Wetland Condition Matters: Amphibian richness and abundance change across wetland condition gradient.

摘要

In the past century, Kentucky has lost more than 80% of its wetlands, and because state-wide monitoring was historically minimal, this number is likely underestimated. The Kentucky Division of Water, with Eastern Kentucky University and a technical working group, developed a rapid wetland assessment method (i.e. KY-WRAM) to assess wetland quality and aid in establishing mitigation levels and long-term monitoring. Validation of the KY-WRAM's ability to reflect wetland condition requires comparison to intensive biotic assessments of amphibian, plant, and bird communities. Wetland and amphibian surveys for the 2014 and 2015 seasons were conducted at 42 riverine wetlands in the Kentucky and Salt river basins in Kentucky. Wetlands were chosen from across a gradient of low-, medium-, and high-category scores to compare amphibian communities across a range of wetland condition. Seven were in the low category, twenty-four in medium, and eleven in the high category. Wetlands were surveyed for amphibians via dipnetting and minnow-trapping. Species richness and abundance were tested with AIC modeling using nutrients, dissolved oxygen, landscape disturbance, presence of predatory fish, the pesticide atrazine, and KY-WRAM scores as model parameters. Results indicated KY-WRAM score explained the majority in species richness, and was an important predictor of abundance for seven species of amphibians. Additionally, species richness was significantly and positively related to KY-WRAM score (p<0.001, R 2 = 0.62), and was greater among medium and high category sites than low ones. Species present at low quality sites tended to be present at all sites, and species that are sensitive to disturbance were generally only found at higher-scoring sites. KY-WRAM scores reflect a gradient of wetland condition, and anthropogenic impacts within wetland habitats and surrounding uplands are reflected in these scores. Overall, these results indicate that the KY-WRAM is a good predictor of wetland condition, and strongly relates to amphibian communities.