National accounts for wild crop pollination: tracking long-term changes in the U.S. agricultural landscape and their consequences for society

Abstract:

The pollination of crops by insects is widely recognized as a critical ecosystem service: 75% of global crop species depend to some degree on such pollination. Substantial research has gone into understanding and valuing pollination as an ecosystem service, both in field-scale studies and those that scale up such results to regional, national, and global scales. Studies that have evaluated changes in the area, yield, and value of pollination-dependent crops note increases in the production of such crops when they are in close proximity of pollinators’ habitats, and evidence that a lack of pollinators can limit production. In this study, we used the USDA Cropland Data Layer (30 m resolution) to identify the habitat and pollination-dependent crops in foraging proximity of the native pollinators’ habitats in the contiguous U.S. Our model uses a nonlinear pixel-based approach that incorporates pollination dependency of crops, habitat quality for wild pollinators, and distance decay functions. We evaluated trends in key pollination metrics in 3-year intervals from 2008 to 2020 to quantify changes in the agricultural landscape related to: 1) the area and types of pollination-dependent crops that potentially benefit from wild pollinators and 2) changes in wild pollinator habitat. For selected states where data are available, we extend our analysis back to 1999. We applied the Experimental Ecosystem Accounting framework proposed by the United Nations to quantify ecosystem condition, physical supply and use, and monetary supply and use of wild crop pollination. Our study provides a long-term, large-scale view of how changes in the U.S. agricultural landscape impact crop pollination and the economy. This study shows how pairing such a framework with a national-scale ecosystem service model can provide a useful information for policy.