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Browsing Research Data by Subject "community dynamics"

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    ItemOpen 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.
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    ItemOpen Access
    SGS-LTER live arthropod pitfall trapping across a double catena on the Central Plains Experimental Range, Nunn, Colorado, USA 1995-1998
    (Colorado State University. Libraries, 1995-1998) Stapp, Paul
    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.
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    ItemOpen Access
    SGS-LTER long-term monitoring project: arthropod pitfall trapping on small mammal trapping webs on the Central Plains Experimental Range, Nunn, Colorado, USA 1998-2006, ARS study number 118
    (Colorado State University. Libraries, 1998-2006) Stapp, Paul
    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. With the exception of heteromyids, eg kangaroo rats and pocket mice, most small rodents in shortgrass steppe are omnivorous. Depending on season, arthropods (insects and arachnids) make up 40-85% of the diet of grasshopper mice and thirteen-lined ground squirrels, the most widespread rodents in northern shortgrass steppe. Small mammals are among the most important predators of ground-dwelling macroarthropods and herbivorous insects provide a direct resource link between weather and plant production. Understanding temporal variability in the abundance of arthropods is central to determining the mechanisms that drive small rodent populations. At present, there are no long-term studies of arthropods in shortgrass steppe, despite the important role that these taxa play in grassland food webs. Beginning in 1998, we implemented field protocols to track changes in relative abundance of terrestrial macroarthropods in grassland and shrub-dominated habitats of shortgrass steppe. Sampling was conducted on the six trapping webs (three upland prairie, three lowland saltbush) where we studied rodent populations, and was conducted approximately monthly from May-September (4-5 sessions/year). Ground-dwelling macroarthropods were sampled on each web using pitfall traps, set in one four-by-five grid, with 10 m between traps. Traps consisted of plastic cups (90-mm diameter, 120 mm deep), including a plastic funnel (90-mm diameter), buried flush with the ground surface. Traps were shaded with wooden covers held in place with nails; traps could be closed when not operational by nailing the cover flush to the ground. Traps were usually open for 4 consecutive days (ie 80 trap-days) during a trapping session. On the 4th day, captured arthropods were removed from the traps, identified and released. All arthropods were identified to the ordinal level; beetles (Coleoptera), crickets (Orthoptera), true bugs (Hemiptera) and spiders were identified to the familial level; and a few taxa, eg tenebrionid beetles, were identified to species. We also recorded any reptiles and amphibians captured. The number of individuals of each taxa captured per 100 trap-days was used as an index of relative abundance, with adjustments made for traps that were flooded or disturbed by cattle or for changes to the number of days that traps were open (range 4-7 days). We sampled grasshoppers by counting the numbers flushed from 0.78-m2 circular plots (hoops) placed on each web. Hoops were set out on the day that pitfall traps were opened and were surveyed on the day that traps were closed. A technician used a wooden lath to flush and count all grasshoppers from each hoop. Grasshoppers were not identified to species. Surveys were conducted in 1998, then were discontinued until 2002. In 1998 and from 2002-2005, nine hoops were sampled on each web. Beginning in 2006, we sampled a total of 20 hoops on each web.
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    SGS-LTER long-term monitoring project: carnivore scat count on the Central Plains Experimental Range, Nunn, Colorado, USA 1997 -2006, ARS study number 98
    (Colorado State University. Libraries, 1997-2006) Stapp, Paul
    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. Carnivores are among the most conspicuous, charismatic and economically important mammals in shortgrass steppe, yet relatively is little is known about their populations or of the ecological factors that determine their distribution and abundance, in part because densities tend to be low. Mammalian carnivores represent the top predators in grassland food webs, consuming rodents, rabbits, young ungulates and other small vertebrates. In addition, shortgrass steppe is the primary habitat of the swift fox (Vulpes velox), a species of special conservation concern throughout most of its range. Fox populations are thought to be limited by predation from coyotes (Canis latrans), the most common carnivore in these grasslands and a species of interest, both for its ecological roles and well as a target species for human exploitation, ie hunting and predator control. In 1994, we implemented a low-intensity sampling scheme to monitor long-term changes in relative abundance of mammalian carnivores and help us examine interactions between these predators and their small mammal prey, including rodents and rabbits. We estimated relative abundance of carnivores using scat surveys along a fixed route. Four times each year (January, April, July, October), we drove a 32-km route consisting of pasture two-track and gravel roads on the CPER. We first drove the route to remove all scats ('PRE-census'); we then returned ~14 d later and counted the number of scats deposited on the route ('CENSUS'). We recorded the species that deposited the scat and estimated the scat age based on external appearance (4 categories). Beginning in 1997, we recorded the vegetation (habitat) type and topographic position of all scat locations to describe habitat use. Latrines are indicated by locations containing multiple scats. We used the 'CENSUS' data to calculate a scat index, defined as the number of scats deposited per km of road per night. The scat index can be used to estimate population density using equations for coyotes (Knowlton 1982) and swift foxes (Schauster et al. 2002) that described the rate of scat deposition from surveys where density was known. To estimate density and compare trends among seasons and years, we omitted scats collected along the 8.3 km of the route that occurred on gravel county roads. These roads are graded sporadically, sometimes between pre-census and census surveys, which tended to remove scats. (NOTE: these observations are NOT omitted in the dataset).
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    SGS-LTER long-term monitoring project: small mammals on trapping webs on the Central Plains Experimental Range, Nunn, Colorado, USA 1994 -2006, ARS study number 118
    (Colorado State University. Libraries, 1994-2006) Stapp, Paul
    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. 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. In 1994, we implemented a sampling scheme to monitor long-term changes in relative abundance of small mammals in representative habitats of shortgrass steppe. We live-trapped nocturnal rodents twice each year (spring, late summer) on trapping webs in upland prairie (GRASS) and saltbush-dominated (SHRUB) habitats. Three 3.14-ha webs were established in each habitat. Each web had 124 Sherman traps, which were spaced 10-m apart on 12 100-m spokes, with 30 degrees between spokes. Four traps were set in the center of the web. Traps were set for four consecutive nights in each trapping session. Traps are baited with a mix of peanut butter and oats, set in the evening and checked (and closed) at dawn. We recorded sex, age and weight upon first capture of all individuals. In the early years of the study, individuals were batch-marked (Sharpie colored felt markers) to distinguish recaptures from new individuals, providing the minimum information necessary to use distance-sampling methods to estimate density. Most nocturnal species are now usually marked with aluminum ear tags, although we continue to mark very small (pocket mice) or small-eared (voles) species only with felt pens. For ear-tagged animals, we distinguish new captures (N) from individuals marked during previous sessions (old, O), versus those that are recaptured (R) on 2nd, 3rd or 4th nights of a trapping session. The location of one trapping web was changed from 13NE (1994-1997) to 13SW (1998- present) because of concerns about intensive cattle use in the pasture, as well as activity of CPER Site Manager's cats.
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    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, Paul
    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. 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.
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    SGS-LTER long-term monitoring project: spotlight rabbit count on the Central Plains Experimental Range, Nunn, Colorado, USA 1994-2006, ARS study number 98
    (Colorado State University. Libraries, 1994-2006) Stapp, Paul
    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. Rabbits are the most important small-mammal herbivores in shortgrass steppe, and may significantly influence the physiognomy and population dynamics of herbaceous plants and woody shrubs. Rabbits also are the most important prey of mammalian carnivores such as coyotes and large raptors such as golden eagles and great horned owls. Two hares (Lepus californicus, L. townsendii) and one cottontail rabbit (Sylvilagus audubonii) occur in shortgrass steppe. In 1994, we initiated long-term studies to track changes in relative abundance of rabbits on the Central Plains Experimental Range (CPER). On four nights each year (one night each season, usually on new moon nights in January, April, July, October), we drove a 32-km route consisting of pasture two-track and gravel roads on the CPER. This was the same route as that driven for carnivore scat counts. Surveys began at twilight. Observers with two spotlights sat in the back of a 4WD pick-up driven at <15 mph. We recorded the perpendicular distance (in m) to each rabbit using a meter tape or range finder; the direction of the rabbit relative to the road; and noted if individuals were solitary or in clusters. We also recorded any carnivores or other animals seen during spotlight surveys. Beginning in Spring 1998, we recorded the vegetation type (habitat) and topographic position of each rabbit seen, as well as position relative to human features, eg windmills, cattle guards, on the landscape. We used the number of rabbits of each species spotted per km of route as an index of relative abundance. We used line-transect approaches in DISTANCE to estimate population densities from perpendicular distance data.
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    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, Paul
    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 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.