Accumulation of species and carbon across Indonesia's forests
Figure 2. Accumulation of species and carbon across Indonesia's forests. (a) Cumulative number of 528 mammal species for which habitat target area is achieved across forest areas ordered by descending summed range-size rarity; (b) cumulative carbon in above- and belowground woody biomass across forests ordered by descending carbon density.
Biodiversity loss and climate change both result from tropical deforestation, yet strategies to address biodiversity loss have focused primarily on protected areas while strategies to address climate change have focused primarily on carbon payments. Conservation planning research has focused largely on where to prioritize protected areas to achieve the greatest representation of species at viable levels. Meanwhile research on reducing emissions from deforestation and forest degradation (REDD+) has focused largely on how to design payments to achieve the greatest additional reduction in greenhouse gases relative to baseline rates. This divergence of strategies and research agendas may be attributed to four factors: rare species are more heterogeneously distributed than carbon; species are more difficult to measure and monitor than carbon; species are more sensitive to ecological processes and human disturbance than carbon; and people's value for species diminishes beyond a threshold while their value for carbon storage does not. Conservation planning can achieve greater biodiversity benefits by adopting the concept of additionality from REDD+. REDD+ can achieve greater climate benefits by incorporating spatial prioritization from conservation planning. Climate and biodiversity benefits can best be jointly achieved from tropical forests by targeting the most additional actions to the most important places. These concepts are illustrated using data from the forests of Indonesia.