CANCELLED - Landscape diversity and its effects on agricultural pests

Background/Question/Methods: Transboundary effects of adjoining habitat types can have important management implications in terms of landscape-scale patterns of species distributions. Increased numbers of pest animals and weeds on agricultural lands associated with restored habitats could have negative economic impacts, and in turn affect support for restoration and conservation of natural areas. To determine the relationship between landscape diversity and agricultural pests, I collected seed bank soil samples, conducted pest bird surveys and surveys of two major agricultural lepidoteran pests at regional and local scales on up to 23 orchards at different distances from the edge of restored riparian, remnant riparian and agricultural habitat in the Sacramento River watershed in California.  I determined the abundance and species richness of plant species in the seed bank and analyzed them in terms of management type, dispersal type, and age of adjacent habitat type. I analyzed local and landscape variables associated with bird and insect pests to determine the most important variables explaining their abundances. 

Results/Conclusions:

I found that non-native and agricultural weed species had higher densities at the edge of restored riparian habitat and that native plants had higher densities adjacent to remnant riparian habitat. I also found that pest birds decreased in abundance with increasing area of riparian habitat, and lepidopteran pests had no relationship to area of riparian habitat.