Italian freshwater biodiversity: status, threats and hints for its conservation.

摘要

Freshwater makes up 3% of the planet's water, 67% of which is 'trapped' in glaciers and polar caps. Lakes, ponds, streams, etc. (excluding subterranean waters) constitute approximately 6.5% of freshwater, which is less than 0.2% of the earth water and 0.8% of its surface. Nevertheless, beyond supporting the livelihood of billions of people, especially in poor countries, according to the different estimates 100,000/126,000 animal species are known for inland waters, from 6 to 9.5% of the total animal described. As far as Italy is concerned, there are 5496 freshwater animal species out of 55,732 total; that is, around 10% of its fauna (terrestrial species are 41,923, while marine are 8330, several eurialine species being considered as present in both marine and freshwater environments). This fauna is highly specific: we can estimate a percentage of Italian freshwater endemics that could exceed 10%. Unfortunately, freshwater species are extinct or at risk with loss rates which could be of the same extent of those of previous transitions between geological epochs like the Pleistocene-to-Holocene. In Italy it is difficult to evaluate the conservation status and trends of aquatic faunas due to the lack of previous studies. The analysis of selected taxa seems to depict a critical situation. Besides, inland waters only recently have been addressed by conservation politics and only a reduced part of their fauna is involved in preservation measures. As regards protection politics in Italy, we can safely say that those regarding freshwater animals are badly addressed: out of 841 protected species only 100 are from inland waters, and only 15 of them are invertebrates. Proposals and priorities for conservation and management of Italian freshwaters are discussed.