Linking Habitat Diversity With Spatial Ecology For Agricultural Pest Management
Diverse agricultural landscapes have been shown to support many ecosystem services including clean water, species conservation, and carbon sequestration. However, far less is known about the role of diverse agricultural landscapes in agricultural pest control. This research investigated how diverse agricultural landscapes affect insect pest dynamics and evolution. A comprehensive literature review of this subject revealed that direct effects of landscape diversity on insect pest control have been largely ignored. Nevertheless, increases in pest mortality and decreases in fecundity are likely with increasing landscape diversification. Field surveys of insect populations in agricultural landscapes of varying complexity across New York further illuminated landscape-insect relationships. Surveys showed that populations of insect pests in field corn were generally lower and that natural enemy populations were generally higher as agricultural landscapes increased in their diversity. Spatially-explicit modeling further explored landscape-insect relationships and considered pests with varied life histories and the influence of crop rotation and economic thresholds. Model results suggested that insect diet breadth and regional crop management play pivotal roles in landscape-insect relationships. Furthermore, pest management may be more intense in highly agricultural than in diverse landscapes, which may reduce apparent pest control benefits of landscape diversification. Finally, the role of diverse landscapes in slowing the evolution of insect resistance to Bt crops was explored. A detailed study of the European corn borer’s host utilization, fecundity, and U.S. distribution indicated that diverse agricultural landscapes are not likely to substantively slow the evolution of resistance to Bt corn for this pest. Together, this research supports pest control as an important ecosystem service of diverse agricultural landscapes. Additionally, it highlights the roles that insect life history and regional pest management play in shaping landscapeinsect relationships.
dissertation or thesis