‘Land degradation’ means the reduction and loss of the biological or economic productivity caused by land use change or by a physical process or a combination of the two. ‘Land’ means the terrestrial bio-productive system that comprises soil, vegetation, and other biota and the ecological and hydrological processes that operate within the system (UNEP 1992). The main components of land degradation are ecological degradation, soil loss, and reduction in the amount and quality of the available water resources for human survival and economic sustainability. Conacher and Sala (1998) have edited a major volume on land degradation in Mediterranean environments of the world and soil erosion mechanisms and water resources are considered in other chapters of this book (Chapters 6 and 21). This chapter will focus on the ecological aspects of land degradation by exploring some of the interactions between land use change, vegetation dynamics, grazing patterns, and wildfires. This chapter will also try to identify and avoid repeating the myths that abound in the more popular and/or politically motivated accounts of Mediterranean land degradation. Because of the complex spatial mosaic of environmental and cultural conditions across the Mediterranean (see Blondel 2006), it is not simple to identify the causes or main controls of land degradation or the management strategies required to combat degradation (Lesschen et al. 2007; Märker et al. 2008). As discussed in the context of lake sediment records in Chapter 9, it is certain that the origins of land degradation extend far back into prehistory. Indeed, Naveh and Dan (1973) have proposed a seven-phase history of land degradation for the Mediterranean basin, paraphrased thus: Phase 1 was the Lower Palaeolithic (around 1,000,000 to 100,000 years BP), when the Levant was the main route of biotic and hominid dispersal from Africa to Eurasia and later westwards through the Mediterranean basin. Hunting and gathering were the main activities and the populations were probably very low. Human impact on the environment is not known—but land degradation is assumed to have been negligible. After this, in Phase 2, it is argued that the use of fire as a tool for the opening up of dense forest spread westwards from Greece, possibly reaching France as early as 400,000 BP.
Land use change and land degradation in West Malombe, Mangochi District, Malawi: a geographical study
