Abstracts

Presented by Edward B. Farley - Email: efarley@ducks.org

Wetland managers need to understand food availability of wetlands to adapt management techniques and provide adequate resources for migrating waterfowl. Soil core sampling is an important tool to determine the density of seeds and tubers available to foraging waterfowl. A major issue with soil core sampling is the intensive time it takes to collect and analyze samples in a sufficient sample size to get an accurate estimate of seed and tuber density in a wetland. We developed a rapid assessment tool for estimating food densities without need of full soil core sample protocol. We collected 10 soil core samples in each of 30 randomly selected wetlands in the Montezuma Wetlands Complex, October 2016 - 2018. At each sampling point, we recorded the predominant vegetation type as annuals, mixed perennial emergent, invasive, mudflat, or open water. Annual points (n = 174, mean = 1061.7100.5 kg/ha) had greater mean seed and tuber density than other categories, and mixed perennial emergent points (n = 224, mean = 799.363.8 kg/ha) had greater densities than invasive (n = 229, mean = 347.5325.3 kg/ha), mud flat (n = 67, mean = 263.339.9 kg/ha), and open water points (n = 143, mean = 400.092.2 kg/ha). Our analysis showed that mean invasive, mud flats, and open water points did not differ, so we grouped them together in a new category, other (n = 439, mean = 351.533.2 kg/ha). All habitat categories showed low variation (annuals: coefficient of variation [CV] = 9.5%, mixed emergent: CV = 8.0%, and other: CV = 9.4%). By recording wetland habitat types among 40 points throughout wetlands and using mean seed and tuber density values from our analysis, wetland managers in the northeastern US can rapidly assess wetland food densities to better understand existing habitat needs in relation to local and regional Duck-Energy-Day goals.