Interference competition between wolves and coyotes during variable prey abundance

Area of Science:

• Ecology
• Wildlife Biology
• Interspecific Competition

Background:

• Interference competition occurs when dominant species suppress subordinates.
• Wolves (Canis lupus) and coyotes (C. latrans) coexist in North America, with potential for resource competition.
• White-tailed deer (Odocoileus virginianus) are a key prey species for both canids.

Purpose of the Study:

• To assess niche overlap between wolves and coyotes as evidence of interference competition.
• To investigate activity, diet, and space use overlap during periods of fawn availability.
• To understand coexistence mechanisms between these two sympatric canid species.

Main Methods:

• Activity overlap (Δ) analyzed using GPS collar accelerometer data.
• Dietary breadth (B) and niche overlap (α) estimated from scat analysis.
• Resource Utilization Functions (RUFs) used to compare population-level space use, incorporating prey and landscape data.

Main Results:

• High overlap observed in wolf and coyote activity (Δ=0.86-0.92) and diet (α=0.76-1.0).
• Coyotes consumed fewer deer and more small prey, showing greater dietary breadth (B=3.1-4.9) than wolves.
• Coyotes displayed greater population-level variation in space use and land cover selection compared to wolves.

Conclusions:

• Findings support interference competition between wolves and coyotes due to substantial resource overlap.
• Coexistence is facilitated by coyotes exploiting subtle resource differences and exhibiting greater plasticity in resource use.
• Coyotes' generalist strategy and adaptability allow them to coexist with dominant wolves.