Comparing Alternative Management Strategies Of Fire, Grazing, And Weed Control Using Spatial Modeling

Authors: PROVENCHER, LOUIS - Nature Conservancy; De Queiroz, Tara; FRID, LEONARD - Essa Technologies; MEDLYN, GARY - Bureau Of Land Management

Submitted to: Ecological Modelling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2007
Publication Date: 8/13/2007
Citation: Provencher, L., Forbis, T.A., Frid, L., Medlyn, G. 2007. Comparing Alternative Management Strategies Of Fire, Grazing, And Weed Control Using Spatial Modeling. Ecological Modelling. 209:249-263.

Interpretive Summary: Modeling can be used to resolve controversies generated by differing opinions about the effects of livestock grazing, fire management, and herbicide application on western public lands. We used spatial simulations of 10 vegetation types to compare 6 management scenarios over 20 years in a 141,853 hectare landscape in eastern Nevada. Scenarios were compared by incrementally varying one factor at a time and were based on the Bureau of Land Management’s (BLM’s) potential restoration plans. The following factors were varied: managed fire, livestock grazing, mechanical and chemical treatment of vegetation, and restoration budgets. After 20 years the differences in vegetative composition between scenarios were small. BLM’s level of funding was too low to improve ecological condition because the landscape was too degraded, however, current funding could maintain communities that retained native perennial understories. In general, the effects of livestock grazing were minor and undesirable compared to benefits gained from the use of mechanical and chemical methods followed by seeding. Mechanical methods and herbicide application in addition to current fire management had more desirable effects than without fire management.

Technical Abstract: Modeling can be used to resolve controversies generated by differing opinions about the effects of livestock grazing, fire management, and herbicide application on western public lands. We used spatial simulations of 10 vegetation types to compare 6 management scenarios over 20 years in a 141,853 hectare landscape in eastern Nevada. Scenarios were compared by incrementally varying one factor at a time and were based on the Bureau of Land Management’s (BLM’s) potential restoration plans. The following factors were varied: managed fire, livestock grazing, mechanical and chemical treatment of vegetation, and restoration budgets. After 20 years the differences in vegetative composition between scenarios were small. BLM’s level of funding was too low to improve ecological condition because the landscape was too degraded, however, current funding could maintain communities that retained native perennial understories. In general, the effects of livestock grazing were minor and undesirable compared to benefits gained from the use of mechanical and chemical methods followed by seeding. Mechanical methods and herbicide application in addition to current fire management had more desirable effects than without fire management.