Soil Biodiversity and Ecosystem Functioning


Global Litter Invertebrate Decomposition Experiment

Colorado Shortgrass Steppe LTER, USA

Site Manager

Dr. Diana Wall
Director and Professor
Natural Resource Ecology Laboratory (NREL)
Colorado State University
Fort Collins, CO 80523
Telephone: (+1) 970 491 2504
Fax: (+1) 970 491 3945

Site Description

From 1982 until 1996, the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) site was located on the Central Plains Experimental Range (CPER). The CPER is administered by the U.S. Department of Agriculture's Agricultural Research Service (USDA-ARS). In 1996, the spatial extent of the LTER site was expanded to include both the CPER and the Pawnee National Grasslands (PNG). The PNG represents 78,100 ha of public lands administered by the U.S. Forest Service (USFS) adjacent to the CPER, and extending 90 km to the east. The PNG is discontinuously distributed across northeastern Colorado because these lands are the result of acquisitions of private land beginning in the Dust Bowl era. By expanding to the newly defined site, the realm of inference was increased to 23% of the SGS.

Site Location

The SGS-LTER site is 8 km north of Nunn, Colorado, approximately halfway between Greeley, Colorado and Cheyenne, Wyoming, on the Central Plains Experimental Range (CPER). The 6280-ha tract of shortgrass rangeland located in the piedmont of north central Colorado approximately 61km northeast of Fort Collins and the campus of Colorado State University (lat. 40°49'N; long.104°46'W; elevation 1650 m).

Site Area

The CPER is a 6280-ha research area maintained by the USDA Agricultural Research Service for applied rangelands research.

Site Elevation

Site elevation ranges from 1200-2000 m.

Annual Rainfall

Annual precipitation at the CPER averaged 322 mm over the past 51 years and ranged between 107 and 588 mm. Approximately 70% of the mean annual precipitation occurs during the April to September growing season.

Annual Temperature

Mean monthly temperatures range from -4 to 22 degrees C seasonally and have a daily average max-min range of 17 degrees C.

Soil type

The soils of the CPER are dominantly Aridic Argiustolls (Mollisols) and Ustic Haplargids (Aridisols)formed in alluvium, wind-reworked alluvium and loess. Ustic Torriorthents and Ustic Torrifluvents (Entisols) occur in areas of more recent alluvial or eolian activity, particularly along modern drainages.=A0 Typic Haplusterts (Vertisols) occur in several of the low-lying, closed depressions on the site.

The soils of the CPER are relatively young, considered Holocene in age.

Native Forest/Vegetation Types

The vegetation of the SGS is dominated by shortgrasses (64%), forbs (7%), succulents (21%), and half-shrubs (8%). The key species of these groups are Bouteloua gracilis and Buchloe dactyloides; Sphaeralcea coccinea; Opuntia polyacantha; and Chrysothamnus nauseosus, Gutierrezia sarothrae, and Eriogonum effusum, respectively. Average above ground net primary production is 125 g/m2 and ranges from 60 to 180 g/m2 depending on available soil water. Major differences in vegetation structure occur in saltgrass meadows dominated by Distichlis stricta and Sporobolus asper, and on floodplains where the shrub Atriplex canescens is an important component.

Principal Biome/Ecoregion

The climate of the SGS is typical of mid-continental semiarid regions in the temperate zone except for the strong influence of the Rocky Mountains approximately 60 km to the west.

Photo Gallery

Photos courtesy of CPER employees and Diana Wall's lab group




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This webpage is funded by the Soil Science Society of America.

Please contact the GLIDE headquarters (email: if you have any comments or questions.

GLIDE was a project of the International Biodiversity Observation Year 2001-2002

This material is based upon work supported in part by the National Science Foundation under Grant No. 98 06437 Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


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This page was last updated on March 3, 2005

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