Beneath the Leaf-Litter: Can Salamander Personality Influence Forest-Floor Dynamics?

Ecological research demonstrates how intraspecific phenotypic variation can have consequences for community dynamics. However, the effects of animal personalities (i.e., intraspecific behavioral variation) on ecological processes remains relatively understudied. Using Red-backed Salamanders (Plethodon cinereus) and the detrital food web as a model system, we conducted a laboratory mesocosm experiment to explore whether or not the personality type of a top-level predator could affect the community structure within a complex, terrestrial food web. We used behavioral assays to investigate the repeatability of salamander behaviors, and classified individuals as either active or inactive. We then subjected laboratory mesocosms to one of four treatments for 3 mo: one active salamander, one inactive salamander, control (no salamander), and a pre-experimental reference. Our results indicate that the effect of P. cinereus on the detrital food web might be behaviorally mediated, with only the most active salamanders affecting community structure. Specifically, mesocosms housing active salamanders contained less diverse invertebrate communities than all other treatments. This difference was primarily driven by springtails, which were more abundant within mesocosms housing active salamanders. We also found that salamander personality was associated with cover board use inside mesocosms, with inactive salamanders exhibiting a more philopatric use of cover objects than active individuals. Leaf-litter degradation did not differ between treatments, indicating that the ecological effects of salamanders were too weak to influence basal resources within the detrital food web. Our study prompts further questions regarding the potential for animal personalities to influence ecological processes within terrestrial communities.