Boundaries

The Ionian Drainages ecoregion follows the west coast of Greece from the Thyamis drainage as well as the island of Corfu and its surrounding islands south to the Peloponnese and the islands of Kythira and Antikythira. It is bounded to the east by the Pindus Range, to the west by the Ionian Sea, to the south by the Mediterranean Sea, and to the southeast by the Sea of Crete.

Topography

This coastal ecoregion has an active tectonic history due to its location at the edge of the Eurasian and African plates. It has a dissected and rugged landscape with many promontories, islands, karstic features, canyons, and gorges such as the Vikos gorge. The Pindus Range, formed during the Alpine orogeny, is the backbone of the ecoregion. The same chain extends down to the Peloponnese Peninsula and beyond to offshore islands, including Crete(Dermitzakis et al. 1997). The Peloponnese Peninsula is also rugged, with the Taygetos Mountains forming a 100 km long range that ends at the Mani Peninsula.  High peaks include Mt. Tymfi (2499 m asl), Kakarditsa (2429 m asl), Taygetus (2405 m), and Lakmos (2294 m) (Nezis 2010). The landscape is generally barren, with elevations averaging 555 m asl (Hijmans et al. 2004). The basins consist largely of limestones, dolomites, and flysch (Skoulikidis et al. 2009).

In 10 different islands of the ecoregion are 105 small wetlands respresenting total area of 2258.3 ha. Most of them are located in Kerkyra island (50 natural and 2 artificial) (WWF Greece 2010).

Freshwater habitats

The Arachthos rises in the Pindus Range, and flows 110 km, including a 30 km stretch through the Arachthos Gorge, before emptying into the Ionian Sea at the Amvarkikos Gulf. This delta is recognized as a Ramsar site, and contains Greece’s most extensive reedbed and saltmarsh system, as well as wet meadows, lagoons, and barrier spits (Wetlands International 2005). This delta plain is also fed by the Louros, which is a spring-type river that has continual flow throughout the year. This has resulted in a greater diversity of aquatic habitats and fish composition than the adjacent Arachthos, which has more seasonal discharge variation (Economou et al. 2003). The Acheloos also rises in the Pindus Range and flows 235 km before emptying into the Ionian Sea. In its lower reaches it flows through the Agrinio basin and meanders along a lowland plain. The Agrinio basin was once a large lake, remnants of which are lakes Trichonis, Lysimachia, Amvrakia, and Ozeros (Skoulikidis et al. 2009). The Acheloos estuary is connected to Messolongi lagoons, a Ramsar site noted for its brackish coastal lagoons, mudflats, saltmarshes, freshwater marshes, reedbeds, and dune systems (Wetlands International 2005). Both of these rivers historically have had a pluvial flow regime, with maximum discharge in winter (December-January) and a minimum in August. Dam construction has since changed the flow regime of the Acheloos (Skoulikidis et al. 2009).

The ecoregion’s two largest rivers on the Peloponnese Peninsula are the Alfeiós and the Evrotas. The Alfeiós rises at Taygetos Mountain, and flows 110 km across the Megalopis Plateau before emptying into the Kyparissiakos Gulf. It has a pluvial flow regime, with maximum discharge in January and a minimum in August. Its flow is supplied in part by karstic runoff. Rising near the source of the Alfeiós, the Evrotas, flows along a narrow plain enclosed by the Taygetos and Parnon mountains and south through the Laconia basin and Vrodamas gorge before emptying into the Lakonikos Gulf. In contrast to the Alfeiós, the Evrotas has a nivo-pluvial regime with maximum discharge in March and a second peak in summer. Karstic inputs and snowmelt contribute to the peak in March. Most of the headwater streams of this basin have an intermittent flow regime, whereas the Oinous is the only tributary that has a permanent flow (Skoulikidis et al. 2009). The Peloponnese Peninsula also contains internally drained basins (poljes), the largest of which occurs around Tripolis (WWF & IUCN 1994). The Evrotas river basin represents a geologically older section of the Greek peninsula and contains a distinct ichthyofauna with a couple of endemic species, as well as distinctive hydrogeologic and macroclimatic attributes (Economou et al. 2003).

Another Ramsar site is the Kotychi lagoon, situated in the northwestern corner of Peloponnisos. The site is characterized by several diverse habitats within a restricted area, caused primarily by a varied surface geology. It is a system of flooded areas either isolated or connected (permanently or seasonally). Part of the system is inside the Strofilia forest. The main water body is the Kotychi lagoon, a large shallow (30 –40cm) brackish lagoon fed by eight torrents. Its surface presents strong seasonal fluctuations depending on the annual precipitation. It is connected to the sea by a 30m wide opening at its western side. The site also includes the brackish Araxos lagoon, the freshwater Procopos lagoon, the Kalogria (Pappa) lagoon, extensive sand dunes, numerous small pools and river channels and the larger shallow Lamia marsh. The site is the southernmost wetland on the west migration route. For this reason it is a major resting station for many migratory birds.

The islands of the Ionian Sea are characterized by developed and complex karstic systems that outflow in a series of springs. There are no important rivers, but the high precipitation together with numerous springs creates many seasonal torrents as well as some permanent streams.

Terrestrial habitats

Aegean and Western Turkey sclerophyllous and mixed forests (PA1201) dominate the western and southern part of this ecoregion. Other terrestrial ecoregions include the Illyrian deciduous forests (PA1210) in the northwest and Pindus Mountains mixed forests (PA1217) at higher elevations (WWF 2001). Going from the north-northwest and the Pindus Range towards the south–southeast in the mountains of the Peloponnese we find trees such as the Hungarian oak (Quercus frainetto), European black pine (Pinus nigra), beech (Fagus sylvatica), Greek fir (Abies cephalonica), and downy oak (Quercus pubescens), and semi-deciduous scrub such as foetid juniper (Juniperus foetidissima) and Syrian juniper (J. drupacea), kermes oak (Quercus coccifera) and Pistacia lentiscus (WWF & IUCN 1994). The high mountains of the ecoregion represent a center of plant diversity. More specifically, the mountains of northern Pindus represent one of the most important hotspots of endemism regarding serpentine flora because of their high number of endemic species (32-42), but also due to their evolutionary history since many of these endemic species belong to isolated or remnant groups. Such species include Cerastium smolikanum, Aubrieta glabrescens, Viola dukadjinica, Taraxacumpindicum, the hawksbeard species Crepis merxmuelleriana, the bellflower Campanula hawkinsiana, species of Bormuellera, and campion species such as Silene pindicola, S. haussknechtii, and S. schwarzenbergeri. The Taygetos on Peloponnese is a botanical paradise and a hotspot of endemism with more than 850 plant taxa, of which 191 are endemic and 20 of them are narrow endemics of the Taygetos itself (Grivas et al. 2011). Some of these include the critically endangered Jurinea taygetea and Campanula papillosa and the endangered Aethionema carlsbergii and Draba laconica (Phitos et al 2009). At least 70 endemic species and subspecies are found on Mt. Parnonas, among which 36 are endemic to the Peloponnese and 16 are locally endemic, such as Astragalus agraniotii (EN) (Tan & Iatrou 2001).

The forest ecosystem of Strofilia is of great ecological interest because it is the most extensive Pinus pinea forest in Greece and one of the biggest in Europe. It also belongs to the group of littoral forests which have been strongly degraded or even more completely eliminated by human activities all over Europe.

Riparian vegetation includes species such as Oriental plane (Platanus orientalis), holm oak (Quercus ilex), bay laurel (Laurus nobilis), and white poplar (Populus alba) (Skoulikidis et al. 2009).

Description of endemic fishes

The Ionian drainages ecoregion represents an area that has a high proportion of endemic fish based on its long isolation. Despite having fewer species than the Southeastern Adriatic Drainages [420] to its north, it boasts the highest proportion of endemic fish in Europe (59%), including almost all primary freshwater fish (Skoulikidis et al. 2009). The ecoregion includes two endemic genera, Tropidophoxinellus (Cyprinidae) and Economidichthys (Gobiidae). Their species include the gournara (T. hellenicus), restricted to the Acheloos and Pinios drainages; the Golden Menida or bafa (T. spartiaticus, VU), located in southernmost Peloponnese from the Nedas to Evrotas drainages; the Louros goby (E. pygmaeus), found in streams and lakes of the Kalamas and Acheloos drainages; and the Trichonis dwarf goby (E. trichonis, EN [or LC according to the Greek Red Data Book]), restricted to lakes Trichonis and Lysimachia. The tsima (Pelasgus epiroticus, CR) is a species restricted to the endorheic Lake Ioaninna. Other endemics include Barbus albanicus (also reckognized as Luciobarbus albanicus), Peloponnese barbel (B. peloponnesius), Arachthos spined loach (Cobitis arachthosensis, EN), Louros spined loach (C. hellenica, EN), Acheron spring goby (Knipowitschia milleri, CR [or VU according to the Greek Red Data Book]), Louros trout (Salmo louroensis, EN), Evrotas minnow (P. laconicus, CR), Peloponnese chub (Squalius peloponnensis), and Epiros riffle dace or liara (Telestes pleurobipunctatus), many of which are threatened according to the IUCN Red List (IUCN 2009; Kottelat & Freyhof 2007: Legakis & Maragou 2009). Some local endemics to the Acheloos drainage include the Trichonis rudd or tseroukla (Scardinius acarnanicus), Acheloos catfish or glanidi (Silurus aristotelis), Trichonis blenny (Salaria economidisi, CR [or LC according to the Greek Red Data Book]), Trichonis dwarf goby, and Trichonis spined loach (Cobitis trichonica, EN [or LC according to the Greek Red Data Book]). In Kerkyra there is the critically endangered and possibly already extinct endemic Corfu dwarf goby (Knipowitschia goerneri, CR). Of the four species in the Evrotas drainage, the Evrotas chub (Squalius keadicus, EN), Evrotas minnow (P. laconicus, CR), and bafa (Tropidophoxinellus spartiaticus, VU) are endemic (Skoulikidis et al. 2009).

Other noteworthy fishes

The West Balkan trout (Salmo farioides, VU in Greece) is formally considered the dominant trout of western Greece (Economou et al. 2007). It is endemic to the Western Balkan river basins, from the Peloponnese to the north, along the Ionian and Adriatic drainages, up to Croatia. Within the ecoregion we find around 50% of its total population, restricted to upland coldwater reaches of seven river basins (Legakis and Maragou 2009). The West Balkan trout was formerly listed under Salmo macrostigma and there is still need for a full phylogenetic and taxonomic review of the taxon.  

Ecological phenomena

The anadromous Twaite shad (Alosa fallax) moves into the Thyamis, Arachthos, Louros, and Acheloos rivers to spawn (Bobori et al. 2001).

Justification for delineation

Southern European ecoregions were delineated based on a bottom-up approach employing both published and unpublished field data and expert assessment (Abell et al. 2008). This ecoregion falls within the Ionian ichtyofaunal subdivision of the West Balkans as defined by Economidis and Banarescu (1991). It includes the drainages between the Thyamis and Evrotas, which represents an isolated region with a high proportion of endemic species (Bianco 1986; Economou et al. 1999 in Skoulikidis et al. 2009). As a result there is little species overlap with adjacent ecoregions (M. Kottelat pers. comm. Jan 16, 2006).

Level of taxonomic exploration

The level of taxonomic exploration is uneven within the ecoregion and among different taxa. Knowledge is good regarding freshwater fish, especially in Western Greece. The situation is different in southern Greece and especially Peloponnisos where the level of taxonomic exploration is good for plants and fair for certain fauna species groups such as reptiles and amphibians, land snails (Gastropoda: Pulmonata), woodlice (Isopoda: Oniscidea), grasshoppers (Hexapoda: Orthoptera), and ground beetles (Hexapoda: Coleoptera) belonging to the families Carabidae and Tenebrionidae.