Boundaries

This ecoregion includes coastal drainages along the eastern Adriatic Sea, Strait of Otranto, and Ionian Sea from the Drin basin in the north to the Vjosa (Aoos) basin in the south. It covers all of Albania and small portions of southern Montenegro, Kosovo (as defined by UNSCR 1244), western part of the Former Yugoslav Republic of Macedonia, and western Greece. Natural borders include the North Albanian Alps (an extension of the Dinaric Alps), the Eastern Highlands (including the Korab Mountains), and Pindus Mountains. The border stretches inland to incorporate lakes Ohrid and Prespa in the east.

Topography

Outside the Alps, the Balkan Peninsula is the second most mountainous region in Europe. This ecoregion stretches from flat coastal and alluvial lowlands to the central uplands, and the rugged peaks, parallel ridges, plateaus, steep valleys, and karstic landscapes of the North Albanian Alps, Eastern Highlands, and Pindus Mountains. These are part of the Dinarides and Hellenides that formed during the Alpine orogeny, and are the backbone of the western Balkans (Skoulikidis et al. 2009). The highest elevation in the ecoregion is Mt. Korab, which extends more than 2760 m asl on the border between Albania and Macedonia. Other high peaks include Smolikas (2637 m) and Tito Vrv (2747 m). The Albanian Alps and Pindus Mountains are composed of carbonate rocks overlain by Mesosoic limestone, whereas the Ionian coast is composed of limestones and dolomites overlain by flysch. There is also a serpentine zone that features rounded mountains with limestone and sandstone outcroppings (Dermitzakis et al. 1997). Mt Varnous in Greece and its extended massif Mt Baba in FYROM form the ecoregion’s southeastern border. They contain several peaks that extend above 2000 m asl, with the highest peak being Pelister at 2601 m asl.

Freshwater habitats

The western Balkan Peninsula is characterized primarily by small and medium-sized mountainous rivers that descend through steep, narrow valleys to the Adriatic and Ionian coasts. Rivers of this area typically have naturally high sediment loads at roughly 2800 t/km²/yr, which is two to three times higher than rivers in northern Europe (Milliman & Farnsworth 2011).The Drin is the largest drainage in the ecoregion with the third largest discharge in Europe into the Mediterranean Sea. Its two main tributaries are the White Drin and Black Drin, which flow from the Dinaric Alps and lakes Ohrid and Prespa before meeting to form the Drin. From the confluence the Drin flows 160 km to the Adriatic Sea. Just 1.5 km before reaching its mouth the Drin meets the Buna, which drains Lake Skadar (Lake Shkodra). Maximum flow occurs on the Drin in winter and spring, resulting in winter floods that often back up into the Buna River and Lake Skadar (Skoulikidis et al. 2009).

The southwestern part of Albania, usually known as the “Albania Riviera,” that is not part of the Vjosë drainage includes Ionian drainage rivers, of which the most important are the Bistrica and Pavlo rivers.

The Vjosë (Aoos) is the southernmost river in the ecoregion. It originates in the Pindus Mountains and flows through deep gorges and steep ravines to the Adriatic Sea with inputs from the tributaries Voidomatis, Drino, Zagori, and Bënçë. Like the Drin, it has a pluvio-nival flow regime with a maximum discharge in winter and a second discharge in spring (Skoulikidis et al. 2009).

Lakes Skadar, Ohrid, and Prespa are tectonic lakes formed on rifts during the late Miocene (Skoulikidis et al. 2009). Lakes Ohrid and Macro Prespa are only 10 km apart, but are separated by the high Galičica Mountains. Despite this barrier, the two lakes are connected through subterranean karstic channels. Lake Ohrid is recognized as the oldest lake in Europe, ranging in age from 2 –5 mya (Albrecht et al. 2008). Lake Macro Prespa may be just as old, and it is referred to as having formed during the Pliocene, also at roughly 2-5 mya (Wagner et al. 2011). At an altitude roughly 853 m asl, Lake Micro Prespa is the highest lake in the Balkan Peninsula. The two Prespa lakes are separated by an isthmus and are hydraulically connected via a surface channel as well as underground openings through which Micro Prespa water outflows to Macro Prespa. Lake Micro Prespa’s water level is artificially managed with a weir so as to ensure both the effective conservation of waterbird habitats and populations (i.e. temporal flooding of wet meadows in spring, which are important habitats for feeding waterbirds and other breeding grounds for aquatic fauna - LIFE-NATURE, 2002) and the meeting of irrigation needs. The water level of Lake Macro Prespa has decreased ~10m over the last thirty years (GFA Consulting Group 2005), possibly owing to a combination of factors, such as water abstraction for irrigation and variations in climatic conditions (reduced rainfall) (GFA Consulting Group 2005).

With a surface area of 5100 km², Lake Skadar is the largest lake on the Balkan Peninsula and is fed mostly by the Morača River.

There are several coastal wetlands recognized by Ramsar, including Lake Butrint and the Karavasta lagoon, which is one of the largest lagoons in the Mediterranean Sea (Wetlands International 2005).

Terrestrial habitats

This ecoregion spans four terrestrial ecoregions, including the Dinaric Mountains mixed forests (PA0418) in the North Albanian Alps, the Illyrian deciduous forests (PA1210) along the coast up to around 800 m asl, the Pindus Mountains mixed forests (PA1217), and the Balkan mixed forests (PA0404) in the northeast. Most of the forested areas in the ecoregion range from mixed broadleaf forests at lower elevations to conifer forests at higher elevations (between 1200 – 2400 m asl). Dominant species include deciduous oaks such as Hungarian oak (Quercus frainetto), downy oak (Q. pubescens), Turkey oak (Q. cerris), and sessile oak (Q. petraea) in the mixed broadleaf forest zone and species like spruce (Picea abies), Greek fir (Abies cephalonica), Balkan fir (A. borisii-regis), silver fir (A. alba), and black pine (Pinus nigra) in the conifer zone. Mixed fir, spruce, and beech (Fagus sylvatica) forests also occur on continental facing slopes (WWF 2001).

Prespa is recognized as one of the most significant areas in Europe in regards to habitat diversity, types of vegetation and wild flora. For example, 26% of its 49 habitat types are considered priority habitat types (according to the EU Habitats Directive 92/43/EEC) (Vrahnakis et al 2011). In addition, it contains more than 2100 recorded species and sub-species of plants, of which 194 are considered to be important (Floristic catalogues 2012). 

Description of endemic fishes

The Balkan Peninsula hosts an endemic-rich fish fauna that resulted from long periods of isolation of the western Balkan drainages from the eastern Balkans. For example, this ecoregion boasts 23 endemics versus four in the Vardar ecoregion [422] directly to the east. The lakes in the Drin drainage (Ohrid, Prespa, and Skadar) alone host more than 30 endemic species (Skoulikidis et al. 2009). Lake Ohrid, in particular, is home to many endemic fish like belvica (S. ohridanus); Ohrid roach (Rutilus ohridanus); and summer trout (Salmo aphelios), pestani trout (S. letnica), struga trout (S. balcanicus), and lumi trout (S. lumi), which may be four stocks of different trout species or variants of a single species (Kottelat & Freyhof 2007). The Prespa is also home to nine endemic species: Prespa trout (S. peristericus), Prespa spirlin (Alburnoides prespensis), Prespa bleak (Alburnus belvica), Prespa nase (Chondrostoma prespense), Prespa barbel (Barbus prespensis), Prespa spined loach (Cobitis meridionalis), Prespa minnow (Pelasgus prespensis), Prespa roach (Rutilus prespensis) and Prespa chub (Squalius prespensis). All, with the exception of Prespa chub, are either Endangered or Vulnerable (Smith et al 2006). Other endemics in the Drin drainage include the newly described Skadar rudd (Scardinius knezevici) in lakes Ohrid and Skadar, Drin brook lamprey (Eudontomyzon stankokaramani), and the now extinct Skadar nase (Chondrostoma scodrense) (Skoulikidis et al. 2009).

Other noteworthy fishes

Lake Ohrid is home to the bleak (Alburnus alburnus), the scales of which are used to make the famous “Ohrid pearl.”

Ecological phenomena

The anadromous Adriatic sturgeon (Acipenser naccarii) occurs along the eastern Adriatic in the lower portions of rivers as far south as the Drin (Kottelat & Freyhof 2007). Other migrants include European eel (Anguilla anguilla) and twaite shad (Alosa fallax).

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 Adriatic ichtyofaunal subdivision of the West Balkans as defined by Economidis and Banarescu (1991). It is based on an area between the Drin and Vjosë that is rich in endemic fish, particularly in lakes Ohrid and Prespa (Bianco 1986; Georgiev 1998; Marić 1995).

Level of taxonomic exploration

Poor. However, there has been fair taxonomic exploration on the fish species of the Prespa Lakes (Berrebi et al. 1989; Snoj et al. 2009; Markova et al. 2010; Berrebi et al 2013-In press).