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Full-Text Articles in Physical Sciences and Mathematics

Survey Of Resource Managers Completed On Monitoring And Management Actions For Rare Plants In Arizona And Nevada, Scott R. Abella Jul 2010

Survey Of Resource Managers Completed On Monitoring And Management Actions For Rare Plants In Arizona And Nevada, Scott R. Abella

Public Policy and Leadership Faculty Publications

In a collaborative project with Northern Arizona University and more than 35 resource managers in Arizona and Nevada, we completed a survey of monitoring and management activities that are ongoing in these states for conserving populations of rare plants. We sent questionnaires consisting of 16 questions to as many resource managers as possible in these states and had follow-up conversations with several managers willing to share their perspective on ongoing conservation actions. The findings may be interesting for managers to see what issues and management strategies other managers in the same or different regions are grappling with. Results will be …


Relating Surface Backscatter Response From Trmm Precipitation Radar To Soil Moisture: Results Over A Semi-Arid Region, Haroon Stephen, Sajjad Ahmad, Thomas C. Piechota, Chunling Tang Jan 2010

Relating Surface Backscatter Response From Trmm Precipitation Radar To Soil Moisture: Results Over A Semi-Arid Region, Haroon Stephen, Sajjad Ahmad, Thomas C. Piechota, Chunling Tang

Public Policy and Leadership Faculty Publications

The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σº) of the surface. σº is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σº primarily depends on the soil water content. In this study we relate TRMMPR σº measurements to soil water content (m(s)) in the Lower Colorado River Basin (LCRB). σº dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σº that couples incidence angle, m(s), and NDVI is used …


Progress In Strategic Research Areas, Scott R. Abella Jan 2009

Progress In Strategic Research Areas, Scott R. Abella

Public Policy and Leadership Faculty Publications

Three years ago through conversations with resource managers, assessing the status of knowledge of the scientific literature, and our own interests, we set forth several strategic research areas that we believed would be timely for advancing Mojave Desert conservation and management.


Plant Recruitment In A Northern Arizona Ponderosa Pine Forest: Testing Seed- And Leaf Litter- Limitation Hypotheses, Scott R. Abella Aug 2008

Plant Recruitment In A Northern Arizona Ponderosa Pine Forest: Testing Seed- And Leaf Litter- Limitation Hypotheses, Scott R. Abella

Public Policy and Leadership Faculty Publications

Seed availability and leaf litter limit plant establishment in some ecosystems. To evaluate the hypothesis that these factors limit understory plant recruitment in Pinus ponderosa forests, I conducted a seeding and litter removal experiment at six thinned sites in the Fort Valley Experimental Forest, northern Arizona. Experimental seeding of four native species (Penstemon virgatus, Erigeron formosissimus, Elymus elymoides, and Festuca arizonica) and raking of litter occurred in 2005. Seeding resulted in a substantial recruitment of 14 to 103 seedlings/m2 (1 to 10/ft2) one month after seeding for two species (P. virgatus and E. elymoides), but these densities subsequently declined by …


Plant Community Response To Fire: A Chronosequence Study, Scott R. Abella, E. Cayenne Engel Apr 2008

Plant Community Response To Fire: A Chronosequence Study, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Fires are becoming more prevalent events across the landscape in the southwestern US. Over the next several decades the already arid southwest is predicted to become warmer and drier, with longer summers, and an increase of “extreme” weather events such as lightening inducing thunderstorms. While the “hotter and drier” forecast may indicate less abundant plant life, and thus less available biomass for fuel, exotic invasive plant species are becoming more dominant across the landscape with increases in human travel and commerce. Exotic species (particularly many of the invasive grasses) are adding fuel for the fires to burn when the annuals …


Fire History And Forest Structural Change In The Spring Mountains, Scott R. Abella Jan 2008

Fire History And Forest Structural Change In The Spring Mountains, Scott R. Abella

Public Policy and Leadership Faculty Publications

Since early 2006 we have been working to develop a partnership with the Spring Mountains District of the Humboldt-Toiyabe National Forest to provide science support for understanding fire history and forest structural changes in support of ecologically based management strategies. We teamed up with the Ecological Restoration Institute (ERI) at Northern Arizona University and the University of Arizona Tree Ring Lab to deliver a workshop on March 6, 2008 at the interagency office in Las Vegas, Nevada. On September 16-18, we again teamed up with colleagues at ERI to conduct a preliminary field assessment of forest change at 10 sites …


Opportunities For New Collaborative Projects, Scott R. Abella, Jill E. Craig Jan 2008

Opportunities For New Collaborative Projects, Scott R. Abella, Jill E. Craig

Public Policy and Leadership Faculty Publications

The Research Group is currently working in successful partnerships with Lake Mead National Recreation Area, BLM Las Vegas, Desert National Wildlife Refuge (U.S. Fish and Wildlife Service), Joshua Tree National Park, and in collaboration with the Ecological Restoration Institute, the U.S. Forest Service (Region 3).


Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer Jan 2004

Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer

Public Policy and Leadership Faculty Publications

Midwest oak savanna communities are noted for their unusual plant assemblages, but these communities have been reduced by more than 98% because of changing land uses and conversion to closed-canopy forests. We initiated an ongoing 15-year experiment in 1988 to restore a 40-ha black oak (Quercus velutina) savanna by applying burn treatments that historically maintained this vegetation type. Groundlayer composition changed significantly for both the burn treatment and the control, with the burn treatment exhibiting slight increases in herbs such as wild lupine (Lupinus perennis) and hairy puccoon (Lithospermum caroliniense), both of which are species requiring greater insolation. Burn treatments …