Glyptemys Insculpta Research Articles

A New Variation on Nest Protection for Wood Turtle Nest Sites

A New Variation on Nest Protection for Wood Turtle Nest Sites

Wood Turtle Habitat Use and Agricultural Mortality at a Farm Landscape in Eastern New York

Wood Turtle Habitat Use and Agricultural Mortality at a Farm Landscape in Eastern New York

Survival and Age at Maturity in Head-Started Wood Turtles (Glyptemys insculpta) with Implications for Population Recovery

Survival and Age at Maturity in Head-Started Wood Turtles (Glyptemys insculpta) with Implications for Population Recovery

Wood Turtle Use of Agricultural Hayfields and Their Behavior During Hay Harvest: Implications for Wood Turtle Management in Agricultural Landscapes

Wood Turtle Use of Agricultural Hayfields and Their Behavior During Hay Harvest: Implications for Wood Turtle Management in Agricultural Landscapes

Baseline Abundances and Population Demographics at Wood Turtle (Glyptemys insculpta) Monitoring Sites in Wisconsin

Baseline Abundances and Population Demographics at Wood Turtle (Glyptemys insculpta) Monitoring Sites in Wisconsin

Increased Mortality in Wood Turtles (Glyptemys insculpta) during Drought Years

Increased Mortality in Wood Turtles (Glyptemys insculpta) during Drought Years

Home Range and Movement Patterns in a Maine Population of Wood Turtles (Glyptemys insculpta)

Home Range and Movement Patterns in a Maine Population of Wood Turtles (Glyptemys insculpta)

Water Depth Used by Wood Turtles (Glyptemys insculpta) in Iowa during Seasonal Activity Periods

Water Depth Used by Wood Turtles (Glyptemys insculpta) in Iowa during Seasonal Activity Periods

Influences of aquatic and terrestrial habitat characteristics on abundance patterns of adult wood turtles

AbstractWood turtles (Glyptemys insculpta) are a species of conservation concern throughout their geographic distribution. Several studies have investigated individual‐level habitat selection of wood turtles in the Upper Midwest in the United States, but the effects of habitat characteristics on abundance are poorly understood. This information is needed to improve landscape‐level habitat management and conservation initiatives for the species. Our study aimed to identify important aquatic and terrestrial habitat characteristics and quantify their influence on abundance dynamics of adult wood turtles in the Laurentian Mixed Forest Province ecoregion of Wisconsin and Minnesota, USA. We collected standardized population survey data at 57 sites within the ecoregion between 2016 and 2022. We used N‐mixture models with a multi‐stage model selection procedure to assess the influence of aquatic and terrestrial predictors on abundance, including several 3‐dimensional forest structure metrics derived from airborne Light Detection and Ranging (LiDAR) data. Several aquatic and terrestrial habitat characteristics influenced local abundance patterns of adult wood turtles. The most influential aquatic predictors were stream velocity and stream width, and the most influential terrestrial predictors were mean return height and vertical coefficient of variation of height. Abundance was high at sites containing comparatively narrow streams with moderate velocities. The most supported terrestrial predictors were derived from LiDAR and indicate that complex forest structures support larger wood turtle populations. Our results can be used in forest management strategies to improve habitat quality for wood turtles, such as selective tree harvesting to increase structural diversity, and potentially identify robust populations in under‐surveyed areas.

Preliminary Results of Variation in Plasma N-acetyl-beta-D-glucosaminidase Concentration Among Bearded Dragons (Pogona vitticeps), Corn Snakes (Pantherophis guttatus), and Wood Turtles (Glyptemys insculpta)

Abstract N-acetyl-beta-D-glucosaminidase (NAG) is a lysosomal enzyme found in renal tubular epithelial cells whose concentration can be measured in blood as a possible diagnostic tool to monitor renal disease; however, no reference values are currently available in reptiles. This study investigated the presence of plasma NAG concentrations in 3 reptile species. Blood samples were obtained from clinically healthy bearded dragons (Pogona vitticeps; n = 13), corn snakes (Pantherophis guttatus; n = 9) and wood turtles (Glyptemys insculpta; n = 13). To further assess renal health, a biochemistry panel was performed for all animals, and renal biopsies were collected from the bearded dragons and snakes, but not from the turtles. Biopsies were not taken from wood turtles to limit the risk associated with anesthetizing an endangered species. Of the 35 animals sampled, 29 were considered healthy and included in the study. Plasma NAG concentrations in the wood turtles were significantly lower than in the corn snakes (P = 0.004) and plasma NAG concentrations in the corn snakes were significantly higher than in bearded dragons (P = 0.038). Wood turtles had the lowest NAG concentrations, followed by bearded dragons and corn snakes. In conclusion, NAG reference intervals should be established for each reptile species and analyte validation is needed for this assay in reptiles. Further research is needed to establish NAG reliability as a diagnostic tool in reptiles.

Systematic evaluation of the influence of Taq enzyme choice and amplification conditions on targeted environmental DNA assay performance and detection in field samples

AbstractTargeted environmental DNA (eDNA) studies mainly rely on quantitative real‐time polymerase chain reaction (qPCR) to amplify extremely low concentrations of DNA present in environmental samples. Understanding factors that influence targeted eDNA assay performance and detection in field samples, such as Taq DNA polymerase enzyme type and thermocycle protocol, is critical for the interpretation of qPCR results. We completed a systematic performance evaluation of five distinct targeted eDNA assays (eANFI6, eFISH1, eANBO5, eGLIN1, and eLICA3 targeting sablefish, general fish, Boreal toad, wood turtle, and the American bullfrog) by subjecting the same samples to analysis by five different Taq enzyme reagent mixes (Immolase, Environmental Master Mix (EMM), Amplitaq, QIAcuity, and QuantiNova) and the commonly used 2‐step (95°C, 60°C) and 3‐step (95°C, 64°C, 72°C) thermocycle protocols. We evaluated assay performance using a standardized dilution series of synthetic dsDNA target sequences and calculated limits of detection (LOD) and quantification (LOQ) and 95% confidence intervals for each combination of Taq enzyme and thermocycle protocol. All assays performed within acceptable performance criteria as defined by the Canadian national standard for targeted eDNA assays. Based on data generated by synthetic dsDNA fragments, the eDNA assays performed comparably regardless of the enzyme reagent mix and protocol used, except for eANFI6 and eGLIN1 using EMM and the 3‐step protocol, where no amplification was observed. On freshwater field samples, EMM and Immolase performed best. On marine field samples, Immolase, EMM, Qiacuity, and QuantiNova performed equally well, although EMM failed to amplify some samples. The work reveals that an enzyme reaction mix or thermocycle protocol can affect the result of an eDNA assay, but the appropriate choice also depends on the nature of the field sample. It is therefore imperative that these are considered when selecting appropriate reaction conditions and that they are clearly reported.

Influence of temporary emigration on wood turtle (Glyptemys insculpta) detectability, with implications for abundance estimation.

Reliable population estimates are important for making informed management decisions about wildlife species. Standardized survey protocols have been developed for monitoring population trends of the wood turtle (Glyptemys insculpta), a semi-aquatic freshwater turtle species of conservation concern throughout its distribution in east-central North America. The protocols use repeated active search surveys of defined areas, allowing for estimation of survey-specific detection probability (p) and site-specific abundance. These protocols assume population closure within the survey area during the survey period, which is unlikely to be met as wood turtles are a highly mobile species. Additionally, current protocols use a single-pass design that does not allow for separation of availability (pa) and detectability (pd). If there are systematic influences on pa or pd that are not accounted for in the survey design or data analysis, then resulting abundance estimates could be biased. The objectives of this study were to determine if pa is a random process and if pa and pd are influenced by demographic characteristics. We modified the wood turtle survey protocol used in the upper Midwest to include a double-pass design, allowing us to estimate pa and pd using a robust design capture-recapture model. The modified protocol was implemented at 14 wood turtle monitoring sites in Minnesota and Wisconsin between 2017 and 2022. Our results indicated that pa was non-random and that pd increased with turtle carapace length. Our study suggests that model assumptions for current wood turtle population models may be violated, likely resulting in an overestimation of abundance. We discuss possible protocol and modeling modifications that could result in more accurate wood turtle abundance estimates.

Evidence of handedness in turtles

AbstractAlthough research supporting cerebral lateralization, or handedness, in non‐human vertebrates is expanding, reptiles represent one of the least studied. While assessing wood turtle shells, we noticed more dents, scrapes, chips, and other forms of damage on the right side of turtles than on the left. Asymmetrical injury has been attributed to cerebral lateralization in other taxa, and current research supports handedness in testudines. After creating a “scute damage index” to catalog damage location, we confirmed turtles had more damage on the right side of their shells than on the left. We offer four hypotheses that explain this pattern.

Hemolivia species infecting Central American wood turtles (Rhinoclemmys pulcherrima manni) and problems with differential diagnosis within the genus Hemolivia.

Blood parasites of the genus Hemolivia Petit, Landau, Baccam and Lainson, 1990 (Adeleorina: Karyolysidae) are hemogregarines of ectothermic vertebrates, such as lizards, chelonians, and toads. Only five species of Hemolivia from vertebrate hosts and one from their tick vector have been described so far. In the present study, Central American wood turtles (Rhinoclemmys pulcherrima manni) originating from Southern Nicaragua were screened for the presence of hemogregarines. Ten out of 30 specimens (33.3%) were positive for Hemolivia using both approaches - microscopy and PCR-based analyses. Phylogenetic analyses based on the 18S rRNA gene revealed the presence of two haplotypes, both placed as sister taxa in the Hemolivia clade. Their phylogenetic position was supported by high bootstrap values and high posterior probabilities, suggesting that there are at least two new distinct haplotypes corresponding to two distinct species. However, the specimens of each haplotype were microscopically indistinguishable from each other based on the gamont morphology, therefore, only a single species could be described and named, as Hemolivia pulcherrima n. sp. We consider that the uniform morphology of the most common blood stages of species of the genus Hemolivia complicates their differential diagnosis. Sequence divergence and different host spectra, therefore, remain the only differentiating tools.

A Test of Intersexual Trophic Niche Partitioning within a Population of Wood Turtles (Glyptemys insculpta)

A Test of Intersexual Trophic Niche Partitioning within a Population of Wood Turtles (Glyptemys insculpta)

Advancing Forensic Chemical Analysis to Classify Wild and Captive Turtles

The diets and environments that individuals experience can vary greatly within and among wildlife populations. These individual experiences can be compared using the chemical signatures of animal tissues, which can differentiate animals into groups, including those raised in the wild versus those held in captive facilities. In this study, we compared different combinations of four stable isotope ratios and 15 trace elements derived from the claw tips of captive wood turtles throughout the eastern U.S. and wild wood turtles (Glyptemys insculpta) from Maine to develop predictive models used to determine their origins. The purpose of this work is to develop an objective statistical tool that law enforcement can use to help prosecute poachers. We found that the chemical signatures of 14 (12 trace elements and 2 stable isotope ratios) of the 19 markers we explored were different between wild and captive wood turtles, thus reflecting the differences in their diets and environments. We found that our stable isotope ratio model had nearly perfect predictive accuracy in classifying wild wood turtles as wild and captive wood turtles as captive, whereas our trace element and combined model were 100% accurate, thus validating this statistical approach for determining the origins of confiscated wood turtles from Maine.

Demography and Viability of a Central Maine Population of Wood Turtles (Glyptemys insculpta)

Demography and Viability of a Central Maine Population of Wood Turtles (Glyptemys insculpta)

Headstarting turtles to larger body sizes for multiple years increases survivorship but with diminishing returns

AbstractHeadstarting is a conservation tool that assumes raising turtles in protected ex situ environments to larger body sizes, then releasing them back into the wild, increases their survivorship compared to wild, non‐headstarted turtles. Our goal was to quantitatively test this fundamental assumption by comparing somatic growth and survivorship among 3 age classes of headstarted juvenile wood turtles (Glyptemys insculpta) monitored for 3 years (2016–2018) in Ontario, Canada. Our age classes were turtles headstarted for 2 years (n = 15), turtles headstarted for 1 year (n = 30), and turtles incubated and hatched ex situ, then released (i.e., no headstarting; hatchlings, n = 30). Both age classes of headstarted turtles were radio‐tracked for 1 year after release. We released hatchlings in August and radio‐tracked them for 1 month. All cohorts exhibited positive somatic growth after release. One‐month post‐release survival of hatchlings was 70%. Turtles headstarted for 2 years had slightly higher 1‐year post‐release survivorship (67%) than turtles headstarted for 1 year (47%), but there was little to no evidence for a difference (P = 0.17). Modeling these survivorship results with real‐life constraints of only 100 hatchlings available for headstarting each year (biological constraint from source population), and a 100‐turtle capacity in our headstarting facility (economic constraint), projected similar population growth in 2‐year and 1‐year headstarting programs. When removing the 100‐turtle facility limit, the 2‐year program projected higher population growth but required space for 200 turtles in the headstarting facility, which may not be feasible for many programs. Our results support the fundamental assumption that headstarting increases survivorship, but we observed diminishing returns if headstarting was increased for longer than 1 year. Given the growing number of turtle headstarting projects globally, our study provides data that can aid in establishing cost‐ and resource‐effective best practices.

A late Pleistocene Wood Turtle (<i>Glyptemys insculpta</i>) from Iowa, USA: response of the taxon to glaciation and formation of the current range

The partial shell of a Wood Turtle (Glyptemys insculpta) was collected from the West Branch of the East Nishnabotna River in southwestern Iowa, near Malvern. By direct accelerator mass spectrometry, it radiocarbon dates to the late Pleistocene (10 220 ± 30 years before present [BP], 11 975–11 813 calibrated years [cal] BP). Other subfossil evidence indicates that Wood Turtles moved far south of their current range, into the southeastern United States, in response to late Pleistocene glaciation. The specimen suggests that the species also moved south and west, into a previously undocumented western range, where favourable habitat and, in particular, somewhat cooler summer temperatures prevailed until ~10 200 cal BP. My assessment of the Holocene subfossil record suggests that establishment of the western portion of the current range may have occurred within the past 1000 years. Phylogenetic analysis and direct radiometric dating of subfossil specimens are needed to determine additional details about the late Pleistocene dispersal of Wood Turtle and the postglacial formation of their current range.

Forensic Application of Stable Isotopes to Distinguish between Wild and Captive Turtles.

Wildlife traffickers often claim that confiscated animals were captive-bred rather than wild-caught to launder wild animals and escape prosecution. We used stable isotopes (δ13C and δ15N) derived from the claw tips of wild wood turtles from Maine and captive wood turtles throughout the eastern U.S. to develop a predictive model used to classify confiscated wood turtles as wild or captive. We found that the claw tips of wild and captive wood turtles (Glyptemys insculpta) were isotopically distinct. Captive turtles had significantly higher δ13C and δ15N values than wild turtles. Our model correctly classified all wild turtles as wild (100%) and nearly all captive turtles as captive (94%). All but two of the 71 turtles tested were successfully predicted as wild or captive (97.2% accuracy), yielding a misclassification rate of 2.8%. In addition to our model being useful to law enforcement in Maine, we aim to develop a multi-species model to assist conservation law enforcement efforts to curb illegal turtle trafficking from locations across the eastern United States and Canada.