World’s Soil Resources

2 - Land degradation assessment mapping
The assessment used a standard methodology (Liniger et al., 2011) that allowed the participatory mapping
of the major types of ecosystem degradation (soil, water and biological) and sub-types (for instance, water
erosion, compaction, decline in ground water quality or reduction of vegetative cover). At the same time the
intensity (degree) and the trend of the ongoing ecosystem change was evaluated on the basis of arbitrary
classes (typically ranging from none to severe or slow to fast). The evaluation was conducted in a participatory
way involving various stakeholders in the assessment and using hard data where they were available. The
direct pressures (for instance improper soil management, deforestation or natural causes) and the indirect
socio economic causes (for instance lack of knowledge or investment) were also determined in the same
participatory way, as was the impact on ecosystem goods and services. Examples illustrating the outcome of
the assessment are given in the following maps which evaluate water erosion (Figure 13.7a) and wind erosion
(Figure 13.7b). Differences in the extent of ongoing degradation processes in the country could also be mapped.
Figure 13.7 Assessment of Water (a) and Wind Erosion (b) in Tunisia
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in the Near East and North Africa