David Stroppel (MS)

Title: Grassland bird response to patch burn grazing in native tallgrass prairie

Advisor: Dr. Mark R. Ryan

The use of mechanical farm machinery converted most tallgrass prairies into crop fields, fragmenting the prairies, reducing the prevalence of fires and shrinking the prairie to 5% of its presettlement range. Along with the loss of the tallgrass prairie, we have seen dramatic declines in grassland bird populations in spite of land managers’ efforts. The North American Breeding Bird Survey data show that 70% of the 29 bird species characteristic of North American prairies declined between 1966 and 1993. If we are to reverse this decline, we must find ways to manage the remaining tracts of tallgrass prairie in a way that provides for the diverse habitat needs of the grassland avian community.

The presence of grazing during the evolution of prairie ecosystems helped result in great plant and animal diversity. This would suggest that biodiversity can be enhanced on today’s remaining grasslands by mimicking the temporal and spatial grazing patterns of presettlement prairies. This study will help us evaluate patch burn grazing (PBG) as a management tool to increase bird diversity, abundance, and density on native prairies. The goal of the grazing treatment is to change the vegetative structure to increase bird diversity. We need to test this linkage to determine if PBG is meeting that goal. I hope to link the vegetation created by PBG to the presence or absence of various bird species so that managers can better predict the outcomes of their management.

To obtain information on avian diversity, abundance and density, transects will be placed within each patch in each treatment unit. Using a distance sampling method, we will be able to estimate avian density using DISTANCE software. Results of the study will be used to make recommendations to public and private grassland managers who wish to increase the wildlife habitat value of their lands.