Biological resources are essential elements of ecosystems and of natural capital, providing the raw materials of production and growth in many sectors of the economy. Their diversity plays an essential role in maintaining life-support systems and quality of life.
Pressures on biodiversity can be physical (e.g. habitat alteration and fragmentation through changes in land use and cover), chemical (e.g. toxic contamination, acidification and oil spills) or biological (e.g. alteration of population dynamics and species structure through the release of exotic species or the commercial use of wildlife resources).
The indicators presented here relate to selected aspects of biodiversity. They concern:
The number of threatened species compared to the number of known or assessed species. “Threatened” refers to the “endangered” , “critically endangered” and “vulnerable” species (definitions in Annex B). Data cover mammals, birds and vascular plants but exclude other major groups (e.g. fish, amphibians, reptiles, invertebrates, fungi).
Major protected areas (terrestrial and marine), i.e. areas under management Categories I to VI of the World Conservation Union (IUCN) classification. Wilderness areas, strict nature reserves and national parks reflect the highest protection level.
These indicators should be read in connection with information on the density of population and of human activities as well as information on the sustainable use of biodiversity as a resource (e.g. forest, fish) and on habitat alteration.
Since the 1990s, terrestrial and marine protected areas have increased in many OECD countries. But, pressures on biodiversity and threats to global ecosystems and their species are increasing.
Many natural ecosystems have been degraded, limiting the services they provide. Many wetlands, highly valued habitats for biodiversity, have been converted to agricultural use, although at a declining rate.
The targets agreed in 2002 by parties to the CBD to “significantly reduce the rate of biodiversity loss” by 2010 have not been met at the global level.
In most OECD countries, the number of animal and plant species identified as endangered is increasing. Many species are threatened by habitat alteration or loss, both within and outside protected areas (e.g. on farms and in forests). Threat levels are particularly high in countries with high population density and a high concentration of human activities.
Total OECD terrestrial and marine protected areas reach about 11% of the total area and territorial sea. The areas protected vary significantly among OECD countries and are not always representative of national biodiversity, nor sufficiently connected. The challenges facing most countries are increasing marine protected areas, which are under-represented, and creating ecological “networks” with connecting corridors between protected areas
Actual protection levels and related trends remain difficult to evaluate, as protected areas change over time as: new areas are designated, boundaries are revised and sites are destroyed or changed by economic activities or natural processes. Environmental performance depends both on the designation of the area and on management effectiveness.
See Annex A for trends of major terrestrial and marine protected areas.
Data on threatened species are available for all OECD countries with varying degrees of completeness. The number of species known or assessed does not always accurately reflect the number of species in existence, and the definitions that should follow IUCN standards are applied with varying degrees of rigour in countries. Historical data are generally not comparable or not available.
International data on protected areas are available for all OECD countries. The definitions, although harmonised by the World Conservation Monitoring Centre (WCMC), may however still vary among countries.