Ambhibian Community Response to Variation in Habitat Structure and Competitor Density

• Published in: Herpetologica Vol. 65; no. 1; pp. 14 - 30
• Main Authors: Purrenhage, Jennifer L., Boone, Michelle D.
• Format: Journal Article
• Language: English
• Published: The Herpetologists' League, Inc 01-03-2009
• Subjects: Amphibians; Density; Habitat conservation; Larvae; Larval development; Metamorphosis; Ponds; Vegetation structure; Wetland ecology; Wildlife habitats
• ISSN: 0018-0831; 1938-5099

Habitat destruction and alteration is a major cause of population declines; thus, habitat restoration is essential for preventing species extinctions. Habitat restoration, however, may be hindered by an inadequate understanding of species' habitat requirements. Habitat structure may play a major role in influencing the biotic interactions among species. Pond-breeding amphibians are one group that has experienced loss and alteration of critical habitats. Vegetation structure in wetland environments may be important to amphibian larvae if its presence mediates biotic interactions, such as competition, which can affect growth and survival to metamorphosis. Despite the potential importance of habitat structure and competition, few studies have examined these factors simultaneously. In a full-factorial pond mesocosm experiment, we tested for the effects of variation in habitat structure and density of a larger tadpole competitor (Rana pipiens, northern leopard frog) on development and survival of three species of larval amphibians: Bufo americanus (American toad), Hyla versicolor (gray treefrog), and Ambystoma maculatum (spotted salamander). Survival of Bufo was greater in mesocosms with live or artificial cattails than in those lacking vegetation. Although responses varied among species, our data suggest that time to metamorphosis, survival, and species evenness can be influenced by both aquatic habitat structure and competition, whereas size at metamorphosis is affected primarily by competition. Our study is the first to demonstrate that vegetation structure alone can affect the expression of metamorphic traits for some anuran species.