Reliability of different mark-recapture methods for population size estimation tested against reference population...

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• Reliable population size estimates are fundamental for ecological studies and biodiversity conservation.
• Selecting appropriate abundance estimation methods is challenging, particularly with scarce data.
• Previous reliability studies often used simulation data not reflecting natural population variability.

Purpose of the Study:

• To assess the bias, precision, and accuracy of twelve population size estimators.
• To evaluate estimator performance using real field data from an intensively studied gecko population.
• To identify optimal mark-recapture methods for ecological and conservation applications.

Main Methods:

• Used field data from a closed population of arboreal geckos (Gehyra variegata) to create reference population sizes.
• Assessed twelve different population size estimators, including Lincoln-Petersen variations, MARK/CARE-2 models, and a truncated geometric distribution.
• Evaluated estimators based on bias, precision, accuracy, and 95%-confidence intervals, considering individual heterogeneity.

Main Results:

• Models accounting for individual heterogeneity consistently outperformed others across all assessment criteria.
• For heterogeneous habitats without clear covariates, the moment or interpolated jackknife estimators are recommended.
• For substantial capture frequency data, sample coverage or estimating equation models are advised; Lincoln-Petersen and truncated geometric distributions showed good results depending on catchability distribution.

Conclusions:

• This study provides a robust evaluation of mark-recapture estimators under field conditions.
• Models incorporating individual heterogeneity are essential for accurate population size estimation.
• The findings aid in selecting appropriate methods for reliable ecological and conservation management.