The problems associated with land degradation in Iberia have been the focus of a growing research effort and, increasingly, of action since at least the mid-1980s (Thornes, 1996. As elsewhere in the Mediterranean region, a particularly prominent concern, has been the incidence, causes and management of desertification, especially in semiarid areas of Spain (Mairota, Thornes and Geeson, 1998). This is reflected in the work of EU-funded international research programmes such as Medalus (Brandt and Thornes, 1996;Medalus, 2001), Archaeomedes (Van der Leeuw, 1998), Medchange (Coelho et al., 2001) and the recent Medafor programme (which has generated some of the work reported in this volume). The research focus on land degradation has been increasingly complemented by environmental planning and action by national authorities (Moura ˜o, 1998;Rojo Serrano, 1998; Ministerio de Medio Ambiente, 2001). Other prominent challenges for environmental management in Iberia include the pressures on water resources (Ecologistas en Accio ´n, 2000a), forest management (Garcia Pe ´rez and Groome, 2000) and forest fires (Ecologistas en Accio ´n, 2000b).
The following papers are a contribution to the maturing debate on land degradation and management in Iberia, from a geographical perspective. They result from a special session at the Annual Conference of the Royal Geographical Society-Institute of British Geographers held at Plymouth University in January 2001. British geographers have had a long engagement with Iberia both as a location for undergraduate fieldcourse teaching, (greatly assisted by the availability of low-cost package tours), and diverse research activity by individuals and collaborative groups (for instance, within the EU-funded Medalus and Medafor programmes).
The Plymouth session on Iberia brought together geographers with a common interest in land management issues in Spain and Portugal, but whose contributions reflected the great diversity of contemporary geography. The intention was to avoid the narrow perspectives typical of the more specialized study group meetings, and thereby emphasize geography's strong credentials in terms of the holistic perspective now widely regarded as fundamental for the understanding and solution of land management problems, particularly those relating to land degradation. There was an explicit concern to break down traditional divisions between physical and human geography. Contributors were encouraged (with varying degrees of success!) to take on the challenge of presenting complex ideas and technical material in a mutually accessible fashion, while maintaining scientific integrity. It is undeniable that these papers deal mainly with biophysical dimensions of land degradation and land management, which may suggest that there is still a need to widen social, economic and political perspectives on land degradation. Despite this, the papers demonstrate a range of perspectives and approaches that can contribute to a more holistic approach to understanding and managing land degradation in Iberia, while also identifying some common themes. Besides the mix of physical environmental and socio-economic research, the contributions range from complex geostatistical procedures to simple erosion risk-ranking methodologies, and examine erosion processes operating over time-scales ranging from a few years to 100 000 years. They also illustrate the problems of variability in space and time.
The value of multiple perspectives is demonstrated in the papers by Shakesby et al. ('Ground level changes . . . ') and Carvalho et al. Based on research in central Portugal, the former shows how some soils can lose half their thickness within a few years following wildfire and rip-ploughing disturbance in vulnerable terrain. Despite such dramatic evidence of the effects of inadequate and inappropriate land management, survey research reported by Carvalho et al. showed that the majority of farmers in the Mac ¸ao region of central Portugal had little understanding of the concept or causes of soil erosion. They believed such degradation to be mainly due to drought or intense rain. Clearly a more holistic perspective embracing such diverse findings is fundamental to the success of any strategy to combat land degradation.