Biodiversity, biocapacity and better choices

Tropical and Temperate Living Planet IndicesThe tropical Living Planet Index declined by just over 60 percent from 1970 to 2008, while the temperate Living Planet Indexincreased by 30 per cent over the same period (Figure 8). Thisdifference holds true for mammals, birds, amphibians and fish; forterrestrial, marine and freshwater species (Figures 9-11); and acrossall tropical and temperate biogeographic realms (Figures 16-20).Due to the lack of published data prior to 1970, historicchanges to biodiversity cannot be captured in the Living PlanetIndex and so all indices are set to an equal value of one in 1970.However, as described in more detail in the following pages, therehas been considerable variation in population trends both betweenindividual species and species that share the same broad habitats.Index Value (1970 = 1)2.01.00.0+31%-61%Figure 8: The tropicaland temperate LivingPlanet indicesThe tropical index iscalculated from terrestrialand freshwater populationsfrom the Afrotropical,Indo-Pacific and Neotropicalrealms and from marinepopulations between theTropics of Cancer andCapricorn. The temperateindex is calculated fromterrestrial and freshwaterpopulations from thePalearctic and Nearcticrealms, and marinepopulations found northor south of the tropics. Theglobal tropical index showsa decline of around 61%between 1970 and 2008.The global temperate indexshows an increase of around31% over the same period(WWF/ZSL, 2012).KeyTemperate LivingPlanet IndexConfidence limitsFigure 9: The terrestrialLiving Planet Index(a) The global terrestrialindex shows a decline ofaround 25% between 1970and 2008; (b) The temperateterrestrial index shows anincrease of about 5%, whilethe tropical terrestrial indexshows a decline of around44% (WWF/ZSL, 2012).KeyGlobal terrestrialindexConfidence limitswhales (Balaena mysticetus), which was estimated at 1,000-3,000 individuals at the end of commercial whaling but has sincerecovered to an estimated 10,545 individuals in 2001 (Angliss andOutlaw, 2006).The Terrestrial Living Planet IndexThe global terrestrial Living Planet Index declined by 25 per centbetween 1970 and 2008 (Figure 9a). The terrestrial index includes3,770 populations from 1,432 species of birds, mammals, amphibiansand reptiles from a broad range of temperate and tropical habitats,including forests, grasslands and drylands. The tropical terrestrialindex declined by almost 45 per cent, while the temperate terrestrialindex increased by about 5 per cent (Figure 9b).Index Value (1970 = 1)2.01.0-25%1970 19751980 1985 1990 1995 2000 2005 2008YearRecent average population increases do not necessarily mean thattemperate ecosystems are in a better state than tropical ecosystems.The observed temperate Living Planet Index trend is the resultof four intertwined phenomena: a recent baseline; differencesin trajectory between taxonomic groups; notable conservationsuccesses; and recent relative stability in species’ populations. Ifthe temperate index extended back centuries rather than decades, itwould very likely show a long-term decline at least as great as that ofthe tropical index in recent years. Conversely, a long-term tropicalindex would likely show a much slower rate of change prior to 1970.Populations of some temperate species have increased inrecent years due to conservation efforts. These include US wetlandbirds (BirdLife International, 2008), UK breeding birds, seabirdsand overwintering birds (Defra, 2010), and certain cetaceanpopulations, such as the western Arctic population of BowheadTropical LivingPlanet IndexConfidence limitsKeyTemperate terrestrialindexConfidence limitsTropical terrestrialindexConfidence limitsIndex Value (1970 = 1)0.02.01.00.01970 19751970 19751980 1985 1990 1995 2000 2005 2008Year+5%-44%1980 1985 1990 1995 2000 2005 2008YearWWF Living Planet Report 2012 page 22 Chapter 1: The state of the planet page 23