Thursday, August 11, 2011: 8:40 AM
16B, Austin Convention Center
Mid-continent rangelands are increasingly subject to encroachment of woody plants that reduces agricultural production and biodiversity. Although an effective practice to limit encroachment and restore grassland from woodland, prescribed burning too often is limited by social constraints and the perception that herbage used to fuel fire competes directly with herbage used as livestock forage. This recalcitrant barrier to more widespread prescribed burning is exacerbated by climate variability, reflected in variable precipitation that often limits herbage production within and among years. In this paper, we explore an approach to rangeland herbage management that restores a key ecosystem process, specifically pyric-herbivory, that existed in the Great Plains before European settlement. We hypothesized that restoring pyric-herbivory through application of patch burning increases heterogeneity. Increased heterogeneity subsequently enhances effectiveness of prescribed burning while managing the forage-fuel duality, contains woody plant encroachment and invasion by exotic forage plants, and reduces risk associated with increasing precipitation variability associated with climate change.
Results/Conclusions Results from empirical studies conducted at multiple locations in North American rangelands support our hypothesis that patch burning increases heterogeneity. Observations and models indicate that fire-grazing feedbacks operate to enhance managing the fuel-forage duality, controlling undesirable plants (encroaching woody plants and invasions of exotic forage plants), and mitigating the impact of below-average precipitation. The Great Plains regularly experiences economic and social upheaval from intense drought and now faces an equally formidable threat from woody plant encroachment. Our evidence suggests that managers of mid-continent rangelands can use patch burning to their advantage to buffer the impact of climate variation on their agricultural enterprises, ultimately leading to increased stability of human communities within the region.