Biological diversity is the basis of all life. Without it, Earth would be a planet like Mars - an inhospitable and dead place. We benefit in many ways from the great diversity of species - plants, animals, and micro-organisms. They provide the basis for vital goods such as food, medicines, clothing and building materials. The species, in their diversity, also maintain balance in ecosystems. More species-rich ecosystems are more stable and more productive than those that are less species-rich; they clean water, filter the air, maintain soil fertility and keep pests in check. Last but not least diversity is also the essence of beauty in nature: People enjoy the beauty of butterflies, birds, flowers, and many other species.
In addition to species diversity, the extent of biodiversity is also defined by genetic diversity and diversity at the level of ecosystems.
The number of species in the selected groups increased by about 1.3 per cent between 1997 and 2012. This increase is not only due to the spread of neobiota (non-native species in the region concerned). It also results from conservation measures and from the re-colonisation of areas formerly inhabited by certain species, as well as from new arrivals. However, the increase in species numbers must not obscure the decline in populations at the national, regional and local levels which has already culminated in the extirpation of a number of species.
It is estimated that Switzerland as a whole hosts about 40 000 animal species and 3 000 plant species. However, by no means all the species present have been discovered.
Surveys, analysis of statistics, analysis of find reports in data banks; see www. biodiversitymonitoring.ch; indicator Z3