Influence of the direct and indirect effects of habitat fragmentation, via microclimate change, on animal locomotion

Context: Intensive use of agricultural land often modifies the landscape by dividing continuous natural habitat into smaller and more isolated patches. While the effects of habitat fragmentation on species abundance and diversity have been widely studied, little is known about how fragmentation impacts the function of organisms that do persist in the modified environment. Understanding these effects is complicated by the fact that fragmentation can affect organisms directly but also indirectly, by altering the patch microclimatic conditions. Objectives: We tested the hypothesis that fragmentation-induced microclimate change might be an important mechanism driving changes in animal locomotion in an agricultural landscape. Methods: We used satellite image analysis, behavioral assays, and patch analyses, to disentangling the direct and indirect effects of fragmentation on the locomotor behavior of a darkling beetle, Zophosis punctata (Tenebrionidae), in the Southern Judea Lowlands in Israel. Results: We found that fragmentation in an agricultural ecosystem may lead to changes in the thermal conditions of natural habitat patches. Importantly, such fragmentation-related increases in patch temperature played an important role in explaining variation in beetle locomotion across an agricultural landscape. Specifically, beetles from highly fragmented landscapes, which included warmer habitat patches, showed high locomotor intermittence -frequent pausing events during locomotion. Conclusions: This study shows that the potential consequences of habitat fragmentation on organism function are likely to be underestimated when fragmentation-related microclimate change is ignored. Intermittent locomotion, as opposed to steady locomotion, may provide physiological and fitness benefits in fragmented landscapes, like mitigating performance limitations imposed by extreme thermal conditions.