In all regions of the world, human activities fragment habitats into spatially isolated parts. It is clear this isolation can harm populations of animals. In particular, there is evidence that the number of animals per unit area of habitat declines as the area of habitat decreases. The reasons why this occurs are poorly understood. A possible explanation for the effect of habitat area on population density is that animals in fragmented habitats have restricted access to variety in the foods they need to survive and reproduce. The proposed work will test the hypotheses that habitat fragmentation causes reduced population density by restricting access of animals to diversity in the foods. Researchers will conduct an experiment where one population of grasshoppers has access to a wide range of foods that vary in quality over space and time. Another population of the same size will be divided into subpopulations, each of which will have limited access to the total range of resources. Researchers will also construct mathematical models of fragmentation effects on interactions between consumers and resources.
This work will improve the scientific foundation for decisions on human land-use world wide. In addition, we will use the project to provide research problems for interdisciplinary training to graduate students in mathematics, ecology, and statistics.
