1 Tahrcountry Musings: Resource selection studies should be coupled with mechanistic data

Thursday, September 29, 2011

Resource selection studies should be coupled with mechanistic data

Predators choose prey over prey habitats: evidence from a lynx–hare system

Jonah L. Keim, Philip D. DeWittt, and Subhash R. Lele

Ecological Applications  Volume 21, Issue 4 (June 2011)

In this paper the researchers recommend that resource selection studies should be coupled with mechanistic data (e.g., metrics of diet, forage, fitness, or abundance) when investigating mechanisms of resource selection.

Resource selection is grounded on the assumption that animals select resources based on fitness requirements.

There exists certain uncertainty in how mechanisms relate to the landscape. Despite this fact resource selection studies often assume, but rarely demonstrate, a relationship between modeled variables and fitness mechanisms.

Here using Canada lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) as a model system, the researchers assess whether prey habitat is a viable surrogate for encounters between predators and prey. They simultaneously collected winter track data for lynx and hare in two study areas.

The researchers used the information criteria to determine whether selection by lynx is best characterized by a hare resource selection probability function (RSPF) or by the amount of hare resource use.
The results demonstrated that lynx selection is better explained by the amount of hare use (SIC = −21.9; Schwarz's Information Criterion) than by hare RSPF (SIC = −16.71), and that hare RSPF cannot be assumed to reveal the amount of resource use, a primary mechanism of predator selection.

The study amply demonstrates an obvious and  important distinction between selection and use that is applicable to all resource selection studies.

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