The Living Planet Index

Anemone fish and anemone Chagos
The Living Planet Index (LPI) is a measure of the state of the world’s biological diversity based on population trends of vertebrate species from around the world.

The LPI has been adopted by the Convention on Biological Diversity (CBD) as an indicator of progress towards its 2011-2020 target to ‘take effective and urgent action to halt the loss of biodiversity'. It also played a pivotal role in measuring progress towards the CBD's 2010 target.

ZSL and WWF are developing rigorous and robust methods for aggregating species population trends to produce indices of the state of biodiversity, expanding the coverage of LPI data to more broadly represent vertebrate biodiversity from all around the globe, and disaggregating the index to measure trends in different thematic areas. This includes assessing the changes in different taxonomic groups, looking at species trends at a national or regional level, and identifying differences in decline trajectories under various threat processes.

The Global Living Planet Index

The Living Planet Index reveals a global decline in vertebrate population abundance of 30% between 1970 and 2008, with no indication of this decrease abating.

All life depends on the Earth’s biological productivity, and as the human population continues to increase its demands upon the biosphere, wild species and their habitats are being placed under increasing pressure across all biomes and regions of the world.

Declines in biodiversity have consequences for the ecosystem services on which humans depend for a multitude of purposes including provision of food, medicine and freshwater.

Temperate and tropical regions

The global index is calculated as an average of the population trends in temperate and in tropical regions (see method) . Figure 1 shows that the temperate index increased by 31% overall whereas the tropical index reveals a 61% decline in species abundance over the 36 year period.

It does not necessarily imply, however, that tropical biodiversity is in a worse state than temperate biodiversity. Rather, current rates of decline in population size are more rapid in tropical systems and represent a severe and ongoing loss of biodiversity in tropical ecosystems.

Calculating the index

The Living Planet Database (LPD) holds time-series data for over 11,000 populations of more than 2700 vertebrate species from around the world. The global LPI is calculated using over 9000 of these population time-series which are gathered from a variety of sources such as journals, online databases and government reports.

A generalised 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, freshwater and marine systems. The three system indices are weighted equally within tropical and temperate regions which are then aggregated to produce the global LPI. More information on how the LPI is calculated.

Understanding trends across scales

The population time-series data are augmented with further information relating to the species’ taxonomy, location and ecology, which enables the analysis of trends at different scales.

For example, subsets of populations of the LPI can provide a basis for tracking progress with respect to multi-lateral agreements such as the Convention for the Conservation of Migratory Species or the Ramsar Convention on Wetlands, for exploring trends in selected groups of species such as utilised species or specific taxonomic groups, and for producing global indices representing particular habitats or biomes.

Living Planet Report

The results of the LPI are also published biennially in the Living Planet Report, which acts as a tool to communicate global biodiversity trends to a wide audience.

The 2010 edition of WWF’s Living Planet Report shows populations of tropical species are plummeting and humanity’s demands on natural resources are sky-rocketing to 50 per cent more than the earth can sustain. The biennial report, produced in collaboration with the Zoological Society of London and the Global Footprint Network, uses the global Living Planet Index as a measure of the health of almost 8,000 populations of more than 2,500 species.

The good news is that temperate species have increased by 29 per cent over the last 40 years. This is probably indicative of a gradual recovery of some systems subsequent to a long period of degradation and decline. Overall the global Index shows a decrease by 30 per cent since 1970, with the tropics hardest hit showing a 60 per cent decline in less than 40 years.