Spatial ecology and habitat use of the reeves’ turtle (Mauremys reevesii) in lentic and lotic systems

<title>Abstract</title> Background The Reeves' turtle ( <italic>Mauremys reevesii</italic> ), a globally endangered species listed on CITES Appendix Ⅲ, faces significant threats in South Korea, including habitat fragmentation and competition with invasive species. Effective conservation requires a deep understanding of its spatial ecology, particularly how it differs between distinct habitat types. We compared the spatial ecology of <italic>M. reevesii</italic> in lentic (reservoir) and lotic (river) ecosystems to elucidate how their spatial behavior and habitat use are shaped by these distinct environments. Methods We used GPS telemetry to track 12 adult turtles (6 in a reservoir, 6 in rivers) in South Korea from April to November 2022. We analyzed differences in home range (Minimum Convex Polygon [MCP], Kernel Density Estimation [KDE 95%], Local Convex Hull [LoCoH 99%]), daily movement distance (Generalized Linear Model [GLM] testing habitat, sex, and season), diel terrestrial activity (circular statistics), road-crossing behavior (GLM), and seasonal displacement (Generalized Additive Model [GAM]). Results (1) Home range size (LoCoH 99%) did not differ significantly between habitats, but males exhibited significantly larger home ranges than females (MCP: p = 0.015). (2) Daily movement distance was significantly greater in the reservoir than in rivers (t=-5.92, p &lt; 0.001) and significantly greater in spring than in autumn (t=-2.67, p = 0.008). (3) Diel terrestrial activity patterns differed significantly between habitats (Watson’s u ² test, p &lt; 0.001); while both groups peaked activity around 14:00 h, the activity of the river population was significantly more concentrated at this time. (4) The rate of road crossing was significantly positively correlated with the area of adjacent paddy fields, but not the length of roads within the home range. (5) GAM analysis revealed distinct movement patterns: reservoir turtles exhibited stable, non-linear displacement (100–400 m), while river turtles showed erratic, linear movements (100–900 m, max 1300 m) with a distinct peak in August. Conclusions <italic>M. reevesii</italic> displays significant plasticity in spatial ecology, adopting divergent movement patterns in response to lentic versus lotic environments. We recommend habitat-specific conservation buffers (e.g., 400 m radius for reservoirs, 1300 m linear distance for rivers) and prioritizing road mitigation measures (e.g., eco-passages, fences) in areas adjacent to paddy fields. These findings underscore the necessity of connectivity within these defined core habitats for effective population management.