Next Steps for a Healthy Gulf of Mexico Watershed
Landscape at a Glance
The Rainwater Basin Focal Area is a 6,150 square mile wetland complex located in south-central Nebraska that includes parts of 21 counties. The focal area has expansive rolling loess plains formed by deep deposits of windblown silt with a high density of clay-pan playa wetlands. These wetlands are annually filled by overland runoff from intense summer storms and melting winter snowfall. Historic surveys suggest that at one time there were approximately 11,000 individual playa wetlands totaling about 204,000 acres. There were also more than 10,000 temporary and another 1,000 semi-permanent wetlands. Today, approximately 82 percent of the major wetlands have been converted to agriculture, and today playa wetlands comprise about one percent of the total Rainwater Basin landscape. Because of extensive loss and continued degradation, these wetlands were given a Priority 1 ranking, the most imperiled status, in the Nebraska Wetlands Priority Plan.
Despite the extensive wetland loss, the Rainwater Basin Focal Area still hosts one of the greatest wildlife migration spectacles on earth. This region is often described as “the neck of the hour glass” due to the constriction of the Central Flyway through this region during spring migration. During this migration, the focal area provides roosting, loafing and foraging habitat for millions of migratory waterfowl and other wetland-dependent species that have wintered along the Gulf coast, across Texas and Mexico and farther south. It provides essential staging habitat for approximately 8.6 million waterfowl and nearly 500,000 shorebirds. The Rainwater Basin Focal Area also serves as an important stopover habitat for many of the 400+ endangered whooping cranes migrating Aransas NWR on the Gulf coast of Texas to nesting grounds on Woods Buffalo National Park, Alberta, Canada. Approximately 50 percent of the mid-continent mallard and 30 percent of the continental northern pintail population use this region. More than twenty species listed in the Deepwater Horizon Programmatic Damage Assessment and Restoration Plan are estimated to use focal area sometime during their annual cycle, 11 of which are priorities for conservation action by the Service.
Almost 99 percent of the lands within the focal area are under private ownership, with land use that is dominated row-crop agriculture (predominantly a corn and soybean rotation). Grasslands make up approximately 20 percent of the region, with the remainder being savannas, woodlands and forest communities that are confined to steeper drainages associated with the Republican and Blue River systems. Riverine wetlands associated with these systems comprise about two percent of the landscape.
Wetland function across the Rainwater Basin landscape continues to decline as a result of intentional human activity that has added to natural and agriculturally accelerated sedimentation. For example, this focal area is a major source of the Platte River’s nutrient runoff into the Mississippi River. Wetland modifications, such as concentration/irrigation reuse pits, land leveling, culturally accelerated sediment and drainage ditches have directly impacted wetlands by limiting the amount of natural runoff reaching them. The combination of sedimentation and altered watershed hydrology subsequently contributes to conditions that promote invasive species growth. While the scale of the conservation challenge in this focal area is great, the Service believes in the possibility of equally significant conservation successes through a more concerted approach in engaging partners and the wider public, especially in support of voluntary land acquisition and easement practices. The combination of wetland habitat restoration and the protection of lands through fee title and easement acquisition with willing landowners in the Rainwater Basin Focal Area could provide about 80 percent of the total forage capacity needed to meet population objectives for waterfowl, the whooping crane, the least tern and the piping plover.
Eleven priority duck species identified by the North American Waterfowl Management Plan (NAWMP) use the Rainwater Basin through some portion of their annual cycle. Seven of these are listed as “high” or “moderately high” in continental priority, and five (i.e., northern pintails, American wigeons, blue-winged teals, canvasbacks and redheads) commonly use wintering habitat within the tidal zone of Gulf coastal marshes. When continental waterfowl are at the long-term average as described in the NAWMP goals, an estimated 8.6 million waterfowl will migrate through the basin (i.e., approximately 4.2 million mallards and 800,000 northern pintail, with the remainder being a combination of blue-winged teals, green-winged teals, northern shovelers, American wigeons and gadwalls). In addition, 500,000 mid-continent white-fronted geese, 400,000 Canada geese and millions of snow geese use the region. These birds would require 15.6 billion kcals, with 4.4 billion kcals coming from wetland-derived foraging resources. In addition to waterfowl that use migration habitat, an estimated 275,000 waterfowl rely on Nebraska’s Sandhills (comprised of 34 percent mallards, 27 percent blue-winged teals, 20 percent gadwalls, 14 percent northern shovelers and six percent northern pintails).
There are 24 priority shorebird species identified in the U.S. Shorebird Conservation Plan that rely on habitat within the Rainwater Basin Focal Area and associated areas. Many of these species will frequently use tidal zones of Gulf coastal marshes for brief periods during spring and fall migration. The Rainwater Basin Joint Venture has targeted providing habitat for a non-breeding population estimate of 2.9 million shorebirds such as the Wilson’s phalarope (2.1 million), the buff breasted sandpiper (216,000), the killdeer (122,000), the lesser yellowlegs (92,700), the semipalmated sandpiper (91,098), and the least sandpiper (35,026). In addition, the Rainwater Basin Joint Venture has set breeding habitat for another 400,000 shorebirds such as the Wilson’s phalarope (241,490), the long-billed curlew (22,474) and the upland sandpiper (15,746). It is estimated that it will require an estimated 2.1 billion kilocalories (kcals) of foraging resources to meet the nutritional needs of 2.9 million migrating and breeding shorebirds when the Rainwater Basin Focal Area is at the population goal.
Waterbirds are probably the least understood of all the bird groups. The Rainwater Basin Joint Venture identified 52 species within the region, but sufficient information was only available to plan for Interior least terns, sandhill cranes and whooping cranes. Using bioenergetics modeling, the Rainwater Basin Joint Venture estimated that the 560,000 sandhill cranes that use the focal area for staging while migrating would require 10.8 billion kcals of foraging resources. It was assumed if sufficient habitat were available for sandhill cranes along the Platte River, there would also be sufficient habitat for breeding Interior least terns (1,120 birds) and piping plovers (2,300 pairs in Northern Great Plains), as well as for the millions of waterfowl and the endangered whooping cranes (1,000 birds of the Wood Buffalo Population). According to the Rainwater Basin Joint Venture, enhancement and restoration of wetlands on public lands within the focal area could provide more than 50 percent of the natural forage resources needed to sustain focal area target populations of whooping cranes, least terns and piping plovers.
While many of the proposed actions in this focal area specifically target benefits to migratory birds, implementation of these actions will be advantageous to other species as well. For example, we place an overall emphasis on land conservation in order to meet the needs of whooping cranes, least terns and piping plovers. Those actions will also benefit northern bobwhite quail, ring-necked pheasant, white-tailed deer, and potentially wild turkey through protection of valuable wetland and grassland habitats. Similarly, we promote working with private landowners to restore or sustain food resources for our trust resource species which, in turn, will also supply sufficient resources to meet the energetic demands of upland game species, amphibians, reptiles, insects, and other mammals.
High Priority Actions Based on the Service’s Vision
Focus public lands conservation delivery on habitat restoration and/or enhancements to support migrating birds that stage in the Rainwater Basin enroute to southern wintering areas or spring breeding areas.
- Maintain 80 percent of public wetland acres in early successional plant communities and increase ponding frequency under average natural moisture conditions to optimize moist-soil seed production.
- Restore wetland and watershed function so public properties exhibit a ponding frequency of 45 percent under average weather conditions. Restore wetland and watershed function so that perpetually protected wetlands privately owned exhibit a ponding frequency of 33 percent under average weather conditions.
- Restore and maintain wetland vegetation communities on perpetually protected public lands (NWRs, NE Game and Parks, etc.) at 60 percent early-successional, 30 percent cropland (farmed), and 10 percent late-successional in wetlands created in partnership with federal and/or NGO conservation programs such as NAWCA.
- Maintain wetland vegetation communities on lands protected by perpetual wetland easements that are 30 percent early-successional, 50 percent cropland (farmed), and 20 percent late-succession.
- Encourage or expand the development of short-term conservation programs for the establishment of grassland buffers around these wetlands. This may be accomplished through the establishment of Conservation Reserve Program easements or other compatible national-, state- or nongovernmental organization-sponsored farm programs.
Work with willing landowners to target land acquisition and easement opportunities to target high priority habitats for whooping crane, least tern and piping plover.
- Acquire an additional 17,225 acres of wetlands and adjacent uplands through fee title acquisition, most of which would be “roundouts” to existing public lands, that will facilitate restoration and management of the existing public wetlands (managed by the Service or Nebraska Game and Parks Commission) in the Rainwater Basin.
- Protect and restore 13,585 additional acres of wetlands and uplands through perpetual conservation easements.
- Conduct outreach with landowners to incentivize, restore and maintain 7,350 acres of wetlands enrolled in short term conservation programs (> 30 years).
Focus private lands conservation actions on habitat restoration and other programs to ensure the approximately 62,500 acres of functional wetland habitat needed, along with postharvest waste grain, to meet the food requirements of the whooping crane, the least tern, the piping plover and waterfowl.
- Work with partners to ensure sufficient and appropriately placed wet-meadow habitat to provide high-quality foraging habitat for sandhill and whooping cranes in the Central Platte River and the North Platte River Valley.
- Monitor harvested cornfields along the Rainwater Basin’s Central and North Platte River valley with a goal to maintain sufficient acreage (~80,000 acres at 35.6 kg/ac) waste grain.
- Develop resources for geospatial analysis to that permit development of decision support tools that quantify and map current nesting habitat for least terns and piping plovers to facilitate targeting of conservation efforts.
- Work with partners to assist federal, state and NGO land managers in prioritizing restoration and management projects to provide the greatest biological return for priority nesting species.