Park, Washington, in 2005 and 2006. Although nearly the entire marmot range is protected within the park, declines and local extirpations of the species have been documented. Through analyses of carnivore scat across the range of the Olympic marmot we determined the distribution and relative density of coyotes and characterized the extent to which coyotes and native carnivores preyed on marmots. We used mitochondrial DNA analysis of scats to determine carnivore species, and microsatellite markers for individual coyote identification. Scat analysis indicated that invasive coyotes are widespread and the numerically dominant carnivore on sampled trails within the Olympic highlands—71% (301 of 426) of all scats verified to species arose from coyote. Out of all carnivore scats collected, 11.6% (111 of 958) contained marmot remains. For 85% of the samples with marmots, coyotes were confirmed as the predator. The remainder arose from bobcat (13%) and cougar (2%). Coyotes were the predominant marmot predator across all months and in most regions of the park. Twelve out of 13 coyote individuals identified with genetic markers preyed on marmots. Marmots ranked 5th in frequency of coyote diet items, after snowshoe hares (Lepus americanus), mountain beavers (Aplodontia rufa), voles, and cervids. Scat analysis indicated that in the Olympic Mountains, the coyote as an invasive generalist predator is subsidized by abundant multiple prey, and appears to be the primary terrestrial predator on the endemic Olympic marmot. We conclude that predation by coyotes on marmots is widespread and substantial across the marmot's species range, and therefore likely driving observed marmot declines and extinctions. DA - 2013/6// PY - 2013/6// DO - 10.1644/12-mamm-a-199.1 VL - 94 IS - 3 SP - 702-713 SN - 1545-1542 KW - bobcat KW - Canis latrans KW - decline KW - diet KW - food habits KW - Lynx rufus KW - Marmota olympus KW - Olympic marmot KW - Olympic National Park KW - scat analysis ER - TY - JOUR TI - Combined Effects of Energy Development and Disease on Greater Sage-Grouse AU - Taylor, Rebecca L. AU - Tack, Jason D. AU - Naugle, David E. AU - Mills, L. Scott T2 - PLOS ONE AB - Species of conservation concern are increasingly threatened by multiple, anthropogenic stressors which are outside their evolutionary experience. Greater sage-grouse are highly susceptible to the impacts of two such stressors: oil and gas (energy) development and West Nile virus (WNv). However, the combined effects of these stressors and their potential interactions have not been quantified. We used lek (breeding ground) counts across a landscape encompassing extensive local and regional variation in the intensity of energy development to quantify the effects of energy development on lek counts, in years with widespread WNv outbreaks and in years without widespread outbreaks. We then predicted the effects of well density and WNv outbreak years on sage-grouse in northeast Wyoming. Absent an outbreak year, drilling an undeveloped landscape to a high permitting level (3.1 wells/km²) resulted in a 61% reduction in the total number of males counted in northeast Wyoming (total count). This was similar in magnitude to the 55% total count reduction that resulted from an outbreak year alone. However, energy-associated reductions in the total count resulted from a decrease in the mean count at active leks, whereas outbreak-associated reductions resulted from a near doubling of the lek inactivity rate (proportion of leks with a last count = 0). Lek inactivity quadrupled when 3.1 wells/km² was combined with an outbreak year, compared to no energy development and no outbreak. Conservation measures should maintain sagebrush landscapes large and intact enough so that leks are not chronically reduced in size due to energy development, and therefore vulnerable to becoming inactive due to additional stressors. DA - 2013/8/5/ PY - 2013/8/5/ DO - 10.1371/journal.pone.0071256 VL - 8 IS - 8 SP - SN - 1932-6203 ER - TY - JOUR TI - Camouflage mismatch in seasonal coat color due to decreased snow duration AU - Mills, L. Scott AU - Zimova, Marketa AU - Oyler, Jared AU - Running, Steven AU - Abatzoglou, John T. AU - Lukacs, Paul M. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Most examples of seasonal mismatches in phenology span multiple trophic levels, with timing of animal reproduction, hibernation, or migration becoming detached from peak food supply. The consequences of such mismatches are difficult to link to specific future climate change scenarios because the responses across trophic levels have complex underlying climate drivers often confounded by other stressors. In contrast, seasonal coat color polyphenism creating camouflage against snow is a direct and potentially severe type of seasonal mismatch if crypsis becomes compromised by the animal being white when snow is absent. It is unknown whether plasticity in the initiation or rate of coat color change will be able to reduce mismatch between the seasonal coat color and an increasingly snow-free background. We find that natural populations of snowshoe hares exposed to 3 y of widely varying snowpack have plasticity in the rate of the spring white-to-brown molt, but not in either the initiation dates of color change or the rate of the fall brown-to-white molt. Using an ensemble of locally downscaled climate projections, we also show that annual average duration of snowpack is forecast to decrease by 29-35 d by midcentury and 40-69 d by the end of the century. Without evolution in coat color phenology, the reduced snow duration will increase the number of days that white hares will be mismatched on a snowless background by four- to eightfold by the end of the century. This novel and visually compelling climate change-induced stressor likely applies to >9 widely distributed mammals with seasonal coat color. DA - 2013/4/30/ PY - 2013/4/30/ DO - 10.1073/pnas.1222724110 VL - 110 IS - 18 SP - 7360-7365 SN - 0027-8424 KW - phenotypic plasticity KW - snow downscaling KW - rhythm KW - phenological mismatch KW - threshold trait ER - TY - CHAP TI - Wildlife population dynamics AU - Mills, L. S. AU - Johnson, H. E. T2 - Wildlife management: Contemporary principles and practices PY - 2013/// PB - Baltimore : John Hopkins University Press SN - 9781421409863 ER - TY - BOOK TI - Conservation of wildlife populations : demography, genetics, and management (2nd Ed.) AU - Mills, L. Scott DA - 2013/// PY - 2013/// PB - Chichester, West Sussex ; Hoboken, NJ : Wiley-Blackwell SN - 9780470671504 ER - TY - JOUR TI - How invader traits interact with resident communities and resource availability to determine invasion success AU - Mata, T. M. AU - Haddad, N. M. AU - Holyoak, M. T2 - OIKOS AB - Competition for limited resources is considered a key factor controlling invasion success. Resource availability can be viewed in either the long or short‐term. Long‐term availability depends on the baseline nutrient availability in the ecosystem and how those conditions shape the ecological community. Short‐term resource availability fluctuates with disturbances that alter nutrient availability and/or the density and composition of the ecological community. We investigated how species’ traits interact with short and long‐term resource availability to determine the outcome of invasions. We manipulated long‐term baseline resource availability, disturbance intensity, disturbance frequency, and propagule pressure in a fully factorial design using protist microcosms. Our results show that short and long‐term resource availability and the direct mortality from disturbance interact with the traits of resident community members and traits of invaders to determine community invasibility. While competitively dominant invaders with slow growth rates may suffer rather than benefit from short‐term resource fluctuations, quickly growing but competitively inferior invaders can benefit from both the resource fluctuations and the heterogeneity in community composition created by disturbance. Our findings empirically synthesize two explanations for invasion success, namely short‐term resource fluctuations and long‐term resource availability, and highlight the importance of considering traits of invaders and residents, such as growth rate and competitive ability, in the context of productivity and disturbance gradients. This species’ traits approach could resolve idiosyncratic results from natural systems undergoing disturbance and invasion that do not follow patterns predicted by traditional invasion frameworks. DA - 2013/1// PY - 2013/1// DO - 10.1111/j.1600-0706.2012.20401.x VL - 122 IS - 1 SP - 149-160 SN - 1600-0706 ER -