Spatial capture-mark-resight estimation of animal population density

Area of Science:

• Ecology
• Wildlife Biology
• Population Dynamics

Background:

• Capture-recapture methods are fundamental in animal population studies.
• Existing spatial models often require known distributions of marked animals or complex fitting procedures.
• Mark-resight methods offer cost-effective data augmentation but require robust spatial modeling.

Purpose of the Study:

• To develop novel likelihood-based spatial mark-resight models.
• To integrate both marking and resighting phases or utilize known marked animal distributions.
• To provide accurate population density estimates with reduced sampling effort.

Main Methods:

• Development of spatial mark-resight models using pseudolikelihood estimation.
• Simulation-based adjustment for overdispersion in unmarked animal sightings.
• Application to ship rat (Rattus rattus) population studies using traps and cameras.

Main Results:

• The developed models provide low bias in population density estimates.
• Adequate confidence interval coverage was observed under typical sampling conditions.
• The models were successfully applied to real-world ecological data.

Conclusions:

• Spatial mark-resight models offer a valuable, cost-effective approach for animal population estimation.
• Further research is needed to optimize precision when ignoring covariance structures.
• These methods enhance ecological survey efficiency and data richness.