OOS 10-2 - Soil degradation legacies and soil restoration as a basis for grassland and shrubland stewardship

Tuesday, August 9, 2011: 8:20 AM
12A, Austin Convention Center
Nicole M. DeCrappeo, U.S. Geological Survey, DOI Northwest Climate Science Center, Corvallis, OR and David A. Pyke, Forest & Rangeland Ecosystem Science Center, U.S. Geological Survey, Corvallis, OR
Background/Question/Methods

In arid and semi-arid grasslands and shrublands, disturbances such as fire, overgrazing, and invasive species can dramatically alter native plant communities and the physical, chemical, and biological properties of the soil in which they grow. Legacies of soil degradation include decreased soil organic matter, soil stability, biological soil crust cover, and water infiltration rates and increased erosion and compaction. Changes in soil community structure and composition and nutrient cycling rates have also been documented. Yet restoration goals in these areas are often plant-focused, with success or failure being determined by the number of seeded plants that have established after one or two years. Little consideration is given to the impact of disturbances on soils or the recovery of overall ecosystem functioning. We use examples from studies done in the Great Basin, USA, in cheatgrass (Bromus tectorum)-invaded sagebrush steppe to explore the utility of including soil assessments and manipulations in restoration efforts.

Results/Conclusions

Characterizing biotic and abiotic soil properties is a necessary first step in assessing grassland and shrubland status, and continued soil monitoring can be useful in documenting site degradation or recovery. When native plant revegetation is necessary, preparation of microsites by removing litter, inoculating or “seeding” soils with beneficial biological organisms (e.g., arbuscular mycorrhizal fungi or nitrogen-fixing lichens), or manipulating soil nutrients with carbon amendments are examples of strategies that have been shown to enhance restoration success. However, much work is needed to determine under which climatic conditions and spatial scales these strategies will be successful in for future climate scenarios. Most importantly, a more holistic ecosystem approach may aid in managing and restoring grasslands and shrublands.

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