Current Research Projects
Can sustainable agriculture promote diverse insect communities and ecosystem services?
Agricultural intensification degrades the biodiversity of insect communities and their ecological services. Evidence suggests, however, that organic and/or sustainable agricultural practices may promote diversity and aid in restoring communities. Our research attempts to determine the effects of agricultural practices, including comparisons of conventional vs. organic, on the structure of insect communities, and determine the consequences of these variable community structures on ecosystem services such as biological control and pollination.
- Crowder DW, Reganold JD (2015) Financial performance of organic agriculture on a global scale. Proceedings of the National Academy of Sciences, 112 7611-7616.
- Crowder DW, Jabbour R (2014) Relationships between biodiversity and biological control in agroecosystems: current status and future challenges. Biological Control 75, 8-17.
- Crowder DW, Northfield TD, Gomulkiewicz R, Snyder WE (2012) Conserving and promoting evenness: Organic farming and fire-based wildland management as case studies. Ecology 93:2001-2007.
- Crowder DW, Northfield TD, Strand MR, Snyder WE (2010) Organic agriculture promotes evenness and natural pest control. Nature 466:109-112.
Promoting pollinator health and pollination services
Abundant and diverse pollinator communities are critical for sustainable crop yields, yet the services provided by pollinators on farms are often threatened by abiotic and biotic stressors. We are currently working on a project to assess pollinator community health and pollination services in the Puget Sound Region, while educating local community members to increase pollinator literacy. Our research takes place primarily on diversified organic farms and urban gardens in collaboration with an active group of growers. We also have several citizen science initiatives as part of our Citizen Science Initiative for Bees (CSI: Bees). Check out our websites for more information:
Agricultural systems in Washington and many other states are diverse, yet we often lack a basic understanding of how insects move across landscapes, and how landscape diversity and configuration affects the distribution of pests and beneficial species. Our research seeks to identify how characteristics of landscapes (i.e., habitat diversity and configuration) affect insect distributions and their associations with plants.
- Schmidt-Jeffris RA, Beers EH, Crowder DW (2015) Phytoseiids in Washington commercial apple orchards: biodiversity and factors affecting abundance. Experimental and Applied Acarology 67, 21-34.
- Crowder DW, Dykstra EA, Brauner JM, Duffy A, Reed C, Martin E, Peterson W, Carriere Y, Dutilleul P, Owen JP (2013) West Nile virus prevalence across landscapes is mediated by local effects of agriculture on vector and host communities. PLoS ONE 8, e55006.
- Carrière Y, Ellers-Kirk C, Hartfield K, Larocque G, Degain B, Dutilleul P, Dennehy TJ, Marsh SE, Crowder DW, Li X, Ellsworth PC, Naranjo SE, Palumbo JC, Fournier A, Antilla L, Tabashnik BE (2012) Large-scale, spatially-explicit test of the refuge strategy for delaying insecticide resistance. Proceedings of the National Academy of Sciences USA 109:775-780.
Many insects transmit pathogens that threaten the health of humans, livestock, and wildlife. Our laboratory is exploring the dynamics of several insect-plant-pathogen systems, including the transmission of Pea-enation mosaic virus by pea aphids to pea plants and the transmission of Liberibacter solanaceurum by psyllids to potato plants. Our work involves experimental approaches to elucidate the mechanisms governing pathogen spread, and quantitative approaches to model the spread of pathogens within crop fields.
- Reif KE, Palmer GH, Crowder DW, Ueti MW, Noh SM (2014) Restriction of Francisella novicida genetic diversity during infection of the vector midgut. PLoS Pathogens 10:e1004499.
- Crowder DW, Dykstra EA, Brauner JM, Duffy A, Reed C, Martin E, Peterson, W, Carriere Y, Dutilleul P, Owen JP (2013) West Nile virus prevalence across landscapes is mediated by local effects of agriculture on vector and host communities. PLoS ONE 8:e55006.