Threat type information is available for about a third of declining populations. The main threats to these populations are habitat loss and degradation, for example conversion of natural areas for agricultural expansion, followed by overexploitation of species, such as unsustainable fishing.
Populations of terrestrial species declined by 38 per cent between 1970 and 2012. The majority of Earth’s land area is now modified by humans, which has had a large impact on biodiversity.
However, designated protected areas cover 15.4 per cent of the Earth’s land surface, which is likely to have slowed the decline in the terrestrial index compared to freshwater and marine indices.
The LPI for freshwater species shows the greatest decline, falling 81 per cent between 1970 and 2012. The main threats are habitat loss and degradation for example through direct impacts from dams and unsustainable water extractions, followed by overexploitation.
Marine species populations declined 36 per cent between 1970 and 2012. The majority of the decline in the marine LPI occurred between 1970 and the late 1980s, after which the trend stabilizes.
Overfishing is the most common threat, and while some fisheries are now showing recovery because of stronger management measures, the majority of the fish stocks that contribute most to global fish catch are now either fully fished or overfished.
For more information : Living Planet Index