The Effects of Habitat Geometry on Territorial Defense Costs: Intruder Pressure in Bounded Habitats |
| |
Authors: | STAMPS JUDY A; BUECHNER MARYBETH; KRISHNAN VV |
| |
Institution: | Department of Zoology, University of California Davis, California 95616
Animal Behavior Graduate Group, University of California Davis, California 95616
Department of Engineering, San Francisco State University San Francisco, California 94132 |
| |
Abstract: | Computer simulation models were used to explore the effect ofhabitat geometry on intruder pressure for territories in differentlocations within a patch of uniformly high quality habitat,for territories in patches of different shapes and sizes, andfor patches surrounded by different types of suboptimal habitats. In models in which the edges of the habitat patch are impermeable(hard-edged), intruders do not leave the central territorialhabitat, H, and intruder pressure is lower for territories onthe edge of H than for more centrally located territories. Averageintruder pressure for any given loop of territories ( , for loop = i) is positively relatedto both the proportion of territories on the edge of the patch(ESR) and the average distance moved by intruders. In models in which the edges of H are permeable (soft-edged),intruders are able to move between H and the surrounding habitats,which were of two types: sinks (no intruders generated there)and reserves (a source of intruders). The presence of sinksdramatically reduces both and average intruder pressure over H ( ) as compared to hard-edged habitats, and both and are negatively related to the proportion of territories on theedge of the patch (ESR). Conversely, and are positively related to ESR when the surrounding habitat acts as an intruder-reserve. Data from empirical studies of territorial species agree withmany of the direct and indirect qualitative predictions of thesemodels. The effects of habitat geometry on defense costs maybe important in many territorial species, and should be takeninto account in future studies. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|