Urbanization and anthropogenic development across North America are contributing to habitat loss and fragmentation. Urbanization also alters surface water systems, resulting in the elimination, alteration, and creation of aquatic ecosystems. Habitat loss is one factor contributing to the current native bee and honeybee (Apis mellifera) population declines across the continent. Previous studies on the effect of urbanization on bee populations have produced conflicting results, which suggest that further research is required. The effect of surface water availability on bee populations is not well studied. Using bee bowl traps and sweep net sampling techniques in household yards across the Twin Cities in Minnesota, I assessed bee abundance and bee community composition across an urban to rural gradient using housing density as a measure of degree of urbanization. I also examined and compared bee communities in yard sites both near to and far from major surface waters. Specifically, I tested the hypothesis that bee community assemblages are affected by both housing density and proximity to water, independently. I found no significant difference in bee abundance across the urban to rural gradient or at varying distances from water. However, I found a positive correlation between yard size and bee abundance and a significantly different community composition of bees near to and far from water. The results of this study imply that bee populations are not affected by housing density alone, and that other factors, such as habitat patch size as measured by yard size, may be contributing to reported declines in bee populations. Results also imply that altering surface waters in urban areas can impact bee community composition. These results can help guide future studies and inform urban planning and surface water alteration methods in order to conserve bee populations.
PDF title page date: 19th day of May 2014.
The author has given permission for this work to be deposited in the Digital Archive of Colorado College.
Includes bibliographical references.
Colorado College Honor Code upheld.
PDF title page date: 19th day of May 2014.
The author has given permission for this work to be deposited in the Digital Archive of Colorado College.
Colorado College Honor Code upheld.
