The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Kevin Mcgarigal - One of the best experts on this subject based on the ideXlab platform.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Context Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. Objectives We examined habitat selection of the federally threatened eastern indigo snake ( Drymarchon couperi ) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Methods Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. Results At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Conclusions Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. We examined habitat selection of the federally threatened eastern indigo snake (Drymarchon couperi) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Seasonal Variation in Eastern Indigo Snake (Drymarchon couperi) Movement Patterns and Space Use in Peninsular Florida at Multiple Temporal Scales
Herpetologica, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Abstract: Many snake populations display seasonal variation in movement patterns in response to spatiotemporal variation in prey, mates, and other resources. Eastern Indigo Snakes (Drymarchon couperi) are federally threatened and endemic to the southeastern coastal plain of the United States. Although previous studies have described seasonal variation in D. couperi movement patterns at the northern limit of their range (southern Georgia), such information is currently lacking from peninsular Florida. We describe sex-specific seasonal variation in D. couperi movement patterns and space use in peninsular Florida across multiple temporal scales. We found that males made longer, more frequent movements, and had larger home ranges than females during the winter breeding season. Although movement frequency and distance were similar between sexes during the nonbreeding season, males still had larger home ranges. The degree of within-individual home-range overlap was consistent over time and not indicative of se...
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the influence of sex and season on conspecific spatial overlap in a large actively foraging colubrid snake
PLOS ONE, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Understanding the factors influencing the degree of spatial overlap among conspecifics is important for understanding multiple ecological processes. Compared to terrestrial carnivores, relatively little is known about the factors influencing conspecific spatial overlap in snakes, although across snake taxa there appears to be substantial variation in conspecific spatial overlap. In this study, we described conspecific spatial overlap of eastern indigo snakes (Drymarchon couperi) in peninsular Florida and examined how conspecific spatial overlap varied by sex and season (breeding season vs. non-breeding season). We calculated multiple indices of spatial overlap using 6- and 3-month utilization distributions (UD) of dyads of simultaneously adjacent telemetered snakes. We also measured conspecific UD density values at each telemetry fix and modeled the distribution of those values as a function of overlap type, sex, and season using generalized Pareto distributions. Home range overlap between males and females was significantly greater than overlap between individuals of the same sex and male home ranges often completely contained female home ranges. Male home ranges overlapped little during both seasons, whereas females had higher levels of overlap during the non-breeding season. The spatial patterns observed in our study are consistent with those seen in many mammalian carnivores, in which low male-male overlap and high inter-sexual overlap provides males with greater access to females. We encourage additional research on the influence of prey availability on conspecific spatial overlap in snakes as well as the behavioral mechanisms responsible for maintaining the low levels of overlap we observed.
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Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
Javan M. Bauder - One of the best experts on this subject based on the ideXlab platform.
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taxonomic and conservation implications of population genetic admixture mito nuclear discordance and male biased dispersal of a large endangered snake Drymarchon couperi
PLOS ONE, 2019Co-Authors: Brian Folt, Javan M. Bauder, Dirk J. Stevenson, Stephen F. Spear, Michelle Hoffman, Jamie R. Oaks, Christopher M. Jenkins, Perry Jr L Wood, David A. SteenAbstract:Accurate species delimitation and description are necessary to guide effective conservation of imperiled species, and this synergy is maximized when multiple data sources are used to delimit species. We illustrate this point by examining Drymarchon couperi (Eastern Indigo Snake), a large, federally-protected species in North America that was recently divided into two species based on gene sequence data from three loci and heuristic morphological assessment. Here, we re-evaluate the two-species hypothesis for D. couperi by evaluating both population genetic and gene sequence data. Our analyses of 14 microsatellite markers revealed 6–8 genetic population clusters with significant admixture, particularly across the contact zone between the two hypothesized species. Phylogenetic analyses of gene sequence data with maximum-likelihood methods suggested discordance between mitochondrial and nuclear markers and provided phylogenetic support for one species rather than two. For these reasons, we place Drymarchon kolpobasileus into synonymy with D. couperi. We suggest inconsistent patterns between mitochondrial and nuclear DNA are driven by high dispersal of males relative to females. We advocate for species delimitation exercises that evaluate admixture and gene flow in addition to phylogenetic analyses, particularly when the latter reveal monophyletic lineages. This is particularly important for taxa, such as squamates, that exhibit strong sex-biased dispersal. Problems associated with over-delimitation of species richness can become particularly acute for threatened and endangered species, because of high costs to conservation when taxonomy demands protection of more individual species than are supported by accumulating data.
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Phylogenetic, population genetic, and morphological analyses reveal evidence for one species of Eastern Indigo Snake (Drymarchon couperi)
2018Co-Authors: Brian Folt, Javan M. Bauder, Dirk J. Stevenson, Stephen F. Spear, Michelle Hoffman, Jamie R. Oaks, Christopher M. Jenkins, David A. Steen, Craig GuyerAbstract:Accurate species delimitation and description are necessary to guide effective conservation management of imperiled species. The Eastern Indigo Snake ( Drymarchon couperi ) is a large species in North America that is federally-protected as Threatened under the Endangered Species Act. Recently, two associated studies hypothesized that Drymarchon couperi is two species. Here, we use diverse approaches to test the two-species hypothesis for D. couperi . Our analyses reveal that (1) phylogenetic reconstruction in Krysko et al. (2016a) was based entirely on analysis of mitochondrial DNA sequence data, (2) microsatellite data demonstrate significant nuclear gene flow between mitochondrial lineages and a clear isolation-by-distance pattern across the species entire range, and (3) morphological analyses recover a single diagnosable species. Our results reject recent conclusions of Krysko et al. (2016a,b) regarding species delimitation and taxonomy of D. couperi , and we formally place Drymarchon kolpobasileus into synonymy with D. couperi . We suggest inconsistent patterns between mitochondrial and nuclear DNA may be driven by high dispersal of males relative to females. We caution against species delimitation exercises when one or few loci are used without evaluation of contemporary gene flow, particularly species with strong sex-biased dispersal (e.g., squamates) and/or when results have implications for ongoing conservation efforts.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Context Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. Objectives We examined habitat selection of the federally threatened eastern indigo snake ( Drymarchon couperi ) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Methods Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. Results At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Conclusions Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. We examined habitat selection of the federally threatened eastern indigo snake (Drymarchon couperi) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Occupancy of Potential Overwintering Habitat on Protected Lands by Two Imperiled Snake Species in the Coastal Plain of the Southeastern United States
Journal of Herpetology, 2017Co-Authors: Javan M. Bauder, Dirk J. Stevenson, Chris Sutherland, Christopher L. JenkinsAbstract:Abstract Eastern Indigo Snakes (EIS, Drymarchon couperi) and Eastern Diamondbacked Rattlesnakes (EDB, Crotalus adamanteus) are species of conservation concern, in large part attributable to anthrop...
Dirk J. Stevenson - One of the best experts on this subject based on the ideXlab platform.
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Ophidiomycosis surveillance of snakes in Georgia, USA reveals new host species and taxonomic associations with disease
Scientific Reports, 2020Co-Authors: Ellen Haynes, Dirk J. Stevenson, Houston C. Chandler, Benjamin S. Stegenga, Emilie Ospina, Laura Adamovicz, Dessireé Zerpa-catanho, Matthew C. AllenderAbstract:Ophidiomycosis (snake fungal disease) is caused by the fungus Ophidiomyces ophiodiicola and threatens snake health worldwide. It has been documented throughout the eastern United States and severe cases have recently been reported in Georgia, USA. To evaluate disease distribution and prevalence in this state, 786 free-ranging snakes were examined for skin lesions consistent with ophidiomycosis and swabbed to detect O. ophiodiicola DNA using qPCR. Sampled snakes represented 34 species and 4 families; 27.5% had skin lesions, 13.3% were positive for O. ophiodiicola DNA, and 77.8% of the qPCR positive individuals had skin lesions. This is the first report of O. ophiodiicola in five of the 22 species that were qPCR positive. Multinomial logistic regression modeling indicated that Drymarchon couperi had a higher relative risk of apparent ophidiomycosis (lesions present and qPCR positive), and the best models predicting qPCR result and ophidiomycosis category included individual factors and excluded temporal and spatial factors. Phylogeny-based bipartite network analysis showed that Nerodia erythrogaster , Nerodia taxispilota , and D. couperi had the highest prevalence of apparent ophidiomycosis; this category was more prevalent in the subfamily Colubrinae and less prevalent in Natricinae. These results provide important information about ophidiomycosis epidemiology, which has implications for snake conservation.
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Patterns of head shape and scutellation in Drymarchon couperi (Squamata: Colubridae) reveal a single species.
Zootaxa, 2019Co-Authors: Craig Guyer, Dirk J. Stevenson, Brian Folt, Michelle Hoffman, Scott M. Goetz, Melissa A. Miller, James C GodwinAbstract:Krysko et al. (2016a) used analyses of DNA sequence data to reveal two genetic lineages of Drymarchon couperi. The Atlantic lineage contained specimens from southeastern Georgia and eastern peninsular Florida, and the Gulf Coast lineage contained specimens from western and southern peninsular Florida as well as western Florida, southern Alabama, and southern Mississippi. In a second paper Krysko et al. (2016b) analyzed morphological variation of the two lineages, which allowed them to restrict D. couperi to the Atlantic lineage and to describe the Gulf Coast lineage as a new species, Drymarchon kolpobasileus. This taxonomic discovery was remarkable for such a large, wide-ranging species and was notable for its impact on conservation. Because of population declines, particularly in western Florida, southern Alabama, and southern Mississippi, D. couperi (sensu lato) was listed as Threatened under the Endangered Species Act (United States Fish and Wildlife Service 1978, 2008) and repatriation of the species to areas where it had been extirpated was listed as a priority conservation goal (United States Fish and Wildlife Service 1982, 2008). Such repatriation efforts were attempted in Alabama, Florida, Georgia, and South Carolina, starting in 1977 (Speake et al. 1987), but failed to create viable populations, likely because too few snakes were released at too many sites (Guyer et al. 2019; Folt et al. 2019a). A second attempt at repatriation was started in 2010 and concentrated on release of snakes at a single site in Alabama (Stiles et al. 2013). However, Krysko et al. (2016a) criticized this repatriation effort because it appeared to involve release of D. couperi (sensu stricto) into the geographic region occupied by D. kolpobasileus (as diagnosed in Krysko et al. 2016b).
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Multiple Paternity and Heritability of Color in Drymarchon couperi (Eastern Indigo Snakes)
Herpetologica, 2019Co-Authors: Jennifer Deitloff, Dirk J. Stevenson, Stephen F. Spear, Erin M. Myers, Craig GuyerAbstract:Abstract: Multiple paternity of clutches is common in many vertebrates, including snakes, and understanding how frequently it occurs within a species is important for determining the role it might ...
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Ophidiomycosis prevalence in Georgia's Eastern Indigo Snake (Drymarchon couperi) populations
PloS one, 2019Co-Authors: Houston C. Chandler, Matthew C. Allender, Benjamin S. Stegenga, Ellen Haynes, Emilie Ospina, Dirk J. StevensonAbstract:Wildlife diseases have posed a significant challenge to the conservation of many species in recent years. Diseases have been implicated in population declines over large geographic areas, with severe disease outbreaks leading to either local or complete extinctions of wild populations. Ophidiomycosis, commonly known as snake fungal disease, is caused by the fungus Ophidiomyces ophiodiicola, which has been documented in snake populations across the eastern and southern United States. We collected swab samples from the federally threatened Eastern Indigo Snake (Drymarchon couperi) in populations across the species' Georgia range. We used quantitative PCR to determine the presence of O. ophiodiicola DNA and also recorded skin abnormalities characteristic of ophidiomycosis. From 1 September 2016 to 4 August 2018, Eastern Indigo Snakes tested positive for O. ophiodiicola DNA on 47 of 107 occasions (43.9%) and tested negative for fungal DNA but had skin lesions consistent with ophidiomycosis on 42 occasions (39.3%). Symptomatic and qPCR positive individuals were more likely to be encountered during January and February when compared to November and December. We found no effect of sex (p = 0.517), age-class (p = 0.106), or body size (snout-vent length: p = 0.083; mass: p = 0.206; body condition: p = 0.063) on ophidiomycosis status. Over the two-year study, we encountered individuals in which infection was clearly negatively impacting overall health and also documented individuals in which infection apparently cleared from one year to the next. These results demonstrate that O. ophiodiicola and lesions characteristic of ophidiomycosis are widespread in Georgia's Eastern Indigo Snake populations. However, there are many unanswered questions regarding this disease, including the effects of disease on populations and individuals, the presence of infection vectors, and the change in prevalence over time. More research is needed to address ophidiomycosis and understand its impacts on ongoing conservation efforts.
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taxonomic and conservation implications of population genetic admixture mito nuclear discordance and male biased dispersal of a large endangered snake Drymarchon couperi
PLOS ONE, 2019Co-Authors: Brian Folt, Javan M. Bauder, Dirk J. Stevenson, Stephen F. Spear, Michelle Hoffman, Jamie R. Oaks, Christopher M. Jenkins, Perry Jr L Wood, David A. SteenAbstract:Accurate species delimitation and description are necessary to guide effective conservation of imperiled species, and this synergy is maximized when multiple data sources are used to delimit species. We illustrate this point by examining Drymarchon couperi (Eastern Indigo Snake), a large, federally-protected species in North America that was recently divided into two species based on gene sequence data from three loci and heuristic morphological assessment. Here, we re-evaluate the two-species hypothesis for D. couperi by evaluating both population genetic and gene sequence data. Our analyses of 14 microsatellite markers revealed 6–8 genetic population clusters with significant admixture, particularly across the contact zone between the two hypothesized species. Phylogenetic analyses of gene sequence data with maximum-likelihood methods suggested discordance between mitochondrial and nuclear markers and provided phylogenetic support for one species rather than two. For these reasons, we place Drymarchon kolpobasileus into synonymy with D. couperi. We suggest inconsistent patterns between mitochondrial and nuclear DNA are driven by high dispersal of males relative to females. We advocate for species delimitation exercises that evaluate admixture and gene flow in addition to phylogenetic analyses, particularly when the latter reveal monophyletic lineages. This is particularly important for taxa, such as squamates, that exhibit strong sex-biased dispersal. Problems associated with over-delimitation of species richness can become particularly acute for threatened and endangered species, because of high costs to conservation when taxonomy demands protection of more individual species than are supported by accumulating data.
David R. Breininger - One of the best experts on this subject based on the ideXlab platform.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Context Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. Objectives We examined habitat selection of the federally threatened eastern indigo snake ( Drymarchon couperi ) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Methods Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. Results At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Conclusions Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. We examined habitat selection of the federally threatened eastern indigo snake (Drymarchon couperi) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Seasonal Variation in Eastern Indigo Snake (Drymarchon couperi) Movement Patterns and Space Use in Peninsular Florida at Multiple Temporal Scales
Herpetologica, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Abstract: Many snake populations display seasonal variation in movement patterns in response to spatiotemporal variation in prey, mates, and other resources. Eastern Indigo Snakes (Drymarchon couperi) are federally threatened and endemic to the southeastern coastal plain of the United States. Although previous studies have described seasonal variation in D. couperi movement patterns at the northern limit of their range (southern Georgia), such information is currently lacking from peninsular Florida. We describe sex-specific seasonal variation in D. couperi movement patterns and space use in peninsular Florida across multiple temporal scales. We found that males made longer, more frequent movements, and had larger home ranges than females during the winter breeding season. Although movement frequency and distance were similar between sexes during the nonbreeding season, males still had larger home ranges. The degree of within-individual home-range overlap was consistent over time and not indicative of se...
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the influence of sex and season on conspecific spatial overlap in a large actively foraging colubrid snake
PLOS ONE, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Understanding the factors influencing the degree of spatial overlap among conspecifics is important for understanding multiple ecological processes. Compared to terrestrial carnivores, relatively little is known about the factors influencing conspecific spatial overlap in snakes, although across snake taxa there appears to be substantial variation in conspecific spatial overlap. In this study, we described conspecific spatial overlap of eastern indigo snakes (Drymarchon couperi) in peninsular Florida and examined how conspecific spatial overlap varied by sex and season (breeding season vs. non-breeding season). We calculated multiple indices of spatial overlap using 6- and 3-month utilization distributions (UD) of dyads of simultaneously adjacent telemetered snakes. We also measured conspecific UD density values at each telemetry fix and modeled the distribution of those values as a function of overlap type, sex, and season using generalized Pareto distributions. Home range overlap between males and females was significantly greater than overlap between individuals of the same sex and male home ranges often completely contained female home ranges. Male home ranges overlapped little during both seasons, whereas females had higher levels of overlap during the non-breeding season. The spatial patterns observed in our study are consistent with those seen in many mammalian carnivores, in which low male-male overlap and high inter-sexual overlap provides males with greater access to females. We encourage additional research on the influence of prey availability on conspecific spatial overlap in snakes as well as the behavioral mechanisms responsible for maintaining the low levels of overlap we observed.
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Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
Michael L. Legare - One of the best experts on this subject based on the ideXlab platform.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Context Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. Objectives We examined habitat selection of the federally threatened eastern indigo snake ( Drymarchon couperi ) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Methods Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. Results At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Conclusions Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake
Landscape Ecology, 2018Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions. We examined habitat selection of the federally threatened eastern indigo snake (Drymarchon couperi) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection. Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection. At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se. Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.
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Seasonal Variation in Eastern Indigo Snake (Drymarchon couperi) Movement Patterns and Space Use in Peninsular Florida at Multiple Temporal Scales
Herpetologica, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Michael L. Legare, Betsie B. Rothermel, M. Rebecca Bolt, Kevin McgarigalAbstract:Abstract: Many snake populations display seasonal variation in movement patterns in response to spatiotemporal variation in prey, mates, and other resources. Eastern Indigo Snakes (Drymarchon couperi) are federally threatened and endemic to the southeastern coastal plain of the United States. Although previous studies have described seasonal variation in D. couperi movement patterns at the northern limit of their range (southern Georgia), such information is currently lacking from peninsular Florida. We describe sex-specific seasonal variation in D. couperi movement patterns and space use in peninsular Florida across multiple temporal scales. We found that males made longer, more frequent movements, and had larger home ranges than females during the winter breeding season. Although movement frequency and distance were similar between sexes during the nonbreeding season, males still had larger home ranges. The degree of within-individual home-range overlap was consistent over time and not indicative of se...
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the influence of sex and season on conspecific spatial overlap in a large actively foraging colubrid snake
PLOS ONE, 2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Understanding the factors influencing the degree of spatial overlap among conspecifics is important for understanding multiple ecological processes. Compared to terrestrial carnivores, relatively little is known about the factors influencing conspecific spatial overlap in snakes, although across snake taxa there appears to be substantial variation in conspecific spatial overlap. In this study, we described conspecific spatial overlap of eastern indigo snakes (Drymarchon couperi) in peninsular Florida and examined how conspecific spatial overlap varied by sex and season (breeding season vs. non-breeding season). We calculated multiple indices of spatial overlap using 6- and 3-month utilization distributions (UD) of dyads of simultaneously adjacent telemetered snakes. We also measured conspecific UD density values at each telemetry fix and modeled the distribution of those values as a function of overlap type, sex, and season using generalized Pareto distributions. Home range overlap between males and females was significantly greater than overlap between individuals of the same sex and male home ranges often completely contained female home ranges. Male home ranges overlapped little during both seasons, whereas females had higher levels of overlap during the non-breeding season. The spatial patterns observed in our study are consistent with those seen in many mammalian carnivores, in which low male-male overlap and high inter-sexual overlap provides males with greater access to females. We encourage additional research on the influence of prey availability on conspecific spatial overlap in snakes as well as the behavioral mechanisms responsible for maintaining the low levels of overlap we observed.
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Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
2016Co-Authors: Javan M. Bauder, Christopher L. Jenkins, David R. Breininger, Rebecca M. Bolt, Michael L. Legare, Betsie B. Rothermel, Kevin McgarigalAbstract:Number of individuals, home range dyads, home range sizes, and tracking intensities for radio telemetered eastern indigo snakes (Drymarchon couperi) used in the analyses of conspecific spatial overlap.
