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Thursday, 02-Apr-2009 13:16:10 MST

 

Research >> Current Research Projects

Title: A hierarchical, geospatial approach to predicting and mitigating shrub invasion in the southwestern United States
Funding Agency: USDA-NRI Biology of Weedy and Invasive Species
PI: Brandon Bestelmeyer, Agricultural Research Service/New Mexico State University
Co-PI: Steve Archer, School of Natural Resources, University of Arizona
Graduate Students: Darroc Goolsby and Nate Pierce

Summary:

photo: Evidence of Grass Loss

Shrub encroachment into grasslands is a worldwide problem whose causes are incompletely understood. In southwestern U.S. rangelands, shrub encroachment threatens the sustainability of rural livelihoods. Large land areas across the region have already undergone grassland-to-shrubland transitions over the last century, but shrubland conversion is an ongoing process threatening remaining grasslands.

photo: Study Area

In spite of the large amounts of private and federal resources dedicated to shrub management, there is little scientific guidance to direct where the limited resources available for such applications will be most effectively implemented. Our goal is to provide analysis, conceptual tools and mapping of land areas to guide the management of native shrub invasion in the southwestern United States. Our work will integrate consideration of soils, land-use history, climate, and shrub invasion patterns in southwestern New Mexico and southeastern Arizona.

figure: Schematic of Image Analysisis

The research will enable us to distinguish four basic classes of land on a regional basis:

  1. shrub dominated areas that are poor candidates for grassland restoration
  2. shrub-dominated areas where restoration to savanna is feasible
  3. grasslands that are at risk of invasion but not yet invaded
  4. grasslands/savannas that are at low risk of shrub domination.

Mapping and decision products will be based on geospatial modeling coupled with field experiments and draw on modern ecological theories addressing the causes and consequences of shrub invasion. The research will integrate multiple, scale-specific hypotheses to provide an unprecedented perspective on the biology of shrub invasion and then use this perspective to increase agricultural security in U.S. rangelands.