1 Tahrcountry Musings: Here is a critique of camera trap study

Thursday, February 09, 2012

Here is a critique of camera trap study

Critique of density estimation from camera-trap data
Rebecca J. Foster, Bart J. Harmsen

The Journal of Wildlife Management

Volume 76, Issue 2, pages 224–236, February 2012

Camera trap study comes in very handy while estimating the densities of elusive terrestrial mammals. It involves two steps.
1) Fitting conventional closed population capture–recapture models to estimate abundance
2) Using ad hoc methods to determine the effective trapping area.

To guide wildlife management, the methodologies per se has to be accurate, robust, and reliable.
The researchers here critically reviewed 47 published studies and discuss the problems associated with contemporary population estimates of elusive species from camera-trap data.

The focus was on
1)      Individual identification
2)      Sample size and capture probability
3)      Camera location and spacing
4)      The size of the study area
5)      Ad hoc density estimation from the calculation of an effective trapping area

They also discuss the recently developed spatially explicit capture–recapture (SECR) models as an alternative approach that does not require the intermediate step of estimating an effective trapping area.

Here are the recommendations of the researchers
1) Greater transparency in study design and quality of the data
2) Greater rigor when reviewing manuscripts
 3) More attention is to be given to the survey design to ensure data are of sufficient quality for analysis

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