scholarly journals A turtle population study in an isolated urban wetland complex in Ontario reveals a few surprises

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 584-597 ◽  
Author(s):  
Marc Dupuis-Désormeaux ◽  
Vince D’Elia ◽  
Ryan Burns ◽  
Brittany White ◽  
Suzanne E. MacDonald
Keyword(s):  
Sex Ratio ◽  
Population Study ◽  
Road Mortality ◽  
Freshwater Turtles ◽  
Sources And Sinks ◽  
Painted Turtles ◽  
Wetland Complex ◽  
Turtle Population ◽  
Urban Wetland ◽  
Northern Map Turtle

We report on the results of the first mark–recapture survey of freshwater turtles in an isolated urban wetland complex in one of Canada’s fastest growing municipalities. Although we found turtles in every surveyed wetland, the density and assemblage of turtles in smaller wetlands were significantly different than in larger wetland bodies. We also documented two species of turtles that were thought to be absent from this wetland complex, the Northern Map turtle and Eastern Musk turtle. We noted that a wetland that was bisected by a high-traffic road showed a male-skewed sex ratio in the population of Midland Painted turtles but not in the population of Eastern Snapping turtles. As a whole, the sex ratios inside the wetland complex were not skewed. These results reinforce the conclusions of a previous study of a single wetland within this same complex that had found a correlation between road mortality and a male-skewed sex ratio in Midland painted turtles. We discuss population sources and sinks within the complex and the importance of protecting the overland corridors that support the safe turtle movements within this provincially significant wetland complex.

scholarly journals Revisiting the hypothesis of sex-biased turtle road mortality

2019 ◽  
Vol 132 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Sue Carstairs ◽  
Marc Dupuis-Desormeaux ◽  
Christina M. Davy
Keyword(s):  
Trauma Centre ◽  
Road Mortality ◽  
Substantial Impact ◽  
Emydoidea Blandingii ◽  
Painted Turtles ◽  
Snapping Turtles ◽  
Turtle Conservation ◽  
Map Turtles ◽  
Graptemys Geographica ◽  
Using Data

Road mortality poses a major threat to turtle populations. Several studies have suggested that the terrestrial movements associated with nesting increase this risk for females. The Ontario Turtle Conservation Centre (OTCC) is home to the Kawartha Turtle Trauma Centre, which admits 900 or more turtles a year, with road injuries the primary cause of admission. We tested the hypothesis that road mortality in turtles is female-biased using data from injured Midland Painted Turtles (Chrysemys picta marginata), Snapping Turtles (Chelydra serpentina), Blanding’s Turtles (Emydoidea blandingii), and Northern Map Turtles (Graptemys geographica) collected over about 126 000 km2 and admitted to OTCC’s hospital from January 2013 to October 2017. There was no difference in the number of male and female admissions of Midland Painted, Blanding’s, or Snapping Turtles (P > 0.05); however, more female Northern Map Turtles than males were admitted (P < 0.001). Admission of female turtles peaked in June during the nesting season, but male admissions were more evenly distributed throughout the season. Our admissions data provide a temporally unbiased and geographically broad snapshot of turtle–vehicle interactions that can directly inform conservation and management policies. Although our data are not equivalent to mortality rates, these results demonstrate that vehicle strikes can have a substantial impact on both female and male turtles.

scholarly journals A Brief Review of Non-Avian Reptile Environmental DNA (eDNA), with a Case Study of Painted Turtle (Chrysemys picta) eDNA under Field Conditions

2019 ◽  
Author(s):  
Clare I. M. Adams ◽  
Luke A. Hoekstra ◽  
Morgan R. Muell ◽  
Fredric J. Janzen
Keyword(s):  
Rank Order ◽  
Environmental Dna ◽  
Chrysemys Picta ◽  
Field Conditions ◽  
Painted Turtle ◽  
Freshwater Turtles ◽  
Detection Rates ◽  
Non Invasive ◽  
Painted Turtles ◽  
Current State

Environmental DNA (eDNA) is an increasingly used non-invasive molecular tool for detecting species presence and monitoring populations. In this article, we review the current state of non-avian reptile eDNA work in aquatic systems, as well as present a field experiment on detecting the presence of painted turtle (Chrysemys picta) eDNA. Thus far, turtle and snake eDNA studies have been successful mostly in detecting the presence of these animals in field conditions. However, some instances of low detection rates and non-detection occur for these non-avian reptiles, especially for squamates. We explored this matter by sampling lentic ponds with different densities (0 kg/ha, 6 kg/ha, 9 kg/ha, and 13 kg/ha) of painted turtles over three months, attempting to detect differences in eDNA accumulation using a qPCR assay. Only one sample of the highest density pond readily amplified eDNA. Yet, estimates of eDNA concentration from pond eDNA were rank-order correlated with turtle density. We present a &ldquo;shedding hypothesis&rdquo;&ndash;the possibility that animals with hard, keratinized integument do not shed as much DNA as mucus-covered organisms&ndash;as a potential challenge for turtle eDNA studies. Despite challenges with eDNA inhibition and availability in water samples, we remain hopeful that eDNA can be used to detect freshwater turtles in the field. We provide key recommendations for biologists wishing to use eDNA methods for detecting non-avian reptiles.

scholarly journals Phenotypic and environmental predictors of reproductive success in painted turtles

2020 ◽  
Author(s):  
Jessica M. Judson ◽  
Luke A. Hoekstra ◽  
Kaitlyn G. Holden ◽  
Fredric J. Janzen
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Mate Choice ◽  
Sex Ratio ◽  
Sex Ratios ◽  
Female Mate Choice ◽  
Painted Turtles ◽  
Weak Evidence ◽  
Adult Sex Ratio ◽  
Siring Success

ABSTRACTSexual selection is often assumed to elicit sexually dimorphic traits. However, most work on this assumption in tetrapod vertebrates has focused on birds. In this field experiment, we assessed relationships between both sexually dimorphic (body size, claw length) and non-dimorphic traits (forelimb stripe color, baseline corticosterone concentrations) and reproductive success in adult painted turtles to explicate the roles of these phenotypes in mate choice and the evolution of sexual dimorphism. We also modified adult sex ratios in experimental ponds to elucidate the role of biased sex ratios on reproductive success, which is a timely test of the potential threat of biased sex ratios on population persistence in a species with temperature-dependent sex determination. We found no strong influence of male phenotypes on male siring success, but female body size and baseline corticosterone concentrations predicted female clutch sizes. We find weak evidence that adult sex ratio influences male siring success, with a male-biased sex ratio producing lower male siring success than a female-biased sex ratio. This study offers evidence that female mate choice may not be an important selective force on male phenotypes, but that instead selection occurs on female phenotypes, particularly body size and corticosterone concentrations. Further, biased adult sex ratios can influence reproductive success of both sexes. Finally, the use of Kompetitive Allele Specific PCR (KASP) was highly successful in parentage analysis, which adds reptiles to the growing list of taxa successfully genotyped with this new technology.Lay SummaryFemale painted turtles aren’t choosy about traits of their mates. In a field experiment, we find that male traits do not predict male fitness, but key female traits (body size and stress levels) do predict female reproductive success. Further, we find weak evidence that adult sex ratio influences individual fitness in this species with environmental sex determination. Ultimately, we reject the long-assumed importance of female mate choice in this freshwater turtle.

scholarly journals Prospects for freshwater turtle population recovery are catalysed by pan-Amazonian community-based management

2018 ◽  
Author(s):  
Darren Norris ◽  
Carlos A Peres ◽  
Fernanda MIchalski ◽  
James P Gibbs
Keyword(s):  
Sustainable Use ◽  
Freshwater Turtle ◽  
Tropical Species ◽  
Area Network ◽  
Freshwater Turtles ◽  
Community Based ◽  
Tropical Regions ◽  
Continental Scale ◽  
Turtle Population ◽  
Business As Usual

Sustainable use as a mechanism for the conservation and recovery of exploited wildlife populations remains intensely debated, including for freshwater turtles, a diverse and imperilled group of aquatic reptiles that are an important food source for many residents of tropical regions. Here we evaluated the geographical extent of recovery options for a heavily exploited tropical freshwater turtle fauna across 8.86 M km2 of South American river catchments under Business-as-Usual (BAU), Protection (Pr) and Community-Based-Management (CBM) scenarios. For the widespread indicator species, Podocnemis unifilis, demographic analysis showed that populations subject moderate levels of female harvest (≤10%) can recover over broad areas if concurrent headstarting of hatchlings is practiced more widely. With regional strengthening of the protected area network unlikely, CBM developed with harvest frameworks derived from demographic rates appropriate to tropical species could catalyse a rapid continental scale recovery of Amazonian freshwater turtles within a few decades.

scholarly journals Prospects for freshwater turtle population recovery are catalysed by pan-Amazonian community-based management

2018 ◽  
Author(s):  
Darren Norris ◽  
Carlos A Peres ◽  
Fernanda MIchalski ◽  
James P Gibbs
Keyword(s):  
Sustainable Use ◽  
Freshwater Turtle ◽  
Tropical Species ◽  
Area Network ◽  
Freshwater Turtles ◽  
Community Based ◽  
Tropical Regions ◽  
Continental Scale ◽  
Turtle Population ◽  
Business As Usual

Sustainable use as a mechanism for the conservation and recovery of exploited wildlife populations remains intensely debated, including for freshwater turtles, a diverse and imperilled group of aquatic reptiles that are an important food source for many residents of tropical regions. Here we evaluated the geographical extent of recovery options for a heavily exploited tropical freshwater turtle fauna across 8.86 M km2 of South American river catchments under Business-as-Usual (BAU), Protection (Pr) and Community-Based-Management (CBM) scenarios. For the widespread indicator species, Podocnemis unifilis, demographic analysis showed that populations subject moderate levels of female harvest (≤10%) can recover over broad areas if concurrent headstarting of hatchlings is practiced more widely. With regional strengthening of the protected area network unlikely, CBM developed with harvest frameworks derived from demographic rates appropriate to tropical species could catalyse a rapid continental scale recovery of Amazonian freshwater turtles within a few decades.

Road mortality of the eastern long-necked turtle (Chelodina longicollis) along the Murray River, Australia: an assessment using citizen science

2018 ◽  
Vol 66 (1) ◽  
pp. 41 ◽  
Author(s):  
Claudia Santori ◽  
Ricky-John Spencer ◽  
James U. Van Dyke ◽  
Michael B. Thompson
Keyword(s):  
Citizen Science ◽  
Management Practices ◽  
Habitat Destruction ◽  
Road Mortality ◽  
Freshwater Turtles ◽  
Introduced Predators ◽  
Murray River ◽  
Time Of Year ◽  
Rain Events ◽  
Chelodina Longicollis

Turtles face a variety of threats (e.g. habitat destruction, introduced predators) that are pushing many species towards extinction. Vehicle collisions are one of the main causes of mortality of adult freshwater turtles. To conceptualise the level of threat that roads pose to Australians turtles, we analysed data gathered through the citizen science project TurtleSAT along the Murray River. We recorded 124 occurrences of turtle road mortality, which included all three local species (Chelodina expansa, Chelodina longicollis, and Emydura macquarii). Chelodina longicollis was the most commonly reported species killed on roads. We found that rain and time of year affect the likelihood of C. longicollis being killed on roads: increased turtle mortality is associated with rain events and is highest during the month of November, which coincides with their nesting season. Chelodina longicollis was most likely to be killed on the Hume Highway and roads around major urban centres; therefore, we recommend that governing bodies focus management practices and increase awareness at these locations. The degree of road mortality that we detected in this study requires mitigation, as it may contribute to the decline of C. longicollis along the Murray River.

scholarly journals Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Diversity ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 72 ◽  
Author(s):  
John P. Vanek ◽  
Gary A. Glowacki
Keyword(s):  
Population Structure ◽  
Sex Ratios ◽  
Monitoring Program ◽  
Chrysemys Picta ◽  
Adult Survival ◽  
Sampling Location ◽  
Road Mortality ◽  
Population Declines ◽  
Road Density ◽  
Painted Turtles

Turtles are particularly susceptible to the negative impacts of urbanization due to low mobility and a life history strategy emphasizing long generation times and high adult survival. In addition to declines directly through habitat loss, urbanization has been hypothesized to limit populations of aquatic turtles through changes in population structure, as adult females are disproportionally killed on and near roads, leading to male-biased populations, which can lead to population declines or local extirpations. The purpose of this study was to better understand how urbanization impacts the sex ratios of painted turtles (Chrysemys picta) in an urban ecosystem, as empirical results linking male-biased turtle populations to roads and urbanization are mixed. Using eight years of trapping data from a long-term monitoring program in a suburb of Chicago, IL, USA, we report one of the most male-biased populations ( x ¯ = 75% male) of turtles in the USA, consistent with prevailing road mortality hypotheses. However, we found no evidence that male-biased populations were related to road density or the amount of protected area around a sampling location and found that impervious surface (a metric of urbanization) was weakly related to less male-biased populations. Our results highlight the importance of replicating ecological studies across space and time and the difficulty in assessing population structure in aquatic turtles. We suggest that active conservation measures may be warranted for the continued persistence of urban turtle populations.

Sign in / Sign up

Export Citation Format

Share Document