Ecosystem Services and Scenarios of Rewilding
Here we estimate the biophysical potential of rewilding to produce benefits, by comparing ecosystem services in the top 5 % wilderness areas with the current supply of ecosystem services in all agricultural areas and in agricultural areas that are projected to be abandoned. We restrict the analysis to the scale of the Iberian Peninsula to control for the large bioclimatic variability across Europe.
There are significant differences in the supply of most ecosystem services between the different land use categories (Table 3.2). HANPP values are significantly higher in agricultural areas than in both land projected to be abandoned and, as expected, in the top 5 % wilderness areas. We thus hypothesize that food production will decrease with the contraction of the agricultural area, although the decrease will be limited because of the lower agricultural productivity of those areas. Several services present higher values for the average supply of the studied indicators in the top 5 % wilderness areas (Table 3.2). The deposition velocity of NOx, an indicator of air quality, depends on the height of the vegetation and the leaf area index, and tends to be much higher in forested areas (Maes et al. 2011), hence, the higher values in the top 5 % wilderness (Table 3.2). The recreation potential is also higher in wilderness areas than in the other land-uses.
Most ecosystem services exhibit higher values in the areas to be abandoned than in other agricultural areas (Fig. 3.3a). We can thus speculate that intensifying agriculture in the areas projected to be abandoned would lead to an overall decrease in the supply of ecosystem services in these areas. On the other hand, rewilding these areas would bring improvements in some ecosystem services, such as nitrogen retention and recreation, and decreases in others (Fig. 3.3b). These inferences have to be interpreted with care as we are making several simplifying assumptions and ecosystem services depend on other biophysical variables besides land cover and
Fig. 3.3 Comparison between land-uses of the average supply of indicators of ecosystem services. The diagrams represent the average supply per km2 in cultivated areas (a), or in the top 5 % wilderness (b), relative to the average supply in areas projected to be abandoned. Values inside the 100 % circle are lower for the studied land-use, while values outside are higher when compared with land projected to be abandoned. See Table 3.2 for the average values.
land use. This is for instance the case for freshwater supply, which depends on the aboveground net precipitation water in catchments and on the area and flows of the freshwater areas (Maes et al. 2011).