FUNCTIONAL RESPONSES IN HABITAT USE: AVAILABILITY INFLUENCES RELATIVE USE IN TRADE-OFF SITUATIONS

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