Species in the Nearctic realm have been extensively monitored, providing a large amount of population trend data. The Living Planet Database (LPD) contains population data on 664 Nearctic vertebrate species, and species population abundance from 1970 to 2006 shows no major overall change.
By contrast, the Neotropical index contains population data on 461 vertebrate species and shows a large decline since 1970. The Neotropics contain 40 per cent of all plant and animal species on the planet, making this the most biodiverse of all the biogeographic realms.
In the Palearctic realm, analysis of population data from 497 vertebrate species reveals that the average trend in abundance from 1970 to 2006 increased. This positive trend may, in part, reflect conservation successes resulting from habitat protection or other environmental improvements. However, trends in the Eastern Palearctic are less certain as fewer data are available.
The Afrotropical index, which encompasses 210 vertebrate species, shows a steady decline since 1970. Recent positive trends in the index could reflect successful conservation efforts on certain species. However, conservation action in the in the Afrotropical realm is still essential for reducing the rate of decline.
The Indo-Pacific index combines species population data from three realms: Indo
Malaya, Australasia and Oceania, as there are insufficient data to produce individual realm results. The index produced for this realm is constructed from data on 280 vertebrate species, and reveals a constant downward trend since the late 1970s. Tropical forest loss has been most severe in the Indo-Pacific realm, where much of the original forest has been cleared for agriculture or plantations, driven by the international demand for products such as palm oil.