AUTHORS: Joseph R. Robb, Big Oaks National Wildlife Refuge, U. S. Fish and Wildlife Service
ABSTRACT: The 50,000-acre Big Oaks National Wildlife Refuge (NWR) contains one of the largest populations of crawfish frogs (Lithobates areolatus) in Indiana. The crawfish frog, a state endangered species in Indiana, is a burrow obligate species that is currently declining throughout much of its range. Sporadic recruitment and woody habitat intrusion were likely responsible for limiting this population at Big Oaks NWR. We initiated several management and research projects to better understand and mitigate this issue during 2004-2024. Occupancy modeling identified focus areas for breeding wetland restoration where quality grassland habitat existed, but populations were absent. This modeling approach also identified aspects of breeding pond use where the most parsimonious model indicated that crawfish frogs selected relatively larger ephemeral wetlands, emergent vegetation present in less than 50% of the wetland, and the absence of woody vegetation. Combining this knowledge with the results from an early pilot project investigating how experimentally drained ponds increased crawfish frog use and reduced their predator and competitor communities, we designed and constructed breeding wetlands to improve the management of this species. We also used several head starting techniques to increase the productivity of this species in quality habitat. Monitoring of these breeding wetlands has shown newly established populations, increased breeding adult use, and increased recruitment. However, the potential for larval disease outbreaks (i.e., Perkinsea sp. and Ranavirus) complicates management. The success of this management regime could be replicated to restore populations in appropriate habitat to stabilize population declines throughout their range especially if management could be used to reduce disease outbreaks.
