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Sage-grouse (Centrocercus urophasianus and C. minimus) historically inhabited much of the sagebrush-dominated habitat of North America. Today, sage-grouse populations are declining throughout most of their range. Population dynamics of sage-grouse are marked by strong cyclic behavior. Adult survival is high, but is offset by low juvenile survival, resulting in low productivity. Habitat for sage-grouse varies strongly by life-history stage. Critical habitat components include adequate canopy cover of tall grasses (? 18 cm) and medium height shrubs (40?80 cm) for nesting, abundant forbs and insects for brood rearing, and availability of herbaceous riparian species for late-growing season foraging. Fire ecology of...
These files contain data necessary for analyzing state-space models for male greater sage-grouse (Centrocercus urophasianus) populations in response to grazing level (relative grazing index), timing, and NDVI (Normalized Difference Vegetation Index) in Wyoming, USA.
The file 'lhs_data.csv' contains data necessary for logistic regression evaluating effects of grazing level (relative grazing index) and timing on the probability of an allotment failing one or more Land Health Standard (LHS) the previous year (Monroe et al. 2017). Relative predictive ability of models are then compared with a 10-fold cross-validation score. Literature Cited: Monroe, A. P., C. L. Aldridge, T. J. Assal, K. E. Veblen, D. A. Pyke, and M. L. Casazza. 2017. Patterns in Greater Sage-grouse Population Dynamics Correspond with Public Grazing Records at Broad Scales. Ecological Applications. doi: 10.1002/eap.1512.
Semi-arid ecosystems cover tens of millions of hectares in the Intermountain West of the United States, and most have altered plant communities due to land use, especially livestock grazing. Thus, relatively unaltered ?reference? plant community information is needed to guide restoration. Plant communities were sampled over a large (600 000 ha) semi-arid landscape in western Colorado, within pi´┐Żon?juniper woodlands, sagebrush shrublands, and grasslands, and over conditions ranging from relict areas without livestock grazing to heavily utilized areas. Ordination was used to group samples into ranked categories of ecological condition within 18 communities, and means?tests and other techniques were used to identify...
Arthropods living in the canopies of two woody shrub species (a sub-shrub (Gutierrezia sarothrae) and a large shrub (Prosopis glandulosa)) and perennial grasses plus associated herbaceous species, were sampled on 18, 0.5 hectare plots in a Chihuahuan Desert grassland for five consecutive years. Mesquite shrubs were removed from nine plots, six plots were grazed by yearling cattle in August and six plots were grazed in February for the last 3 years of the 5 year study. Arthropod species richness ranged between 154 and 353 on grasses, from 120 to 266 on G. sarothrae, and from 69 to 116 on P. glandulosa. There was a significant relationship between the number of families of insects on grass and G. sarothrae and growing...
Increasing demands on arid and semiarid ecosystems, which comprise one-third of Earth's terrestrial environment, create an urgent need to understand their biodiversity, function, and mechanisms of change. Sagebrush (Artemisia) steppe, the largest semiarid vegetation type in North America, is endangered because of losses to agriculture, excessive grazing, and invasive species. Establishment in 1950 of what is now designated as the Idaho National Engineering and Environmental Laboratory (southeastern Idaho, USA) created the largest existing reserve of this extensive vegetation type. We used cover, density, and frequency data for vascular plants sampled on 79 permanent plots nine times during 45 years to (1) assess...
The file 'ssm_data.csv' contains data necessary for analyzing state-space models for male greater sage-grouse (Centrocercus urophasianus) populations in response to grazing level (relative grazing index), timing, and NDVI (Normalized Difference Vegetation Index) in Wyoming, USA, and then to compare models with 10-fold cross validation scores (Monroe et al. 2017). Literature Cited: Monroe, A. P., C. L. Aldridge, T. J. Assal, K. E. Veblen, D. A. Pyke, and M. L. Casazza. 2017. Patterns in Greater Sage-grouse Population Dynamics Correspond with Public Grazing Records at Broad Scales. Ecological Applications. doi: 10.1002/eap.1512.