Biodiversity, biocapacity and better choices

Biogeographic realmsBiodiversity trends at a regional level can give insightsinto how animal populations are faring in different partsof the world.Terrestrial and freshwater populations are assigned to fivebiogeographic realms (Figure 15), three of which are largelytropical (Indo-Pacific, Afrotropical and Neotropical) and two largelytemperate (Palearctic and Nearctic). The Living Planet Indexincludes species’ populations in the Antarctic, however due to a lackof data from this region, it is not yet possible to construct an indexfor that region alone.Temperate realms show stable trends, while tropical realmsexhibit rapid decline. The Palearctic and Nearctic indices showlittle change between 1970 and 2008 (Figures 16 and 17). Thelatter is likely due in part to effective environmental protectionand conservation efforts since 1970. Individual populations inthe Palearctic realm fared differently: Some, such as seabirds andwintering water birds, increased (for example, some UK wild birdpopulations: Defra, 2010), while others, such as saiga antelope(Saiga tatarica) (Milner-Gulland et al., 2001) and amphibians incentral Spain (Bosch and Martinez-Solano, 2006), underwent largescaledecline. The water bird trend may be due in part to betterenvironmental protection since 1970. However, as most data comefrom Europe, with comparatively little data from northern Asia,trends from individual countries could provide a different picture.In contrast, the Afrotropical index declined by 38 per cent;the Neotropical index by 50 per cent; and the Indo-Pacific index by64 per cent (Figures 18, 19 and 20). These declines reflect largescaleforest and other habitat loss across these realms, driven bylogging, growing human populations, and agricultural, industrialand urban developments (Craigie et al., 2010; Norris et al., 2010;MEA, 2005; FAO, 2005; Hansen et al., 2008). Tropical forestcover declined most rapidly in Southeast Asia between 1990 and2005, with an estimated 0.6-0.8 per cent loss per year (FAO, 2005;Hansen et al., 2008). The decline in the Neotropical index alsoreflects catastrophic declines in amphibian numbers, caused inmany cases by the spread of fungal disease.© Michel Roggo / WWF-CanonRio Negro Forest Reserve, Amazonas, Brazil. Flooded forest during rainy season. Aerial view offloating vegetation.WWF Living Planet Report 2012 page 32