Evaluating hill prairie quality in the Midwestern United States using Auchenorrhyncha (Insecta: Hemiptera) and vascular plants: a case study in implementing grassland conservation planning and management

Abstract

In this study a habitat quality index based on Auchenorrhyncha (Insecta: Hemiptera) species composition was used to investigate the index’s ability in discriminating hill prairie quality along a gradient of disturbance, based on the Illinois Natural Areas Inventory grading criteria; whether this index differs from other vegetation-based measures of quality; and examine the relationships between Auchenorrhyncha and vegetation integrity and diversity. Auchenorrhyncha and vascular plants were sampled from 14 Illinois glacial-drift hill prairies representing a range in quality. Insects and plants were sampled from late July through August, 2007 and analyzed using univariate and multivariate analyses. Results from this study showed that Floristic Quality Index, Auchenorrhyncha Quality Index, as well as other Auchenorrhyncha and plant diversity and integrity index values are greater in high, followed by mid, then low quality hill prairie remnants. Also, these analyses showed that perennial C4 grasses are strongly associated with prairie Auchenorrhyncha. These data suggest that judicious used of prescribed burning or brush removal may be needed to prevent woody-encroachment from eliminating prairie vegetation and Auchenorrhyncha on low quality sites; and restoration of perennial C4 grasses on low quality sites are needed to support more prairie Auchenorrhyncha fauna. Reintroductions of conservative (i.e., prairie-dependent and fire-sensitive) Auchenorrhyncha may also be needed to improve Auchenorrhyncha integrity on mid and low quality sites but these reintroductions need to be used in combination with reduced burn management or the inclusion of unburned refugia to reduce the extirpation of these fire-sensitive insects.