Concept
The Living Planet Index (LPI) is an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world. The Zoological Society of London (ZSL) manages the index in cooperation with the World Wide Fund for Nature (WWF). As of 2022, the index is statistically created from journal studies, online databases and government reports for 31,821 populations of 5,230 species of mammal, bird, reptile, amphibian and fish. According to the 2022 report, monitored wildlife populations show an average decline of 69% between 1970 and 2018, suggesting that natural ecosystems are degrading at a rate unprecedented in human history The extent of declines varies with geographic region, with monitored vertebrate populations in Latin America and the Caribbean experiencing average declines of 94%. One of the key drivers of declines has been identified as land-use change and the associated habitat loss and degradation, often linked to unsustainable agriculture, logging, or other development. The Living Planet Database (LPD) has been available online since 2013, and has been maintained by ZSL since 2016. The LPD contains more than 30,000 population trends for more than 5,200 species of fish, amphibians, reptiles, birds and mammals. The global LPI is calculated using these population time-series, which are gathered from a variety of sources such as journals, online databases and government reports. A generalized additive modelling framework is used to determine the underlying trend in each population time-series. Average rates of change are calculated and aggregated to the species level. Each species trend is aggregated to produce an index for the terrestrial, marine and freshwater systems. This process uses a weighted geometric mean method which places most weight on the largest (most species-rich) groups within a biogeographic realm. This is done to counteract the uneven spatial and taxonomic distribution of data in the LPD. The three system indices are then averaged to produce the global LPI.
