Scale-dependent home range optimality for a solitary omnivore

Area of Science:

• Ecology
• Wildlife Biology
• Spatial Ecology

Background:

• Home range structure is influenced by spatial and temporal heterogeneity.
• Optimal space use strategies aim to maximize individual fitness.
• Understanding black bear (Ursus americanus) habitat selection is crucial for conservation.

Purpose of the Study:

• To evaluate optimality hypotheses for American black bear home range use.
• To test predictions regarding vegetation productivity, forest fragmentation, and range size.
• To determine scale-dependent space use strategies in black bears.

Main Methods:

• Utilized radio telemetry data from 143 American black bears across three US states (2008-2017).
• Analyzed annual and seasonal (spring, summer, fall) space use, excluding winter.
• Employed generalized linear mixed models to assess vegetation productivity (NDVI) selection and range size variation.

Main Results:

• Black bears consistently selected highly productive areas at the annual scale, with selection weakening seasonally.
• Increased forest fragmentation led to smaller home ranges, contrary to predictions.
• Greater forest proportion correlated with smaller ranges; increased productivity did not consistently result in smaller ranges.

Conclusions:

• American black bears exhibit scale-dependent space use strategies, prioritizing energy maximization at larger scales and area minimization seasonally.
• Habitat fragmentation and forest cover influence black bear range size in complex ways.
• Black bears demonstrate significant behavioral plasticity in response to environmental conditions.