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Aims Microbiome composition is increasingly considered in species reintroduction efforts and may influence survival and reproductive success. Many turtle species are threatened by anthropogenic pressures and are frequently raised in captivity for reintroduction efforts, yet little is known about turtle microbiome composition in either wild or captive settings. Here, we investigated trends in microbiome composition of captive and wild IUCN-endangered Blanding's turtles (Emydoidea blandingii). Methods and results We amplified and sequenced the V4 region of the 16S rDNA locus from plastron, cloaca, and water samples of wild E. blandingii adults and two populations of captive E. blandingii juveniles being raised for headstarting. Plastron, cloaca, and water-associated microbiomes differed strongly from each other and were highly variable among captive sites and between captive and wild sites. Across plastron, cloaca, and water-associated microbial communities, microbial diversity changed over time, but not in a predictable direction between captive sites. Plastron beta diversity correlated with growth rate in captive samples, indicating that external microbiomes may correlate with individual fitness. Conclusions Our results indicate that external and internal microbiomes vary between captive and wild turtles and may reflect differences in fitness of captive-raised individuals. [ABSTRACT FROM AUTHOR]

Reptiles play a crucial role in maintaining biodiversity and ecosystem health, yet many species face increasing threats because of various anthropogenic factors. To enhance our understanding of reptile diversity and habitat use, evaluation of the effectiveness of diverse survey techniques is necessary. The relative efficacy of different methods may vary significantly across regions or communities, highlighting the need for a comprehensive approach using multiple survey methods over extensive spatial and temporal scales. In this study, we compared the effectiveness of seven survey methods—pitfall traps, funnel traps, spotlighting, arboreal cover boards, incidental encounters, camera traps, and passive acoustic monitoring (PAM)—for assessing reptile biodiversity over several years across an extensive spatial range in open eucalypt woodlands in eastern Australia. Pitfall and funnel traps were the most effective methods for detecting reptiles across all sites and latitudes. A combination of pitfall and funnel traps accumulated species most quickly, had high detection probabilities, and accounted for nearly 90% of all different reptile species detected in this study. However, with a decrease in latitude reptile diversity increased and other survey methods became necessary to document the full extent of the reptile communities. Reptile assemblages captured by different survey methods varied significantly, except for the communities captured by pitfall and funnel traps. No single method captured all species, and no species was detected by every method. PAM failed to detect any reptiles and may not be viable for assessing reptile biodiversity in Australia. Pitfall and funnel traps proved highly effective for detecting terrestrial reptiles within open eucalypt woodlands in Australia; however, the selection of methods for evaluating reptile biodiversity depended on the objectives and target fauna. When possible, to maximize species richness, survey designs should incorporate an array of concurrently deployed methods, particularly in regions with higher overall species richness. Nevertheless, if resources and time are limited, pitfall and funnel traps, combined with incidental encounters, should capture the majority of species. [ABSTRACT FROM AUTHOR]

Introduced red foxes (Vulpes vulpes) are a major predator of freshwater turtle nests in Australia. We evaluated the effectiveness of electric fences, in combination with individual nest protection, for shielding western saw‐shelled turtle (Myuchelys bellii: Chelidae) nests from predation by foxes. We compared the numbers of raided and intact turtle nests found in paired fenced treatment and unfenced control areas of streambank. We also individually protected all intact nests found in both area types with wire mesh or a steel cage. The total numbers of nests found in treatment and control areas did not significantly differ from parity, but significantly more intact nests were found in treatment areas and significantly more raided nests in control areas. The fences were occasionally damaged by livestock, wildlife and flooding, rendering them inoperative for varying periods of time until repair. However, foxes raided nests inside the fences on only two occasions, despite these breaks in functionality. Our study demonstrates that electric fences can provide an effective method of protecting entire nesting areas from depredation by foxes. [ABSTRACT FROM AUTHOR]

Context: Understanding the effects that learned responses to being captured have on subsequent recapture rates and associated abundance estimates is important for developing accurate descriptions of populations and communities. Although variation in the willingness of individual turtles to be trapped is commonly mentioned in the literature, few studies have experimentally tested learned trap avoidance (or fondness) in turtles. Aims: To determine whether turtles learn to avoid traps, whether repositioning traps will lead to increased capture rates, whether this effect varies among species, and whether such relocations yield more accurate depictions of community structure. Methods: We studied a community of turtles in a small lake in south-eastern Kansas that included populations of red-eared slider turtles (Trachemys scripta elegans) and common musk turtles (Sternotherus odoratus). We trapped the lake for 35 consecutive days by using two concurrently deployed groups of traps. One group remained stationary for the duration of the study, whereas traps comprising the other group were moved to new locations on Day 14 and returned to their original locations on Day 28, thus dividing the trapping season into three periods. Key results: For both species, capture rates declined over time. However, traps in the moved group captured more T. s. elegans than did those in the stationary group during the second period and more S. odoratus during the third period. Traps in the moved group also had higher recapture rates in the second period. Population abundance estimates based on captures from the moved group, the stationary group, and the pool of all captures were similar for T. s. elegans , but for S. odoratus the stationary group of traps produced an abundance estimate much lower than those generated from the moved group and the pool of all captures. Conclusions: Both species exhibited learned avoidance of trap locations, but relocating traps had distinct effects on different species, and the accuracy of the observed community structure was improved by relocating traps. Implications: The movement patterns and catchability of individuals of different species within a community must be taken into consideration when developing trapping protocols. Even high-intensity trapping over a long period may not generate an accurate sample of the community if different species use the spatial environment in substantially different ways and learn to avoid trap locations. Learned responses of wildlife to trapping can introduce considerable bias into analyses based on repeated or long-duration surveys of a population. This study investigated the ability of freshwater turtles to learn and avoid the locations of traps. We documented learned trap avoidance and make recommendations for avoiding the sampling bias that results from this behaviour. Photograph by Donald McKnight. [ABSTRACT FROM AUTHOR]

For 57 encounters, we could see the turtles well enough to make general comments on their size and age: juvenile = 9 (including two very young turtles), large juvenile or small adult = 3, small adult = 9, adult (no other size information provided) = 59, large adult = 15. Keywords: behavior; chelonian; flow regime; seasons EN behavior chelonian flow regime seasons 1 5 5 01/04/23 20230101 NES 230101 Many riverine systems experience periodic flooding events as part of their natural flow regimes. Flooding triggers increased surface activity in a bottom-dwelling turtle Furthermore, the fact that multiple juveniles were observed suggests that mating alone likely was not driving the increase in surface activity, but precocial courtship displays have been observed in some turtle species (Kramer & Burghardt, [6]). [Extracted from the article]

Microbiome sequencing data often need to be normalized due to differences in read depths, and recommendations for microbiome analyses generally warn against using proportions or rarefying to normalize data and instead advocate alternatives, such as upper quartile, CSS, edgeR‐TMM, or DESeq‐VS. Those recommendations are, however, based on studies that focused on differential abundance testing and variance standardization, rather than community‐level comparisons (i.e., beta diversity). Also, standardizing the within‐sample variance across samples may suppress differences in species evenness, potentially distorting community‐level patterns. Furthermore, the recommended methods use log transformations, which we expect to exaggerate the importance of differences among rare OTUs, while suppressing the importance of differences among common OTUs.We tested these theoretical predictions via simulations and a real‐world dataset.Proportions and rarefying produced more accurate comparisons among communities and were the only methods that fully normalized read depths across samples. Additionally, upper quartile, CSS, edgeR‐TMM, and DESeq‐VS often masked differences among communities when common OTUs differed, and they produced false positives when rare OTUs differed.Based on our simulations, normalizing via proportions may be superior to other commonly used methods for comparing ecological communities. [ABSTRACT FROM AUTHOR]