Geography

Nebraska Sand Hills mixed grasslands

Introduction

The Nebraska Sand Hills (hereafter, Sand Hills), located almost entirely within the state of Nebraska, is considered by Küchler 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.

Biological Distinctiveness

caption WWF 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).

Conservation Status

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. 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

caption Buffalo (Bison bison) in the Sand Hills, Nebraska, USA. (Photograph by NEBRASKAland Magazine/Nebraska Game and Parks Commission)

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:

  • Valentine National Wildlife Refuge - north central Nebraska - 285 km2
  • Crescent Lake - west-central Nebraska - 175 km2
  • Niobrara Valley Preserve, with Wild and Scenic designation of the Niobrara River - north-central Nebraska - 202 km2
  • Fort Niobrara National Wildlife Refuge - central-norther Nebraska

Types and Severity of Threats

caption Sand Hills Lake, Nebraska, USA. (Photograph by NEBRASKAland Magazine/Nebraska Game and Parks Commission)

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.

 

Suite of Priority Activities to Enhance Biodiversity Conservation

  • Priority activities should focus on creating dialogues with landowners. Key conservation messages to stress are the need to limit stocking rates to promote the health of grazing lands, and where and where not to graze.
  • The Sand Hills contain only a few protected areas. Creation of new areas is not considered to be an urgent need because of the relative degree of intactness of the landscape and a potentially high level of awareness of ecosystem sensitivities among landowners.

Conservation Partners

  • Institute of Agriculture and Natural Resources
  • West Central Research and Extension Station,
  • The Nature Conservancy of Nebraska
  • Natural Resources Conservation Service
  • Nebraska Natural Heritage Program
  • University of Nebraska
  • U.S.Fish and Wildlife Service

Relationship to other classification schemes

The boundary of the Sand Hills is taken from Omernik and is very similar to the boundary described in Bailey unit 332C-Nebraska Sand Hills and Küchler unit 67.

Additional information on this ecoregion

 

 

Disclaimer: This article is taken wholly from, or contains information that was originally published by, the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.

 

 

 

Glossary

Citation

Fund, W. (2014). Nebraska Sand Hills mixed grasslands. Retrieved from http://www.eoearth.org/view/article/51cbee7f7896bb431f698470

0 Comments

To add a comment, please Log In.