Differential vulnerability to predation and refuge use in competing larval salamanders

Area of Science:

• Ecology
• Behavioral Ecology
• Evolutionary Biology

Background:

• Salamander larvae exhibit varying competitive abilities, influencing coexistence.
• Predation risk can shape prey behavior and microhabitat use.
• Understanding predator-prey interactions is crucial for community dynamics.

Purpose of the Study:

• Investigate behavioral mechanisms enabling coexistence between two salamander prey species and a predator.
• Determine if differential predation vulnerability and refugia use contribute to prey coexistence.
• Examine how predator presence and competitor density affect prey microhabitat selection.

Main Methods:

• Comparative analysis of predation vulnerability of two salamander species (A. talpoideum and A. maculatum) to a predator (A. opacum).
• Observation of behavioral responses, including refugia use (leaf litter, deeper water), under varying predation and competition levels.
• Experimental manipulation using pond enclosures to assess diel microhabitat shifts and their drivers.

Main Results:

• Larval A. maculatum was more vulnerable to A. opacum predation than A. talpoideum.
• A. talpoideum significantly increased its use of leaf litter refugia in the presence of the predator.
• Both prey species exhibited diel vertical migration, but this was only significantly affected by an interaction between predator presence and competitor density in A. talpoideum.

Conclusions:

• Refugia play a critical role in mediating coexistence within this salamander predator-prey assemblage.
• Predation by A. opacum can indirectly enhance coexistence by preferentially consuming the superior competitor (A. maculatum), thus reducing its competitive impact on A. talpoideum.