How resource abundance and resource stochasticity affect organisms' range sizes.

Area of Science:

• Ecology
• Zoology
• Behavioral Ecology

Background:

• Organism space use is linked to habitat resource availability.
• Previous research focused on mean resource levels, neglecting resource unpredictability (stochasticity).
• Understanding resource stochasticity is vital for accurate range size determination.

Purpose of the Study:

• To propose a framework on how resource abundance and stochasticity affect organism range sizes.
• To investigate the interaction between resource abundance and stochasticity on range size.
• To test the hypothesis using empirical data.

Main Methods:

• Literature review to develop a unifying hypothesis.
• Simulated movement data to model range size patterns.
• Tracking data from a lowland tapir (Tapirus terrestris) in the Brazilian Cerrado for empirical validation.

Main Results:

• Range size decreases nonlinearly with resource abundance.
• Range size increases nonlinearly with resource stochasticity.
• The impact of resource stochasticity on range size is contingent on resource abundance.

Conclusions:

• Resource abundance and stochasticity are critical factors in understanding free-ranging organism movement.
• Ignoring resource stochasticity leads to incomplete and inaccurate conclusions about animal movement.
• Accurate ecological models must incorporate resource variability for predicting organism behavior.