Size Structure and Intraguild Interactions between Two Ambystoma Species
Intraguild interactions affect population and community structure through a combination of competition and predation. Changes in size structure influence intraguild interactions by affecting the strength and direction of these species’ interactions. I tested for size-structured intraguild interactions in temporary pond ecosystems between marbled salamanders (Ambystoma opacum) and tiger salamanders (Ambystoma tigrinum) using an outdoor mesocosm experiment. I hypothesized that 1) A. opacum survivorship and growth would be negatively impacted when both species start at a similar size because tiger salamanders grow faster and are more aggressive 2) A. tigrinum will grow slower and have lower survivorship when they occur with large A. opacum because A. opacum will outcompete A. tigrinum and prey upon them. There was no support for the second hypothesis, A. tigrinum grew and survived the same regardless of A. opacum size. However, I found support for the first hypothesis. Small A. opacum mortality was greatest when they occurred with small A. tigrinum suggesting changes in size structure resulting in these two species occurring together at similar sizes will negatively impact A. opacum populations through intraguild predation. Climate change will likely affect the distribution and abundance of species in temporary pond ecosystems and influence size-structured interactions that impact population and community structure.
Amphibian Larvae Survivorship, Mesocosm, Intraguild Predation, Size-Structure, Ambystoma Opacum, Ambystoma Tigrinum, Biology, Ecology and Evolutionary Biology, Life Sciences
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