Land management effects in Missouri conservation areas on pond-breeding amphibians

Background/Question/Methods

Currently, extinction rates for plants and animals are estimated to be 1,000 times higher than background rates from the fossil record. Of the vertebrate groups that have been completely evaluated (birds, mammals, and amphibians), the IUCN found that 30% of all amphibian species were at risk of extinction. While there are a number of factors that have contributed to these declines, it is widely accepted that the primary threats facing amphibians are habitat loss and degradation. Federal and state managed conservation areas in the U.S. are generally viewed as protected lands that contain increased levels of species richness and abundance when compared to the surrounding landscape and serve as reservoirs to buffer these overall declines. However, land management and use within these conservation areas may greatly influence species richness and abundance. We sampled 40 total amphibian breeding ponds in two adjacent conservation areas of similar size in east-central Missouri to test predictions about the effects of land management and use on amphibian species richness. Our objectives were to estimate and compare pond-breeding amphibian species richness and wetland conservation coefficients among two conservation areas that have different land management practices.

Results/Conclusions

Twenty-three ponds were sampled in August Busch Conservation Area (ABCA) and 17 ponds were sampled in Weldon Spring Conservation Area (WSCA). In ponds that were unoccupied by predatory fish, we found no significant difference in species richness (p = 0.086) between the two conservation areas; however wetland conservation coefficients (p = 0.022) were significantly higher in WSCA. Wetland conservation coefficients provide an adjustment for a species’ tolerance of disturbance, its rarity, and its distribution. No significant differences were found for leaf litter depth (p = 0.778) or canopy cover (p = 0.294) surrounding ponds between the two conservation areas, but forested buffer zone width was significantly greater (p < 0.001) surrounding breeding ponds in WSCA. Our results show that land management practices that fragment a conservation area have the greatest effect on more sensitive species (as shown by the reduced wetland conservation coefficients in ABCA). Additionally, a generic metric such as species richness may not provide appropriate insight into the overall importance of a given wetland since it treats all species equally (i.e. a generalist is scored the same as a specialist).