Submitted to: Journal of Arid Environments
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/28/2003
Publication Date: 8/1/2004
Citation: Krueger-Mangold, J., Sheley, R.L., Engel, R., Jacobsen, J., Svejcar, A.J., Zabinski, C. 2004. Identification of the limiting resource within a semi-arid plant association. Journal of Arid Environments. 58(2004):309-320. Interpretive Summary: Accurate models predicting how plants will respond to management requires an understanding of the causes of plant community change. Since resource availability controls plant growth and competition, identification of the most limiting resource for a particular group of plants is central to predicting their response to management. In this study, we added various resources to a native plant community and monitored each species response. It appeared that nitrogen was the most limiting resource in the Idaho fescue and bluebunch wheatgrass plant community. Based on our literature review, the limiting resource in areas drier than this one (<14 inches per year) is water, while in those areas wetter than this one (>18 inches per year), mitrogen is the most limiting resource. This information is useful in predictive models predicting plant community change.
Technical Abstract: Our objective was to determine the resource most limiting to plant growth within a semi-arid plant association. We hypothesized that the addition of nitrogen (N) would elicit an increase in biomass more than additions of water, light, phosphorus (), potassium (K), or sulfur (S). Treatments included the addition of water, N, P, K, or S, or reduction of ambient light on two sites in southwestern Montana within the F. Idahoensis/A. Spicatum plant association. Nitrogen was the only treatment that increased plant community/biomass, specifically native grass biomass (about 50% greater than the control). The addition of water decreased aboveground plant community biomass. Our results suggest that N is the primary limiting resource for the dominant functional group within the F. Idahoensis/A. Spicatum plant association.