The decline is greatest for freshwater species, whose populations show an average 37 per cent decline. The tropical freshwater index declined even more precipitously, by 70 per cent.
These declines are on average – as for the overall tropical and temperate LPIs
, tropical and temperate species living in each habitat type show starkly different trends.
Overall, the global tropical index declined by 60 per cent since 1970. In contrast, the index for temperate regions increased by 31 per cent over the same period. (see figure on right)
However, this does not necessarily mean that temperate biodiversity is in a better state than tropical biodiversity, as the temperate index disguises huge historical losses prior to the start of the analysis.
(The animal populations tracked by the global Living Planet Index
can be divided according to their habitat type – terrestrial, freshwater or marine.)