Department of Fish and Wildlife Conservation

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Browsing Department of Fish and Wildlife Conservation by Subject "11 Medical and Health Sciences"

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    Does a complex life cycle affect adaptation to environmental change? Genome-informed insights for characterizing selection across complex life cycle
    Albecker, Molly A.; Wilkins, Laetitia G. E.; Krueger-Hadfield, Stacy A.; Bashevkin, Samuel M.; Hahn, Matthew W.; Hare, Matthew P.; Kindsvater, Holly K.; Sewell, Mary A.; Lotterhos, Katie E.; Reitzel, Adam M. (Royal Society, 2021-12-08)
    Complex life cycles, in which discrete life stages of the same organism differ in form or function and often occupy different ecological niches, are common in nature. Because stages share the same genome, selective effects on one stage may have cascading consequences through the entire life cycle. Theoretical and empirical studies have not yet generated clear predictions about how life cycle complexity will influence patterns of adaptation in response to rapidly changing environments or tested theoretical predictions for fitness trade-offs (or lack thereof) across life stages. We discuss complex life cycle evolution and outline three hypotheses—ontogenetic decoupling, antagonistic ontogenetic pleiotropy and synergistic ontogenetic pleiotropy—for how selection may operate on organisms with complex life cycles. We suggest a within-generation experimental design that promises significant insight into composite selection across life cycle stages. As part of this design, we conducted simulations to determine the power needed to detect selection across a life cycle using a population genetic framework. This analysis demonstrated that recently published studies reporting within-generation selection were underpowered to detect small allele frequency changes (approx. 0.1). The power analysis indicates challenging but attainable sampling requirements for many systems, though plants and marine invertebrates with high fecundity are excellent systems for exploring how organisms with complex life cycles may adapt to climate change.
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    Does long-term fire suppression impact leaf litter breakdown and aquatic invertebrate colonization in pine flatwoods wetlands?
    Chandler, Houston C.; Colon-Gaud, J. Checo; Gorman, Thomas A.; Carson, Khalil; Haas, Carola A. (PeerJ, 2021-11-29)
    Ephemeral wetlands are commonly embedded within pine uplands of the southeastern United States. These wetlands support diverse communities but have often been degraded by a lack of growing-season fires that historically maintained the vegetation structure. In the absence of fire, wetlands develop a dense mid-story of woody vegetation that increases canopy cover and decreases the amount of herbaceous vegetation. To understand how reduced fire frequency impacts wetland processes, we measured leaf litter breakdown rates and invertebrate communities using three common plant species (Longleaf Pine (Pinus palustris), Pineland Threeawn Grass (Aristida stricta), and Black Gum (Nyssa sylvatica)) that occur in pine flatwoods wetlands located on Eglin Air Force Base, Florida. We also tested whether or not the overall habitat type within a wetland (fire maintained or fire suppressed) affected these processes. We placed leaf packs containing 15.0 g of dried leaf litter from each species in both fire-maintained and fire-suppressed sections of three wetlands, removing them after 103±104 days submerged in the wetland. The amount of leaf litter remaining at the end of the study varied across species (N. sylvatica D 7.97 ± 0.17 g, A. stricta D 11.84 ± 0.06 g, and P. palustris D 11.37 ± 0.07 g (mean ± SE)) and was greater in fire-maintained habitat (leaf type: F2,45 D 437.2, P < 0.001; habitat type: F1,45 D 4.6, P D 0.037). We identified an average of 260 ± 33.5 (SE) invertebrates per leaf pack (range: 19±1,283), and the most abundant taxonomic groups were Cladocera, Isopoda, Acariformes, and Diptera. Invertebrate relative abundance varied significantly among litter species (approximately 39.9 ± 9.4 invertebrates per gram of leaf litter remaining in N. sylvatica leaf packs, 27.2 ± 5.3 invertebrates per gram of A. stricta, and 14.6 ± 3.1 invertebrates per gram of P. palustris (mean ± SE)) but not habitat type. However, both habitat (pseudo-F1,49 D 4.30, P D 0.003) and leaf litter type (pseudo-F2,49 D 3.62, P D 0.001) had a significant effect on invertebrate community composition. Finally, this work was part of ongoing projects focusing on the conservation of the critically imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds exclusively in pine flatwoods wetlands, and we examined the results as they relate to potential prey items for larval flatwoods salamanders. Overall, our results suggest that the vegetation changes associated with a lack of growing-season fires can impact both invertebrate communities and leaf litter breakdown.
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    Exploring spatial nonstationary environmental effects on Yellow Perch distribution in Lake Erie
    Liu, Changdong; Liu, Junchao; Jiao, Yan; Tang, Yanli; Reid, Kevin B. (PeerJ, 2019-07-25)
    Background: Global regression models under an implicit assumption of spatial stationarity were commonly applied to estimate the environmental effects on aquatic species distribution. However, the relationships between species distribution and environmental variables may change among spatial locations, especially at large spatial scales with complicated habitat. Local regression models are appropriate supplementary tools to explore species-environment relationships at finer scales. Method: We applied geographically weighted regression (GWR) models on Yellow Perch in Lake Erie to estimate spatially-varying environmental effects on the presence probabilities of this species. Outputs from GWR were compared with those from generalized additive models (GAMs) in exploring the Yellow Perch distribution. Local regression coefficients from the GWR were mapped to visualize spatially-varying species-environment relationships. K-means cluster analyses based on the t-values of GWR local regression coefficients were used to characterize the distinct zones of ecological relationships. Results: Geographically weighted regression resulted in a significant improvement over the GAM in goodness-of-fit and accuracy of model prediction. Results from the GWR revealed the magnitude and direction of environmental effects on Yellow Perch distribution changed among spatial locations. Consistent species-environment relationships were found in the west and east basins for adults. The different kinds of species-environment relationships found in the central management unit (MU) implied the variation of relationships at a scale finer than the MU. Conclusions: This study draws attention to the importance of accounting for spatial nonstationarity in exploring species-environment relationships. The GWR results can provide support for identification of unique stocks and potential refinement of the current jurisdictional MU structure toward more ecologically relevant MUs for the sustainable management of Yellow Perch in Lake Erie.
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    The importance of migratory connectivity for global ocean policy
    Dunn, Daniel C.; Harrison, Autumn-Lynn; Curtice, Corrie; DeLand, Sarah; Donnelly, Ben; Fujioka, Ei; Heywood, Eleanor; Kot, Connie Y.; Poulin, Sarah; Whitten, Meredith; Akesson, Susanne; Alberini, Amalia; Appeltans, Ward; Manuel Arcos, Jos; Bailey, Helen; Ballance, Lisa T.; Block, Barbara A.; Blondin, Hannah; Boustany, Andre M.; Brenner, Jorge; Catry, Paulo; Cejudo, Daniel; Cleary, Jesse; Corkeron, Peter; Costa, Daniel P.; Coyne, Michael; Crespo, Guillermo Ortuno; Davies, Tammy E.; Dias, Maria P.; Douvere, Fanny; Ferretti, Francesco; Formia, Angela; Freestone, David; Friedlaender, Ari S.; Frisch-Nwakanma, Heidrun; Frojan, Christopher Barrio; Gjerde, Kristina M.; Glowka, Lyle; Godley, Brendan J.; Gonzalez-Solis, Jacob; Granadeiro, Jose Pedro; Gunn, Vikki; Hashimoto, Yuriko; Hawkes, Lucy M.; Hays, Graeme C.; Hazin, Carolina; Jimenez, Jorge; Johnson, David E.; Luschi, Paolo; Maxwell, Sara M.; McClellan, Catherine; Modest, Michelle; di Sciara, Giuseppe Notarbartolo; Palacio, Alejandro Herrero; Palacios, Daniel M.; Pauly, Andrea; Rayner, Matt; Rees, Alan F.; Salazar, Erick Ross; Secor, David; Sequeira, Ana MM M.; Spalding, Mark; Spina, Fernando; Van Parijs, Sofie; Wallace, Bryan; Varo-Cruz, Nuria; Virtue, Melanie; Weimerskirch, Henri; Wilson, Laurie; Woodward, Bill; Halpin, Patrick N. (Royal Society, 2019-09-18)
    The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.
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    Using historical dip net data to infer absence of flatwoods salamanders in stochastic environments
    Brooks, George C.; Haas, Carola A. (PeerJ, 2021-10-28)
    Local extinction and undetected presence are two very different biological phenomena, but they can be challenging to differentiate. Stochastic environments hamper the development of standardized monitoring schemes for wildlife, and make it more challenging to plan and evaluate the success of conservation efforts. To avoid reintroductions of species at risk that could jeopardize extant populations, managers attempting translocation events require a higher level of confidence that a failure to confirm presence represents a true absence. For many pond breeding amphibians, monitoring of the breeding population occurs indirectly through larval surveys. Larval development and successful recruitment only occurs after a sequence of appropriate environmental conditions, thus it is possible for a breeding population of adults to exist at a site but for detectability of the species to be functionally zero. We investigate how annual variability in detection influences long-term monitoring efforts of Reticulated Flatwoods Salamanders (Ambystoma bishopi) breeding in 29 wetlands in Florida. Using 8 years of historic dip net data, we simulate plausible monitoring scenarios that incorporate environmental stochasticity into estimates of detection probability. We found that annual variation in environmental conditions precluded a high degree of certainty in predicting site status for low-intensity monitoring schemes. Uncertainty was partly alleviated by increasing survey effort, but even at the highest level of sampling intensity assessed, multiple years of monitoring are required to confidently determine presence/absence at a site. Combined with assessments of habitat quality and landscape connectivity, our results can be used to identify sites suitable for reintroduction efforts. Our methodologies can be generally applied to increase the effectiveness of surveys for diverse organisms for which annual variability in detectability is known.
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    Using host traits to predict reservoir host species of rabies virus
    Worsley-Tonks, Katherine E. L.; Escobar, Luis E.; Biek, Roman; Castaneda-Guzman, Mariana; Craft, Meggan E.; Streicker, Daniel G.; White, Lauren A.; Fountain-Jones, Nicholas M. (PLoS, 2020-12-01)
    Wildlife are important reservoirs for many pathogens, yet the role that different species play in pathogen maintenance frequently remains unknown. This is the case for rabies, a viral disease of mammals. While Carnivora (carnivores) and Chiroptera (bats) are the canonical mammalian orders known to be responsible for the maintenance and onward transmission of rabies Lyssavirus (RABV), the role of most species within these orders remains unknown and is continually changing as a result of contemporary host shifting. We combined a trait-based analytical approach with gradient boosting machine learning models to identify physiological and ecological host features associated with being a reservoir for RABV. We then used a cooperative game theory approach to determine species-specific traits associated with known RABV reservoirs. Being a carnivore reservoir for RABV was associated with phylogenetic similarity to known RABV reservoirs, along with other traits such as having larger litters and earlier sexual maturity. For bats, location in the Americas and geographic range were the most important predictors of RABV reservoir status, along with having a large litter. Our models identified 44 carnivore and 34 bat species that are currently not recognized as RABV reservoirs, but that have trait profiles suggesting their capacity to be or become reservoirs. Further, our findings suggest that potential reservoir species among bats and carnivores occur both within and outside of areas with current RABV circulation. These results show the ability of a trait-based approach to detect potential reservoirs of infection and could inform rabies control programs and surveillance efforts by identifying the types of species and traits that facilitate RABV maintenance and transmission.