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Item Open Access SGS-LTER long-term seasonal root biomass on the Central Plains Experimental Range, Nunn, Colorado, USA 1985-2007, ARS study number 3(Colorado State University. Libraries, 1985-2007) Milchunas, Daniel G.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The belowground system in arid and semiarid regions can be of relatively greater importance than in more mesic systems because plant competition is most often for soil water rather than for light in aboveground canopies. Belowground plant biomass in the shortgrass steppe represents approximately 80% of the total. These data, entitled Long-Term Seasonal Root Biomass, were obtained in section 21 of the Central Plains Experimental Range from 1985-2008 in conjunction with a 14C labeling experiment designed to test isotope methods of estimating root production. Paired plots for each of eight replicate 14C labeled plots were established and cored on average six times per year over 13 years (five cores each plot each date as above). There were two primary objectives for collecting these data, 1) to compare estimates of root production (or belowground net primary production - BNPP) obtained using the sequential coring of biomass methods with various isotope, minirhizotron, ingrowth, and other methods, and 2) to examine long-term controls on the temporal dynamics of root biomass. This shortgrass steppe LTER site is the only place we are aware of that has compared most methods of estimating BNPP, including sequential coring, ingrowth cores, and ingrowth donuts, 14C pulse-isotope dilution, 14C pulse-isotope turnover, rhizotron windows, and minirhizotron, and indirect methods including nitrogen budget, carbon flux, simulation carbon flow model, and regression model. All production methods are compared in Milchunas (2009), and more detailed comparisons among particular methods can be found in Milchunas and Lauenroth (1992, 2001), and Milchunas et al. (2005a, and 2005b). Results and conclusions concerning root biomass dynamics and relationships with precipitation, season, and aboveground biomass are reported primarily in Milchunas and Lauenroth (2001).Item Open Access SGS-LTER effects of water and nitrogen additions on plants in shortgrass ecosystems on the Central Plains Experimental Range, Nunn, Colorado, USA 1997-2011, ARS study number 143(Colorado State University. Libraries, 1997-2011) Lauenroth, William K.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The objective of this research is to evaluate the response of shortgrass ecosystems to additional water and nitrogen inputs at levels observed in Hayes, Kansas, as well as effects of elevated temperature. An experiment was conducted during the LTER project in which water, nitrogen, combined water and nitrogen were applied and warming cones were installed in ungrazed plots on the shortgrass steppe, just east of the field site headquarters. Nitrogen and water application levels are available in the zipped metadata file.Item Open Access SGS-LTER paleopedology study-pedon descriptions on the Central Plains Experimental Range, Nunn, Colorado, USA 1992-1993(Colorado State University. Libraries, 1992-1993) Kelly, Eugene F.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. CPER Paleopedology Study – Pedons - Forty-one pedons representing sites of contrasting geomorphic position (upland plain, upland ridge, dissected upland, terrace, dune) were chosen for pedologic and geomorphic analyses. These pedons are located on the major physiographic units at the CPER, and contain deposits of suspected fluvial and eolian origin. To examine spatial variability, the pedons were typically sampled along transects spaced at 30m intervals. Samples were taken with a hydraulic soil probe to the depth of probe refusal and from suitable stream and road cuts. All soils were described and sampled by genetic horizon (Soil Survey Staff, 1992), and analyzed at Colorado State University. Analyses included particle size and organic C. Nineteen of the 41 pedons were subjected to stable isotopic analysis of organic C and carbonate.Item Open Access SGS-LTER cross-site study: natural abundance N15 study-plants and soils on the shortgrass steppes of Colorado, USA and Patagonia, Argentina(Colorado State University. Libraries, 1993-1993) Burke, Ingrid C.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection.Item Open Access SGS-LTER effects of grazing on ecosystem structure and function (GZTX): vegetation measurements on the Central Plains Experimental Range, Nunn, Colorado, USA 1992-2008, ARS study number 32(Colorado State University. Libraries, 1992-2008) Milchunas, Daniel G.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. When the CPER was established in 1939, researchers constructed a .5-1 ha grazing exclosure in each of the pastures. These areas have remained protected from grazing for the past 70 years. The remaining areas have been grazed for the past 20+ years. This collection of pastures and exclosures provided an extraordinary opportunity to reinitiate grazing and protection, and evaluate the balance between degradation and aggradation. We proposed to rearrange fences and expose areas to grazing that have been protected for 50 years, and protect areas from grazing that had been grazed for 50 years. The combinations of grazing conditions were: 1. Long-term protection; 2. Long-term grazing (moderate); 3. 50 years of protection followed by grazing; 4. 50 years of grazing followed by protection. Net primary production, nitrogen dynamics, cattle utilization, and community dynamics of vegetation, and components of the belowground food web were measured.Item Open Access Biochemical responses of US Great Plains grasslands to regional and interannual variability in precipitation (1999-2001)(Colorado State University. Libraries, 1999-2001) Burke, Ingrid C.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Carbon (C) sequestration potential in grasslands is thought to be high due to the large soil organic carbon pools characteristic of these ecosystems. Inputs of C (aboveground net primary productivity) are highly correlated to precipitation across the Great Plains region; however, changes in C pool size at a specific site are governed by the relative input and output rates across time. Our objective was to quantify the ecosystem C response of three grassland community types (shortgrass steppe, mixed grass and tallgrass prairie) to interannual variation in precipitation. At five sites across a precipitation gradient in the Great Plains, we measured net primary production (NPP), soil respiration (SRESP), and litter decomposition rates for three consecutive years. NPP, SRESP, and litter decomposition increased from shortgrass steppe (175, 454, and 47 g C m-2 yr-1) to tallgrass prairie (408, 1221, and 348 g C m-2 yr-1 for NPP, SRESP, and litter decomposition respectively). Increased growing season precipitation between study years resulted in increased NPP, SRESP, and litter decomposition at almost all sites. However, the regional patterns of the interannual NPP, SRESP, and litter decomposition responses differ from each other. This data suggests NPP and SRESP are more sensitive to interannual changes in precipitation than litter decomposition, and that shortgrass steppe sites are more responsive to interannual variability in precipitation than mixed grass and tallgrass prairie.Item Open Access SGS-LTER impact of labile and recalcitrant carbon treatments on plant communities in a semiarid ecosystem on the Central Plains Experimental Range, Nunn, Colorado, USA 1997-2012, ARS study number 3(Colorado State University. Libraries, 1997-2012) Burke, Ingrid C.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. In a 10-year study, we assessed the influence of five carbon (C) treatments on the labile C and nitrogen (N) pools of historically N enriched plots on the Shortgrass Steppe Long Term Ecological Research site located in northeastern Colorado. For eight years, we applied sawdust, sugar, industrial lignin, sawdust + sugar, and lignin + sugar to plots that had received N and water additions in the early 1970s. Previous work showed that past water and N additions altered plant species composition and enhanced rates of nutrient cycling; these effects were still apparent 25 years later. We hypothesized that labile C amendments would stimulate microbial activity and suppress rates of N mineralization, whereas complex forms of carbon (sawdust and lignin) could enhance humification and lead to longer-term reductions in N availability. Results indicated that of the five carbon treatments, sugar, sawdust, and sawdust + sugar suppressed N availability, with sawdust + sugar being the most effective treatment to reduce N availability. The year after treatments stopped, N availability remained less in the sawdust + sugar treatment plots than in the high-N control plots. Three years after treatments ended, reductions in N availability were smaller (40-60%). Our results suggest that highly labile forms of carbon generate strong short- term N sinks, but these effects dissipate within one year of application, and that more recalcitrant forms reduce N longer. Sawdust + sugar was the most effective treatment to decrease exotic species canopy cover and increase native species density over the long term. Labile carbon had neither short- nor long-term effects on exotic species. Even though the organic amendments did not contribute to recovery of the dominant native species Bouteloua gracilis, they were effective in increasing another native species, Carex eleocharis. These results indicate that organic amendments may be a useful tool for restoring some native species in the shortgrass steppe.Item Open Access Open top chamber experiment carbon dioxide (CO2) elevation experiment at the Central Plains Experimental Range, Nunn, Colorado, USA(Colorado State University. Libraries, 1997-2001) Morgan, JackDatasets related to the Shortgrass Steppe Long-Term Ecological Research project and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive collection within the Repository (http://hdl.handle.net/10217/100254). The data tables and associated metadata documents, which are generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The Open Top Chamber Experiment Carbon Dioxide (CO₂) Elevation Experiment was conducted in collaboration with partners at the USDA, Agricultural Research Service. Six open-top chambers were installed on the shortgrass steppe in north-eastern Colorado, USA from late March until mid-April from 1997 to 2001 to evaluate how this grassland will be affected by rising atmospheric CO₂. Three chambers were maintained at current CO₂ concentration (ambient treatment), three at twice ambient CO₂, or approximately 720 µmol mol-1 (elevated treatment), and three non-chambered plots served as controls. Each growing season, variables related to soil water, plant physiology, biomass production and community dynamics were measured.Item Open Access SGS-LTER standard met data: Cr21x station 12 - meteorological data on the Central Plains Experimental Range in Nunn, Colorado, USA 1986-2010, ARS study number 4(Colorado State University. Libraries, 1986-2010) Parton, WilliamThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The objective of this study is to collect baseline meteorological data for the CPER. Datasets auto12_climdb and man11_climdb have been processed for quality and missing values.Item Open Access SGS-LTER standard met data: 1969-2010 manually collected aboveground and belowground meteorological data collected on the Central Plains Experimental Range, Nunn, Colorado, USA, ARS study number 4(Colorado State University. Libraries, 1969-2010) Parton, WilliamThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The objective of this study is to collect baseline meteorological data for the CPER. Datasets auto12_climdb and man11_climdb have been processed for quality and missing values.Item Open Access SGS-LTER spatial variability in seed production of the perennial bunchgrass Bouteloua gracilis on the Central Plains Experimental Range, Nunn, Colorado, USA 1992-2005, ARS study number 20(Colorado State University. Libraries, 1992-2005) Lauenroth, William K.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Production of seeds of Bouteloua gracilis was evaluated for a semiarid grassland in northeastern Colorado. Ten locations were chosen to represent the range in soil textures and grazing intensities found at the Central Plains Experimental Range research site. Number of flowering culms, inforescences and seeds, length of each flowering culm, total biomass or reproductive structures (culms, inforescences and seeds), and basal areas were assessed for each plant sampled. Community-level estimates of density of flowering culms and density of viable seeds are made for each location. Both soil texture and grazing intensity by cattle are important to spatial variability in seed production and other indicators of reproductive effort by B. gracilis.Item Open Access SGS-LTER avian road counts, breeding bird survey, on the Pawnee National Grassland in eastern Colorado, USA(Colorado State University. Libraries, 1968-2002) Ryder, RonaldThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The Breeding Bird Survey is a large-scale survey of North American birds. It is a roadside survey, primarily covering the continental United States and southern Canada, although survey routes have recently been initiated in Alaska and northern Mexico. The BBS was started in 1966, and the over 3,500 routes are surveyed in June by experienced birders. Routes 305, Nunn and 901, Rockport are located in the area of the SGS research site. The primary objective of the BBS has been the estimation of population change for songbirds. However, the data have many potential uses, and investigators have used the data to address a variety of research and management objectives. In the USGS-BBS Home Page, results from the BBS are summarized and pictures of birds and other species are information. Data from 1966-2002 were managed by the SGS-LTER project.Item Open Access SGS-LTER standard meteorological data on the Central Plains Experimental Range, Nunn, Colorado, ARS study number 4(Colorado State University. Libraries, 1969-2010) Parton, WilliamThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The objective of this study is to collect baseline meteorological data for the CPER. Datasets auto12_climdb and man11_climdb have been processed for quality and missing values.Item Open Access SGS-LTER Earthwatch project: nitrogen and carbon in native, abandoned and cultivated fields in eastern Colorado, USA(Colorado State University. Libraries, 1991-1995) Burke, Ingrid C.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Our objective in this study was to evaluate effects of land use on in situ net N mineralization in shortgrass steppe by comparing native and abandoned fields and cultivated fields, and by comparing soil under and between plants within native and abandoned fields. We also compared mineralization patterns between in situ and laboratory incubations to evaluate the role of environmental restrictions in determining N supply across management treatments and microsites.Item Open Access SGS-LTER CPER hillslope soil spatial variability on the Central Plains Experimental Range, Nunn, Colorado, USA 1983-1984(Colorado State University. Libraries, 1983-1984) Kelly, Eugene F.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. CPER Hillslope Soil Spatial Variability - Pedons were characterized along three parallel transects, spaced at approximate 40 m intervals perpendicular to a hillslope at the CPER. Pedons were described at 7 landscape positions along each transect: summit, shoulder, upper backslope, middle backslope, lower backslope, footslope, and toeslope. Pedons were described by genetic horizon according to the standards of the National Cooperative Soil Survey. Analyses included: particle size; organic C; total N; organic and total P. Bulk Density was estimated using particle size and organic C data, according to: Rawls, W.J. 1983. Estimating soil bulk density from particle size analysis and organic matter content. Soil Sci. 135: 123-125.Item Open Access SGS-LTER graduate student research: cattle use of prairie dog towns on the shortgrass steppe of Colorado(Colorado State University. Libraries, 1999-2000) Detling, James K.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. We investigated the use of prairie dog towns by cattle (Bos taurus) on the shortgrass steppe of northeastern Colorado by conducting surveys of cattle and vegetation from June to August 1999. Cattle presence and behavior were recorded 3 times a week during driving surveys of 15 black-tailed prairie dog (Cynomys ludovicianus) towns. A subset of 3 pastures with prairie dog towns was intensively surveyed twice weekly wherein the habitat and activity of a randomly chosen focal animal was recorded every 6 minutes for 3.5 hours. Bite and step counts of other individuals were recorded for 5-minute intervals. Vegetation height and cover data were collected monthly on each of 6 habitats. Results from driving surveys and intensively surveyed pastures were similar; cattle neither significantly preferred nor avoided prairie dog towns. Bare ground cover on prairie dog towns did not significantly differ from most other habitats, but vegetation on prairie dog towns was significantly shorter on (mean = 6.7 cm) than that off (mean = 11.9 cm) prairie dog towns. Nevertheless, foraging observations indicated that there was no significant difference between cattle foraging rates on swales (70.9 bites/min) and prairie dog towns (69.5 bites/min). Thus, cattle on the shortgrass steppe appear to use prairie dog towns in proportion to their availability and, while there, they graze as intensively as they do on habitats not inhabited by prairie dogs.Item Open Access SGS-LTER genetic structure of metapopulations of black-tailed prairie dogs on the Central Plains Experimental Range and Pawnee National Grassland in Nunn, Colorado, USA 1997-1998(Colorado State University. Libraries, 1997-1998) Antolin, Michael F.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Thirteen colonies of black-tailed prairie dogs were studied within a 264-km2 area of the Central Plains Experimental Range and the Pawnee National Grasslands in Weld County, Colorado. Tissue Collection, DNA Extraction, and microsatellite genotype scoring was performed.Item Open Access SGS-LTER long term nitrogen concentration in LTNPP monitoring on the Central Plains Experimental Range, Nunn, Colorado, USA 1983-2011, ARS study number 6(Colorado State University. Libraries, 1983-2011) Milchunas, Daniel G.This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Aboveground plant nitrogen dynamics monitoring consists of two separate data sets. a) Long-term peak-crop nitrogen concentrations have been sampled since 1983 annually from sites sampled for ANPP estimates across the CPER. Plots are clipped for ANPP in August each year and include moderately grazed sites in sections 24 and 25, ungrazed treatments at ESA and owl creek, coarse textured soils in owl creek, fine textured soils in section 25, as well as three catena topopositions in section 24. These datasets have been designed for monitoring and so it is advised to consider calculating average based at the transect level. B) Seasonal dynamics of life-form (dominant grass, forb, shrub species) nitrogen concentrations were obtained from random grab samples of aboveground plant tissue are taken monthly from May-Aug. and in Oct., Dec., Feb., and April from 1983 – 2007 at sites where ANPP has been collected since 1983 (ESA, ridge, mid-slope and swale in section 24). The objectives are to assess annual/seasonal weather and site productivity/management with quantity and quality of forage and/or litter production. Combined, these two data sets also provide an estimate of nitrogen yield. These data can be linked with secondary producer data sets such as annual cattle weight gains, grasshopper abundance, small mammal monitoring, etc., to assess how forage/plant tissue quantity and quality drive population dynamics.Item Open Access SGS-LTER long-term monitoring project: vegetation cover and structure on small mammal trapping webs on the Central Plains Experimental Range, Nunn, Colorado, USA 1999 -2006, ARS study number 118(Colorado State University. Libraries, 1999-2006) Stapp, PaulThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. The abundance and diversity of small mammals in shortgrass steppe is strongly influenced by the structure and composition of vegetation. Vegetation structure provides cover from predators and harsh abiotic conditions. Plant species composition affects the types of seeds and herbaceous material available to granivores and herbivores, and influences arthropod populations, which are important prey for the omnivorous species that dominate in shortgrass steppe. Both vegetation structure and plant community composition are sensitive to the availability of precipitation as well as the activity of large mammalian herbivores. In 1999, we began measuring vegetation structure and plant community composition on the three grassland and three shrubland trapping webs where we live-trap small mammals. Vegetation measurements are made once each year, usually in mid-July. Percent canopy cover of each plant species was estimated visually in 30 0.10-m2 Daubenmire quadrats on each web. To estimate habitat structure, we measured the height of grass, forb and shrub plants adjacent to each quadrat, the density of half-shrubs, small mammal mounds and burrows, harvester ant mounds and the dimensions of large shrubs and animal mounds.Item Open Access SGS-LTER long-term monitoring project: Spermophilus tridecemlineatus on small mammal trapping webs on the Central Plains Experimental Range, Nunn, Colorado, USA 1999 -2006, ARS study number 118(Colorado State University. Libraries, 1999-2006) Stapp, PaulThis data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Small mammals (rabbits, rodents) are integral components of semiarid ecosystems because of their roles as consumers of plants, seeds and arthropods, as soil disturbance agents, and as food for raptors, snakes and mammalian carnivores. Because of their vagility and intermediate trophic position, populations of small mammals may track changes in vegetation and the abiotic environment that may result from shifts in land-use and other anthropogenic disturbances. However, these populations are variable over space and time, and their response to environmental changes may not be immediately apparent given their behavioral flexibility and relatively long life-spans and generation times. Patterns in the distribution and abundance of small mammals thus may simultaneously reflect and affect the stability of the shortgrass-steppe ecosystem. Long-term studies of population and community dynamics therefore are needed to fully understand the role of small mammals in grassland ecosystems. Thirteen-lined ground squirrels (Spermophilus tridecemlineatus, SPTR) are the most widely distributed rodent species in shortgrass steppe and the most important in terms of abundance and biomass. Like most rodents in shortgrass steppe, they are omnivorous; unlike other species, however, they are diurnal and active aboveground only 5-6 months each year, and therefore required a separate sampling scheme from other rodents. In 1999, we initiated studies to track long-term changes in relative abundance of ground squirrels in representative habitats of shortgrass steppe. We live-trapped squirrels twice each year, which corresponded to periods of high aboveground activity of adults (early June, SPR) and the emergence of juveniles (mid-July, SUM). Three 3.14-ha webs were established in upland prairie (GRASS) and saltbush-dominated (SHRUB) habitats. Each web had 62 Sherman traps, which were spaced 20-m apart on 12 100-m spokes, with 30 degrees between spokes. Two traps were set in the center of the web. Traps were set for four consecutive mornings in each trapping session. Traps were baited with a mix of peanut butter and oats, set at dawn and closed 4-6 hours later. Traps were shaded with pieces of PVC pipe to reduce heat mortality in traps. We recorded sex, age and weight upon first capture of all individuals. Because the ears of squirrels are too small to consistently hold ear tags, all individuals were batch-marked with a colored Sharpie felt marker to distinguish recaptures ® from new (N) individuals, providing the minimum information necessary to use distance-sampling methods to estimate density. NOTE: In this dataset, ages and weights may not correspond well. Weight, combined with sampling date, can be used to better determine age class; contact Paul Stapp for more information.