Specialist and generalist amphibians respond to wetland restoration treatments

Abstract

ABSTRACTAvailable habitat within a landscape is often more limited for specialist species than for generalists. Therefore, specialists are potentially more vulnerable to extinction. The goal of our study was to better understand the ephemeral wetland habitat associations of specialist and generalist amphibians within a longleaf pine landscape in the southeastern United States. We also sought to determine specialist (e.g., oak toad [Anaxyrus quercicus], Maybee's salamander [Ambystoma maybeei], pine woods treefrog [Hyla femoralis], carpenter frog [Lithobates virgatipes]) and generalist (e.g., spotted salamander [Ambystoma maculatum], Cope's gray treefrog [Hyla chrysoscelis], southern leopard frog [Lithobates sphenocephalus]) species’ responses to specific habitat restoration treatments. From 2005–2010, we examined the relationship between aquatic specialist and generalist amphibian species occupancy and wetland vegetation structure. We measured vegetation and amphibian responses to prescribed fire and vegetation mulching (a fire surrogate), plus a combination of mulching and burning. Untreated controls were wetlands that had not burned for 4–15 years. We combined data from this study and a previous study to elucidate patterns in amphibian assemblages in relation to fire history. Specialist relative species richness was highest when canopy openness was high and leaf litter depth was low, conditions best achieved by mulching plus burning. Some specialist species were not detected in wetlands with >8 years since fire, and some generalist species were not detected in wetlands with <2 years since fire, indicating that as vegetation structure changes with time since fire, there is a corresponding shift in the amphibian assemblage. Important patterns in species distributions can be overlooked if relationships to environment and responses to habitat change are too generalized and do not account for shifts in community composition. For conservation of longleaf pine specialist species, we recommend that uplands continue to be prescribed‐burned on a 1–3‐year return interval. Burning should occur during the early growing season when possible to maximize the probability that wetland basins burn. In cases where species of high conservation value are at imminent risk of extinction, we recommend a combination of mulching and burning to most quickly restore suitable habitat structure. © 2016 The Wildlife Society.