Competition between Bufo larvae in a eutrophic pond.

Area of Science:

• Ecology
• Amphibian Biology
• Evolutionary Biology

Background:

• Anuran larvae exhibit complex competitive interactions.
• Previous research implicated the pathogen Anurofeca richardsi in interference competition between Bufo species.
• Field conditions can significantly alter the mechanisms and intensity of interspecific competition.

Purpose of the Study:

• To investigate interspecific competition between Bufo bufo and Bu. calamita larvae under conditions unfavorable for known interference mechanisms.
• To determine the primary drivers of competition (resource vs. interference) in a novel habitat.

Main Methods:

• Field experiment using replicated cage treatments in a farm pond habitat.
• Monitoring tadpole survival, growth, and algal community composition.
• Analyzing gut contents for food acquisition and feeding niche overlap.

Main Results:

• Bu. calamita larval survival and growth were inversely related to density, with interspecific effects being more severe than intraspecific effects.
• No evidence of A. richardsi was found, indicating competition occurred without disease-mediated interference.
• Tadpole presence altered algal community structure; however, larval growth was not directly correlated with food availability, though food acquisition decreased with density.

Conclusions:

• Resource competition, not interference, was the primary mechanism driving intense competition between Bufo larvae in this farm pond.
• High feeding niche overlap decreased with increasing larval density, supporting resource competition as the main driver.