Figure 3.

Conservation, biodiversity richness (change in occupancy), productivity and food output under three agri-environmental conservation policies, each implemented through three land allocation rules, and all applied to two conservation land-use types. Panels (a) and (b) show results from applying a Sharing approach where conservation area targets are set. Here (a) shows changes in domestic food output under different conservation area targets, while (b) illustrates corresponding species richness gains (the gain in species occupancy for 100 at-risk species summed across all grid cells). Panels (c) and (d) show comparable results from applying a Sparing approach where increases in productivity (varied from 1% to 5% increases in yield) allow land to be moved into conservation up to the point where total food output is kept constant. Here (c) shows the potential for land sparing into conservation under constant total agricultural output under varying productivity gains, while (d) illustrates corresponding species richness gains as productivity varies. Panels (e), (f) and (g) show results from a Three-Compartment Sparing approach. Here again productivity is increased, allowing land to be spared from conventional agriculture without lowering food output. Now one-third of that land is converted into low-yield agriculture suited to farmland specialist species, while the remaining two-thirds are consigned to natural habitat. Implications of the results from panels (e–g) are considered in panels (h) and (i) which show the relationships between area conserved and (h) corresponding change in food output and (i) biodiversity. All three strategies are implemented under three rules for allocating the location of conservation land: equal allocation (shown in blue); cost minimization (green); biodiversity maximization (red). Furthermore, each strategy and allocation is assessed for two forms of conservation land-use; conversion into semi-natural grassland (solid line curves) and woodland (broken lines).