Indicator biodiversity

To date, one fifth of the around 56,000 known species has been assessed for the Red Lists. 35% of these species are threatened or extinct (see Chart "Species"). This percentage is significantly higher than the average in OECD countries. Every forty-fifth species that was once native to Switzerland is already extinct in this country.

Of the 167 Swiss habitat types, 48% (79 natural and semi-natural habitats) are included in the Red List of natural habitats. Aquatic ecosystems, mires and bogs and agroecosystems are the most threatened (see "Natural habitats").

The high proportion of endangered species and natural habitats provides evidence of the ongoing pressure on species diversity. Therefore, the state is assessed as negative.

The International Union for Conservation of Nature (IUCN) developed the Red List Index as a means of visualising long-term trends in the risk of extinction. With a single value, it shows for each Red List the extent to which a group of organisms is endangered. The lower the index, the higher the risk of extinction. If the index is 0, all species in that species group are extinct. If the index is 1, this means that all species qualify as unendangered. The development can only be observed for species groups for which a revised Red List is available. This is the case for six groups of organisms (see 'Development' chart).

For four groups of organisms (reptiles, fish, birds and vascular plants), the endangerment situation has worsened, i.e. the number of species that had to be reclassified in a higher endangerment category is greater than the number of species reclassified at a lower level. This implies a higher risk of extinction.

The index for dragonflies and amphibians is increasing, i.e. the risk of extinction has decreased. Certain species have clearly benefited from the fact that many habitats particularly suitable for them have been revitalised, upgraded or newly created in recent years. However, a disproportionately high number of species, especially amphibians, are still endangered. In many places, these species continue to suffer population losses or have a severely constrained area of distribution.

Overall, the development is still considered unsatisfactory.

The endangerment categories and criteria defined in accordance with the guidelines of the International Union for Conservation of Nature (IUCN) have been applied for each of the Swiss National Red Lists compiled since 2000.

Red Lists have existed in Switzerland for over 30 years. The classification of species in endangerment categories is based on criteria determining the likelihood of extinction. For example, the smaller and more fragmented an area populated by a particular species and the more rapidly the population declines, the higher its risk of extinction.

Because national field campaigns lasting several years are required for these assessments, the endangerment status of species can only be updated at relatively long intervals (10 to 20 years depending on the species groups).  To evaluate the development of the threat level, two Red Lists evaluated on the basis of the same criteria are needed. The Red List Index (RLI) compiled by the UICN summarises all changes that occur when a Red List is revised. The UICN’s Red List Index is calculated based on the method published in Butchart et al. 2007, Bubb et al. 2009.