English - Convention on Biological Diversity

42
COUNTRY STUDY FOR BIODIVERSITY OF THE REPUBLIC OF MACEDONIA
Ohrid Lake, with its relict and endemic organisms, represents the most significant
lake ecosystem in Europe (under the protection of the United Nations Educational,
Scientific and Cultural Organization [UNESCO]). It is the largest lake in the Republic of
Macedonia and is situated in a tectonic valley in the far southwest of the country. It is a
typical oligotrophic lake with outstanding transparency, low nutrient content and low
production.
The diversity of phytoplankton and zooplankton in Ohrid Lake is relatively poor. The
phytoplankton is dominated by Bacillariophyta, Chlorophyta and Cyanophyta while the
zooplankton by Rotifers (Rotatoria), Copepods (Copepoda) and Water fleas
(Cladocera). The benthos at shallow depths is represented by abundant macrophytic
vegetation (representatives of Charophyta), and at deeper depths by the dominant
diatoms. Zoobenthos consists primarily of sponges (Porifera), segmented worms
(Annelida), flatworms (Plathelmintes), snails (Gastropoda) and Ostracods (Ostracoda).
Among the nektonic organisms, the most important are the relict and endemic species of
salmonid fishes.
Prespa Lake is the second largest natural lake, located at the juncture of the three
countries, Macedonia, Greece and Albania. Rich encrusted layers of Green and Bluegreen
algae and diatoms can be found on the rocky submerged substrate in the southern
portion of the lake. Zooplankton is represented primarily by species of Rotifers
(Rotatoria), Copepods (Copepoda) and Water fleas (Cladocera); the zoobenthos is
dominated by representatives of sponges (Porifera), segmented worms (Annelida), flat
worms (Plathelmintes), snails (Gastropoda) and Ostracods (Ostracoda). Among the
nektonic organisms, the relict species of fishes which are distinguished by a level of high
endemism are also dominant in this lake.
Doyran Lake is the smallest tectonic lake in the Republic of Macedonia. It is located
in the south-eastern area of the country and is a typical eutrophic lake of the Aegean lake
group. It is characterised by high floristic and faunal diversity and low endemism.
Diatoms are dominant among the phytoplankton and periphyton. Among the
zooplankton, Protozoans (Protozoa), Rotifers (Rotatoria), Water fleas (Cladocera) and
Copepods (Copepoda) are dominant while, within the zoobenthos, sponges (Porifera),
segmented worms (Annelida), flat worms (Plathelminthes), Molluscs (Mollusca) and
Ostracods (Ostracoda) are dominant. Cyprinid species of fishes are dominant among
nektonic organisms.
The three natural lakes provide favourable conditions for the development of aquatic
macrophytic (floating and submersed) vegetation, as well as the development of
shoreline marsh species. In the past, plant communities of these vegetation types used to
develop in the numerous swamps and marshes present in most of the valleys of
Macedonia (Katlanovo Marsh, Prespa Marsh, Ohrid Marsh, Struga Marsh, Pelagonia
Marsh, the marsh near Negortsi Spa, the marsh near the village of Bansko, Monospitovo
Marsh, the marsh in Upper Polog [near Gostivar] etc.), of which today only fragments
remain.
The Republic of Macedonia has a very rich network of rivers divided among three
watersheds: the Vardar, Crni Drim and Strumitsa. The watershed of the Vardar River is
the largest. In its upper reaches, thick accumulations of the water mosses Fontinalis
antypiretica and Rhynostegium riparoides are present, as well as the Algae, Cladophora
glomerata and Vaucheria sp. In winter and early spring months, microfloral rock
encrusting communities occur, formed mainly by Blue-green algae and diatoms. The
substrate is covered with a large quantity of organic sediment, which also covers these