Carabid Beetle Assemblages within an Agricutlural Landscape
Harpalus affinis photo.

The greatest threat to biodiversity is habitat destruction. Habitat destruction results when naturally occurring habitats are disturbed by human activities or when they are replaced by new human-created habitats. The most wide spread of these disturbances is agriculture. However, agricultural disturbance need not result in the local extinction of species. Depending on the amount of natural habitat remaining in a area, the spatial configuration of that natural habitat, and the agricultural practices within the region many, if not most, native species can persist in an agroecosystem. By understanding how the distribution of agricultural activities and the nature of specific agricultural practices influence the distribution and abundance of species we will be better able to suggest ways to manage biodiversity so that it can coexist with large-scale agricultural production.

Ground beetles (Family: Carabidae) are an ideal model system on which to study the effects of agriculture on biodiversity. They are abundant and diverse (>700 species that occur on the central Great Plains) and relatively easily sampled. This high diversity and the observation that different species respond in different ways to similar disturbances – allow this group to make relative fine distinctions between different types of disturbance. The ground beetles are ecologically important. Most ground beetles are predaceous on other insects. Some of these beetles prey on insects that are agricultural pests and may be important in limiting the population size and distribution of these pests. Ground beetles are also an important link the food web as they are prey for small mammals and birds. Understanding how these beetles are affected by agriculture will also allow us to better conserve other elements of biodiversity.

 
Small Mammal Communities at Continental Scales
The assemblage of species that occur at any one site is the result of interactions that occur at many different spatial scales.  Most work on the community ecology of small mammals has concentrated on the local scale and has examined the influence of species interactions on the community composition.  However the regional species pool from which the members of the community are drawn are not solely a function of the conditions at single or even several sites, but depends on the evolutionary and biogeographic history of the biota. At even larger extents (geographic range of the species), the distribution and abundance of most species exhibit several distinct patterns.  Whether these patterns emerge as a function of the interactions of species at different sites across the range of the species or are the individualistic responses of a species to larger environmental gradients (precipitation, temperature, etc.) is not known.

To examine the influence of the different levels of organization impose on small mammal communities I have assembled a data set of small mammal communities for over 4200 sites in North America.  I hope that by using a meta-analysis approach I can lend new insights to how communities are structured
Deer mouse (Peromyscus maniculatus) photo.