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2003

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Articles 151 - 152 of 152

Full-Text Articles in Other International and Area Studies

Sampling Designs For Carnivore Scent-Station Surveys, Glen A. Sargeant, Douglas H. Johnson, William E. Berg Jan 2003

Sampling Designs For Carnivore Scent-Station Surveys, Glen A. Sargeant, Douglas H. Johnson, William E. Berg

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Scent stations usually are deployed in clusters to expedite data collection and increase the number of stations that can be operated for a given cost. Presumed benefits of cluster sampling may not be realized, however, unless cluster sizes are chosen with respect to sampling variation within and among clusters. To encourage and facilitate the use of efficient designs and reporting standards, we used data collected in Minnesota, USA, during 1986-1991 to (1) compare the performance of survey designs with various numbers of stations/cluster; (2) estimate relations between required sample sizes and visitation rates, changes in visitation rates, and error rates; …


Effects Of Ungulates And Prairie Dogs On Seed Banks And Vegetation In A North American Mixed-Grass Prairie, Jace T. Fahnestock, Diane L. Larson, Glenn E. Plumb, James K. Detling Jan 2003

Effects Of Ungulates And Prairie Dogs On Seed Banks And Vegetation In A North American Mixed-Grass Prairie, Jace T. Fahnestock, Diane L. Larson, Glenn E. Plumb, James K. Detling

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

The relationship between vegetation cover and soil seed banks was studied in five different ungulate herbivoreprairie dog treatment combinations at three northern mixed-grass prairie sites in Badlands National Park, South Dakota. There were distinct differences in both the seed bank composition and the aboveground vegetation between the off-prairie dog colony treatments and the on-colony treatments. The three on-colony treatments were similar to each other at all three sites with vegetation dominated by the forbs Dyssodia papposa, Hedeoma spp., Sphaeralcea coccinea, Conyza canadensis, and Plantago patagonica and seed banks dominated by the forbs Verbena bracteata and Dyssodia papposa. The …