Reduced-Variance Methods for Detectability Correction of Population Abundance

Abstract

Detectability issues create uncertainty in field surveys of animal and plant populations. Detectability correction is one method employed to deal with this problem when there is reasonable certainty that detectability is roughly constant with time or in different areas. Two new reduced-variance estimators of detectability are introduced and evaluated for the case of using a detectability correction for new areas that are surveyed only once. The new estimates are unbiased or nearly unbiased and produce population estimates with smaller variance than the Lincoln–Petersen estimate.

Keywords:

• Double sampling
• Population estimation
• Sampling efficiency
• Sampling effort

Mathematics Subject Classification:

• 62D05

Acknowledgments

Thanks to J. Giudice, M. Kéry, I. Lama, M. Mazerolle, and P. Van Deusen for suggestions on the manuscript. Research was funded by the forest products industry.