The Status of<i>Macrochelys temminckii</i>(Alligator Snapping Turtle) in the Flint River, GA, 22 Years after the Close of Commercial Harvest

King, Rachel; Hepler, Benjamin P.; Smith, Lora L.; Jensen, John B.

doi:10.1656/058.015.0402

Cited by 18 publications

(32 citation statements)

References 13 publications

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“…Macrochelys temminckii populations have declined significantly throughout their range (Sloan and Lovich, 1995;Pritchard, 2006;Folt et al, 2016;King et al, 2016). The IUCN lists the species as vulnerable, and most states within their range list M. temminckii as endangered, threatened, or in need of management (Rhodin et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…The IUCN lists the species as vulnerable, and most states within their range list M. temminckii as endangered, threatened, or in need of management (Rhodin et al, 2017). The decline of M. temminckii is mainly due to commercial overharvesting that peaked in the 1970s; this decimated many populations with several never recovering (Sloan and Lovich, 1995;Folt et al, 2016;King et al, 2016). Populations of turtles, in general, are sensitive to decreases in adult survival due to life history traits (i.e., longevity, delayed maturity, and low fecundity) that effect on recovery rates (see Congdon et al, 1993;Congdon et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Ontogenetic and seasonal shifts in movement and habitat selection of the alligator snapping turtle (Macrochelys temminckii)

2021

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We aimed to discern the seasonal movement patterns, home range sizes, and microhabitat associations of subadult Macrochelys temminckii in a West Tennessee population. Because this population was previously monitored (i.e., telemetry and habitat use) as juveniles after the initial release in 2005, studying the movement ecology and habitat use of the same released cohort 12 years later allows for unique comparisons between hatchling and subadult ecology. We used radio telemetry to collect movement and microhabitat data of 16 subadult M. temminckii during one year. Our results suggest that seasonal and ontogenetic variation in movement patterns and habitat selection occur within a cohort of M. temminckii. Compared to juveniles, subadults used deep slough areas with high overstory tree cover and had larger home ranges (100% minimum convex polygons [MCP]). Additionally, as subadults, the mean distance moved (m) varied among seasons and furthest during summer. Subadults used deeper water, with higher temperatures and significantly more tree canopy cover, than random locations. Overall, the home range estimate for subadults (mean MCP ± SE; 1.64 ± 0.57 ha) was greater than for juveniles (0.044 ± 0.021 ha). These home-range estimates and habitat usage patterns were similar to subadults in other studies. The seasonal and ontogenetic variations suggest that habitat heterogeneity is critical to sustain populations of introduced M. temminckii.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ontogenetic and seasonal shifts in movement and habitat selection of the alligator snapping turtle (Macrochelys temminckii)

2021

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“…Catch per unit effort did show a clear latitudinal pattern in relative abundance across the study area, which was corroborated after quantifying false-negative error rate. This suggests that alligator snapping turtle hoop trap surveys standardized only by use of CPUE (Folt and Godwin 2013, Lescher et al 2013, King et al 2016, Huntzinger et al 2019) are capable of capturing general patterns in relative abundance, albeit with biases that arise from other sources of inter-survey and inter-site heterogeneity. Our data provide little support that abundance of the species declines at longitudes closer to its western range edge in the state.…”

Section: Determinants Of Distributional Patternsmentioning

confidence: 99%

“…Hoop trap surveys have contributed much of the current ecological understanding of patterns in distribution and abundance of the alligator snapping turtle (Macrochelys temminckii) (Jensen and Birkhead 2003, Riedle et al 2005, Boundy and Kennedy 2006, Howey and Dinkelacker 2013, Huntzinger et al 2019. Many studies using these surveys assume CPUE to be an adequate proxy of relative abundance (Folt and Godwin 2013, Lescher et al 2013, King et al 2016, Huntzinger et al 2019. With a few exceptions (Dreslik et al 2017, Johnson 2020, hoop trap surveys do not explicitly account for environmentally caused variation in p. As potential sources of such variation, there is evidence alligator snapping turtles may decrease activity and be captured at lower rates during temperature extremes brought about during summer and winter (Riedle et al 2006, Fitzgerald and Nelson 2011, Munscher et al 2020), and Pritchard (2006 reported an anecdote that capture rate of the species decreased during bright, full moon nights.…”

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confidence: 99%

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confidence: 99%

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Detection, occupancy, and abundance of the alligator snapping turtle in Texas

et al. 2023

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The alligator snapping turtle (Macrochelys temminckii) is a long‐lived species that is widely distributed across the southeastern United States. Both these characteristics make monitoring its occupancy and abundance particularly challenging. In 2020 and 2021, we conducted hoop trap surveys at 51 permanent water bodies across the Texas, USA, range of the species to estimate occupancy and average abundance with site occupancy models and multinomial N‐mixture models, respectively. We confirmed the species to be present at 61% of surveyed locations. Mean detection probability was 0.77, and was influenced methodologically by the spacing of traps, and environmentally by lunar phase and water flow velocity. Mean occupancy probability was 0.82, and mean estimated abundance was 7.57 turtles/site. Our data provided evidence that the species has a higher occurrence probability in waters of highly forested catchments, and is most probable to occur in highest abundances at median latitudes within its Texas range. Despite known microhabitat preferences of the species, instream habitat characteristics (e.g., canopy coverage, depth, sinuosity) did not strongly influence its occupancy or abundance. Spatial dynamics of the occupancy and abundance of the species in Texas are influenced by landscape features more than local habitat. These results further corroborate the importance of watershed land cover to aquatic organisms, and our methods provide a standardized template for monitoring and quantifying important demographic parameters of the species across multiple locations while accounting for imperfect detection.

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Comparing cost, effort, and performance of environmental DNA sampling and trapping for detecting an elusive freshwater turtle

Sternhagen,

Davis,

Larson

et al. 2024

Environmental DNA

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Environmental DNA (eDNA) analysis is an effective and non‐invasive technique for surveying and monitoring rare, threatened, or endangered (RTE) species. Compared to conventional capture‐based sampling, eDNA analysis may offer a more cost‐effective approach for surveying RTE species, yet few studies have compared their cost‐efficiency—a critical consideration for conservation planning. We compared the costs, effort, and relative performance of aquatic eDNA sampling and conventional trapping for detecting the Alligator Snapping Turtle, Macrochelys temminckii Troost, 1835, in southwest Louisiana, United States. Environmental DNA was sampled quarterly over 1 year (2018–2019) at 19 streams, including three streams where M. temminckii presence had been previously confirmed via conventional trapping efforts (2012–2013). Water samples from each stream were analyzed using quantitative polymerase chain reaction (qPCR) to assess M. temminckii eDNA presence/absence. Time and costs (i.e., labor, travel, wages, and supplies) per detection via eDNA analysis and trapping were calculated and compared. Environmental DNA analysis documented the presence of M. temminckii DNA at two of the three streams where individuals had previously been trapped and yielded detections (qPCR amplifications) at 16 additional streams not previously sampled, expanding M. temminckii's documented distribution at our study sites by 84%. Environmental DNA analysis returned a detection rate (per site) 5.55 times higher than conventional trapping and was 18.7% less expensive. Our results provide evidence that strategically deployed eDNA surveys may be an effective and cost‐efficient approach for detecting freshwater RTE species. With eDNA analysis, additional resources can be invested toward expanding survey coverage and increasing sampling frequency, allowing managers to more effectively target subsequent intensive monitoring efforts.

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The Status ofMacrochelys temminckii(Alligator Snapping Turtle) in the Flint River, GA, 22 Years after the Close of Commercial Harvest

Cited by 18 publications

References 13 publications

Ontogenetic and seasonal shifts in movement and habitat selection of the alligator snapping turtle (Macrochelys temminckii)

Ontogenetic and seasonal shifts in movement and habitat selection of the alligator snapping turtle (Macrochelys temminckii)

Detection, occupancy, and abundance of the alligator snapping turtle in Texas

Comparing cost, effort, and performance of environmental DNA sampling and trapping for detecting an elusive freshwater turtle

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