Disparity between ecological and political timeframes for species conservation targets

The Convention on Biological Diversity’s (CBD) Aichi Target 12 aimed to prevent species extinctions and improve the conservation status of known threatened species by 2020 but has not been met. As the post-2020 global biodiversity framework is negotiated, it is essential that we learn lessons from past failures. Here, we investigate whether a reduction in extinction risk could realistically be achieved within the ten-year timeframe of the Aichi Targets. We identified threatened bird and mammal species for which a population increase could lead to down-listing on the IUCN Red List and created population models that assumed exponential population growth to predict how long it would take to reach the population size threshold required for down-listing. We found that in the best-case scenario, 39/42 birds (93%) and 12/15 mammals (80%) could be expected to show the population increase required to achieve down-listing by one Red List category within a ten-year timeframe. In contrast, under the worst-case scenario, 67% birds and 40% mammals were predicted to take > 10 years to reach the population threshold. These results indicate a disparity between the ecological timeframes required for species to show a reduction in extinction risk, and the political timeframes over which such ecological change is expected to be achieved and detected. We suggest that quantitative analyses should be used to set realistic milestone targets in the post-2020 framework, and that global indicators should be supplemented with temporally sensitive measures of conservation progress in order to maintain political and societal motivation for species conservation.