PARENT SESSION
Poster Session 20: Biodiversity.

Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.

Ecological constraints on faunal recovery in restored tallgrass prairies: A case study using Lepidoptera.

Summerville, Keith^*,1, Lewis, Michelle¹, Steichen, Renae¹, ¹ Department of Environmental Science and Policy, Des Moines, IA, USA

ABSTRACT- Tallgrass prairie and oak savannas once spanned a vast portion of the upper midwestern United States, but now comprise less than 1% of the vegetation. Because large patches of remnant vegetation are virtually absent in the upper Midwest, the conservation of native plant and animal diversity will require a commitment to habitat restoration. Animal communities are often too costly to re-introduce over broad areas, so many land managers have opted for a passive approach to faunal restoration. The success of this technique, however, is predicated on the assumption that colonization of a site from the regional species pool is favorably influenced by changes in environmental variables following restoration. The goal of this study was to test whether estimates of habitat quantity or quality, measured at different spatial scales, were significant predictors of lepidopteran diversity in mixed woodlands being restored to oak savanna. In 2003, we sampled Lepidoptera and 11 environmental variables from 13 woodland remnants at Neal Smith National Wildlife Refuge in central Iowa. Principle components analysis partitioned the environmental variation among the 13 sites into three significant axes defined by: stand size, shape, and topography (axis 1), past management history (axis 2), and regional connectivity (axis 3). Multiple regression analysis detected that total moth richness was a function the first principle component. In contrast, richness of moth species known only to feed on oaks was significantly affected by all three principle components. Unexpectedly, increased connectivity was negatively correlated with the species richness of oak feeders. Our results suggest that the success of restoring native lepidopteran communities will be significantly influenced by the size of the remnant being managed. More importantly, however, our data indicate that historic land use and regional patterns in habitat availability are critical factors in determining the re-assembly of lepidopteran communities in restored savannas.

Key words: Biodiversity, Restoration Ecology, Connectivity, Moths