Drivers of waterfowl variability in the Arkansas Mississippi Alluvial Valley

Abstract

Wintering waterfowl populations in the Arkansas Mississippi Alluvial Valley (ARMAV) are influenced by a combination of habitat availability and climate variability, but the relative importance of these factors at a regional scale remains unclear. Therefore, my study evaluated the influence of wetland cover, rice agriculture, and seasonal climate variables on Mallard (Anas platyrhynchos) and total duck abundance across 11 watersheds in Arkansas from 2012 to 2024. I obtained waterfowl survey data from standardized aerial counts, and derived land-cover data from United States Geological Survey and United States Department of Agriculture datasets and processed them using QGIS. I obtained climate variables, including temperature and precipitation, from National Oceanic Atmospheric Administration stations and analyzed them for both winter (November–February) and summer (June–August) seasons. I conducted linear and multiple regression analyses to assess relationships among environmental variables and waterfowl abundance at the watershed scale. My results indicated an overall decline in waterfowl populations across the ARMAV, with notable spatial variability among watersheds. Rice cover increased substantially across all watersheds but showed no significant relationship with waterfowl abundance. In contrast, wetland cover exhibited moderate to strong relationships with duck and Mallard populations in several watersheds, although the direction and strength of these relationships varied spatially. Multiple regression models demonstrated that land cover variables explained a significant proportion of variation in select watersheds but not across the entire region. Climate variables showed limited correlation with wintering waterfowl abundance, with no significant relationships observed for winter temperature or precipitation. However, summer temperature exhibited moderate correlations with Mallard abundance in some regions, suggesting potential indirect effects. Overall, my study highlights the importance of wetlands as a key driver of waterfowl abundance in the ARMAV and emphasizes the spatial differences of habitat relationships. My findings suggest that habitat management, particularly wetland conservation and hydrologic management, may be more effective than reliance on agricultural extent alone.