Military training areas as refuges for threatened dragonfly species: Effect of spatial isolation and military activity

A long-term decline in habitat quality and freshwater species diversity has forced conservation managers to consider secondary habitats, such as military training areas (MTAs), that were previously overlooked but have conservation potential. Isolation from many negative anthropogenic influences combined with disturbances associated with military activities can benefit the diversity of terrestrial species. However, little is known about the conservation potential of freshwater habitats that are an integral part of MTAs. In this study, we used dragonflies and damselflies as valuable indicators of habitat quality to compare the diversity of freshwater sites inside and outside MTAs. We randomly selected 16 sites inside four extensive MTAs and 16 reference sites outside MTAs and examined the differences in traits of species occurring inside and outside the MTAs. We found that the diversity and conservation value of dragonfly communities inside MTAs was comparable to that in the most valuable freshwater habitats outside MTAs. Inside MTAs, species were primarily those associated with habitats in the late successional stages, while species associated with early successional stages were absent. Undoubtedly, the conservation potential of MTAs for freshwater invertebrates is in the long-term isolation from negative anthropogenic influences. Paradoxically, the main potential problem in protecting freshwater habitats inside MTAs is the cessation of military activity.