Skip to main content
ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #199993

Title: The Within-Site and Regional Impacts of Leafy Spurge: Hierarchical Bayesian Methods Estimate Invasive Weed Impacts at Pertinent Spatial Scales

Author
item Rinella, Matthew - Matt
item LUSCHEI, EDWARD - UNIV OF WISCONSIN

Submitted to: Western Society of Weed Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2006
Publication Date: 3/1/2006
Citation: Rinella, M.J., Luschei, E.C. 2006. The Within-Site and Regional Impacts of Leafy Spurge: Hierarchical Bayesian Methods Estimate Invasive Weed Impacts at Pertinent Spatial Scales. Western Society of Weed Science.

Interpretive Summary:

Technical Abstract: Without information on the severity of invasive weed impacts, natural resource managers cannot compare costs and benefits of weed management actions. The spatial scale of interest to weed managers ranges from very local (e.g. ranchers, park managers) to regional (e.g. policy makers). Our goal was to estimate local and regional impacts of leafy spurge (Euphorbia esula L.) on associated species biomass production (and related variables). Our basic approach was to use an empirical model that characterizes weed densities across landscapes in combination with another empirical model that predicts weed impact from weed density. In developing these models, we gave substantial formal attention to parameter uncertainty and sampling error. Our investigation revealed that, without local plant density data, estimates of site-specific leafy spurge impacts are highly imprecise. Supplementing our general predictive model with small quantities of on-site data increased precision considerably. For the 17-state region we considered, 95% Bayesian credibility intervals indicate leafy spurge reduces cattle carrying capacity by 50 to 217 thousand animals, and reduces grazing land value by 8 to 34 million dollars a year. The precision of these estimates would improve substantially if plant density data were collected from randomly selected sites that are occupied by leafy spurge.