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George Amato - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity and population genetic structure of the Wood Turtle (Glyptemys insculpta) at Delaware Water Gap National Recreation Area, USA
Conservation Genetics, 2009Co-Authors: Christina M. Castellano, John L. Behler, George AmatoAbstract:Glyptemys insculpta is considered to be one of the most endangered freshwater turtles in North America. Here microsatellite markers were employed to investigate the genetic variation and population structure of G. insculpta at Delaware Water Gap National Recreation Area (USA). Seven microsatellites revealed high allelic variation with 13–30 alleles per locus. Observed and expected heterozygosities per locus ranged from 0.875–0.925 to 0.888–0.952, respectively. Pairwise estimates of population structure ( θ ) ranged from 0.000–0.013 to θ estimated over all loci and aggregations was not significantly different from zero. Gene flow ( Nm ) was high and ranged from 19 migrants per generation to infinity in pairwise comparisons. No significant relationship between geographic distance and genetic distance was detected. These data indicate that G. insculpta at DEWA represent a single, genetically diverse management unit for conservation.
Jacqueline D. Litzgus - One of the best experts on this subject based on the ideXlab platform.
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Predation and disease limit population recovery following 15 years of headstarting an endangered freshwater turtle
Biological Conservation, 2020Co-Authors: Damien I. Mullin, Ronald J. Brooks, Rachel C. White, Andrew M. Lentini, Karine R. Bériault, Jacqueline D. LitzgusAbstract:Abstract Recovery strategies for endangered species vary in scope and scale, and uncertainties regarding their effectiveness make it necessary to implement evidence-based methods to ensure best management practices and the most efficient use of limited conservation dollars. Assessing recovery actions for species with slow life histories requires decades of study. We quantitatively assessed the putative recovery of two populations (PopA, PopB) of globally endangered Wood Turtles (Glyptemys insculpta) after 30 years of mark-recapture study and 15 years of headstarting implemented in response to a 57% reduction in population size attributed to poaching. We modeled population-specific demographic parameters to evaluate recovery efforts to date, and determine the next phase of management. Both populations showed limited recovery despite the release of 490 headstarted turtles. Recovery has been hindered by lower than expected 1-year post-release survivorship of headstarts (36%, 52% in each population, respectively), and only moderate (for turtles) adult survivorship (89%, 93%). Six headstarted turtles have, however, reproduced suggesting both populations may eventually become self-sustaining. From 2015 to 2018, subsidized predators killed 11 adult turtles, and we detected three diseases (mycotic shell disease, ranavirus, Glyptemys herpesvirus 2) in the headstarts. Our population viability analysis projected that both populations would recover if a predator-management strategy were implemented. Headstarting alone is not enough to save at-risk populations from local extinction when they face multi-faceted problems, including the cascading effects of landscape-scale habitat modification, for which management is challenging.
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Impact of natural resource extraction on thermal properties of wood turtle (Glyptemys insculpta) habitat.
Journal of Thermal Biology, 2019Co-Authors: Geoffrey N. Hughes, Jacqueline D. LitzgusAbstract:Abstract One of the main threats to freshwater turtle populations is habitat destruction, which occurs as a result of human activities such as infrastructure development, forestry, aggregate extraction, and agriculture. However, the impacts of these activities on thermoregulatory opportunities for turtles are not well understood. We examined the impacts of forestry and aggregate extraction on thermal characteristics of wood turtle (Glyptemys insculpta) habitat in the Sudbury District, Ontario, by measuring the differences in absolute temperature, thermal landscape structure, and habitat thermal quality among relatively undisturbed sites (N = 2), harvested forestry sites (N = 2), and aggregate pits (N = 2) in 2015. We also tested the potential use of the thermal landscape concept as a predictor of habitat thermal quality. Undisturbed habitats were of higher thermal quality than impacted sites in terms of temperatures experienced in situ by wild wood turtles in their natural home ranges, and never reached temperatures that would be injurious to turtles (i.e., below CTMIN or above CTMAX). The undisturbed sites were of lower quality in terms of optimal temperatures (i.e., Tset), and were generally cooler and their temperatures less variable than those in impacted habitats. The thermal landscape concept provided a useful predictor of habitat thermal quality when the influence of time of day was factored into the predictive model. Our data are important to the conservation and management of wood turtles because they provide a preliminary quantification of the thermal impacts of natural resource extraction on the habitat of an endangered species, and can guide the development of mitigation and rehabilitation plans by providing measures of, and targets for, thermal habitat quality.
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Geographic Variation in Somatic Growth Rate of Wood Turtles (Glyptemys insculpta)
Copeia, 2018Co-Authors: Kelsey A. Marchand, Geoffrey N. Hughes, Jacqueline D. LitzgusAbstract:Life history traits, such as body size and age at maturity, display intraspecific variation across a species' geographic range. Previous studies that examined body size variation among conspecific populations of turtles found that body size generally increases with increasing latitude, with the exception of Wood Turtles (Glyptemys insculpta) and Spotted Turtles (Clemmys guttata), which follow a non-linear relationship with larger body sizes at the two range extremes. Similarly, growth rates are influenced by climatic variables and should display geographic patterns reflective of different environments. The objectives of our study were to a) quantify somatic growth in a northern population of Wood Turtles, and b) determine if the observed geographic variation in body size was the result of interpopulation variation in somatic growth rates. In the northern population, as turtles approached maturity, somatic growth increments varied between the sexes such that on average males grew to larger mean carapace le...
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Effects of body size, habitat selection and exposure on hatchling turtle survival
Journal of Zoology, 2014Co-Authors: James E. Paterson, Brad D. Steinberg, Jacqueline D. LitzgusAbstract:Iteroparous species invest little energy into annual reproduction and tend to experience low and variable survivorship in young life stages. However, juveniles with traits that increase survival will have a fitness advantage over conspecifics, and usually bigger is better for juvenile vertebrates. Understanding behavioural and morphological characteristics that increase fitness is important for our understanding of the evolution of life-history strategies. We outfitted naturally emerging hatchlings of two species of turtles (Blanding's turtles Emydoidea blandingii and wood turtles Glyptemys insculpta) with radio transmitters to test five hypotheses related to survival from nests to overwintering sites using logistic regression models. In contrast to the widely supported hypothesis that bigger is better for survival of juveniles, we found that smaller hatchlings of both species were more likely to survive from emergence to overwintering. In E. blandingii, hatchlings that emerged later in the year, which reduced exposure time to predators and environmental risks, and spent less time in upland open habitat, were also more likely to survive. Our results demonstrate that bigger is not always better in juvenile ectotherms. Assuming bigger is better without observations of survival can lead to erroneous conclusions related to fitness proxies and the ontogeny of body size in populations. The observed relationship between habitat selection and survival in E. blandingii indicates a direct link between behaviour (habitat selection) and fitness through mortality caused by predators and environmental stressors.
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Revealing a cryptic life-history stage: differences in habitat selection and survivorship between hatchlings of two turtle species at risk (Glyptemys insculpta and Emydoidea blandingii)
Wildlife Research, 2012Co-Authors: James E. Paterson, Brad D. Steinberg, Jacqueline D. LitzgusAbstract:Context Turtles are one of the most imperilled taxonomic groups worldwide and information about population ecology is essential to species recovery. Although the spatial ecology and demography of adults of several turtle species have been well studied, little is known about early life stages. The small size, soft shell, and limited mobility of hatchling turtles may cause differences in survivorship and habitat selection compared with adults. Aims We tested the hypothesis that hatchling turtles select habitat as they move away from nests, so as to reduce the risk of predation and desiccation. Methods We examined survivorship, behaviour and habitat selection at two spatial scales in hatchling Blanding’s turtles (Emydoidea blandingii) and wood turtles (Glyptemys insculpta) in 2009 and 2010, using radio-telemetry in Algonquin Provincial Park, Ontario, Canada. In addition, temperatures of sites used by hatchlings during winter were compared with those at haphazard stations in various habitats. Key results The mortality rate was high, with 42% of E. blandingii and 11% of G. insculpta hatchlings surviving to winter; most mortality was caused by predation. Most behavioural observations for both species were of individuals hiding under cover. Both species showed evidence of macrohabitat and microhabitat selection as they dispersed from nests towards overwintering sites, and important variables in the models differed between species. Likewise, the adult stages of these two species differ in their macrohabitat specialisation. There was also evidence that hatchlings chose overwintering sites on the basis of temperature. Conclusions Despite significant differences in survivorship between hatchlings and adults, resource selection was similar between these two demographic stages, and conservation plans based on adult habitat use should simultaneously protect hatchlings. Implications Understanding habitat selection by juveniles is important for testing hypotheses about ontogenetic shifts in resource selection and for protecting habitat for species at risk.
Christina M. Castellano - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity and population genetic structure of the Wood Turtle (Glyptemys insculpta) at Delaware Water Gap National Recreation Area, USA
Conservation Genetics, 2009Co-Authors: Christina M. Castellano, John L. Behler, George AmatoAbstract:Glyptemys insculpta is considered to be one of the most endangered freshwater turtles in North America. Here microsatellite markers were employed to investigate the genetic variation and population structure of G. insculpta at Delaware Water Gap National Recreation Area (USA). Seven microsatellites revealed high allelic variation with 13–30 alleles per locus. Observed and expected heterozygosities per locus ranged from 0.875–0.925 to 0.888–0.952, respectively. Pairwise estimates of population structure ( θ ) ranged from 0.000–0.013 to θ estimated over all loci and aggregations was not significantly different from zero. Gene flow ( Nm ) was high and ranged from 19 migrants per generation to infinity in pairwise comparisons. No significant relationship between geographic distance and genetic distance was detected. These data indicate that G. insculpta at DEWA represent a single, genetically diverse management unit for conservation.
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Terrestrial Movements of Hatchling Wood Turtles (Glyptemys insculpta) in Agricultural Fields in New Jersey
Chelonian Conservation and Biology, 2008Co-Authors: Christina M. Castellano, John L. Behler, Gordon R. UltschAbstract:ABSTRACT Hatchling Glyptemys insculpta did not travel to water directly upon emergence from their nests but remained in agricultural fields for several days to weeks, during which time they fed and grew. Hatchlings were less active and occupied sites with significantly lower air and substrate temperatures than adult turtles. A management scheme to delay agricultural harvesting until turtles have entered aquatic habitats for hibernation is advised.
François-joseph Lapointe - One of the best experts on this subject based on the ideXlab platform.
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Watersheds influence the wood turtle’s (Glyptemys insculpta) genetic structure
Conservation Genetics, 2019Co-Authors: Cindy Bouchard, Nathalie Tessier, François-joseph LapointeAbstract:The wood turtle ( Glyptemys insculpta ) is a freshwater species endemic to eastern North America and is currently listed as endangered by the International Union for Conservation of Nature. Wood turtle local populations are considered units for the species recovery, and are defined as discrete interbreeding populations in a distinct watershed; however, there are no studies to date supporting this definition. The main objective of this paper was to genetically characterize wood turtles from a northern portion of their range, and test an isolation-by-watershed hypothesis, the first of its kind at such a large geographical scale. Turtles were sampled in 24 watercourses from 12 different watersheds for a total of 331 individuals, each genotyped for nine microsatellite loci. Within each watershed, genetic diversity was similar between sites, and observed heterozygosity ranged from 0.677 to 0.754. Partial redundancy analyses then confirmed that watershed isolation contributed to 18% of the total observed genetic variation, while spatial autocorrelation and the post-glacial Expansion Model did not significantly explain any variation. Clustering methods revealed substantial spatial genetic structure, with sampled groups falling into ten nested hierarchical clusters. We recommend further consideration of these ten clusters to determine if they meet the evolutionary significance criterion to become designatable units, whose genetic structures were influenced by watershed structure.
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watersheds influence the wood turtle s Glyptemys insculpta genetic structure
Conservation Genetics, 2019Co-Authors: Cindy Bouchard, Nathalie Tessier, François-joseph LapointeAbstract:The wood turtle (Glyptemys insculpta) is a freshwater species endemic to eastern North America and is currently listed as endangered by the International Union for Conservation of Nature. Wood turtle local populations are considered units for the species recovery, and are defined as discrete interbreeding populations in a distinct watershed; however, there are no studies to date supporting this definition. The main objective of this paper was to genetically characterize wood turtles from a northern portion of their range, and test an isolation-by-watershed hypothesis, the first of its kind at such a large geographical scale. Turtles were sampled in 24 watercourses from 12 different watersheds for a total of 331 individuals, each genotyped for nine microsatellite loci. Within each watershed, genetic diversity was similar between sites, and observed heterozygosity ranged from 0.677 to 0.754. Partial redundancy analyses then confirmed that watershed isolation contributed to 18% of the total observed genetic variation, while spatial autocorrelation and the post-glacial Expansion Model did not significantly explain any variation. Clustering methods revealed substantial spatial genetic structure, with sampled groups falling into ten nested hierarchical clusters. We recommend further consideration of these ten clusters to determine if they meet the evolutionary significance criterion to become designatable units, whose genetic structures were influenced by watershed structure.
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Paternity Analysis of Wood Turtles (Glyptemys insculpta) Reveals Complex Mating Patterns.
Journal of Heredity, 2017Co-Authors: Cindy Bouchard, Nathalie Tessier, François-joseph LapointeAbstract:Mating system characteristics are of great importance as they may influence male and female reproductive success and reproductive isolation. The wood turtle (Glyptemys insculpta) is a terrestrial freshwater species listed as endangered by the International Union for Conservation of Nature. Considering its conservation status and the paucity of information currently available on parentage relationship for the species, we performed a microsatellite analysis to study the mating system of wood turtles in the Shawinigan River (Quebec). We sampled 38 clutches over 2 years (14 in 2006 and 24 in 2007), for a total of 248 offspring genotyped with 7 microsatellite loci. The reconstructed genotypes of the fathers revealed that reproductive success in the sampled clutches varied greatly between males and are positively correlated with the number of mates and clutches sired. Frequency of multiple paternity was estimated at 37% through a consensus of 3 different estimation methods. Positive correlation was observed between the genetic diversity of clutches and the number of fathers. Repeat paternity, however, was observed in 88% of the clutches by the same female in successive years, which suggests either a frequent use of sperm storage, or remating with the same partner in successive years.
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Conservation genetics of the wood turtle (Glyptemys insculpta) in Quebec, Canada
Canadian Journal of Zoology, 2005Co-Authors: Nathalie Tessier, Sébastien Rioux Paquette, François-joseph LapointeAbstract:Throughout its range, the long-term persistence of the wood turtle (Glyptemys insculpta Le Conte, 1830) is jeopardized by habitat perturbations and commercial collection. The main objective of this study was to acquire knowledge on the genetic structure of wood turtle populations within Quebec, where the species reaches the northernmost limit of its range, to identify proper conservation units. The six known populations in Quebec were genetically characterized using five microsatellite loci. Genetic analyses revealed high variability among all populations (HO ranging from 0.561 to 0.886), suggesting that past population declines have not yet affected their genetic diversity. Since populations are located on both shores of the St. Lawrence River, two colonization hypotheses were tested to determine whether the River acted as a dispersal route or as a barrier. Results of AMOVA tests, phylogenetic analyses, and assignment tests demonstrated the clear distinction between populations from both shores, and thre...
Ron Moen - One of the best experts on this subject based on the ideXlab platform.
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GPS technology for semi-aquatic turtle research
Diversity, 2019Co-Authors: Madaline M. Cochrane, Donald J. Brown, Ron MoenAbstract:Global positioning system (GPS) telemetry units are now small enough to be deployed on terrestrial and semi-aquatic turtles. Many of these GPS units use snapshot technology which collects raw satellite and timestamp data during brief periods of data recording to minimize size. We evaluated locations from snapshot GPS units in stationary tests and on wood turtles (Glyptemys insculpta) in northeastern Minnesota. Stationary GPS units were placed in wood turtle habitat to evaluate location accuracy, fix success rate, and directional bias. The GPS fix success rate and accuracy were reduced in closed canopy conditions and when the stationary GPS unit was placed under a log to simulate wood turtle hiding behavior. We removed GPS location outliers and used a moving average calculation to reduce mean location error in stationary tests from 27 m (SD = 38) to 10 m (SD = 8). We then deployed GPS units and temperature loggers on wood turtles and collected 122,657 GPS locations and 242,781 temperature readings from 26 turtles from May to September 2015 and 2016. Location outliers accounted for 12% of locations when the GPS receiver was on a turtle. We classified each wood turtle location based on the GPS location and by comparing temperature profiles from river, sun, and shaded locations to the temperature logger on the turtle. We estimated that wood turtles were on land 68% (SD = 12) of the time from May to September. The fix success rate for land locations was 38% (SD = 9), indicating that wood turtles often use habitats with obstructed views of the sky. Mean net daily movement was 55 m (SD = 192). Our results demonstrate that snapshot GPS units and temperature loggers provide fine-scale GPS data useful in describing spatial ecology and habitat use of semi-aquatic turtles.
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A regional analysis of Glyptemys insculpta (wood turtle) survival in the Upper Midwest of the USA
Herpetological Conservation and Biology, 2019Co-Authors: Carly N. Lapin, Madaline M. Cochrane, Donald J. Brown, Jeffrey W. Tamplin, James E. Woodford, Ron MoenAbstract:The Wood Turtle (Glyptemys insculpta) is a species of conservation concern in the Upper Midwest of the USA. State agencies and partners in the region are working collaboratively to identify threats to G. insculpta populations and to implement effective management actions. One component of this conservation initiative is to improve our understanding of the impacts of different management strategies on long-term viability of populations. This requires estimates of population vital rates, which are currently lacking for most G. insculpta populations in the Upper Midwest and across the range of the species. In this study, we used individual-level monitoring data to estimate annual survival of adult G. insculpta in Iowa (two populations, four monitoring years, 52 individuals), Minnesota (one population, two monitoring years, 29 individuals), and Wisconsin (two populations, two monitoring years, 32 individuals). We estimated annual survival for each sex, population, and year using a known-fates analysis with a binomial model. Twenty-three (20%) of the monitored individuals died during the study. For 12 turtles for which we knew the cause, predation was responsible for most (n = 9; 75%) mortalities. Estimated annual survival of males and females ranged from 0.49–1.00 and 0.64–1.00, respectively, among populations and years. Estimated survival of all individuals was 0.86 in Iowa for 2012–2015, 0.89 in Minnesota for 2015–2016, and 0.87 in Wisconsin for 2014–2015. This study increases our understanding of adult G. insculpta survival rates and causes of mortality in the western Great Lakes portion of the range of the species and provides useful vital rate estimates for population viability analyses.
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Status of a wood turtle ( Glyptemys insculpta ) population in northeastern Minnesota
Herpetological Conservation and Biology, 2018Co-Authors: Madaline M. Cochrane, Donald J. Brown, Mark D. Nelson, Richard R. Buech, Mike Schrage, Dan Ryan, Ron MoenAbstract:Wood Turtles (Glyptemys insculpta) have experienced population declines across their North American range and are state-listed as threatened in Minnesota, USA. To improve our understanding of the current conservation status of one population in northeastern Minnesota, we: (1) performed a snapshot comparison of population structure and relative abundance in 1990 and 2015 using survey data at 12 sites; (2) estimated the population growth rate (λ) from 1997–2014 based on population monitoring data at six sites; (3) estimated change in abundance between 2016 and 2017 based on population monitoring data at eight sites; and (4) performed a population reconstruction to estimate the minimum Glyptemys insculpta alive each year and geometric mean of λ from 1990 to 2017. The snapshot comparison indicated that relative abundance, adult sex ratio, and juvenile:adult ratio did not significantly differ between years. Captures/hour was higher in 1990 than in 2015. Mean λ from six sites monitored from 1997–2014 was 1.016, indicating the population was stable over that period. However, abundance estimates from surveys at eight sites in 2016 and 2017 indicated a substantial decrease from 247 to 112 individuals. The population reconstruction estimated a mean λ of 1.007 and 0.970 from 1990–2005 and 2006–2017, respectively. In northeastern Minnesota, Glyptemys insculpta exists in a forested landscape with predominantly public ownership and little development pressure, likely avoiding many anthropogenic stressors. However, we obtained equivocal results for our population status assessment. Continued monitoring is necessary to understand the trajectory of this Glyptemys insculpta population.
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Survey and analysis design for wood turtle population monitoring
The Journal of Wildlife Management, 2017Co-Authors: Donald J. Brown, Madaline M. Cochrane, Ron MoenAbstract:Population monitoring is a fundamental component of wildlife management, and is necessary to track site- and regional-level status and recovery of species of conservation concern. The wood turtle (Glyptemys insculpta) is a species of conservation concern for federal and state agencies because of population declines across the species' range. We developed and tested a survey and analysis design to assist agencies in the Upper Midwest, USA, with establishment of long-term monitoring programs for wood turtle populations. In spring of 2016, we conducted 8 replicate population surveys at 8 candidate long-term monitoring sites in northeastern Minnesota, USA. Using field survey data and simulation models, we assessed the influence of distance from river surveyed, number of survey replications, and number of sites on abundance estimates; we also delineated important survey covariates and compared demographic estimates based on distance from river surveyed. We estimated site-level abundances and compared survey designs using a multinomial N-mixture model that included a removal sampling observation process. Mean abundance estimates were similar when surveying 2 transects (i.e., the river-land interface to ~25m inland) or 4 transects (i.e., the river-land interface to ~55m inland), but decreasing the survey distance from river reduced the precision of estimates. Mean abundance estimates were similar with ?6 replications. Air temperature was an important predictor of survey-specific detection probability, with maximum detectability at 19-23?C. Sex ratio and mean carapace length did not differ based on whether we surveyed 2 or 4 transects, and percentage of individuals by size class was nearly identical between the sampling designs. Simulations indicated that 75% of mean abundance estimates were within ?8% of true abundance when ?15 sites were surveyed. The wood turtle survey and analysis design we developed and tested was effective for estimating abundance of wood turtle populations in northeastern Minnesota, and we encourage its use as a template for wood turtle monitoring programs in the Upper Midwest.
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Food Availability for Wood Turtles (Glyptemys insculpta) in Managed and Natural Woodlands
2016Co-Authors: Katelin Goebel, Madaline M. Cochrane, Donald J. Brown, Ron MoenAbstract:University Honors Capstone Project Poster, University of Minnesota Duluth, 2016. Advisor: Dr. Ron Moen; IBS graduate student: Maddy Cochrane. UMD Undergraduate Research Opportunities Program (UROP) and BURST programs.