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The Nebraska Sand Hills (hereafter, Sand Hills), located almost entirely within the state of Nebraska, is considered by Küchler (1964) to be one of three major grassland associations which he grouped as the tallgrass prairie. One of the smallest of the Great Plains ecoregions, the Sand Hills covers an area of about 61,100 km2. The Sand Hills can be distinguished from other tallgrass and mixed grass ecoregions by a combination of physiography, soils, elevation, surface water characteristics, and natural vegetation. The Sand Hills consist of various dune types and interdunal valleys, dominance of Cenozoic sands, and a distinct soil type (entisols). The irregular dunes and sandy soils of the Sand Hills are so distinct within the Great Plains as to warrant elevation of the Nebraska Sand Hills to its own ecoregion. The western and portions of the northern Sand Hills are dotted with small lakes and wetlands. Precipitation and temperature are average among the Great Plains ecoregions. Historically, fire and grazing by migratory herds of bison played a major role in shaping the landscape. Today, the major disturbance factor is cattle grazing on the large ranches that cover much of the ecoregion.
The Sand Hills contain the most intact natural habitat of the Great Plains ecoregions. The Sand Hills contain a distinct grassland association dominated by sand bluestem (Andropogon hallii), Calamovilfa longifolia, and needleandthread (Stipa comata). Habitat Loss and Degradation It is estimated that as much as 85 percent of the Sand Hills is still intact. Toward the eastern section of this ecoregion, habitat loss and degradation are higher than in the rest of the Sand Hills due to central pivot irrigation and development. Degradation of the tallgrass prairie is less in the Sand Hills than in other grassland ecoregions; fragility of soils has dissuaded excessive overgrazing and cropping (Sims 1988). In overgrazed areas, decreases in little bluestem (Schizachyrium scoparium), needleandthread (Stipa comata), and Andropogon hallii, and increases in hairy grama (Bouteloua hirsuta), Calamovilfa longifolia, and dropseed (Sporobolus cryptandrus) are apparent. Remaining Blocks of Intact Habitat Very little of the Sand Hills has been plowed; remaining blocks cover large parts of the ecoregions. Degree of Fragmentation The absence of farming in the region and other developments contribute to an extraordinarily low level of fragmentation for a Great Plains ecoregion. Degree of Protection The most important protected areas in the Sand Hills are:
Types and Severity of Threats Because of the sandy soils and topography, farming is less conspicuous than in other units. Center-pivot irrigation was implemented in the past but has largely proven unfeasible. If it were attempted again, conversion to agriculture might become a more serious threat. The pumping of the vast reservoirs of groundwater is also a potential threat. Drainage and haying of wet prairies and meadows between the dunes potentially could have a major influence. Whether wetland species are being impacted is unknown.
 Relationship to other classification schemes The boundary of the Sand Hills is taken from Omernik (1995) and is very similar to the boundary described in Bailey unit 332C-Nebraska Sand Hills and Küchler (1985) unit 67 (Sand Hills Prairie). Prepared by: S. Chaplin, P. Simms, E. Dinerstein, K. Carney, Rick Schneider, and T. Cook. This text was originally published in the book Terrestrial ecoregions of North America: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of North America's ecoregions. All text by World Wildlife Fund © 2001 For more general information on this ecoregion, go to the WildWorld version of this description.
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