Through a recent contract with the Bureau of Land Management (BLM), Ducks Unlimited is updating the National Wetlands Inventory (NWI) for a large portion of southeast Oregon.
Established in 1986, the NWI is a publicly available resource for classifying and mapping wetlands, evaluating status and trends of wetlands, conservation planning and natural resource management. The NWI provides information on wetland size, flooding frequency, land cover type and vegetation composition. Under the NWI descriptions, wetlands can include habitats such as rivers, dry washes, marshes, lakes and agricultural ditches.
For DU, the NWI can help identify high-quality waterfowl habitat for protection or restoration. The areas DU is mapping are in the Southern Oregon-Northeastern California (SONEC) region, a priority conservation landscape for DU. Wetlands and irrigated grasslands in the SONEC support over 70% of the Pacific Flyway’s dabbling duck population during spring migration, including 30% of the continent’s northern pintail. Large wetland basins that are part of this NWI update include Summer Lake Wildlife Area, Lake Abert and Malheur National Wildlife Refuge.
Most of the work to update the NWI is performed digitally, using aerial imagery and elevation data to delineate waterbodies and wetland habitats. This is accompanied by fieldwork to verify the accuracy of digital wetland classifications and answer questions that cannot be gleaned from imagery alone. For example, observing whether an area is inundated or saturated during site visits gives a better understanding of its typical flooding duration.
Plant species observed during fieldwork can also indicate water regime and wetland characteristics.
Updates to the NWI document changes in wetland distribution or status and help with wetland conservation and policy decisions. Updating the NWI requires imagery analysts and scientists specially trained in the use of Geographic Information System (GIS) software and that follow mapping standards set by the Federal Geographic Data Committee. This use of the NWI and similar GIS products is integral to DU’s science and conservation planning.
DU has mapped regions of Alaska and Minnesota for the NWI. DU is also performing NWI updates for Arizona and southern California, which will be mapped and field-verified by 2023.
Ducks Unlimited Inc. is the world's largest nonprofit organization dedicated to conserving North America's continually disappearing waterfowl habitats. Established in 1937, Ducks Unlimited has conserved more than 15 million acres thanks to contributions from more than a million supporters across the continent. Guided by science and dedicated to program efficiency, DU works toward the vision of wetlands sufficient to fill the skies with waterfowl today, tomorrow and forever. For more information on our work, visit www.ducks.org.