Journal Article

Effects of predatory risk and resource renewal on the timing of foraging activity in a gerbil community

Kotler, B.P. (Ben-Gurion Univ. of the Negev, Sede Boker Campus (Israel). Jacob Blaustein Inst. for Desert Research. Mitrani Center for Desert Ecology), Subach, A, Ayal, Y

1994

Overview

The foraging decisions of animals are often influenced by risk of predation and by the renewal of resources. For example, seed-eating gerbils on sand dunes in the Negev Desert of Israel prefer to forage in the bush microhabitat and during darker hours due to risk of predation. Also, daily renewal of seed resource patches and timing of nightly foraging activity in a depleting environment play important roles in species coexistence. How these factors influence the timing of gerbil foraging was investigated by quantifying foraging activity in seed resource patches that were experimentally renewed hourly during the night. Gerbils showed strong preference for the safe bush microhabitat and foraged less in response to high levels of illumination from natural moon light and from artificial sources. It is demonstrated here for the first time that gerbils also responded to temporal and spatial heterogeneity in predatory risk through their timing of activity over the course of each night. Typically, gerbils concentrated their activity early in the night, but this changed with moon phase and in response to added illumination. These results can be understood in terms of the nature of patch exploitation by gerbils and the role played by the marginal value of energy in determining the cost of predation. They further show the dynamic nature of gerbil foraging decisions, with animals altering foraging efforts in response to time, microhabitat, moon phase, illumination, and resource availability

• Publisher: Springer-Verlag,Springer
• Subject: Animal and plant ecology / Animal, plant and microbial ecology / Animals / Autoecology / Biological and medical sciences / BUSQUEDA DE ALIMENTO / CHOIX DE LA DATE / COMPORTAMIENTO / COMPORTEMENT / DEPREDACION / DESERT / Desert rodents / Deserts / DESIERTOS / ELECCION DE LA EPOCA / Food availability / Foraging / Fundamental and applied biological sciences. Psychology / GERBILLE / Gerbillus / Gerbils / GERBO / GRAINE / HABITAT / ISRAEL / Mammalia / Mammals / Microhabitat selection / Microhabitats / Moonlight avoidance / Natural resources / Natural satellites / Optimal patch use / POBLACION ANIMAL / POPULATION ANIMALE / PREDATION / RECHERCHE DE NOURRITURE / Rodents / SEMILLA / Species / Timing of foraging activity / Vertebrata