PS 55-112 - Effects of corridors on seed dispersal by ants

Thursday, August 10, 2017
Exhibit Hall, Oregon Convention Center
Melissa A. Burt, Department of Applied Ecology, North Carolina State University, New Ellenton, SC, Nick M. Haddad, Department of Applied Ecology, North Carolina State University, De'Aja Sanders, Department of Biological Sciences, North Carolina State University, Raleigh, NC and Julian Resasco, Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO

Corridors, thin strips of habitat connecting otherwise isolated patches, are commonly used to lessen the negative effects of fragmentation. Corridors have been shown to increase plant species richness, and this effect depends on a plant’s seed dispersal mode. Less well known are the potential effects of corridors on myrmecochory (seed dispersal by ants). Landscape features, such as corridors, could affect myrmecochory by altering the context (e.g. connectivity, distance to an edge, temperature, etc.) in which ants are active. We conducted this study within a landscape-scale experiment (N=4 blocks). Each experimental block consists of a center habitat patch surrounded by four peripheral patches, one connected by a 150-meter corridor. By visually observing seed depots containing seeds typically dispersed by ants, we measured the rate (number of seeds removed per minute) and magnitude (total number of seeds removed at the end of an observation) of myrmecochory to ask: (1) What are the relative effects of corridors, distance from edge, and temperature on myrmecochory? and (2) Do these variables interact to affect myrmecochory?


We found no evidence that the presence of a corridor or the distance from an edge affects the rate or magnitude of myrmecochory within our experiment (p > 0.05). Although we found no effect of distance from the edge, we did find an effect of temperature (p = 0.008) such that the rate of myrmecochory decreased as temperature increased. None of these variables interacted to affect myrmecochory (p>0.05). This suggests that although distance from an edge can have direct effects on temperature at a larger scale, the temperature at a smaller scale, which can vary widely in a heterogeneous environment, is a better predictor of seed dispersal by ants. Taken together, these results suggest that variables describing the small-scale environment at which myrmecochory occurs are more important than variables describing the larger landscape-scale.