Prior to European settlement, the Northern Mixed-grass Prairie was a mosaic of wetland, grassland and grass-shrub habitats, with riparian and floodplain forests along major drainages. Even today, the physiographic area can be characterized as being one of the largest still relatively intact grassland landscapes that persist in North America. It is the continent’s most important production area for waterfowl and is the heart of the breeding range for some of North America’s rarest species of grassland birds. A comparison of relative abundance estimates among physiographic areas sampled by the North American Breeding Bird Survey indicates that more than 40% of the world’s population of Baird’s Sparrows, 30% of Nelson’s Sharp-tailed Sparrows and 25% of Sprague’s Pipits are found in the physiographic area during the breeding season. Population objectives are to maintain or increase the abundance of all species in the grassland species suite. Because many priority grassland species have relatively large area requirements and large home ranges, habitat strategies include securing existing landscapes where native prairie exists in abundance and focusing habitat management prescriptions on units of 100 ha (250 acres) or greater.
Most of the priority wetland species appear to be stable or increasing in the physiographic area, perhaps because wetland loss has slowed in recent years as a result of Federal wetland protection regulations. The general population objective for the priority wetland species in this plan is to stabilize or increase current populations. Preservation and restoration of wetlands and wetland complexes should be emphasized and the amount of grassland in wetland landscapes should be maximized for Wilson’s Phalaropes, Willets, and Marbled Godwits.
The ecology of riparian systems of the Northern Mixed-grass physiographic area has received relatively little treatment to date, and warrants more research. However, most of the priority species associated with riparian zones also utilize habitat provided by shelterbelt and other tree plantings and probably are not habitat-limited in the physiographic area. Priority species in the Missouri River floodplain are all federally listed under the Endangered Species Act and are being managed under recovery plans developed by the U. S. Fish and Wildlife Service.
Priority species of prairie grassland and wetland birds require differing amounts and configurations of habitat. However, all species inventoried required large areas of native grassland habitat and benefited from areas that had recently been burned.
Female greater prairie chickens require a 1500m undisturbed radius of native prairie surrounding lek sites for nesting and foraging, and short-eared owls and northern harriers require habitat patches of 100 ha or more. Specific area requirements for several grassland bird species include: <30 ha for sedge wrens, >150 ha for sprague’s pipit, 10-30 ha for dickcissel, >50 ha for Baird’s sparrow, 30-100 ha for grasshopper sparrow, <30 ha for LeConte’s sparrow, and <30 ha for Bobolinks.
|journal||Technical Report, Jefferson City, Missouri: American Bird Conservancy, 1999|