Habitat fragmentation reduces landscape connectivity and alters ecological systems; biological corridors are used to mitigate fragmentation’s negative effects. In addition to promoting connectivity, corridors affect the abiotic environment of landscapes either directly or indirectly through the creation of edge habitat. Though ants vary their behavior and foraging times dependent on thermal body limits, whether preferential foraging niches affect ants’ community composition in fragmented landscapes remains unclear. We used a landscape-scale experiment to examine whether thermal niches affect how ant species occupy different regions within fragmented landscapes. Our experiment had seven replications of three equal area treatments aimed at determining how corridors function: (1) a fragment connected by a corridor, (2) a high edge, isolated fragment, and (3) a low edge, isolated fragment. We used pitfall traps (22/fragment) to obtain occurrence data for ant species. We measured ants’ thermal foraging niches by measuring the surface temperature at which ants visited tuna baits in habitat similar to our experimental fragments. We compared our measured ant thermal niches to the occurrence data to answer the following question: do thermal foraging niches predict ant species’ responses to habitat fragmentation with respect to distance from habitat edge and fragment shape?
Results/Conclusions
We found that all ant species foraged less at higher temperatures during the day in the summer (F = -1.45, p < 0.001). Differences in ant foraging niches led to statistically significant differences in the ant communities present in fragmented habitats related to shape (Chisq = 6.27, Df = 2, p = 0.04). Specifically, ant communities in fragments with corridors exhibited stronger negative relationships between temperature and foraging than ant communities in high-edge fragments (~116% stronger). We did not observe an effect of distance to edge (Chisq = 3.07, Df = 4, p = 0.55). Stronger and more frequent wind in connected compared to high-edge fragments could explain the lower niche preference in connected fragments, but not the contrast between high-edge and connected. In addition, previous research showing fragment type does not affect temperature in our sites does not coincide with the foraging niche dependence on fragment type found in our study. Therefore, the higher foraging temperature preference of ants in high-edge fragments could relate to variation in microhabitat or other abiotic factors not yet measured in our sites. Overall, our study contributes to growing research investigating thermal ecology and how landscape change impacts ecological communities.