Habitat fragmentation and climate change, two of the biggest threats to biodiversity around the globe, might potentially cause synergistic effects that are as yet unknown. Will climate change exacerbate the isolation of fragmentation? Will patchier landscapes lose species more quickly as temperatures shift? In their upcoming paper in Functional Ecology, Barnes et al. focus these broader issues by closely examining how animal behavior might shift under different temperature regimes in a fragmented landscape. They focus specifically on animal behavior in corridors, and ask how individual use and encounter rate may be affected by increasing temperatures.
Using woodlice (Oniscus asellus) in differently heated experimental chambers of two habitat patches connected by a corridor, they looked at how often woodlice encountered and used corridors using novel tracking methods via video. According to metabolic theory, rising temperatures should encourage individuals to cross corridors more efficiently because, in general, warmer temperatures lead to more body movement. If true, climate change might actually lead to behavior that increases connectivity.
The authors found that, in general, woodlice moved faster and more often in corridors than patches. This was an expected result, since corridors are often assumed to be used more for connectivity rather than as high quality habitat. However, corridor crossing rate actually decreased with increasing temperature. Were lower encounter and movement rates at higher temperatures due to low humidity (a barrier to woodlice movement), as the authors hypothesize, or some other unaccounted for factor?
The study not only highlights an interesting experimental setup to test behavioral response to corridors, but also gives more food for thought on exactly how animals encounter corridors and why they choose to cross them. Few studies so far have looked in such detail at how climate change may affect behavior in corridors.
Barnes, A., I. Spey, L. Rohde, U. Brose, and A. I. Dell. 2015. Individual behavior mediates effects of warming on movement across a fragmented landscape. Functional Ecology. DOI: 10.1111/1365-2435.12474.