Movement patterns of the rodent Trinomys dimidiatus in Atlantic Forest

Abstract

Animal movements of wild species are in theory related to individual and species' traits such as sex and reproductive condition, and temporal variation in resource availability or population density. Understanding how individuals move within an area throughout life, how frequent exploratory and dispersive movement are in the population and which individual traits and environmental conditions influence movement are of great importance for understanding how animals respond to environmental changes. Using capture‐mark‐recapture data of Trinomys dimidiatus gathered for 8 years in a montane Atlantic Forest area, we describe movement patterns by comparing two distance metrics (ORL—Observed Range Length and SDT—Mean Successive Distance/Time); we also evaluate the influences of sex on these distance metrics and residence time and number of captures on ORL. Additionally, model selection was used to evaluate the role of individual traits and environmental factors on T. dimidiatus' movements. We recorded 44 individuals (60.27%) with restricted movement pattern and 29 individuals (39.73%) with broad movement pattern within our grid. Broad movement pattern was observed in individuals with both long and short residence time. Males presented larger distance metrics and movements than females. Individuals with greater residence time presented larger ORL, mainly males. Heavier individuals of both sexes presented larger movements than lighter ones, especially males. Males presented shorter movements in periods of increased rainfall, but females' movements did not respond to rainfall variations. Overall, body mass was more important than rainfall in determining movements. The results here show that T. dimidiatus may present different movement patterns, including exploratory or dispersive movements to a new core area. Also, we highlight the importance of individual traits and environmental factors and reinforce sexual differences in individuals' movements and lifetime use of space.