Flow of Organisms in Agricultural Landscapes

Colunga-Garcia, M. and S.H. Gage

Presented at the All Scientist Meeting (1998-07-21 to 1998-07-22 )

During the first 10 years of the KBS LTER we have assessed the response of beneficial insects to landscape structure in row crop ecosystems. We selected a group of plant-dwelling predators (ladybird beetles) to serve as indicators of biological activity in the agricultural landscape. This species complex is highly mobile and uses a broad range of habitats during their life cycle. The patterns of predator dynamics we have observed in response to landscape structure have provide an increased understanding of the dynamic role that predatory organisms play as chemical substitutes in agricultural landscapes. During the next phase of the KBS LTER we will continue our monitoring of ladybird beetle species. This is important because changes in plant succession and poplar, as well as the maturation of agronomic treatments will potentially affect the species composition of coccinellids in the landscape. We also need to document the changes in species composition in the community of native coccinellids in response to the establishment of the exotic species Coccinella septempunctata and Harmonia axyridis in Michigan. In addition to maintaining this long-term assessment, we will expand the scope of our observations to assess patterns of insect activity at increased scales. We will increase the number of species of predators observed, and expand our observation network to a regional scale. In this new phase of the KBS LTER and in anticipation of potential changes in weather patterns, we also will include in our monitoring efforts selected outbreak-prone herbivore species whose population dynamics are very susceptible to weather fluctuations. Changes in weather patterns can change the competitive balance between plants, herbivores, and predator favoring the outbreak of the herbivore populations.Return to Contents

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