PURRENHAGE, Jennifer L*; BOONE, Michelle D; Miami University: Effects of Habitat Structure and Competition on Larval Amphibian Development

Habitat structure and competitor density can have important impacts on the growth and development of many species. Structure and competition may be especially important for larvae of pond-breeding amphibians that must complete metamorphosis prior to pond drying. Despite their importance, few studies have examined these factors simultaneously. The purpose of this study was to investigate the effects of aquatic habitat structure and competitor density on larval development and survival in several species of amphibians. Using replicated pond mesocosms, we manipulated the type of structure present (cattails, artificial cattails, or none) and the density of a larger heterospecific competitor (Rana pipiens) in a full-factorial design. We measured survival, time to metamorphosis, and size at metamorphosis (mass and snout-vent length) in three species of amphibians: Bufo americanus, Hyla versicolor, and Ambystoma maculatum. Additionally, we measured response of R. pipiens to intraspecific competition across structure treatments. Although response varied among species, our data suggest that time to metamorphosis and survival may be influenced by both aquatic habitat structure and competition, whereas size at metamorphosis may be affected primarily by competition. Our findings have important implications for wetland management and amphibian conservation. It remains unclear whether mitigated wetlands provide suitable replacement habitat for wildlife, but habitat structure and community composition should be considered when making these assessments.