Prey availability and ambient temperature influence carrion persistence in the boreal forest

Area of Science:

• Ecology
• Wildlife Biology
• Food Web Dynamics

Background:

• Vertebrate scavenging significantly impacts food web stability and nutrient cycling.
• Scavenging communities remain understudied, with limited understanding of biotic drivers.
• Snowshoe hare population cycles create natural fluctuations in prey density and carrion biomass.

Purpose of the Study:

• To investigate how snowshoe hare (Lepus americanus) population cycles influence vertebrate scavenging communities in the northern boreal forest.
• To examine the effects of habitat and temperature on scavenging dynamics.
• To identify key scavenger species driving community patterns.

Main Methods:

• Experimentally placed snowshoe hare carcasses over four years in the southwestern Yukon.
• Monitored carcass persistence time, time to first scavenger, and species richness.
• Assessed snowshoe hare density, carrion biomass, temperature, habitat, and seasonal effects.
• Developed species-specific scavenging models for primary scavengers.

Main Results:

• Carcass persistence decreased with declining snowshoe hare density, mainly due to increased Canada lynx (Lynx canadensis) scavenging.
• Prey density influenced carrion recycling efficiency but not the number of scavenging species.
• Scavenging rates increased with warmer temperatures, and seasonality strongly affected scavenger community richness.

Conclusions:

• Vertebrate scavenging communities are highly sensitive to demographic changes in prey species and environmental shifts.
• Scavenging dynamics play a crucial role in nutrient cycling and food web persistence.
• Future food web assessments must incorporate scavenging interactions to fully understand ecosystem dynamics.