Not just crop or forest: building an integrated land cover map for agricultural and natural areas

Authors: KAMMERER, MELANIE - Oak Ridge Institute For Science And Education (ORISE); IVERSON, AARON - Lawrence University; LI, KEVIN - University Of Michigan; Goslee, Sarah

Submitted to: Earth System Science Data
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2023
Publication Date: 1/26/2024
Citation: Kammerer, M., Iverson, A., Li, K., Goslee, S.C. 2024. Not just crop or forest: building an integrated land cover map for agricultural and natural areas. Earth System Science Data. 11(1):137. https://doi.org/10.1038/s41597-024-02979-w.
DOI: https://doi.org/10.1038/s41597-024-02979-w

Interpretive Summary: Understanding and managing agricultural systems frequently requires thinking beyond the field to include surrounding natural habitats. For example, both beneficial insects and some crop pests move between agricultural fields and adjacent forests or wetlands, so considering nearby natural areas is important for predicting future pest populations. Researchers and land managers need reliable maps of agricultural and natural lands, but current maps of land cover provide detailed information on either agriculture or natural land, not both. To solve this problem, we joined together two existing maps of land cover to create new national maps for 2012-2021. Our maps show the location and area of specific crops and detailed types of natural habitat. By creating combined maps of land cover that are ready to use, our work prevents the wasted effort of each project creating custom maps. These maps will be widely useful in supporting agricultural and environmental research, conservation, and land management.

Technical Abstract: Due to our increasing understanding of the role the surrounding landscape plays in ecological processes, a detailed characterization of land cover, including both agricultural and natural habitats, is ever more important for both researchers and conservation practitioners. Unfortunately, in the United States, different types of land cover data are split across thematic datasets that emphasize agricultural or natural vegetation, but not both. To address this data gap and reduce duplicative efforts in geospatial processing, we merged two major datasets, the LANDFIRE National Vegetation Classification (NVC) and USDA-NASS Cropland Data Layer (CDL), to produce an integrated land cover map. Our workflow leveraged strengths of the NVC and the CDL to produce detailed rasters comprising both agricultural and natural land-cover classes. We generated these maps for each year from 2012-2021 for the conterminous United States, quantified agreement between input layers and accuracy of our merged product, and published the complete workflow necessary to update these data. In our validation analyses, we found that approximately 5.5% of NVC agricultural pixels conflicted with the CDL, but we resolved a majority of these conflicts based on surrounding agricultural land, leaving only 0.6% of agricultural pixels unresolved in our merged product. These ready-to-use rasters characterizing both agricultural and natural land cover will be widely useful in environmental research and management.