Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Functional Responses in Habitat Use: Availability Influences Relative Use in Trade-Off Situations

Atle Mysterud and Rolf Anker Ims
Ecology
Vol. 79, No. 4 (Jun., 1998), pp. 1435-1441
Published by: Wiley
DOI: 10.2307/176754
Stable URL: http://www.jstor.org/stable/176754
Page Count: 7
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Functional Responses in Habitat Use: Availability Influences Relative Use in Trade-Off Situations
Preview not available

Abstract

Current methods for evaluating habitat selection from animal space-use observations ignore possible interactions between time allocation patterns relative to different resources, their relative abundance, and their spatial arrangements. Habitat selection may occur in situations in which animals experience a trade-off, e.g., between time used foraging in areas with abundant forage but poor protective cover, and time used for resting in areas with good protective cover but low forage abundance. We show how functional responses in habitat use (i.e., change in preference with availability of one of two main habitat types) may be tested. Given radio-telemetry data for a sample of individuals, binomial logit models can be used to regress proportionate use of a habitat type p(u) against the proportion of that habitat available, p(a). Given an appropriate fit to the data by a linear predictor on a logit scale, functional response will be indicated by a estimated slope parameter ≠ 1, while a slope = 0 will indicate a consistent use as availability changes. Habitat preference is inferred from the logit regression parameters when the fitted value of the proportion of use at a specified proportion of availability, is significantly greater than the proportional availability.

Page Thumbnails

  • Thumbnail: Page 
1435
    1435
  • Thumbnail: Page 
1436
    1436
  • Thumbnail: Page 
1437
    1437
  • Thumbnail: Page 
1438
    1438
  • Thumbnail: Page 
1439
    1439
  • Thumbnail: Page 
1440
    1440
  • Thumbnail: Page 
1441
    1441