Fine-scale movement behaviors of calopterygid damselflies are influenced by landscape structure: an experimental manipulation

We explore the effect of differences in landscape structure, arising from h abitat loss, on the fine-scale movement behaviors of two congeneric damself lies - Calopteryx aequabilis and C. maculata. Both species require streams for breeding and naiad development and both often use forest for foraging. We compare movement behaviors across three types of landscape: forested lan dscapes, where stream and forest habitat are adjacent; partially forested l andscapes, where streams and forest habitat are disjunct, and non-forested landscapes, where little to no forest habitat is available. We employ a rec iprocal transplant experiment to determine the extent to which movement alo ng and away from streams is influenced by landscape structure and historica l behavior or morphological adaptations. For both species, we show that bot h the propensity to move away from streams and rates of net displacement di ffer among landscape types. Both species move away from streams on landscap es with high or moderate levels of forest cover but neither moves away from streams on landscapes with little or no forest. Furthermore, C. maculata n ative to predominantly forested landscapes are more likely to move away fro m streams, regardless of the landscape structure they encounter, than are i ndividuals native to moderately forested or non-forested landscapes. There was no effect of natal landscape on C. aequabilis. Comparisons with microla ndscape studies suggest that there may be some general similarities among t he different systems but these are clouded by uncertainty regarding the sim ilarity of the underlying precesses responsible for observed behavioral res ponses to landscape structure. Despite this uncertainty, animal movement be haviors are contingent upon the structure of the broader landscape, regardl ess of the absolute scale of the landscape.