Support for the size-mediated sensitivity hypothesis within a diverse carnivore community

Area of Science:

• Ecology
• Wildlife Conservation
• Environmental Change

Background:

• Carnivore communities face complex, interacting factors influenced by global change.
• Research often focuses on large carnivores, potentially overlooking smaller species' sensitivity.
• The size-mediated sensitivity hypothesis suggests smaller carnivores are more responsive to environmental shifts.

Purpose of the Study:

• To investigate the drivers influencing carnivore occurrence in the Blue Ridge Mountains.
• To test the size-mediated sensitivity hypothesis in a diverse mammalian carnivore community.
• To assess the impact of interspecific competition, habitat complexity, food availability, and anthropogenic disturbance on carnivore occupancy.

Main Methods:

• Camera traps deployed at 197 sites over 4 years to monitor 10 mammalian carnivore species.
• A two-step occupancy modeling-structural equation modeling framework was employed.
• Analysis focused on four hypothesized drivers: competition/predation, habitat complexity, food availability, and anthropogenic disturbance.

Main Results:

• All 10 carnivore species showed differential responses to the four hypothesized drivers.
• Small and medium-sized carnivores exhibited more significant pathways influenced by these drivers than large carnivores.
• The smallest carnivore species was uniquely influenced by all four hypothesized drivers.

Conclusions:

• The study supports the size-mediated sensitivity hypothesis, identifying small carnivores as valuable sentinel species for global change.
• A 'middle-out' approach, focusing on smaller carnivores, is recommended for future carnivore community dynamics research.
• Findings underscore the importance of monitoring small carnivores for effective ecosystem management and conservation.