Vegetation and water of lowland spring-wells in Po Plain (Northern Italy): ecological features and management proposals

Spring-wells (lowland springs, “ fontanili ”) are elements of Po Plain (Northern Italy) with ecological and historical importance. There, spring-water flows naturally and rises to the surface at a relatively constant temperature, generating unique ecosystems dependent on the groundwater outflow. Despite their importance, they are endangered by degradation processes as the expansion of urban areas and/or the intensification of agriculture, very marked in Po Plain. This research describes four spring-wells of Po Plain from a botanical and ecological perspective through phytosociological relevés and different ecological indexes. Water chemical-physical features are also considered (pH, temperature and ammonium ion, nitrite, nitrate, orthophosphate, chloride and organic matters contents). Plant communities of the spring-well beds show a low number of species (5.8 ± 2.9) but also no exotic species while the vegetation of the banks has a high number of species (32.4 ± 9.8) but several of them are exotic/ornamental. The low value of the Ecological Index of Maturity of the vegetation of the banks (EIM = 4.4 ± 1.5) indicate disturbances, however moderate compared to the surrounding corn fields (EIM ~ 0). All the water samples has high ammonium content (> 0.50 ppm), the water of the spring-well B results the most polluted and both algae and Callitriche obtusangula (rare native species) grow largely in it, while spring-well C has less phosphates and more nitrite and is marked by Equisetum telmateia . Management proposals to protect and enhance the studied spring-wells, as the gradual removal of exotic species and the planting of native species, are discussed.