Movement behaviour of woodland salamanders is repeatable and varies with forest age in a fragmented landscape

Abstract

Landscape modification (loss, fragmentation and degradation of habitat) is a universal form of human-induced rapid environmental change that creates strong spatial variation in environmental conditions. Behaviourally mediated responses to landscape modification may generate behavioural divergence among populations along environmental gradients. We tested whether movement behaviour of red-backed salamanders, Plethodon cinereus, is repeatable and whether it varies within and between forest stands of different ages in a fragmented landscape in New York, U.S.A. Water loss is a major constraint on P. cinereus mobility, and forest fragmentation creates spatial variation in desiccation risk. We quantified multiple components of individual movement behaviour in an unfamiliar environment in the laboratory and used ordination to identify behavioural variation among individuals in multivariate space. We tested for repeatability of individual behaviour and then examined behavioural differences between individuals captured from populations at two spatial scales where desiccation risk was expected to vary: (1) between edge and interior locations within forest stands and (2) between forest stands varying in time since agricultural abandonment. Variation in movement behaviour among individuals was characterized by three components: total movement activity (e.g. surface activity, distance moved, boundary crossings), substrate use (time on moist soil versus dry sand) and latency to initial movement. Each behavioural component was significantly repeatable. At the population level, individuals from old forest stands (≥77 years) showed greater movement activity than individuals from young stands. Movement behaviour did not differ between individuals from edge and interior locations within forest stands. Our results demonstrate that P. cinereus individuals show consistent differences in movement behaviour in an unfamiliar environment. Moreover, we show that movement behaviour can be spatially structured within fragmented landscapes, but that behavioural divergence among populations depends on spatial scale.