02 December, 2005

Efford et al. (2005): A field test of two methods for density estimation.

Efford, M.G., Warburton, B., Coleman, M. C. and Barker R. J. 2005. A field test of two methods for density estimation. Wildlife Society Bulletin 33: 731–738.

Population density estimation with a new spatially explicit capture–recapture method was tested in the field and compared to distance analysis of data from trapping webs. Brushtail possums were trapped in pine forest at Waitarere, near Foxton. Capture–recapture with hollow trapping squares gave an estimate (1.9/ha) that was close to the result from nearly complete removal (2.3/ha). Trapping webs gave highly biased estimates (6.5–8.0/ha), consistent with Monte Carlo simulations. The spatially explicit capture–recapture method places few constraints on the spatial configuration of sampling; dispersed configurations (e.g. randomly sited trap clusters) may be used to estimate mean density across landscapes. See www.landcareresearch.co.nz/services/software/density for software and a pdf of the paper.

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