||The area is located at the NE part of Attiki, 40 km from Athens, at Marathon plain and is fringed by the low-lying mountains of Karoumpalo, Pounta and Drakonera to the north-east. The central part of the site is covered by the remaining part of the once extensive Marathon wetland, which has been suffering from drainage works (canalisation) since 1923. The slightly brackish Makaria spring lies at the north-western edge, while lake Stomi lies at the SE part of the wetland. The highly brackish Drakonera spring, located at the foothills of Drakonera hill, today features a reduced discharge evident only during wet periods. A sandy coastal zone extends from east to west at the southern part and Kynossoura peninsula delineates the south-eastern part. A longitudinal zone near Makaria spring of a total surface of 450 Ha at the western part of the wetland had been until recently occupied by a small airport, while a USA military communication base of a total surface of 100 Ha had been operating for several years at the central part of the wetland. The Schinias coastal zone consists of sandy - gravelly dunes of Olocene age. Northwards, the swamp area is covered by silty - clayey, and locally sandy, alluvial deposits of the same age. Eastwards, the Mytika's and Drakonera's hills consist of the Upper-Cretaceous marbles of Agia Marina, which are locally covered by scree and talus cones. The area belongs to the broader geographical region of Attiki, and shares its typical climatological conditions. The climate is Mediterranean, with prominent features the dry-hot summers and the mild-rainy winters. The atmosphere's average annual temperature ranges from 16.5° C to 19° C. The most cold month of the year is January, while the most hot are July and August. Annual precipitation averages around 378 mm, while humidity ranges between 59% - 64%. Cloudy days average around 50 annually, while sunny days around 130, giving a total of 2,920 sunlight hours each year. Prior to 1923 the discharge of both Makaria and Drakonera springs had been providing the wetland with slightly brackish water, which was subsequently conducted to the sea via lake Stomi formed near the eastern coast of the site. It is estimated that Makaria spring alone had been supplying the wetland with 6-7 millions of cubic metres of water yearly. Runoffs from the upstream mountain catchment had been an additional source of water. In order to convert the swamp to agricultural land a drainage channel was constructed in 1923 along the western border of the site. This channel was conducting the Makaria spring waters directly to the sea. Subsequently, a network of flood protection and drainage channels was constructed upstream the wetland, which also drove the flood waters directly into the sea. Secondary flood protection and drainage channels were embedded to that network during the 60's and the 70's in order to protect the military installations and the airport, which were meanwhile constructed inside the wetland area. As a result, the wetland's freshwater supply was restricted to the precipitation received by the plain (which quantified for about 0,7 million of cubic metres of water annually), while at the same time it received significant quantities of sea water both subterraneously and through the superficial communication of Stomi lake. Consequently, the permanent salt lake of Stomi was converted to a seasonal pond and the wetland area shrunk significantly due to the dry conditions and the land reclamation that followed. The remaining wetland was inundated during the rainy season and dried up in summer. It featured a variable salinity, with salty or brackish water generally dominating most of its parts and the fresh or slightly brackish element being restricted to a small area around Makaria spring, along a drainage ditch west of Drakonera hill and, to a lesser degree, along other drainage channels. The above described hydrological status and changes in land uses shaped the current natural habitat type status of the wetland and influenced the site's sandy coastal zone. In 2004 the Olympic Rowing Centre was constructed at the area formerly occupied by the airport. The following have also taken place: the removal of the airport's constructions and runway, removal of the idle military installation and area's soil mitigation, the abolishment of an extensive network of telecommunication antenna mounting structures and the elimination of all through-traffic roads, which are currently fragmenting the biotope and heavily disturbing the wild fauna. Currently halophytic vegetation occupies the central and most extensive part of the wetland, as a result of the ongoing heavy drainage activities and human pressure on the area during the past 80 years. Halophytic communities often form mosaics: salt meadows with Juncus (habitat type 1410) and salt scrubs are intermixed, giving way to glasswort swards (habitat type 1420) near Stomi lake, where the vegetation is established on a substrate of decomposing sea-grasses (mainly Posidonia oceanica). Juncus maritimus is the dominant species, while other characteristic species include Juncus heldreichianus, Limonium narbonense, Aster tripolium, Scirpoides holoshoenus, Scirpus littoralis, Bolboschoenus maritimus (=Scirpus maritimus), Puccinelia distans, Plantago crassifolia. The salt scrub is the main vegetation type, dominated by Sarcocornia perennis (at the lower sites) and Arthrocnemum macrostachyum (at the higher, better aerated sites), while other species participating are Puccinelia festuciformis, P. distans, Limonium narbonense, L. virgatum, L. bellidifolium, Centaurium spicatum, Suaeda vera, Salsola soda, Atriplex portulacoides. Annual halophilous pioneer communities (habitat type 1310) with Cressa cretica develop along dry channel beds and sometimes in patches with increased salinity that remain inundated longer. Other Saginetea species, such as Spergularia salina, Parapholis incurva, P. filiformis, Salsola soda, appear among the salt scrub but rarely form representative communities. Reedbeds with Phragmites australis and Typha angustifolia (Corine 53.1) occupy chiefly parts of the central and north-western part of the wetland. Tamarisk galleries (habitat type 92D0) develop at channel banks and at embankments throughout the wetland and notably at the main channel of Makaria spring, at the area of airport with Tamarix tetrandra (mainly at the eastern part) and Tamarix hampeana (mainly at the western part). These two habitats form mosaics at the north-western part of the site. Freshwater aquatic habitats develop at Makaria spring and along its drainage channel. At stagnant waters at the small pond created at Mati (Makaria spring) Magnopotamion vegetation with Potamogeton nodosus (habitat type 3150) occurs. Along the channel, at slow flowing points, there are floating communities of Apion nodiflori (habitat type 3260) with a benthic mat of Chara (habitat type 3140 is included in 3260). Close to the estuary the flow is not permanent and there Potamogeton pectinatus and Nasturtium officinale communities (habitat type 3290) develop. Typical communities of the habitat "Mediterranean temporary ponds" (habitat type 3170) have not been identified in the wetland. Small temporary ponds do develop near Makaria spring and at other spots, mainly at the western part, but lack the characteristic Isoeto-Nanojuncetea communities. A single small patch of dwarf pioneer annuals characterised by Crassula sp. and Herniaria hirsuta has been located at a road bank (SW part of the site) on sandy, temporarily water logged substrate. Also, small communities with Juncus bufonius, Poa annua, Plantago coronopus develop at small temporary ponds among the juniper matorral at the lower parts of Drakonera. These communities, with the participation of Isoeto-NanoJuncetea species, could be assigned as habitat type 3170, but their representativity is non-significant. Other species characteristic of this synclass of vegetation (such as Juncus articulatus, Mentha pulegium, Serapias lingua, Centaurium pulchellum, Lotus angustissimus) have been reported from the site. The site's coastal sandy part maintains successive zones of ammophilous habitats. At a zone of 50 metres from the sea there is only naked sand with loose driftline communities of Cakile maritima, Matthiola tricuspidata, Salsola kali (habitat type 1210), followed by ridges of low embryonic dunes (habitat type 2110) with Elytrigia juncea (=Elymus farctus), Eryngium maritimum, Medicago marina. Pseudorlaya pumila, Lotus halophilus, Allium staticiforme, Rhagadiolus stellatus, Silene colorara also participate in the ammophilous communities. To the western part, closer to the mouth of Makaria channel and in front of the Park's inhabited zone the structure of the dunes is even more degraded. There develop ammophilous communities with Cyperus capitatus and Sporobolus pungens and a low dune front with Centaurea spinosa. Behind this zone and all along the coast there are low, stabilised dunes forested with Pinus pinea at the western part and Pinus halepensis at the eastern part (the two pines intermix towards the centre). The understorey is composed of maquis species, mainly Pistacia lentiscus, and also Quercus coccifera, Juniperus phoenicea, Myrtus communis, Rhamnus alaternus, Rubia peregrina, Ruscus aculeatus, Smilax aspera, Asparagus acutifolius and by phryganic species such as Helichrysum stoechas, Phagnalon graecum, Anthyllis hermaniae, Cistus incanus, C. salvifolius, Coridothymus capitatus. The herb layer includes species such as Cyclamen hederifolium, C. graecum, Ophrys lutea, Serapias lingua. A zone at the northern part of Pinus pinea forest is covered by low to medium height matorral dominated by Pistacia lentiscus (habitat type 2260). Malcolmietalia annual grasslands (habitat type 2230) with dominance of Silene colorata, Anthemis tomentosa, Medicago littoralis develop mainly at extended patches on mostly flat, stabilised sand of the rear dune at the western part of the site. In the more disturbed zone towards the wetland synanhtropic grassland of Stellarietea mediae develops to the expense of the typical dune grassland. Isolated Juniperus oxucedrus ssp. macrocarpa individuals and small stands of Pinus pinea grow at these places. It should be noted that the dune therophytic grasslands of Malcolmietalia (2230) of the site, belonging to the synclass of Thero-Brachypodietea, were previously assigned as habitat type 6220, which is of similar floristic composition. However since these communities are part of the dune system, they are better described as habitat type 2230. In a narrow zone between the embryonic dunes and the forest there are small stands of Juniperus oxycedrus ssp. macrocarpa (habitat type 2250) with Pistacia lentiscus. Pistacia lentiscus formations in sand dunes are better assigned as habitat type 2260, instead of 9320, which was previously used for the area. These formations most probably constitute remnants of previously well-developed post dunal communities of the type found elsewhere in the Aegean. The Kynosoura peninsula is covered across its greatest part by maquis, medium to high, at places scattered but generally quite thick. Juniperus phoenicea (habitat type 5212) is dominant in most of the stands while other shrubs participating are Pistacia lentiscus, P. terebinthus, Ceratonia siliqua, Olea europaea L. ssp. oleaster, Ephedra foemina, Quercus coccifera, Rhamnus alaternus, Calicotome villosa, Prunus webbii, Prasium majus. In the herb layer and at openings a multitude of therophytes, grasses and geophytes develop, among which the endemics Fritillaria obliqua and Scorzonera crocifolia, as well as some orchids. Phryganas Satureja juliana, S. nervosa, S. graeca, Euphorbia acanthothamnos, H. stoechas, Phagnalon graecum, Coridothymus capitatus, Teucrium capitatum, T. divaricatum develop in the understorey and at openings of the maquis mainly at the western part. At open rocky places with boulders, at the crest of the promontory and also at some slopes Euphorbia dendroides dominates the shrub, growing along with Anagyris foetida, Phlomis fruticosa, Ephedra foemina (habitat type 5331). At the same sites small chasmophytic communities (habitat type 8216) with Asplenium cetarach, Cheilanthes acrostica, Cosentinia vellea, Umbilicus rupestris develop at rock crevices. The shrub descents the steep slopes over the sea. Juniper matoral of similar composition but generally thinner and lower (due to recent fire and grazing) covers Drakonera hill as well. Chasmophytic vegetation of good representativity developes at a small rock face at the hillcrest. Therophytic grassland patches (Thero-Brachypodietea, habitat type 6220) grow at openings of the shrub but at the flat areas of the foothills Stellarietea and Artemisetea species take over, apparently due to grazing. Schinias wetland has traditionally been an important waterfowl and waterbird migration station. Visitors include Plegadis fancinellus, Botaurus stellaris, several Ardeidae, Rallidae, Ciconiidae, Anatidae, Tringa, Calidris species, as well as numerous birds of prey (mainly Falconidae). Nevertheless, due to low prey availability the site's significance has been reduced to this of a degraded stop-over site for waterbirds rather than a dynamic large-scale migration station. Passing birds usually just stage in the area for a few days' rest without actively utilizing it. Wintering avifauna among others includes the protected (dir.79/409/EEC) Αcrocephalus melanopogon. Although small in numbers, the presence of several species of birds of prey at the surrounding hills is significant. These species, which prey on the wetland plain, among others include Circaetus gallicus, Buteo rufinus, Falco peregrinus, Bubo bubo, as well as the more common Buteo buteo, Falco tinunculus, Tyto alba, Otus scops. At the maquis vegetation covering the hillsides protected species typical of this habitat type breed, such as Sylvia hortensis and Sylvia rueppelli. Along the channels' and the ponds' banks one can find the reptiles Emys orbicularis, Mauremys caspica, Testudo hermanni, Testudo marginata, Elaphe situla, as well as the endemic fish Pseudophoxinus stymphalicus marathonicus.