Skip to main content

David A. Pyke

thumbnail
Potential future greater sage-grouse (Centrocercus urophasianus) habitat restoration was projected (2018-2068) for three sage-grouse Priority Area for Conservation (PACs) populations located along the northwestern, central, and eastern edge of the Great Basin using outputs from a spatially explicit state-transition simulation model (STSM) developed for sagebrush ecosystems. These datasets, for the NW-Interior Nevada, USA (NWINV) sage-grouse population, include: 1) a set of 78 categorical raster layers illustrating a time series (decade intervals) of potential future habitat, and 2) a set of 15 uncategorized raster layers illustrating potential change in habitat classification across space, after simulating 50 years...
thumbnail
This is a spatially-explicit state-and-transition simulation model (STSM) of sagebrush-steppe vegetation dynamics for greater sage-grouse (Centrocercus urophasianus) Priority Areas for Conservation (PACs) in the Great Basin. The STSM was built using the ST-Sim platform and uses an integrated stock-flow submodel (STSM-SF) to simulate and track continuous vegetation component cover changes caused by annual growth, natural regeneration, and post-fire sagebrush seeding and planting restoration. Spatially explicit models were built for three sage-grouse PACs (Klamath Oregon/California [KLAM], NW Interior Nevada [NWINV], Strawberry Utah [STRAW]) that differed in historic wildfire patterns and the amounts of various component...
thumbnail
The dataset supports a larger study that examined the impacts of three tackifiers (guar, psyllium, and polyacrylamide) on growth of two dryland mosses (Bryum argenteum and Syntrichia ruralis). Moss fragments were grown in petri dishes and subjected to individual tackifiers in one of three possible concentrations (0.5x, 1x, or 2x) of the respective manufacturer's recommended application rate. Distilled water was used as a control treatment, giving a total of ten treatments (nine tackifier-concentration combinations and a water control). Bryum fragments were watered four times daily for six weeks and Syntrichia fragments were watered twice daily for five weeks, after which the experiments were concluded. Shoot length,...
thumbnail
This dataset contains data supporting the paper: DeCrappeo, N.M., DeLorenze, E.J., Giguere, A.T., Pyke, D.A., and Bottomley, P.J. Fungal and bacterial contributions to nitrogen cycling in cheatgrass-invaded and uninvaded native sagebrush soils of the western USA (accepted at the journal Plant and Soil). The purpose of the study was to evaluate the relative contributions of soil bacteria and fungi to inorganic nitrogen (N) cycling in sagebrush and cheatgrass-invaded soils using a 15N isotope dilution experiment. Soils were collected from sagebrush and cheatgrass rhizospheres at six paired sites in southwest Idaho and southeast Oregon. In order to partition the contribution of each microbial group to N cycling, soils...
thumbnail
Drylands cover 40% of the global terrestrial surface and provide important ecosystem services. While drylands as a whole are expected to increase in distribution and aridity in coming decades, temperature and precipitation forecasts vary by latitude and geographic region suggesting different trajectories for tropical, subtropical, and temperate drylands. Uncertainty in the future of tropical and subtropical drylands is well constrained, whereas soil moisture and ecological droughts, which drive vegetation productivity and composition, remain poorly understood in temperate drylands. Here we show that, over the 21st century, temperate drylands may contract by a third, primarily converting to subtropical drylands,...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.