I recently retired in October 2012 and was the Acting Unit Leader of the Iowa Cooperative Fish and Wildlife Research Unit, which promotes graduate education in fish and wildlife conservation.
Compositional and structural changes will vary with the kinds of grasses planted (cool-season vs. warm-season), soils, topography, and other factors. Additional cover in agricultural landscapes is provided by tracts of public and private land managed to benefit wildlife. Some of these tracts are reclaimed cropland and some are remnants of prairie. The variety of grassland habitats available, together with a variety of management regimes, provides a basis for designed observational studies examining the effects of this variation on bird communities.
I have worked with distribution of Henslow's Sparrows in Iowa and Missouri, and habitat fragmentation of grasslands in North Dakota. I am supervising students working on songbirds in Northern Iowa and the U.S. Prairie Pothole Region. A brief account of this research can be found in a document describing my current research projects.
My research focused on developing information needed by managers seeking to provide high-quality habitat for diverse bird communities in Iowa and nearby midwestern states. Birds that breed in grasslands are of particular interest because some are harvested and others are in trouble. My research program was built on my earlier examination of the effects of the Conservation Reserve Program on bird densities and nest success. In many parts of the Midwest, this program has doubled the amount of grass/forb cover in landscapes dominated by agriculture. As this cover ages, its plant-species composition can be expected to change.