Seed dispersal by ants has been shown to play an important role in plant community dynamics. Less understood is how landscape factors such as habitat connectivity and edge effects play a role in this important plant-animal interaction. Connectivity and edge effects may affect seed dispersal by ants in a least a couple of ways: 1. more connected habitats may result in more colonization events of ants into a habitat patch changing the community of ant seed dispersers and 2. altered abiotic environments resulting from changes to the landscape can change the abiotic context of seed dispersal. We conducted observations of caches of ant-dispersed seeds in a landscape-scale experiment in which we manipulated habitat connectivity with corridors, linear strips of habitat that connect isolated habitat patches. Each replicate (N=4) consisted of a center patch surrounded by four equal in area (~1.4 ha) patches, one connected to the center by a 150m corridor. Caches were located in the center and along the edge of each patch. We asked: 1. Does connectivity and amount of edge habitat affect seed dispersal by ants?, 2. Does proximity to an edge within a patch affect ant seed dispersal? and 3. What are the effects of ant diversity on ant seed dispersal?
Results/Conclusions
Across all patch types we observed a total of 12 ant species that dispersed seeds. We did not find evidence that connectivity or edges affect the number of seeds removed or the time it took ants to detect seeds, however we did find that habitat connectivity and edge proximity interact such that ants moved seeds almost five times further in the center of connected patches than in the center of winged patches. In isolated patch types seeds were moved about two times further when caches at the edge of patches than in the center, but we saw no difference in the length dispersed between edge proximities in connected patches. Finally, we did not detect an effect of the number of ant species dispersing seeds within a patch on the number of seeds that ants dispersed. Overall, these results suggest that connectivity may have effects on seed dispersal by ants that are mediated through edge effects.