Biodiversity is the shortened form of two words "biological" and "diversity". It refers to all the variety of life that can be found on Earth (plants, animals, fungi and micro-organisms) as well as to the communities that they form and the habitats in which they live.
Biodiversity is species, genetic and ecosystem diversity
Biodiversity is not only the sum of all ecosystems, species and genetic material. Rather, it represents the variability within and among them. Biological diversity is often understood at three levels:
- Species diversity refers to the variety of different species;
- Genetic diversity corresponds to the variety of genes contained in plants, animals, fungi and micro-organisms;
- Ecosystem diversity refers to all the different habitats that exist, like tropical or temperate forests, hot and cold deserts, wetlands, rivers, mountains, coral reefs, etc.
Biodiversity loss is not only the extinction of species
Initially the loss of biodiversity could be defined as the extinction of species. Curiously the species richness of a particular ecosystem may hardly change or may even increase because new -often wide spread- species replace the original ones. It is therefore important not only to look at species, but also at the abundance (the number of individuals) of species. Species extinction is just a last step in a long degradation process.
Biodiversity loss is increasing under human influence
The loss of biodiversity has increased in the 20th century. Identified anthropogenic drivers influencing the loss of biodiversity are land conversion, exploitation, fragmentation, water extraction, pollution, eutrophication and climate change. Although climate is a slow changing factor, studies on the impacts of climate change concluded that climate change is already affecting species distributions all over the world and will impact nature to a considerable amount in the 21st century.
The importance of biodiversity
The intrinsic value of biodiversity is not the only reason biodiversity is important. The natural environment provides the basic conditions without which humans could not survive. Ecosystem services are the benefits provided by ecosystems. These include provisioning services such as food, water, timber, fiber, and genetic resources; regulating services such as the regulation of climate, floods, disease, and water quality as well as waste treatment; cultural services such as recreation, aesthetic enjoyment, and spiritual fulfillment; and supporting services such as soil formation, pollination, and nutrient cycling.
The Convention on Biological Diversity
At the 1992 Earth Summit in Rio de Janeiro, world leaders agreed on a comprehensive strategy for "sustainable development". One of the key agreements adopted at Rio was the Convention on Biological Diversity (CBD). This pact among the vast majority of the world's governments establishes three main goals: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from the use of genetic resources. In The Hague 2002, the member states of the CBD agreed to significantly reduce the rate of loss by 2010 at the global, regional and national level. Shortly afterwards the Council of Europe agreed upon a halt of the loss of biodiversity by 2010 (Kiev, 2003).
The role of PBL
The Netherlands Environmental Assessment Agency (PBL) performs assessments on biodiversity to evaluate policy and to explore policy options. For these assessments PBL develops indicators and models to determine the past, current and future state of biodiversity and its causes. PBL also reviews the Dutch national policies on biodiversity and nature in the yearly Nature Balance. This annual report presents facts and figures on and evaluations of nature policy effectiveness in the social and economic context.