| The site presents a complex ecosystem that is located in western Sterea Ellada. It is one of the most significant wetlands in Greece. It is also reaching the Ionion Sea and containg the terrestrial areas of the Echinades islands group. Here, a very large lagoon, the Mesolongi lagoon (11,200 ha) predominates in the central part of the wetland system. There are also a number of other smaller lagoons to the north (Aitoliko lagoon, 1400 ha), east (Kleisova, 3000 ha), and the west (Gourounopoules, Paliopotamos, 800 ha). The lagoons of Mesolongi lie behind a fragmented sandy coastal ridge which is located between the mouth of the river Evinos to the east and the Koutsilaris hill to the west; they are connected with the Patraikos Gulf (which forms part of the Ionian Sea) by a large opening. A part of delta of the river Evinos is included in the eastern part of the Mesolongi plain. In the extreme west of the area a part of delta of the river Acheloos occurs. Most of the plain is formed from the sediments deposited by these two rivers. Evinos has deposited sediments that cover a part of the area from Mesolongi eastwards, while sediments from the river Acheloos cover the area from Mesolongi to the west. In the western part of the site, the sediments of the river Acheloos surround rocks and hills, of which the Koutsilaris (433 m) is the highest. In the same part several former beds of the river Acheloos can be distinguished. In places within the area of the lagoons close to Ag. Triada, Ag.Taxiarchis and Megalo Vouno, former sand-dune ridges may be observed. The Mesolongi lagoon system was formed in the Holocene. The basin of the lagoon is divided into the Aitoliko and Mesolongi lagoons, which are connected to each other by a narrow channel. From a geological point of view, the area belongs to the Ionian and Gavrovo zones and is composed mainly of sedimentary rocks. A small area of the Gavrovo zone is composed mainly of Upper Cretaceous limestones, Eocenic limestones and flysch. A larger area, in which Echinades islands are included, belonging to the Ionian zone and is composed of Triassic crystalines and evaporites, Jurassic limestones with ceratoliths, Cretaceous and Eocenic limestones and flysch. The soil of the area has originated from erosion of the above rocks. In the whole area dominates the clay deposited in salt water; only along the river beds we find clay deposited in fresh water. The salt water clay has a bluish colour, while the fresh water clay is brownish. The coastal ridge consists of sand. As mentioned above, the lagoons of Mesolongi are connected with the sea by means of several wide openings in the coastal ridge. Nevertheless some parts of the lagoons are rather isolated. This results in large fluctuations of salinity during the course of the year. The salinity of the shallow waters south of Aitoliko and probably near the former monastery Ag. Taxiarchis, also fluctuates considerably. The high salinity in summer, caused by evaporation, is tempered by fresh water flowing into the lagoons from the surrounding fields and some small brooks. During the winter large amounts of fresh water drain into the lagoons. In winter water from the Evinos and Acheloos rivers probably also flows into the lagoons on occasions. The lagoons studied are shallow. Their maximum depth is about 2 m but large areas have a depth of about 1m. Only the Aitoliko lagoon has a maximum depth of 28 m. The principal human activity in the lagoons is fishing. For this purpose elaborate pile screens have been constructed in many creeks using the stems of Arundo donax. In some places large quantities of this material are washed ashore and become substrate for a special type of vegetation. The Mesolongi lagoons were formerly surrounded mostly by extensive salt marshes, large parts of which were drained for agricultural purposes, but still remain infertile and serve as a wildlife habitat. Despite land reclamation, salt marshes, sand-banks and mudflats still occur around the lagoons. A detailed description of the area's plant communities is given by Wolff (1968) and Szijj (1983). Generally the area is characterized by variable habitats. Extensive areas of salt marshes exist where the plant genera Salicornia and Arthrocnemum are dominant, as well as extensive areas of shallow water with a rich submerged vegetation of Ruppia, Enteromorpha and Zostera. Apart from the vegetation units already mentioned (section 3.1) extensive, dense reed communities (Phragmitetum) cover substantial areas, mainly in places where freshwater flows into the lagoons. Such areas occur mainly on the north and northeast shores of the Kleisova lagoon, along the western shore of the Mesolongi lagoon, along the eastern shore of the Aitoliko lagoon at the shore of the Skantzochoiros lagoon, along drainage channels and along the edges of the Acheloos river. In these reed communities, Phragmites australis and Typha latifolia dominate. Despite intense agricultural activities, sufficient hedges of natural vegetation with Phragmites australis, Tamarix parviflora and Juncus maritimus grow between the small fields. In these microbiotopes live importand taxa populations. Furthermore, more animals exist in the drainage channels and the surrounding natural vegetation. Close to the reed belts, stands of Scirpetum maritimi occur. These communities are observed mainly at the Mesolongi lagoon (near Poros) as well as several places to the NE of the Kleisova lagoon. It is also worth mentioning that a long, wide coastal strip with sand-dunes occurs mainly to the south-west of the area. The main plant communities are Agropyretum mediterraneum, Ammophiletum arenariae and Cakiletea maritimae. On the islet of Louros at the inner places behind the dunes, a significant cluster of Juniperus phoenicea grows. All this area is extremely valuable. On the surrounding hills clusters of Quercus macrolepis, macchie and phrygana (with Phlomis fruticosa as the dominant taxon) grow. The Acheloos river is the second largest river in the Balkans. On its estuaries as well as along its banks three main types of riparian forests grow: 1) Riparian forests with Salix alba and Populus nigra as dominant species (such forests occur mainly in the southern area of the delta as well as along the river banks); 2) A forest of Fraxinus angustifolia near Lesini, which is the most valuable part of the riparian vegetation of this area; 3) Clusters with Tamarix parviflora and Vitex agnus-castus (mainly in the southern part of the Delta at Kali Chitsa, as well as along the bank of the river). The estuaries of the Evinos river extend from the east shore of the Kleisova lagoon to the foot of Mt. Varasova. The River Evinos springs from Mt. Vardousia and flows into the Patraikos Gulf. It has a length of 110 km and its drainage basin is 1070 km2. It is noticeable that the riparian vegetation of river Evinos appears significantly different from the equivalent vegetation of River Acheloos. This happens because the Evinos river has not a constant and satisfactory flow during all the year. Therefore the clusters with Salix, Fraxinus and Ulmus, as well as the reed belts (Phragmitetum), all along the edge of the river are rare. On the contrary, the development of Nerium oleander in the area is very intense. About 5 km from the mounth of the river clusters of Populus alba, P. nigra and Arundo donax occur. Close to the mouth of the river riparian vegetation with Platanus orientalis, Nerium oleander and Vitex agnus-castus is developed. At the estuaries of the river, the flow is slow, and poor vegetation with Zostera noltii, Myriophyllum spicatum and Valisneria spiralis occur. Despite the intense agricultural activities enough hedges of natural vegetation with Phragmites, Tamarix and Juncus grow between the small fields. Small isolated formations with Phragmites communis occur at the estuaries of the Evinos river as well as in several places along the edge of the river. Close to the reed belts, stands of Scirpetum maritimum occur, at the place where the salinity increases. At the coastal zone extending from the east shore of the Kleisova lagoon to the west of the mouth of the Evinos river (ca. 3 km in length and 0.5 km in width) the land is lower than sea level and is devoid of discharge, resulting in overflow due to rain water. In that place an extensive saltmarsh with a gradiated natural vegetation (Tamaricetum, Juncetum, Arthocnemetum, Salicornietum) is developed. The coasts of Echinades islands provide a number of submarine and semi-submarine sea caves wich are important seal habitats. The species Tursiops truncatus and Delphinus delphis which are recorded as being present in this area, are included in Directive 92/43/EEC, the Bern and Bonn Conventions, CITES and Corine-Biotopes. They are also recorded by the Presidential Decree 67/1981, and Delphinus delphis is recorded in thw Greek Red Data Book as "Vulnerable". Another important habitat type in thw area are the small Posidonia fields. The non-coastal parts of the islands are preserved in very good natural, ecological condition, they are used by seabirds for their breeding grounds. They also present special interest from phytosociological and management points of view. The most important vertebrate taxa are the fow bats of the generate Rhinolophus and Myotis (both threatened taxa recorded in the Red Data Book as "Endagered" and "Vulnerable" respectively). The tortoise Testudo hermanni and the snake Elaphe quatuorlineata, which are all included in Annex II of the Directive 92/43/EEC. The other importand species (section 3.3) are allocated C and D motivations because they are protected by the Bern Convention and the Presidential Decree 67/1981. A number of raptors are recorded as occuring in the area (Aquila chrysaetos, Circactus gallicus, falco peregrinus, Gyps fulvus, Phalacrocorax aristotelis) and most of these are classified as "Threatened" in the Greek Red Data Book. Lycaena dispar is excluded, as it was not recorded, and the Natura area does not include optimal habitats for that species. |