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Grassland, Shrubland and Desert Ecosystems
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  • Grassland, Shrubland and Desert Ecosystems
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  • Albuquerque, NM 87102-3497
  • 505-724-3660
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You are here: Grassland, Shrubland and Desert Ecosystems / Research by Project / Annual Grass Invasion

Understanding Ecological Resistance to Annual Grass Invasion

Project Title

Understanding Ecological Resistance to Annual Grass Invasion and Resilience to Disturbance

Abstract

The invasion of non-native annual grasses, especially cheatgrass (Bromus tectorum), into sagebrush ecosystems depleted by livestock grazing is having widespread ecological and economic effects. The highly flammable annual grasses are increasing fine fuels and causing larger and more frequent fires in sagebrush ecosystems. Few mechanistic studies have focused on the environmental and ecological factors that influence ecological resistance or, conversely, susceptibility of ecosystems to invasion by B. tectorum. Research in other ecosystems indicates that several different factors affect the establishment and persistence of invasive species. These include (1) the ecological amplitude of the species or its ability to establish and persist under a given set of environmental conditions, (2) the ecological memory of the site as reflected in the site potential (precipitation and soils), species composition and ecological condition, and presence, abundance and type of invasive species, and (3) the type, severity and frequency of disturbance. In the Great Basin, invasion of B. tectorum varies across the landscape but is occurring most rapidly in mid-elevation Wyoming sagebrush types, in degraded rangelands with depleted understories and in response to fire. Research conducted by the Great Basin Ecology Lab is attempting to (1) better define the ecological amplitude of the species, (2) determine the effects of site conditions and species composition on resistance to B. tectorum, and (3) evaluate the effects of disturbance s like fire and herbaceous species removal on both community composition and B. tectorum. Specific areas of investigation include the following:

  • effects of fire and herbaceous species removals on soil resource availability and B. tectorum establishment and reproduction over elevation gradients in sagebrush ecosystems;
  • effects of fire and herbaceous species removals on soil resource availability and plant community resistance to B. tectorum over elevation gradients in sagebrush ecosystems;
  • effects of feedback mechanisms and resource preemption by B. tectorum on seedling establishment processes in sagebrush steppe;
  • influence of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by B. tectorum;
  • influence of fire and a common legume, Lupinus argenteus, on nitrogen availability and B. tectorum invasion in sagebrush ecosystems;
  • the use of repeated burning to restore sagebrush ecosystems dominated by B. tectorum.

Selected Publications

GSD Principal Investigators

Chambers, Jeanne C    Research Ecologist    775-784-5329
Board, David    Ecologist/Data Analyst    775-784-5329

Cooperators and Sponsors

Collaborators

  • Bob Blank, USDA Agricultural Research Station
  • Dale Johnson, University of Nevada, Reno
  • Beth Leger, University of Nevada, Reno

Sponsors

  • Bureau of Land Management
  • Joint Fire Sciences Program