Proceedings of the 2023 Mississippi Water Resources Conference

Year: 2023 Authors: Heintzman L., McIntrye N.

Industrial agricultural systems are subject to land use/land cover (LULC) changes via field rotation. These pattern changes may consequently influence a diversity of embedded ecological processes. Even though wetlands—which are integral components of, and provide interfaces for, ecosystem services—are not directly subject to crop rotation, their structure (and, thus, function) may be shaped by LULC changes. Among the most productive North American agroecosystems, the Yazoo-Mississippi Delta (colloquially, "The Delta") exemplifies the challenges faced by these areas with dual aquatic and terrestrial status within mosaics of land ownership and legal protections. Although historical LULC within The Delta is well-documented, few studies have examined contemporary field rotation patterns and corresponding LULC effects on wetlands. To address this gap, we used NASS Cropland Data Layers from 2008–2021 to quantify LULC change around 43,524 wetland features in The Delta. We initially reclassified >35 LULC classes in the NASS data to nine mutually exclusive LULC types. We then identified 43,524 features which had been classified as wetlands during all focal years. For each of those wetland features, we buffered by 90m and grouped these results into four buffer size categories (small [x < 3.63 ha], medium [3.63 ha < x < 4.17 ha], large [4.17 ha < x < 9.25 ha], and extra-large [x > 9.25 ha]). We quantified LULC change within buffers of each wetland feature on a pixel-by-pixel basis, measuring LULC variety, majority LULC type, minority LULC type, and LULC stability (relative to baseline data from 2008). Overall, our results indicated that wetlands were dispersed throughout The Delta, with highest concentrations in Bolivar, Leflore, Sunflower, and Washington counties. LULC variety and stability were positively associated with spatial scale. Soybeans were the majority LULC type around wetlands at all spatial scales and years, indicating relative LULC stability around wetlands. LULC minority was other agriculture for medium, large, and extra-large categories. For the small category, LULC minority was wetlands- indicating isolation effects. Our study examined regional field rotation patterns and highlighted mixed management of wetlands in Delta agroecosystems. Our results indicate that wetlands of The Delta are especially subject to practices associated with soybeans. Our approach and results can be used to direct conservation efforts for ecosystem services and wetland resources. Additionally, our study augments emerging theory that dynamic landscape pattern management is necessary in industrial agricultural systems.