Risorgive dello Stella
3 Regional nature biotopes were instituted in the SCI (LR 42/1996): Flambro Springs, Virco Springs and Zarnicco Springs. Within the biotopes there are norms in force that protect the environments and species that are most vulnerable and of higher naturalistic value, they create incentives for activities of environmental restoration, allowing in any case agricultural activities to be maintained.
The site represents one of the most important and vast groups of fresh-water wetlands in the Friuli Venezia Giulia Region, areas that survived the simplification of the hydrographic grid and the drainage that affected this part of the plain during the last century. The area, situated at an average height of 22 meters above sea level and at about twenty kilometres from the Adriatic, is characterised by the emergence of ground waters that, having gone underground along the Southern feet of the Alps and flowing towards the South in deep detrital deposits of fluvioglacial origin, rise to the surface in correspondence with individual springs of rather small size or with vast depressions and flow freely with no regime inside the alkaline fens, before joining the artificial channels that feed the resurgence rivers, which are characterised by a considerable volume of water. The water that emerges is very clear and has a nearly constant temperature.
The sites are characterised by a complete series of humid habitats, with specimens of aquatichabitats including populations of Utricularia spp. and Chara spp., springs with Cladium mariscus, natural humid grassland characterised by Molinia caerulea, alkaline fens characterised by Schoenus nigricans and providing refuge for many animal and plant micro thermal species (glacial relicts).
Due to the continuous reduction of these habitats habitats in the plain, the following are also of great interest: the dry grassland, the meso-hygrophilous hedges, the strips of plain micro thermal woodland with Quercus robur, the alluvial forests with Salix cinerea and Alnus glutinosa.
The sites host some of the rare populations of endemic and steno-endemic species. In particular, the SCI hosts the Armeria helodes Martini & Poldini, a species that is a priority interest of the European Community, and the Erucastrum palustre (Pirona) Vis and Euphrasia marchesettii, two species that are also of Community interest. The SCI also hosts the endemic species Centaurea forojulensis Poldini.
There are also some of the rare specimens in Italy of the Liparis loeselii orchid, a species of Community interest, that was previously thought to be extinct in this area, and some specimens of the also rare Anagallis tenella, a very small flower belonging to the primrose family found in Atlantic areas.
There are also many other species to be found that are endangered or in any case rare because of the big reduction of humid environments, among which: Allium suaveolens, Allium angulosum, Cirsium canum, Gentiana pneumonanthe, Hippuris vulgaris, Hottonia palustris, Orchis palustris, Plantago altissima, Senecio paludosus, Senecio fontanicola, Sesleria uliginosa, Spiranthes aestivalis, Utricularia vulgaris.
All the species of flora listed so far are included in the Red Book of thePlants of Italy, since they are considered as endangered species, for a total of 19 botanical species. There are also many species that represent precious glacial relicts of the post-Wurmian era, such as Drosera rotundifolia, previously thought to be extinct in this area, Parnassia palustris, Pinguicula alpina, Primula farinosa, Tofieldia calyculata, Gentiana verna.
There are also numerous zoological emergencies in these spring environments, and those concerning reptiles and amphibians are particularly important.
Among the reptiles, mention should be made of those of European Community interest, such as Elaphe longissima, Coronella austriaca, Natrix tessellata and Coluber viridiflavus in the snake family and Podarcis muralis and Lacerta bilineata (mentioned in the Habitats Directive as Lacerta viridis) in the lizard family. Emys orbicularis is still quite commonin the area.
Important relict populations of Zootoca vivipara carniolica are also present. This is a micro-thermal lizard that in these areas represents a glacial relict of the post-Wurmian era.
Among the amphibians that are of Community interest, Rana latastei is particularly widespread, as are Rana dalmatina, Rana esculenta and Rana lessonae. In the stagnating waters specimens of Triturus carnifex can be found, as well as considerable populations of Bombina variegata and Hyla intermedia (mentioned in the Habitats Directive as Hyla arborea), which is widespread in all the environments included in the sites.
From the ornithological point of view, the area is interesting due to the presence of aquatic birds, in particular during the migration period. The presence of herons with Ardea purpurea, Ixobrychus minutus (nesting locally), Nycticorax nycticorax, Ardeola ralloides, Casmerodius albus, Botaurus stellaris should be pointed out. The area is also populated by various raptors such as Milvus migrans, Pandion haliaetus, Circus aeruginosus, Circus macrourus and Pernis apivorus (also nesting). The area hosts important sites for the reproduction and hibernation of Circus pygargus and Circus cyaneus, of which the most numerous roosts in the Region have been observed (up to 20 individuals).
Species such as Lanius collurio, Lanius minor, Alcedo atthis, Phalacrocorax carbo (recently considerably increased), Ciconia ciconia, Ciconia nigra, Aythia nyroca, Porzana parva, and Porzana porzana have also been sighted. Dryocopus martius was recently sighted to demonstrate a phase of expansion of this species in the plain, which probably started during the first years of the Nineties. The presence of Remiz pendulinus is considerable, thanks to the great extension of water courses and alluvial forests.
Among the mammals, Mustela putorius, Neomys anomalus, Apodemus agrarius, Microtus minutus and Arvicola terrestris italicus are relatively frequent. Meles meles is present with sporadic examples perhaps coming from the Tagliamento River. Quite a number of populations of Muscardinus avellanarius and Sciurus vulgaris are also present.
The distribution of fish is influenced by the particular characteristics of the emerging waters, which are purity, low temperature with modest thermal differences and high oxygen content. This particular situation allows cyprinids and salmonids to live together. Species characteristic of waters that are slow and rich in vegetation can therefore be found, such as Rutilus erythrophtalmus, Scardinius erythrophtalmus, Podogobius martensis, Anguilla anguilla, Orsinigobius punctatissimus,Cobitis taenia, Sabanejewia larvata, Esox lucius and species living in flowing waters such as Salmo trutta, Salmo marmoratus, Thymallus thymallus, Cottus gobio, Phoxinus phoxinus, and Leuciscus souffia.
Among the aquatic invertebrates the presence of 4 species of Community interest should be pointed out: Vertigo angustior, a snail that lives near water, on plants or in the wet mud of the shore; Lucanus cervus, a coleopter that is present only in woods of mature oaks; Coenonympha oedippus, a butterfly that only lives in humid areas and that is very rare in the whole Europe and Austropotamobius pallipes fulcisianus, a Decapoda crustacean that is present in clean and uncontaminated water courses.
Among the terrestrial invertebrates, the grasshopper Chrysochraon dispar giganteus has recently been discovered, until now known to live only in brackish waters of the lagoon, very rare and in danger of becoming extinct in the whole Europe. The presence of the rare micro-thermal grasshopper Micropodisma salamandra is also very interesting. Among the over 150 species of lepidopterans that have been registered, mention should be made of the rare Elophila rivulalis.
The site represents the strip of land remaining from the much vaster habitats that characterised the springs of this Region before the great drainages carried out in the Thirties and Fifties. In 1930 the surface of these habitats, between the Tagliamento River and the Isonzo, was estimated to be over 6000 hectares, while the present habitats summed all together do not amount to more than 200 hectares, fractioned into many areas of limited extension.
The SCI (according to a census taken in 2005) hosts 95% of the world’s population of Armeria helodes Martini & Poldini, a species listed as of priority interest for the European Community, and 34% of the Erucastrum palustre (Pirona)Vis, also a species of Community interest. These species, due to the continuous reduction in number and the limited areas in which they live, are to be considered as in danger of imminent extinction. The SCI also hosts the main world population of Euphrasia marchesettii (Annex II).
For many other species of flora, mentioned in the previous part, the three sites that are the subjects of this project represent the only places within the Veneto-Po valley plain where the species themselves can be found.
These habitats represent a key area for the conservation of various species of amphibians, such as Triturus carnifex, Bombina variegata, Rana latastei, Rana lessonae, Rana dalmatina and Hyla intermedia, which by now have nearly completely disappeared from more intensely worked agricultural lands because of the destruction of humid environments.
For this same reason the area is of fundamental importance for the survival of Emys orbicularis, a species that because of the destruction and deterioration of humid environments now appears to be extremely localised and at risk in many Italian regions.
The site hosts abundant populations of the rare Zootoca vivipara carniolica, a subspecies that is present exclusively in the plain. Even though it is not mentioned in the Habitats Directive, the populations in the Po valley of this oviparous lizard are of extraordinary scientific and biogenetic value and importance.
The site represents one of the rare places within the Veneto-Po valley plain where the Vipera aspis francisciredi can be found.