Aegean Drainages




Jennifer Hales (WWF US), Panagiota Maragou (WWF Greece)




Giorgos Catsadorakis (WWF Greece)

Major Habitat Type

Temperate coastal rivers

Drainages flowing into

Aegean Sea, Ionian Sea, Sea of Crete, Mediterranean Sea

Main rivers to other water bodies

The main rivers include the Spercheios, Asopos and Boeotic Kifissos. Natural lakes include the Yliki (25 km2)-Paralimni complex and Vouliagmeni.



This coastal ecoregion includes basins that drain mainly the Aegean Sea south of the Pineios basin. It spans southeastern Greece east of the Pindus Range and south of Mount Othrys, and includes the islands of Evoia (Euboea), Sporades, Saronic, and Cyclades, as well as the islands of Kinaros, Levitha, Astypalaia, and Syrna in the Dodecanese. In the west it extends to eastern Peloponnese and the Gulf of Corinth up to the Strait of Rion. It is bordered to the west by the Ionian Drainages ecoregion [421] and to the north by the Vardar [422] ecoregion.


This ecoregion encompasses coastlines cut by numerous inlets and gulfs as well as plains, hills, and rugged mountains. It also contains numerous islands and a vast number of small islets. Elevations vary from sea level to more than 2400 m asl, with the tallest mountains being Parnassos (2456 m asl), Giona (2508 m asl) in Central Greece, and Kyllini or Ziria (2375 m asl) in the Peloponnisos Peninsula (Nezis 2010). Mesozoic limestones and dolomites are common throughout the landscape (Skoulikidis et al. 2009). The ecoregion also contains volcanic sites at places such as Methana, Milos, and Santorini (Dermitzakis et al. 1997).

Freshwater habitats

This ecoregion contains mainly small intermittent streams and rivers that are dry in summer, but experience torrential flooding in winter. Localized karstic springs also play an important contribution to perennial flows. More than sixty tributaries feed into the free-flowing Spercheios River, which rises at the base of Mt. Tymfristos. The river flows 82 km through a rift valley and then the lower river meanders and empties into a large delta at Maliakos Gulf, which has expanded in the last century due to deforestation and conversion to agricultural land. This delta is almost 200 km2 and contains the largest mudflats in the Aegean region. The river carries large amounts of sediments between November and March that are deposited with a unique potential of around 13 ha /year on its alluvial plain (Maroukian and Pavlopoulos 1995 as cited by Koutsogiannis et al 2008). Its maximum discharge occurs during winter, although over the past century its discharge has declined by nearly 50% due to water extraction for irrigation. At present, its discharge is .703 km3/yr (Skoulikidis et al. 2009).

Another notable river is the Boeotic Kifissos, which lies in the closed Boeotic Kifissos basin. The river’s regular floods formerly emptied into the shallow and now dry Lake Copais, which gradually grew due to the limited drainage capacity of sinkholes in the basin. To alleviate the flooding, water was diverted to Lake Yliki through tunnels and canals (Koukis & Koutsoyiannis 1997).

The islands of this ecoregion do not have rivers but rather intermittently flowing streams. They are characterized by small aquifers that develop on limestone, sometimes together with waterproof formations. Depending on the connection with the sea, these karstic systems outflow either in freshwater springs or in coastal and underwater springs (Koutsogiannis et al. 2008). In these parts of the ecoregion there are 226 small island wetlands in 39 islands that cover a total area of 2348.9 ha (169 natural ones with a total area of 2093.9 ha and 57 artificial ones).

Terrestrial habitats

The dominant vegetation type in the ecoregion is the Aegean and Western Turkey sclerophyllous and mixed forests [PA1201] delineated by the Digital Map of European Ecological Regions (ETC/NPB 2002; WWF 2001). Species include the Aleppo pine (Pinus halepensis), Quercus coccifera and Juniperus macrocarpa. Phryganic vegetation is typical with species such as the Jerusalem sage (Phlomis fruticosa), Sarcopoterium spinosum, thyme (Thymus vulgaris), Cistus species, caper bush (Capparis spinosa), etc. These species exhibit an impressive adaptation and resilience to high summer temperatures and drought. Common maquis species include the Greek strawberry tree (Arbutus andrachne), strawberry tree (A. unedo), Spanish broom (Spartium junceum), and bay laurel (Laurus nobilis). There are also pockets of Pindus Mountains mixed forests [PA1217] at higher elevations in the Pindus Range with species like the European black pine (Pinus nigra) and Greek fir (Abies cephalonica). 

Description of endemic fishes

This ecoregion contains distinct endemics, such as the critically endangered Evvoia barbel (Barbus euboicus), endangered skarouni (Luciobarbus graecus), Greek stickleback (Pungitius hellenicus), marathon minnow (Pelasgus marathonicus), Beotian riffle dace or paskoviza (Telestes beoticus) and Greek rudd or kalamithra (Scardinius graecus). Lake Yliki contains the critically endangered Greek rudd and endangered Yliki roach (Rutilus ylikiensis), a near-endemic (Kottelat & Freyhof 2007). The critically endangered Almiri toothcarp (Aphanius almiriensis) is probably extinct from the ecoregion but may still survive in the neighbouring Ionian drainage (Legakis and Maragou 2009).

Other noteworthy fishes

The Spercheios roach (Rutilus sp.), still undescribed, may be restricted to the Spercheios basin in swamps and slow-flowing water (Kottelat & Freyhof 2007).

Justification for delineation

Southern European ecoregions were delineated based on a bottom-up approach using both published and unpublished field data and expert assessment (Abell et al. 2008; Economidis 1991). This ecoregion falls within the Attiko-Beotia faunal division defined by Economidis and Banarescu (1991) and includes the Sperchios and Kifissos (Cephissus) drainages (Skoulikidis et al. 2009). There is little species overlap with the Ionian Drainages [421] to the west (M. Kottelat pers. comm. Jan 16, 2006). The islands are more or less divided by the mid-Aegean barrier, which divides the central Aegean islands (Kyklades) from those lying close to the coast of Asia Minor.


  • Abell, Robin,M.L. Thieme,C. Revenga,M. Bryer,M. Kottelat,N. Bogutskaya,B. Coad,N. Mandrak,S.C. Balderas,W. Bussing,M.L.J. Stiassny,P. Skelton,G.R. Allen,P. Unmack,A. Naseka,R. Ng,N. Sindorf,J. Robertson,E. Armijo,J.V. Higgins,T.J. Heibel,E. Wikramanayake, (2008). "Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation" BioScience 58 (5) pp. 403-414.
  • European Topic Centre on Nature Protection and Biodiversity (ETC/NPB) (2022) \Digital Map of European Ecological Regions (DMEER)\ (8/2011 from
  • Dermitzakis, M.D.,M. Triantaphyllou;H. Drinia (1997). "Greece" E. Moores (ed) (Ed.) Encyclopedia of European and Asian Regional Geology ( pp. Pp 301-319 ) London, UK: Chapman & Hall.
  • Economidis, P.S. (1991). "Check list of freshwater fishes of Greece (recent status of threats and protection)" Special publication Athens, Greece: Hellenic Society for the Protection of Nature.
  • Economou, A.N,S. Zogaris,S.Giakoumi,R. Barbieri;Petridis, D. (2003) \Developing a biotic river typology and defining reference conditions in the rivers of Greece: a spatially-based approach\ Working Package 6.
  • Hijmans, R. J., S. Cameron and Parra., J. (2004) \WorldClim, Version 1.4 (release 3). A square kilometer resolution database of global terrestrial surface climate\ "<"[]">" (16 July 2009)
  • Kottelat, M.;Freyhof, J. (2007). "Handbook of European Freshwater Fishes" Cornol, Switzerland: Publications Kottelat.
  • Koukis, G.C.;Koutsoyiannis, D. (1997). "Greece" Embleton, C.;Embleton-Hamann, C. (Ed.) Geomorphological hazards of Europe ( pp. Pp. 215-242 ) Amsterdam, The Netherlands: Elsevier Science B.V..
  • Peel, M. C., Finlayson, B. L. and McMahon, T. A. (2007). "Updated world map of the Köppen-Geiger climate classification" Hydrology and Earth System Sciences 11 pp. 1633–1644.
  • Skoulikidis, N.T.,A.N. Economou,K.C. Gritzalis;Zogaris, S. (2009). "Rivers of the Balkans" Tockner, K.;Uehlinger, U.;Robinson, C.T. (Ed.) Rivers of Europe ( pp. Pp 421-466 ) London, UK: Academic Press.
  • World Wildlife Fund (WWF) (2001) \Terrestrial Ecoregions of the World\ "<"">"