PS 11-33 - Effects of prescribed fire on butterflies and ground-dwelling insects in maritime grasslands

Tuesday, August 9, 2016
ESA Exhibit Hall, Ft Lauderdale Convention Center
J. Nicole DeSha1, Joseph E. Colbert2, Scott Coleman3, Kimberly M. Andrews4,5 and C. Tate Holbrook1, (1)Department of Natural Sciences, College of Coastal Georgia, (2)Odum School of Ecology, University of Georgia, (3)Little St. Simons Island, (4)University of Georgia, (5)Jekyll Island Authority

Maritime grasslands along the southeastern coast of the United States are important habitats that are threatened by development and fragmentation. These increasingly rare communities are typically dominated by muhly grass and are home to a variety of plant and vertebrate species whose numbers are declining throughout their range. The insect communities of maritime grasslands, however, are poorly studied and no prior research has examined how insects respond to fire in this particular environment. Prescribed fire is being used as an experimental method to manage and maintain grasslands on Little St. Simons Island, GA. Four plots of maritime grasslands that varied in size from 2.5 to 4.5 hectares were selected for controlled burning in February 2015. Each burn plot was paired with an unburned (control) plot of equal size. During the following summer-fall, we tested for effects of fire on the butterfly (Lepidoptera) and ground-dwelling insect communities. Monthly point count surveys were conducted post-treatment in the burn and control plots to estimate butterfly abundance and richness. Pitfall traps were used to sample ground-dwelling insects in each area. 


Preliminary results show no significant differences in abundance or richness of butterflies between the burn and control plots. Of the four most commonly observed butterfly species, three were evenly distributed between the treatments. However, the Gulf fritillary (Agraulis vanilla) was more likely to occur in burned areas. We will discuss the implications of these findings for maritime grassland management and butterfly conservation. We will also present results on the community structure of ground-dwelling insects and their response to fire, with a focus on trophic guilds and key functional groups that insects occupy.