To prevent population extirpations, we need to understand a species' requirements, especially for critically endangered species inhabiting biodiversity hotspots. Studying animal movement provides necessary insights and gauges protected area effectiveness. Southeast Asian protected areas are becoming isolated, stressing the need for maintaining population viability. We used radio-telemetry with the critically endangered Elongated Tortoise (Indotestudo elongata) to assess: movements, space use, and conspecific overlap in a small protected area-Sakaerat Biosphere Reserve, Thailand.Movements were weakly seasonal, higher in hot and wet seasons than the dry season, and annual space use varied (4.24-55.57 ha), with conspecifics frequently overlapping. Conspecific comparisons revealed males (n = 5) moved similarly to females (n = 12) but used larger areas. Despite more instances of conspecific attraction over avoidance (20:8), avoidance/attraction behavior appeared disconnected from individual size; therefore, interaction patterns may result from resources locations (mates or food) rather than competition (i.e., no evidence of smaller individuals avoiding larger individuals). Female-female attraction suggests no resource exclusion tactics at our temporal resolution. Male-female attraction may indicate seasonal reproductive movements, but we could not detect significant interactive effects linking conspecific attraction or step length to breeding activity. Our observations of annual space use and overlap present critical components when designing robust population assessments underlining any successful I. elongata conservation effort. In the context of previous work connecting space overlap with population viability, our results suggest the biosphere population of I. elongata to be reproductive, with enough resources to be viable, emphasizing the importance of relatively small protected natural areas.

Home range analysis is a standard and fundamental concept in ecology used to describe animal space use over their lifetimes. Connecting home range sizes with animal characteristics, location, and habitat can be used to inform conservation decisions. Reptiles are frequently lacking robust estimates of space use, particularly reptiles in tropical regions. Here we analyse a publicly available dataset, collected by the authors of this study, describing the movements of Critically Endangered Elongated tortoises Indotestudo elongata. The tortoise data included the locations of 17 tortoises (12 females, 5 males) collected on average once every three days for an average duration of 353.76 SE ± 33.10 days. We use these data to estimate the home range of Elongated tortoise, and explore how tortoise size and sex influences home range size. To mitigate issues resulting from low effective sample sizes and low temporal resolution of the data, we used a modern home range estimation method – Autocorrelated Kernel Density Estimators (AKDE). We found 14 of 17 individuals appear to be occupying a stable home range (using variograms to determine range residency). The average AKDE home range for all 14 individuals with range residency was 44.81 ± 10.44 ha. Bayesian Regression Models suggest comparable size estimates between male and female home ranges, despite males being physically larger than females in both mass and carapace length. These AKDE home range estimates have the added utility of being more comparable with other studies, less susceptible to errors from a suboptimal tracking regime, and are well positioned for inclusion in future meta-analyses. Keywords: testudine, autocorrelated kernel density estimator, spatial ecology, space use, Thailand, Indotestudo elongata

To prevent population extirpations we need to understand species’ requirements, especially for critically endangered species inhabiting biodiversity hotspots. Studying animal movement can provide insights into such requirements and gauge protected area effectiveness. Southeast Asian protected areas are becoming isolated; thus, we need to ensure existing areas can sustain populations. We used multi-year radio-telemetry with the critically endangered Elongated Tortoise (Indotestudo elongata) to assess: movements, space-use, and conspecific overlap in a small protected area –Sakaerat Biosphere Reserve, Thailand. Movements were distinctly seasonal, declining in the dry season. Individuals annual space-use varied (4.24–55.57 ha), while frequently overlapping with conspecifics. Conspecific comparisons revealed males moved more than females despite using similarly sized areas. Explorations of temporal avoidance versus attraction reveal more instances of conspecific attraction than avoidance (20:8). The lack of connection to carapace length or mass suggests no benefits from either attraction or avoidance behaviours; therefore, suggesting conspecific interaction patterns are a result of resources (mates or food) rather than competition. Female-female attraction suggests an absence of resource exclusion tactics at the temporal resolution of our data. Male-female attraction may indicate reproductive movements coinciding with hot season, but we failed to detect significant interactive effects linking conspecific attraction or step length to proximity to breeding activity. When considered in the context of previous work connecting space overlap with population viability, our results suggest the biosphere population of I. elongata to be reproductive, and potentially viable.

Home range is a fundamental concept in ecology used to describe animal space use over their lifetimes. Numerous studies use a variety of metrics to quantify home range; however, most of these treat spatial data inappropriately. Here we re-analyse a publicly available data-set, collected by the authors of this study, using a relatively novel and appropriate home range metric Autocorrelated Kernel Density Estimators (AKDE). Our data includes the movements of 17 Elongated Tortoises (Indotestudo elongata; 12 females, 5 males) located on average once every three days for an average duration of 353.76 ±33.10 days. We found 14 of 17 individuals appear to be occupying a stable home range (using variograms to determine range residency). We made use of AKDEs bias-mitigating measures to counteract the low effective sample sizes stemming from low temporal resolution radio-tracking data. The average AKDE home range for all 14 individuals with range residency was 44.81 ±10.44 ha. Bayesian Regression Models suggest considerable overlap between male and female home range estimates despite males being physically larger than females in both mass and carapace length. These home range estimates have the added utility of being comparable with other studies, less susceptible to errors from a suboptimal tracking regime, and are optimised with code and data for inclusion in future meta-analyses.