Sex-biased dispersal in a rare butterfly and the implications for its conservation

To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work.\ud This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://www.springer.com/?SGWID=0-102-0-0-0.The survival of many species may be dependent\ud on their ability to exist in human-altered landscapes\ud within metapopulations; in turn, metapopulation persistence\ud is dictated by the ability of individuals to move\ud effectively among patches to promote recolonization. The\ud Taylor’s checkerspot butterfly (Euphydryas editha taylori)\ud is a species that does not naturally occur in fragmented\ud landscapes, yet it is now restricted to a handful of small\ud isolated prairie habitats. Current recovery plans aim to\ud establish a stable metapopulation; however, to date little is\ud known about the species’ ability to move across the landscape.\ud In 2010 and 2011, we conducted marking, tracking\ud and boundary surveys to explore the movement dynamics\ud of adults within two sites in Oregon, USA. Over the survey\ud period, we marked 136 male butterflies, tracked 174 individuals\ud and observed the behavior of 1,576 individual\ud butterflies at site boundaries. Our study revealed a significant\ud sex-bias in the movement dynamics of the Taylor’s\ud checkerspot in both suitable habitat and surrounding\ud matrix. Males were highly motile, whereas females\ud appeared sedentary, rarely moving from their natal site.\ud The limited dispersal behavior of females indicates that\ud populations cannot persist naturally in a metapopulation\ud and thus are at high risk of extinction. Based on our findings,\ud we recommend that managers take proactive measures\ud to increase or enable dispersal (including\ud translocation) to existing and/or restored sites