<p dir="ltr">Spotted Turtle (Clemmys guttata) populations are declining dramatically across their range primarily due to habitat alteration, fragmentation, and reduction. Fragmented habitats have the potential to affect a population’s genetic diversity and size through the direct loss of individuals and the reduction of gene flow. Understanding genetic variation in Spotted Turtles can provide insight into population dynamics, the geographic distribution of genetic variants, and conservation needs. I examined the genetic variation in Spotted Turtle populations across the western portion of their geographic range including localities in Illinois, Indiana, Ohio, Michigan, and Ontario, Canada. Using blood samples collected during the 2022 and 2023 field seasons as well as previously collected tissues, I genotyped 611 individuals across 17 or more localities using 16 microsatellite loci. Five of 17 sites across the geographic extent of the sample suggested the presence of inbreeding (positive Fis values). Although the precision of estimates was low in most localities (10 of 17 with incalculable confidence intervals), the remaining localities in Ohio were estimated to have effective population sizes of < 20 individuals. Model-based and ordination-based clustering were conducted to assess population structure. Both types of clustering approaches identified four genetic clusters within the dataset. The two Illinois sites fell distinctly into their own cluster, whereas all other sites show a pattern of admixture. Despite these clustering results, incorporation of spatial information in principal component analysis (sPCA), shows that genetic composition gradually changes from west to east across the landscape, a pattern supported by isolation by distance using a Mantel test of the correlation between genetic and geographic distances. My results show that several Spotted Turtle populations have low levels of genetic variation and could benefit from augmentation. The observed pattern of isolation by distance 9 suggests that any translocations of turtles to support populations should be attempt to draw from viable populations that are in closer proximity.</p>

Roads are long linear features on the landscape that impact wildlife and their habitats. Among all forms of wildlife turtles are one of the most negatively affected by roads. Wildlife biologists and civil engineers have developed and implemented road design measures to mitigate the negative effects associated with roads. One common approach used to reduce road mortality and to facilitate movement of turtles is to construct a road mitigation system. There are currently 28 road mitigation systems for wildlife in Massachusetts, of which 14 were specifically built for turtles. We identified all known systems in Massachusetts and collected site and structural design information for each. In addition, we also examined the relative effectiveness of experimental passages for freshwater turtles. Structures were evaluated with respect to how their height, width, and position (at or below-grade), influenced the movements of painted turtles. A total of 190 turtles were exposed to the experiential trials and their behavior was characterized by 3 response variables (Total time to complete the trial, Total hesitations observed, and Success based on no hesitations and completion of the trial in less than 120 minutes). We concluded that painted turtles exposed to below-grade tunnels were less hesitant and traveled faster through them as the tunnel size increased from 0.6 m x 0.6 m to 1.2 m x 1.2 m. The 1.2 m x 1.2 m tunnel size overall proved to be the size with the fewest hesitations observed, fastest total times, and highest success rate.

An ecological study was undertaken on four populations of Krefft�s River Turtle Emydura krefftii inhabiting the Townsville Area of Tropical North Queensland. Two sites were located in the Ross River, which runs through the urban areas of Townsville, and two sites were in rural areas at Alligator Creek and Stuart Creek (known as the Townsville Creeks). Earlier studies of the populations in Ross River had determined that the turtles existed at an exceptionally high density, that is, they were superabundant, and so the Townsville Creek sites were chosen as low abundance sites for comparison. The first aim of this study was to determine if there had been any demographic consequences caused by the abundance of turtle populations of the Ross River. Secondly, the project aimed to determine if the impoundments in the Ross River had affected the freshwater turtle fauna. Specifically this study aimed to determine if there were any difference between the growth, size at maturity, sexual dimorphism, size distribution, and diet of Emydura krefftii inhabiting two very different populations. A mark-recapture program estimated the turtle population sizes at between 490 and 5350 turtles per hectare. Most populations exhibited a predominant female sex-bias over the sampling period. Growth rates were rapid in juveniles but slowed once sexual maturity was attained; in males, growth basically stopped at maturity, but in females, growth continued post-maturity, although at a slower rate. Sexual maturity was at 6-7 years of age for males, which corresponded to a carapace length of 150-160 mm, and 8-10 years of age for females, which corresponded to a carapace length of 185-240 mm. The turtles were omnivorous, although in the Ross River they ate more submerged vegetation (by percent amount and occurrence) than those of the Townsville Creeks. Turtles in Townsville Creeks ingested more windfall fruit and terrestrial insects.

No description available.

La biologie de la conservation est un domaine de recherche en pleine expansion en raison de la perte accélérée de la biodiversité à l’échelle mondiale. Pour mieux comprendre les processus et les menaces au maintien des populations de petite taille et les effets des facteurs anthropiques sur la biodiversité, la génétique est fréquemment utilisée en conservation. Des analyses génétiques peuvent, par exemple, nous informer sur les tendances à long terme, la diversité des populations et les stratégies de reproduction d’une espèce. La tortue des bois (Glyptemys insculpta) est une espèce endémique à l’Amérique du Nord qui est en danger d’extinction selon l’Union internationale pour la conservation de la nature. Dans le cadre de ma thèse, j’avais comme objectif de caractériser la diversité génétique de cette espèce menacée au Canada. À cet effet, j’ai analysé la génétique des populations de tortues des bois à plusieurs échelles spatiales et temporelles, afin de mieux cerner les processus ayant un impact sur la diversité des populations. Dans un premier temps, les relations de parentalité ont été reconstruites au sein d’une population de tortues des bois pour estimer la fréquence de paternité multiple et de paternité répétée. Les résultats de mes travaux suggèrent que l’emmagasinement de sperme chez la femelle et la reproduction multiple avec les mêmes partenaires pour plus d’une saison de reproduction pourraient expliquer ces phénomènes. Ces stratégies de reproduction pourraient dans ce cas être induites par la faible densité de la population à l’étude, ou encore par la fidélité au site d’hibernation où la majorité des évènements de copulation ont lieu. Par la suite, je me suis intéressée à la diversité génétique des populations de tortues de bois. J’ai voulu comprendre les effets de la configuration spatiale des éléments du paysage et les évènements de dispersion géographique sur la diversité des populations. À l’aide d’une approche de génétique du paysage, mes analyses montrent que la division des populations par bassins versants explique une large fraction de la diversité génétique interpopulations. Ces résultats confirment également que les bassins versants représentent des unités de gestion propices à la protection des populations de tortues des bois. Finalement, des analyses de réseaux ont été utilisées pour mieux cerner la dynamique de flux génique entre les populations de la rive nord et de la rive sud du fleuve Saint-Laurent. Plus spécifiquement, la rive nord se caractérise par un réseau robuste de populations isolées, alors que les populations de la rive sud présentent plutôt une structure de métapopulation. En utilisant les réseaux construits à partir de données génétiques, des scénarios hypothétiques furent comparés pour explorer la sélection de populations à l’aide du logiciel BRIDES. Les résultats de ces analyses ont permis de cibler l’importance de certaines populations de tortues des bois pour la connectivité du réseau. L’importance de ces populations n’aurait pu être prédite par les résultats de la diversité et de la différenciation génétique, les indices de centralité et les analyses d’élimination de nœuds. Grâce à la génétique, cette thèse apporte de nouvelles connaissances sur la tortue des bois, les stratégies de reproduction des différents sexes, le flux génique, la connectivité et l’influence du réseau hydrographique sur la diversité des populations. Ces résultats nous permettent d’avoir une meilleure compréhension des processus affectant la diversité génétique de cette espèce afin de mieux la protéger. Toutes les analyses réalisées pour cette thèse sont directement applicables à l’ensemble des autres espèces longévives avec des générations chevauchantes. / Conservation biology is a rapidly expanding field of research due to the accelerating loss of global biodiversity. To better understand the processes and threats to the persistence of small populations and the effects of anthropogenic factors on biodiversity, genetic approaches are frequently used in conservation. Genetic analyzes can, for example, inform us about long-term trends, population diversity and reproductive strategies of a species. The wood turtle (Glyptemys insculpta) is a species endemic to North America that is endangered according to the International Union for the Conservation of Nature. As part of my thesis, my objective was to characterize the genetic diversity of this threatened species in Canada. In order to better understand the impact of reproductive strategy and landscape structure on population diversity, I analyzed the genetics of wood turtle populations at several spatial and temporal scales. First, parentage relationships were reconstructed in a population of wood turtles to estimate the frequency of multiple and repeated paternity. The results of my work suggest that sperm storage in females and multiple reproduction with the same partners for more than one breeding season could explain these phenomena. These reproduction strategies could in this case be induced by the low density of the study population, or by fidelity to the overwintering site where the majority of copulation events take place. Subsequently, I assessed the genetic diversity of wood turtle populations. I wanted to understand the effects of the landscape configuration and geographic dispersion events on the diversity of populations. Using a landscape genetics approach, my analyzes show that the division of populations by watershed explains a large fraction of the genetic diversity between populations. These results also confirm that watersheds represent management units conducive to the protection of wood turtle populations. Finally, network analysis was used to better understand the gene flow dynamics among populations located on the north and south shores of the St. Lawrence River. More specifically, the north shore is characterized by a robust network of isolated populations, whereas the populations on the south shore present more of a metapopulation structure. Using population graphs, hypothetical scenarios were compared to explore the node selection process using the BRIDES algorithm. The results of these analyzes made it possible to point out specific populations of wood turtles, considering their importance for network connectivity. This could have not been predicted by using genetic diversity and distinctiveness estimates, node-based metrics, and node removal analysis for these populations. Thanks to genetics, this thesis brings new knowledge on the wood turtle, the reproductive strategies of both sexes, the gene flow, the connectivity and the influence of the hydrographic network on population diversity. These results allow us to have a better understanding of the processes affecting the genetic diversity of this species in order to better protect it. All analyses performed for this thesis are directly applicable to other long-lived species with overlapping generations.

No description available.