The Living Planet Index (LPI) is a measure of the state of global biological diversity based on population trends of vertebrate species from around the world. It does this in much the same way that a stock market index tracks the value of a set of shares or a retail price index tracks the cost of a basket of consumer goods.
The Living Planet Database (LPD) currently holds time-series data for over 20,000 populations of more than 4,200 mammal, bird, fish, reptile and amphibian species from around the world, which are gathered from a variety of sources such as journals, online databases and government reports. Using a method developed by ZSL and WWF, these species population trends are aggregated to produce indices of the state of biodiversity.
The other function includes assessing the changes in different taxonomic groups, looking at species trends at a national or regional level, identifying how different threats affect populations and providing an insight into how conservation intervention can promote species recoveries.
The global LPI as presented in the Living Planet Report 2018 shows that a subset of 16,704 populations of 4,005 species has declined by 60% in abundance between 1970 and 2014. The Living Planet Report 2018 results indicate that species are faring much worse in freshwater systems and in tropical realms. Freshwater populations declined by an average of 83%, while realms – large regions separated by major barriers to plant and animal migration and therefore characterized by distinct assemblages of species – declined by between 23% and 89%, with the Neotropical and Indo-Pacific realms showing the steepest declines (89% and 64%, respectively).