Variation in Salamander Life History and Community Composition Across an Urban Gradient in Atlanta, Georgia, USA
Urbanization threatens to alter stream systems in watersheds in the eastern United States. These highly disturbed systems may result in many local extirpations of sensitive salamander species. One group of organisms that often persists in urban streams is the Eurycea bislineata (Two-lined Salamander) species complex. Many aspects of Two-lined Salamander life history are linked to environmental factors, particularly stream temperature, prey abundance, and stream hydrology. Urbanization threatens to alter these environmental factors, potentially influencing Two-lined Salamander life history. At 14 sites spanning an urban gradient in Atlanta, GA, I investigated the variation in life history and phenology in the Southern Two-lined Salamander, E. cirrigera. I aimed to investigate 1) the anthropogenic and natural factors influencing thermal profiles in urban streams; 2) the environmental drivers of larval period and size; 3) the relationship between clutch size, female size, and degree of urbanization; and 4) changes in plethodontid salamander species richness across an urban gradient, using environmental DNA. I found that 1) drainage basin area was a better predictor of stream temperature than impervious surface cover; 2) cooler August temperatures predicted a longer larval period and smaller larvae; 3) higher impervious surface cover predicted larger larvae and larger adult females; 4) larger females were associated with significantly larger clutches; and 5) plethodontid salamander species richness decreased with increasing impervious surface cover. The results of this research help to assess the ecological implications of urban development by expanding our understanding of the mechanisms underlying variation in E. cirrigera life history and the impacts of urbanization on salamander species richness.
eurycea, edna, two-lined salamander, plethodontid, larval period, Biology, Integrative Biology
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