Ecosistemi dipendenti dalle acque sotterranee: biodiversità, funzioni ecosistemiche ed effetto dei cambiamenti climatici

The Groundwater Dependent Ecosystems (GDEs) are those ecosystems which depend on groundwater quality and quantity, and are commonly ranked on the basis of the degree of dependency on ground water. This review is aimed at describing these ecosystems (with special emphasis on Subsurface Groundwater Dependent Ecosystems - SGDEs), and at assessing major threats of climate change and of synergistic factors which may alter the ecological functioning of these ecosystems. As primary productivity is missing in the SGDEs due to total darkness, communities are composed of bacteria, protists and animals (predominantly invertebrates). Climate change has detrimental effects on GDEs, along with groundwater withdrawal, excavations in the streambed, intensive agriculture with excessive use of fertilizers and pesticides, urban sewage, increasing pollution from illegal dumping of toxic substances. These activities determine loss of biodiversity and ecosystem services. Up to now the adaptation to climate change in GDEs has received poor attention, as groundwater quality and quantity need to be integrated with ecosystem ability to sustain groundwater biodiversity and related ecosystem services. Mitigation measures should consider period, duration and amount of ground water exploited in order to ensure, for alluvial aquifers, the contact between the surface water body and the underlying aquifer, for karstic aquifers, the maintenance of water saturation of the annexed capacitive subsystems.