Drivers of agricultural diversity in the continental United States

Authors: Goslee, Sarah

Submitted to: US-International Association for Landscape Ecology
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2019
Publication Date: 4/10/2019
Citation: Goslee, S.C. 2019. Drivers of agricultural diversity in the continental United States[abstract]. US-International Association for Landscape Ecology. p. 1.

Interpretive Summary: No Interpretive Summary is required for this Abstract. JLB.

Technical Abstract: The spatial heterogeneity of vegetation types on a landscape has been linked to multiple ecosystem functions, including habitat for wildlife and pollinators, water and nutrient cycling, and human aesthetic values. Although agricultural land uses are sometimes lumped together, diversity of crop types within agroecosystems is also important, and diverse cropping systems are a valuable alternative to near-monocultural croplands. The USDA Cropland Data Layer (CDL) was used to characterize both structural diversity of crop types (annual monocot, annual dicot, perennial herbaceous, shrub fruits, tree fruits) and the species diversity of crop types across the continental US. Percentage of each crop type, along with non-crop uses such as forest and development, were calculated for each 4km PRISM climate data grid cell. Agricultural diversity was unrelated to total area in agriculture: both heavily agricultural and mixed use grid cells could have high or low diversity. To better understand the drivers of crop diversity, Random Forest modeling was used to assess the importance of climate, soils, and irrigation for patterns of agricultural diversity. The models explained about 75% of the variation in crop diversity in 2017, with irrigation being by far the most important explanatory variable, due to the association between vegetable cropping and irrigation. Soil water holding capacity was the second most important variable; other climatic and soils variables were less influential. Substantial structural changes in infrastructure may be necessary to increase agricultural diversity at large spatial extents, and declining availability of water for irrigation could threaten the agricultural systems that are now most diverse.