Habitat management and invertebrate weed seed predation in herbaceous crop systems.
Menalled, Fabian *,1, Landis, Douglas2, Matt, Liebman3, 1 719 Leon Johnson Hall, Bozeman, MT, USA2 204 Center for Integrated Plant Systems, E. Lansing, MI, USA3 Department of Agronomy, Ames, IA, USA
ABSTRACT- Modern agriculture can be characterized as a human enterprise in which the pressure towards increasing crop yield generates ecosystems characterized by biological simplification, subsidized chemical and energetic inputs, output specialization, and decreased environmental heterogeneity. These systems depend on pesticides and other forms of disturbances to reduce the impact of weeds and insect pests. There is growing interest in reducing reliance on pesticides through the maximization of the ecosystem services provided by beneficial organisms, including weed seed predators. However, the joint effect of landscape simplification and disturbances generate harsh environment for these beneficial organisms. Habitat management represents a valuable approach to manipulate plant species and communities to benefit natural enemies in agricultural landscapes. Such efforts aim to provide appropriate food, shelter, and hosts for weed seed predators at different spatial scales; within fields, at field margins, or as a component of the larger landscape. Our research suggests that there is a significant linear relationship between the abundance of generalist predators such as carabid beetles and field crickets and seed predation. Simple habitat management practices, including the establishment of refuge habitats in close spatial association with annual crop fields can help conserve invertebrate weed seed predators. Finally, expanding row cropping systems to include small grains and forages allows the integration of vertebrate and invertebrate weed seed predators with other factors that stress and kill weeds. Field data and simulation models suggest that, if properly combined, these factors can lead to effective weed suppression.
Key words: habitat management, annual crops, integrated weed management
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