Effects of Landscape Structure, Habitat Type and Flower Density on Bee Abundance within the Chicago Wilderness Region
Ellis, Katherine E.
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Urbanization and habitat fragmentation are major threats to the conservation of the tall grass prairie ecosystem once widespread across the American Midwest. Less than 0.01% of the original ecosystem now remains·in North America. Destruction of these important ecosystems is not only harmful to the organisms that inhabit them, but also to the agricultural system that relies heavily on insect pollination. While studies have shown that an increase in nearby native habitat has increased the amount of agriculture pollination by bees, more research still needs to be done to optimize prairie remnant conservation. Inside urban areas, such as the city of Chicago, effort has been placed on the development of urban green spaces like city parks and green rooftops. These human centered green areas are able to serve as both recreation areas for humans, as well as substitute habitat and other resources for many bee species. For this study, 18 different site were studied in the Chicago Wilderness region classified as three different site type categories; city park, green roof, or tall grass prairie. At each of these locations, bee pollinator observations and bee bowl collections were made over a two month period. Using satellite images and ArcGIS software, landscape structure (water, green, urban and suburban land types) was determined within a 500 m radius of each site location. Percent green space, percent urban space, as well as site type and the number of focal flowers per 0.25 m2 were found to be significant factors in the prediction of both the number of bee visitors per fifteen minute observation period and the abundance of bees collected over 24 hours. These results give important insight into the value of preserving substantial natural habitat in order to maximize conservation techniques as well as maintaining sustainable crop pollination.