Shrub-steppe: Balance and Change in a Semi-arid Terrestrial Ecosystem(Developments in Agricultural & Managed-forest Ecology S.)

Owing to man-made intervention, the shrub-steppe now represents a rapidly disappearing landscape in the arid regions of North America. This book represents a systems-level study of ecological variables affecting water balance, and responses to perturbation. The study focused on a very large, protected, landscape unit, comprising a natural ``watershed'' area located in the semi-arid western United States. Long-term and concurrent data sets were established with a view towards establishing system-level responses to manipulative interventions, and natural perturbations like wildfire. These data sets were established for micrometeorology, climatology, mineral cycling in soils, nutrient and mineral pathways in springs and streams, vegetational dynamics, and population changes on the site. In synthesizing nearly twenty years of data, the more interesting ecosystem level responses concerned vegetational recovery and water balance. For instance, the synthesis uniquely demonstrates the interaction of biotic and non-biotic factors and their integrated effect on regional water balance.

Table of Contents:
1. Introduction: Shrub-steppe lands (L.E. Rogers, W.H. Rickard). 2. Climate of the Hanford site (W.H. Rickard). Meteorological data base. Climate patterns at the Hanford site. 3. Soils: Carbon and mineral cycling processes (R.E. Wildung, T.R. Garland). Occurrence and distribution of soils. Physiochemical properties. Carbon cycling: Influence of environmental factors. Relationships of carbon cycling to mineral weathering and mobilization. 4. Water Balance (G.W. Gee et al). General principles applicable to arid sites. Microclimatology of the ALE reserve: Data bases. Model simulations. Conclusions. 5. Springs and streams (C.E. Cushing, B.E. Vaughan). Physical and chemical characterization. Biological investigations. Radionuclides as indicators of aquatic ecosystem processes. Summary. 6. Plant communities: Characteristics and responses (W.H. Rickard, B.E. Vaughan). Characteristics of contrasting shrub-steppe plant communities. Responses of plants and plant communities to disturbances. Radionuclides as indicators of biological fate and transport of materials. Summary. 7. Terrestrial animal habitats and population responses (L.E. Rogers et al). Mammals and reptiles. Birds. Insects and related arthropods. Animals as indicators of radionuclide and chemical contamination. 8. Theoretical perspective on ecosystem disturbance and recovery (P.A. Beedlow et al). Concepts of response and recovery. Characterization of disturbance and stress in the shrub-steppe ecosystem. Future research needs. Epilog (L.E. Rogers, W.H. Rickard).