Variable intraspecific space use supports optimality in an apex predator

Area of Science:

• Ecology
• Animal Behavior
• Wildlife Management

Background:

• Home range behavior in animals is driven by fitness, balancing resource acquisition for survival and reproduction against energetic costs.
• Optimality theory suggests animals either maximize resource patches (Resource Dispersion Hypothesis [RDH]) or minimize space use to meet needs (Temporal Resource Variability Hypothesis [TRVH]).

Purpose of the Study:

• To investigate whether brown bears (Ursus arctos) on two islands adhere to RDH or TRVH at annual and seasonal scales.
• To examine how intrinsic factors like age and reproductive status influence brown bear space-use strategies.

Main Methods:

• Analysis of brown bear space use patterns in two island populations.
• Assessment of home range strategies against RDH and TRVH predictions.
• Evaluation of the influence of age, sex, and reproductive status on space-use decisions.

Main Results:

• Brown bears exhibited dynamic space use patterns, with evidence supporting both RDH and TRVH at annual and seasonal scales.
• Seasonal RDH support suggests bears maximize space for diverse nutritional resources, while annual RDH reflects food distribution in timber stands.
• TRVH support indicates bears minimize space when food is temporally concentrated. Range size and strategy varied by sex and reproductive class, with males using larger ranges.

Conclusions:

• Brown bear space-use strategies are scale-dependent, influenced by resource availability, temporal concentration, and intrinsic factors.
• Understanding these scale-dependent optimal behavioral decisions is crucial for effective wildlife movement ecology and conservation.