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The Economics of Desertification, Land Degradation, and Drought

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output—which is a selection <strong>of</strong> summarized l<strong>and</strong> degradation statuses, processes, <strong>and</strong> impact indexes<br />

within six maps: the Ecosystem Service Status Index (ESSI), the Biophysical Status Index (BSI), the<br />

<strong>L<strong>and</strong></strong> <strong>Degradation</strong> Index (LDI), Goods <strong>and</strong> Services severely affected, the Biophysical <strong>Degradation</strong><br />

Index (BDI), <strong>and</strong> the <strong>L<strong>and</strong></strong> <strong>Degradation</strong> Impact Index (LDII).<br />

<strong>The</strong> ESSI (Figure 2.14) shows the actual state <strong>of</strong> goods <strong>and</strong> services provided by ecosystems,<br />

calculated by combining the four biophysical status axes (biomass, soil, water, <strong>and</strong> biodiversity) <strong>and</strong><br />

the two socioeconomic status axes (economic <strong>and</strong> social status). Figure 2.14 shows that Sub-Saharan<br />

Africa <strong>and</strong> Australia both have a low status <strong>of</strong> ecosystem services. In these two regions, a reduction in<br />

ecosystem goods <strong>and</strong> services (due to l<strong>and</strong> degradation, for example) will have higher negative<br />

pressure on population <strong>and</strong> l<strong>and</strong> than, for example, in Sc<strong>and</strong>inavia, the northwestern United States,<br />

<strong>and</strong> southern Canada, where the ESSI is high.<br />

Figure 2.14—Ecosystem Service Status Index, GLADIS<br />

Source: Nachtergaele et al. 2010.<br />

<strong>The</strong> BSI (Appendix B, Figure B.3) proceeds similarly to the ESSI, but factors only<br />

biophysical variables (status axes <strong>of</strong> biomass, soil, water, <strong>and</strong> biodiversity) into the output map,<br />

excluding socioeconomic ones.<br />

Goods <strong>and</strong> services severely affected (Appendix B, Figure B.4) represent the most severely<br />

affected areas, threatened by a huge decline <strong>of</strong> goods <strong>and</strong> services provided by an ecosystem.<br />

<strong>The</strong>refore, a threshold rule was used that accounts for the critical values <strong>of</strong> the six axes. 14 This map<br />

(Figure 2.15) was superimposed on the overall processes <strong>of</strong> declining ecosystem services by<br />

considering the combined value <strong>of</strong> each process axis in the radar trend diagram, shown with the LDI<br />

(Nachtergaele et al. 2010). In addition to negative impacts, Figure 2.15 also shows improvement <strong>of</strong><br />

l<strong>and</strong> degradation, as seen in the Sahelian zone in Sub-Saharan Africa; this zone is faced by higher<br />

precipitation rates <strong>and</strong> an upcoming economic performance.<br />

14 Critical values <strong>of</strong> the six axes: Biomass < 25, Soil < 37.5 (This value coincides with a loss <strong>of</strong> 25 tons per hectare.),<br />

Water < 25, Biodiversity < 25, Economy < 25, Social/Cultural < 25.<br />

28

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