Desertification and land degradation: origins, processes and solutions

Table of Contents

1. Authors and acknowledgements
2. Introduction
   1. Aims
   2. Definitions and key concepts
   3. Synthesis of previous and ongoing projects
   4. Key issues and outline
3. Evolution of desertification in the Mediterranean
   1. Climatic fluctuation
   2. Human influence
4. Primary drivers of desertification
   1. Biophysical and socio-economic causes
   2. Pathways of desertification
   3. Driving forces in the Mediterranean
   4. Synthesis of causes for DESIRE hotspots
   5. Conclusions
5. Processes and consequences of desertification in the Mediterranean
   1. Socio-economic and political factors
   2. Biophysical processes
   3. Conclusions
6. Indicators: monitoring desertification
   1. History of monitoring
   2. Indicators
   3. Monitoring and mapping techniques
   4. Concluding remarks
7. Modelling desertification
   1. Definition of modelling
   2. Model types
   3. Biophysical modelling
   4. Socio-economic and participatory modelling
   5. Gaps and progression in modelling
8. Solutions
   1. Biophysical solutions
   2. Political and socio-economic solutions
9. References

Pathways of desertification

Lambin et al., in 2001, conclude that various human-environment conditions react to and reshape the impacts of drivers differently, leading to specific pathways of land-use change. Geist and Lambin (2004) underline this for the process of desertification: 'Dominant causative factors and feedbacks, combined with environmental and land-use histories, allow the identification of typical regional pathways of desertification.'. The typical pathways they identified for Africa and Europe are discussed here. This first involves the spatial concentration of pastoralists, resulting from a shift from a nomadic to a sedentary way of life, with farmers living around infrastructure nuclei. This results in overgrazing, extensive fuelwood collection and high cropping intensities, ultimately leading to degraded vegetation and declining soil productivity during periods of drought (Geist and Lambin, 2004). A common trajectory of dryland change in the Mediterranean basin of southern Europe involves the millennia-old tradition of agro-pastoral land use, which removed nearly all forest cover, favouring an highly resilient phrygana (shrub) vegetation, reflecting various stages of soil degradation. Risks are evident when mechanization of farming on skeletal soils induce further soil erosion or when grazing on remote mountain ranges is followed by devastating fires (Geist and Lambin, 2004).

In Lambin et al. (2001), pathways or conditions that appeared repeatedly in the case studies reviewed include: weak state economies in forest frontiers; institutions in transition or absent in developing regions; induced innovation and intensification, especially in peri-urban and market accessible areas of developing regions; urbanized aspirations and income with differential rural impacts; new economic opportunities linked to new market outlets; changes in economic policies or capital investments and inappropriate intervention giving rise to rapid modifications of landscapes and ecosystems.