A habitat selection under predation hazard in the ecology

These 3 habitats vary in prey availability, physiological costs, and risk of predation. On each night, ground and off-ground traps were left out for equal lengths of time 2—6 h. This physical limitation is unlikely to have affected our results because very few observed marks even approached this height.

Between andwe located salamanders under logs and rocks, except on 6 occasions when salamanders were located after dark; we found these salamanders foraging on leaf litter. For each trail, we also measured the maximum displacement Dthat is, the straight linear distance between the salamander capture location and the mark furthest from that location.

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Plethodon cinereus, the red-backed salamander, is potentially a good model species for studying predation risk in terrestrial species because it occupies distinct nocturnal habitats: Each salamander we tracked was searched for and found at least 5 m from other salamanders we tracked in A habitat selection under predation hazard in the ecology to ensure that home ranges did not overlap.

Plethodon cinereus are euryphagic reviewed in Petrankaso we can assess food abundance in a particular microhabitat by collecting small invertebrates in that habitat, without regard to taxon. The best habitat selection models take into account a trade-off between predation risk and foraging success.

We predicted that red-backed salamanders climb plants, despite the physiological constraint of dehydration, to avoid predation but not to increase foraging.

Jaeger concluded, on the basis of high stomach content for individuals on plants combined with these physiological facts, that P. To our knowledge, none of these predators or potential predators typically climb plants shrews reviewed in Churchfield ; plethodontids reviewed in Petrankabut no direct assessment of actual or perceived mortality risk to P.

In the 3 tests with a climbing parameter as the dependent variable, we used SVL, D, and T as covariates. We induced autotomization of 5—10 mm of the tails of treatment individuals by squeezing those sections of tail with tweezers henceforth referred to as tail clipping to simulate a predation attempt.

Liebgold and Jaeger found that the mean home range of P. On the other hand, like all plethodontids, P.

We surveyed each trap with a dissecting scope, and all organisms were recorded. Height of powder found on logs and dead trees and in one case an elevated rock was also recorded.

To ensure that salamanders were not climbing to access greater numbers of prey, we measured prey abundance on and above the ground and found more prey on the ground than on plants. We included T to test whether variation in time powdered and time observed affected our results.

In the present study, we investigated the effect of simulated predation on microhabitat use in light of differences in prey availability, examining this phenomenon in a terrestrial salamander, a taxon not typically studied for these purposes.

Sticky traps were placed within m of the salamander captures i. In this study, we simulated predation on P. We then released the salamander where we had found it. Models that take into account a trade-off between predation risk and foraging success tend to have the most explanatory power Gilliam and Fraser ; Railsback and Harvey However, they are also frequently found on small plants and larger shrubs or trees Burton and Likens ; Jaeger and have been observed to remain on vegetation for over 2 h Wise S, personal communication.

We calculated a prey volume index PVI for each trap by the following method. We conclude that salamanders use the plant habitat as a refuge from predation despite reduced foraging potential and increased physiological cost.

Plethodon cinereus may behave similarly. Powder trail data were collected between and 2—6 h after capture. It is unlikely that an animal should perceive its mortality risk to be zero even in the absence of predators or predator-simulating stimuli Lima and Dill On each night, one of the traps was on the ground, with the rest of the traps off the ground, because in preliminary studies we found that off-ground traps captured significantly lower numbers of insects than on-ground traps; more traps improved the accuracy of our estimate for off-ground prey abundance.

When we located a salamander, we measured its snout-vent length SVL. Hungry three-spined sticklebacks, for example, feed in the denser portions of swarms of prey where predation risk is higher, whereas partially satiated sticklebacks feed in the safer, less dense edges of prey swarms Milinski and Heller ; Heller and Milinski We found that, on average, simulated predation increased the maximum height climbed.

Adjacent to the ground trap, other traps were placed on the trunk of a tree typically Quercus rubra or Acer rubra at 3 possible heights 0,or cmon the leaves of large understory shrubs Acer pensylvanicum and Castanea dentataon small shrubs e.In this study we relate predation mortality to multivariate habitat-selection patterns of woodland caribou, a species thought to be limited primarily by predation from wolves [Canis lupus (Linnaeus)] ().Although our main goal was to further our understanding of caribou ecology, our motivation was also to present a methodology for ecologists.


Theories that model patch use and habitat selection under predation risk all make the prediction that foragers should demand higher feeding rates from risky than from safe habitats (Gilliam and Fraser,; Brown,; Houston et al., ).

Habitat Selection Under Predation Hazard: Test of a Model with Foraging Minnows. Variation and drivers of airflow patterns associated with olfactory concealment and habitat selection, Ecology, 99, 2, (), Feeding under Predation Hazard. Behavioral Ecology, Volume 19, Issue 3, 1 MayPages –, Terrestrial field studies, which have the advantage of addressing habitat selection under natural conditions, Habitat selection under predation hazard: test of.

Gilliam JF, Fraser DF () Habitat selection under predation hazard: test of a model with foraging minnows. Ecology – CrossRef Google Scholar Gilliam JF.

A habitat selection under predation hazard in the ecology
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