Amphibian Communities in Natural and Constructed Ridge Top Wetlands with Implications for Wetland Construction
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Among the many causes linked to amphibian declines, habitat loss and alteration remain the most significant. Lack of federal protection for isolated wetlands has resulted in loss of amphibian breeding habitat without subsequent mitigation. Additionally, wetlands built for mitigation often do not replicate lost natural wetlands in structure or ecological processes. The long-term role of constructed wetlands for amphibian conservation is poorly understood because monitoring is often lacking. Our objective was to compare amphibian communities of natural wetlands to 2 types of constructed wetlands in the Daniel Boone National Forest, Kentucky. We measured habitat variables including canopy closure, hydrology, upland coarse woody debris, aquatic vegetation, maximum water depth, and Ohio Wetland Rapid Assessment Score at each wetland and quantified species-specific amphibian capture per unit effort using dip-netting. Wood frogs (Lithobates sylvaticus) and marbled salamanders (Ambystoma opacum) were almost exclusively found in natural, ephemeral wetlands, whereas large frogs (L. clamitans, L. catesbeianus, L. palustris) were primarily found breeding in permanent, constructed wetlands. Permutational analysis of variance indicated significant differences in amphibian communities between constructed and natural wetland types. Redundancy analysis indicated that hydrology and canopy closure best explained the differences in community composition between natural and constructed wetlands. Regression analyses and subsequent model ranking showed that greater captures per unit effort for eastern newts (Notopthalmus viridescens) and green frogs (L. clamitans) were predicted by increasing wetland size and depth, respectively, whereas mole salamanders (Ambystoma sp.) were negatively associated with the amount of aquatic vegetation and positively associated with wetland depth. As amphibian conservation and management become increasingly important in light of recent population declines and habitat loss, the ability to construct wetlands that provide amphibian habitat and to monitor how amphibians respond will be crucial to preservation of species diversity. Our research underscores the need for monitoring constructed wetlands to assess ecological condition. We provide suggestions to land managers who aim to construct isolated wetlands for amphibians.
Denton, Robert D. and Richter, Stephen C., "Amphibian Communities in Natural and Constructed Ridge Top Wetlands with Implications for Wetland Construction" (2013). EKU Faculty and Staff Scholarship. 658.