Physiological Health and Survival of Captive-Reared and Released Juvenile Blanding’s Turtles

Cann, Armand A.; Weber, Rebecca R.; Harden, Leigh Anne; Thompson, Daniel; Nadolski, Jeremy; Mattes, Jenna; Karwowska, Alexandra; Shahjahan, Sumaiya; Milanovich, Joseph R.

doi:10.1086/716832

Cited by 5 publications

(4 citation statements)

References 98 publications

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“…We suspect raccoons were the most likely culprit in the predation events, though skunks and opossums are also known to be in the area. See Cann et al (2021) for more details of juvenile survival.…”

Section: Resultsmentioning

confidence: 99%

“…Each cohort was raised ex situ for 24 months, bypassing winter dormancy (i.e. brumation) to allow for a longer growing period (see Cann et al 2021 for more details on head‐start animal husbandry methods). The first cohort (hatched in 2014) of twelve turtles, now referred to as ‘recently‐released 2016' (RR 2016 ), was released on 24 May 2016 and studied through the duration of their active season, and during brumation until their emergence in April 2017.…”

Section: Methodsmentioning

confidence: 99%

“…Individual juveniles that did not complete the entire season or seasons of observation were removed from the mean calculation of the group (e.g. deaths, transmitter loss; see Cann et al 2021 for more survivorship details). Beginning in October of each year, once remaining turtles were found in the same location for four consistent weeks we proposed that location as the brumation/overwintering site.…”

Section: Methodsmentioning

confidence: 99%

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Spatial and thermal ecology of juvenile head‐started Blanding's turtles Emydoidea blandingii

et al. 2023

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Declining reptilian populations has been a growing concern over the last couple of decades. One such declining species of concern, the Blanding's turtle Emydoidea blandingii, occurs as isolated populations in North American prairie-wetlands and is at risk of extirpation due to habitat loss and fragmentation, and increased predator (e.g. racoons, coyotes) populations due to supplemented resources in urban environments. To help mitigate declining populations, wildlife managers have invested in the conservation of this species through head-starting (i.e. reared in ex situ) and juvenile release programs to augment wild Blanding's turtle populations. However, much of their spatial and winter/thermal ecology is understudied, and data for juveniles, and juveniles reared ex situ is especially scarce, yet this information is imperative to understanding shortfalls and improving head-starting efforts in the future. In spring 2016 (RR 2016 ) and 2017 (RR 2017 ) we released a cohort (n = 12 each year) of head-started juvenile Blanding's turtles equipped with radio transmitters and temperature dataloggers into a prairie-wetland in the greater Chicago region, North America. Using ground-based radio telemetry, we determined seasonal movement areas (SMAs; spring, summer and fall) and annual home ranges (AHRs) for both RR 2016 and RR 2017 cohorts via kernel density (KD) estimates. We also investigated the thermal characteristics of overwintering for both juvenile cohorts. We found that SMAs for the RR 2016 cohort, but not for the RR 2017 cohort, significantly differed across seasons for most SMA estimators. We also found that juveniles in both cohorts not only survived overwintering, but also displayed similar overwintering phenology (i.e. initiation: October-November; termination: April) and temperature variation as Blanding's turtles adults in other studies. Overall, our results indicate that head-started juvenile Blanding's turtles may be able to acclimatize quickly to their natural environment post-release. Our study provides evidence to the efficacy of well-developed head-starting programs that aim to augment and preserve imperiled turtle populations.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Spatial and thermal ecology of juvenile head‐started Blanding's turtles Emydoidea blandingii

et al. 2023

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“…Although turtle population persistence is more sensitive to adult survivorship than to hatchling and juvenile survivorship [15,16], population models based on freshwater turtles in northern latitudes have indicated that juvenile survival may play an important role in population persistence when improving already high adult survival is impractical [17,18]. Additionally, many headstarting programs are relatively new, with each reporting variable methods, sample sizes, outcomes [8], and challenges [10,19], making it difficult to evaluate headstarting as a viable reintroduction strategy to recover turtles at a local scale. Despite the on-going debate, headstarting remains a popular tool among conservation practitioners.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of headstarting as a conservation tool to recover Blanding’s Turtles (Emydoidea blandingii) in a highly fragmented urban landscape

et al. 2023

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Freshwater turtle populations are declining globally as a result of anthropogenic activities. Threats to turtles in urban areas are exacerbated by road mortality and subsidized predators, which can lead to catastrophic shifts in population size and structure. Headstarting is used as a conservation tool to supplement turtle populations that may otherwise face extirpation. A headstarting program began in 2012 to recover a functionally extinct population of Blanding’s Turtles (Emydoidea blandingii) 26in Rouge National Urban Park (RNUP), Ontario, Canada. The original population included five adults and one juvenile turtle. From 2014 to 2020, 270 headstarted turtles were released. The population has been monitored annually since 2014 using visual-encounter surveys, radio-telemetry, and live trapping (from 2018 onwards). We used mark-recapture and radio-telemetry data to quantify abundance, survival, and sex ratio of the headstarted turtle population. Using a Jolly-Seber model, we estimated abundance to be 183 turtles (20 turtles/ha) in 2020. Estimated survival of headstarted turtles approached 89%, except for turtles released in 2019 when survival was 43% as a result of a known mass mortality event at the study site. Pre- and post-release sex ratios were not significantly different (χ2 = 1.92; p = 0.16), but shifted from 1:1.5 to 1:1 male:female post-release. Given that the headstarted turtles have not yet reached sexual maturity, it is unclear whether headstarted turtles will reach adulthood and successfully reproduce to maintain a self-sustaining population. Thus, to evaluate the success of the headstarting program, long-term monitoring is required.

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Using the health index of the environmental microbiota to predict the health status of aquatic wildlife

Yang,

Zhou,

Guo

et al. 2023

Ecological Indicators

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Physiological Health and Survival of Captive-Reared and Released Juvenile Blanding’s Turtles

Cited by 5 publications

References 98 publications

Spatial and thermal ecology of juvenile head‐started Blanding's turtles Emydoidea blandingii

Spatial and thermal ecology of juvenile head‐started Blanding's turtles Emydoidea blandingii

Evaluation of headstarting as a conservation tool to recover Blanding’s Turtles (Emydoidea blandingii) in a highly fragmented urban landscape

Using the health index of the environmental microbiota to predict the health status of aquatic wildlife

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