Many Stayers, Few Movers: Seasonal and Sex-Based Movement Patterns in an Endangered Forest-Dwelling Salamander.

内容摘要

Understanding movement patterns of low-mobility forest amphibians is challenging because they are often highly localised, and rare displacement events may disproportionately influence space use, connectivity and population dynamics. We investigated individual and population-level spatial ecology in the forest specialist Salamandrina perspicillata, assessing spatial displacements, movement rates, home ranges and population density across sexes and seasons. We analysed multi-session capture-recapture data collected in a temperate forest in central Italy. Spatial displacement was described using cumulative movement distance and maximum step length. Individual space use was estimated using Minimum Enclosing Circles (MEC), while population-level density and movement scale were assessed through spatial capture-recapture (SCR) models. Movement rate showed seasonal variation, with significantly higher values during the first autumn compared to spring and second autumn, indicating temporally constrained movement intensity. Distance-based metrics and MEC home ranges exhibited strongly right-skewed distributions, with a high proportion of individuals showing no detectable displacement and most mobile individuals remaining within very small spatial extents (median MEC home range: males = 160.22 m2; females = 145.30 m2). A few individuals accounted for relatively large movements and space use, generating long right tails. Females showed greater inter-individual variability and a larger movement scale (σ) in SCR models, whereas cumulative distances and home ranges did not differ consistently between sexes after excluding non-moving individuals. No significant relationships were detected between body size and any space-use metric. Population density showed marked variation between seasons (between 345 and 728 individuals/ha for males and between 171 and 690 for females), with animals concentrating close to the breeding stream during spring and being more spread out during autumn. Our results unravel a movement system characterised by many highly sedentary individuals and few relatively mobile ones (many stayers, few movers). Integrating multiple techniques, we provided a multi-scale framework to characterise space use in low-mobility species that yielded important insights for connectivity and conservation in forest-dwelling amphibians.