Calculating the LPI
The LPI is based on population data for mammal, bird, reptile, amphibian and fish species from around the world. In the latest LPI, data from nearly 8,000 populations of over 2,500 animal species were used – many more than ever before.
The LPI first calculates the annual rate of change for each population. Changes for some example populations are shown below:
The LPI first calculates the annual rate of change for each population. Changes for some example populations are shown below:
Figure 5: The LPI is calculated from trends in populations of individual species. As this figure shows, some populations have increased during the time they have been monitored, while others have decreased. Overall, however, more populations have decreased than increased, so the Index shows a global decline. LPR2010
Next, the average change across all populations is calculated for each year from 1970, when data collection began, to 2007, the latest date for which data is available.
The global Living Planet Index is the aggregate of two indices – the temperate and tropical LPIs – each of which is given equal weight. The temperate and tropical LPIs include land, freshwater and marine species, each of which is given equal weight. This process is illustrated below.
The global Living Planet Index is the aggregate of two indices – the temperate and tropical LPIs – each of which is given equal weight. The temperate and tropical LPIs include land, freshwater and marine species, each of which is given equal weight. This process is illustrated below.
Turning population trends into the Living Planet Index.
