Species richness and density of wintering ducks on wetlands reserve program easements in Mississippi

Abstract

ABSTRACT The Mississippi Alluvial Valley provides important habitats for migrating and wintering waterfowl and is a priority area for restoration of wetlands through the U.S. Department of Agriculture's Wetlands Reserve Program (WRP). Management of WRP wetlands varies from no management to active annual management of vegetation and water levels, which may influence wintering waterfowl use. We modeled variation in species richness and density of dabbling and diving ducks (Anatini, Aythyini) relative to a published Vegetative Forage Quality Assessment Index (VFQI; Fleming et al. 2012) of duck foods, other floristic metrics, and management type of WRP wetlands in Mississippi, USA, during autumns–winters 2007–2009. Duck species richness was correlated positively with wetland area when precipitation was below normal (winter 2007–2008), but not in 2008–2009 when landscape‐level flooding occurred. Duck densities varied positively with VFQI on wetlands with active management and late‐summer drawdown, but not on passive or active managed areas with early drawdown. Duck densities decreased with increasing woody vegetation. Models including VFQI explain ≤27% of the variation in duck densities, suggesting that ducks may also be selecting wetlands based on metrics that are not related to VFQI or wetland management. Active managed wetlands may produce the greatest VFQI, but our results suggest this technique need not always result in increased use by ducks. Nevertheless, we recommend active management of WRP wetlands to sustain food at the landscape level for migrating and wintering ducks. We also recommend continued study of metrics other than VFQI that may potentially influence use of wetlands by waterfowl. © 2015 The Wildlife Society.

Keywords

• Mississippi
• moist‐soil management
• species richness
• waterfowl
• wetlands
• Wetlands Reserve Program