Evaluating the effects of landscape configuration on site occupancy and movement dynamics of odonates in Iowa

Odonates contribute highly to global biodiversity and are considered good indicators of environmental quality, but they are under-studied and quantitative information on their habitat associations is lacking. Our objective was to examine the effects of landscape configuration on site occupancy and movement dynamics of four odonate species in Iowa: Tramea onusta, Epitheca princeps, Pantala flavescens, and Calopteryx maculata. We conducted standardized visual encounter surveys for odonates at 233 public properties in Iowa from 2007 to 2011 and computed landscape variables within a 200, 600 m, and 1 km radius of each surveyed site. Using a robust design occupancy model in Program MARK, we estimated detection probability and site occupancy, site extinction, and site colonization probabilities for each species. We found few significant effects of landscape variables on site occupancy, extinction, or colonization, although landscape variables at 600 m were included in the best model for all species. Detection probability (SE) ranged from 0.30 (0.04) for Pantala flavescens to 0.49 (0.04) for Calopteryx maculata. Our study provides information to aid habitat restoration and management efforts on sites having suitable characteristics in the surrounding landscape and ultimately help conserve odonates.