Following their failure to achieve a significant reduction in the global rate of biodiversity loss by 2010, world governments adopted 20 new ambitious Aichi biodiversity targets to be met by 2020.There is growing recognition that efforts to achieve one particular biodiversity target can contribute to achieving others, yet little attention is given to the fact that different targets may require conflicting solutions. Consequently, there is a risk that lack of strategic thinking might result, once again, in a failure to achieve governmental commitments to biodiversity conservation. We illustrate this dilemma by focusing on Aichi Target 11. This requires an expansion of terrestrial protected area coverage, which could also contribute to reducing the loss of natural habitats (Target 5), reducing human-induced species decline and extinction (Target 12), and maintaining global carbon stocks (Target 15). We consider the potential impact of expanding protected areas to mitigate global deforestation and the consequences for the distribution of suitable habitat for >10000 species of forest vertebrates (amphibians, birds and mammals). We found that expanding protected areas toward locations with the highest deforestation rates (Target 5) or the highest potential loss of aggregate species’ suitable habitat (Target 12) would result in partially different protected area network configurations (overlapping with each other by ca. 73%). Moreover, the latter approach would contribute to safeguarding ca. 30% more global carbon stocks (measures as tons/ha) than the former. Further investigation of synergies and trade-offs between targets would shed light on these and other complex interactions, such as the interaction between reducing overexploitation of natural resources (Targets 6, 7), controlling invasive alien species (Target 9) and preventing extinctions of native species (Target 12). Synergies between targets must be identified and secured soon and trade-offs must be minimized, before the options for co-benefits are reduced by human pressures.
Current protected areas and areas with highest deforestation impact. The maps represent: (a) current extension of the protected area network; (b) areas of synergy, i.e. places where highest forest loss correspond to highest habitat loss aggregated across species; (c) areas of forest trade-off, where highest forest loss is expected, but not highest loss of aggregate species habitat; (d) areas of species trade-off, where highest loss of aggregate species habitat is expected, but not highest forest loss. See Supporting Information for a color version of the map.