Differential resource selection within shared habitat types across spatial scales in sympatric toads

Area of Science:

• Ecology
• Evolutionary Biology
• Amphibian Ecology

Background:

• Differential habitat selection is key to species evolution but rarely quantified for sympatric species across spatial scales.
• Understanding resource impacts on habitat selection is crucial for explaining species coexistence.

Purpose of the Study:

• To quantify terrestrial summer habitat selection by two sympatric amphibians (Bufo bufo spinosus and B. viridis) in an Italian floodplain.
• To assess the influence of habitat type, prey density, and temperature on habitat selection at multiple spatial scales.
• To explore how large-scale processes influence small-scale space use and facilitate coexistence.

Main Methods:

• Applied a Bayesian resource selection model to analyze habitat use at three spatial scales: home range placement, 95% home range use, and 50% core area use.
• Investigated the roles of habitat type, prey density, and temperature in shaping amphibian habitat selection.
• Compared habitat selection patterns between Bufo bufo spinosus and B. viridis.

Main Results:

• Habitat selection for both species was influenced by habitat type, prey density, and temperature across all spatial scales.
• Home range placement was primarily driven by habitat type, while prey density and temperature were more critical for space use within home ranges.
• Both species preferred similar habitat types but utilized them differently, indicating niche differentiation.

Conclusions:

• Amphibians perceive habitat types and resource gradients (prey, temperature) at multiple spatial scales.
• Niche differentiation in resource selection within shared habitats is a key mechanism facilitating the coexistence of these two amphibian species in terrestrial environments.