Desertification has occurred worldwide. The biophysical and socio-economic complexity of this phenomenon has challenged our ability to categorize, inventory, monitor and repair the condition of degraded lands. One of the most important distinctions to be made in relation to land degradation is between cultivated land used for annual crop production and 'rangelands'. Grazing by free-roaming livestock is the traditional primary use of the world's rangelands. However, there is growing recognition of the importance of these vast acreages for wildlife habitat, hydrology and ground water recharge, recreation and aesthetics. This text focuses on the desertification of rangelands and explores processes, problems and solutions. Chapters in the first section evaluate interactions between 'natural' and human-induced disturbance regimes, thresholds, and non-linear change with respect to vegetation, hydrology, nutrients and erosion. Chapters in the second section examine socio-economic constraints and approaches for preventing and reversing degradation. The book provides a contemporary, process-oriented perspective on rangeland degradation of value to students, policy-makers and professionals alike.
Table of ContentsPreface. Introduction. Processes. Desertification: an appeal for a broader perspective; O. Arnalds. Stress, disturbance and change in rangeland ecosystems; S. Archer, C. Stokes. Viewing rangelands as landscape systems; J.A. Ludwig, D.J. Tongway. Hydrologic effects on rangeland degradation and restoration processes; T.L. Thurow. Erosion models: use and misuse on rangelands; F.B. Pierson, Jr. Desert rangelands, degradation and nutrients; K.M. Havstad, et al. Assessing and monitoring desertification with soil indicators; D. Tongway, N. Hindley. Scaling up from field measurements to large areas using the Desertification Response Unit and Indicator Approaches; A. Imeson, E. Cammeraat. Agricultural and ecological perspectives of vegetation dynamics and desertification; M.T. Hoffman. Policy. The United Nations data bases on desertification; W.F.G. Cardy. The implementation of soil conservation programmes; D. Sanders. Evolution of rangeland conservation strategies; A. Arnalds. Policy and law for rangeland conservation; I. Hannam. Rangelands issues and trends in developing countries; H. Narjisse. The United Nations Convention to Combat Desertification: constraints to implementation in Eastern Africa; N.M. Onchere.