29.03.2019 change 29.03.2019

Researchers study the fauna of Lake Skadar with molecular barcodes

Researchers from Łódź and Montenegro want to estimate the diversity of water fauna of the largest lake of the Balkan Peninsula - Lake Skadar - with DNA barcodes. This will allow to create a comparative database for future biomonitoring of the ecological status of the lake.

"Our project +DNA barcode reference library as a tool for sustainable management of freshwater ecosystems in the highly threatened Lake Skadar Basin+ has gained the recognition of experts and obtained EUR 80 thousand funding from the Ministry of Science of Montenegro" - told PAP Prof. Michał Grabowski from the Department of Invertebrate Zoology and Hydrobiology, University of Lodz.

According to the scientist, the Mediterranean Region is one of the most important hotspots of biodiversity and endemism on a global scale. The local uniqueness of fauna and flora applies to both terrestrial and aquatic environments.

One of the most unusual places in this region is Lake Skadar, located on the border between Montenegro and Albania. It is the largest of the Balkan Peninsula`s lakes, with seasonal area variations from 360 to 550 square kilometres. Its average depth is only about 5 m. The lake rarely freezes in winter, and in summer the temperature of its waters exceeds 25 degrees C.

The beginnings of the lake - as Prof. Grabowski emphasized - are still shrouded in a haze of mystery. Analysis of historical records, such as Ptolemy, Strabo or Livy, proves that Lake Skadar did not exist in ancient times, and in its place were today`s Morača River and extensive swamps.

"Studies of its bottom sediments also indicate that the lake suddenly appeared around the year 750 AD, most likely due to the flooding of a large karst field by the Drim River, which changed its course as a result of earthquakes, frequent in this region" - said Prof. Grabowski.

The karst field, rich in cold water springs and streams, has existed for at least 3 million years. Some of these springs - karst funnels with a depth of several dozen meters - are now under the surface of the lake. The karst field is surrounded by dry limestone mountains, where you can also find springs and streams flowing down to the lake, as well as underground rivers and numerous caves.

The scientist emphasized that the high but still insufficiently known diversity of the fauna of the Lake Skadar basin is the result of its specific history.

"It consists of quite numerous endemic species, including fish. This particularly applies to springs inhabited, for example, by various species of snails or crustaceans, not found anywhere else in the world. The lake is also a very important nesting place for wetland birds, including pelicans" - added Prof. Grabowski.

The natural values of the lake were the reason for covering it with protection as a cross-border Lake Skadar National Park. In spite of this, the lake and its surroundings are subject to progressing anthropopression, harmful human activity. This is mainly due to the growing inflow of tourists to Montenegro and the expansion of accompanying infrastructure, including hotels, lodging houses and the gastronomic base.

"As a result, the springs are transformed into water intakes, the shoreline is built up, and more pollutants flow into the lake" - noted the researcher from Łódź.

For many years, a team of scientists from the Department of Zoology of Invertebrates and Hydrobiology, University of Lodz, in collaboration with Prof. Vladimir Pešić from the University of Montenegro and the team of Prof. Andrzej Zawala from the University of Szczecin have been conducting taxonomic, phylogeographic and ecological studies of the water fauna of the Lake Skadar basin.

These studies have led to the discovery of new species of animals, as well as finding that the origin of spring fauna is largely different from that of the fauna of the lake itself. "We have even shown that populations of the same species inhabiting various springs within the lake basin are isolated from each other and have evolved independently for hundreds of thousands of years" - emphasised the leader of the team of scientists from the University of Lodz.

When the Ministry of Science of Montenegro announced its first grant competition, Prof. Pešić proposed a joint project with the Lodz scientists. "We decided that in the face of the growing threat of environmental degradation of the lake and its catchment, we should focus on a reliable assessment of probably underestimated diversity of water fauna and creating a comparative database for future biomonitoring of ecological status" - explained Prof. Grabowski.

As part of the project, the researchers decided to apply the method for estimating the diversity of selected groups of macroinvertebrates based on DNA barcodes. It allows for assigning a short section of mitochondrial DNA with a characteristic nucleotide system, also called a molecular bar code, to each known species.

In addition - as the scientist points out - the method allows to detect potential new species, including cryptic species, those that have escaped the attention of specialists due to their external similarity to already known species.

Professor Grabowski assures that in the future the resulting reference library of barcodes will allow to quickly identify the composition of the fauna composition and changes in its diversity through DNA metabarcoding: DNA extraction and sequencing barcodes from the whole collected sample, without the need for prior sorting and taxonomic identification. Another option is to acquire and identify barcodes from the so-called environmental DNA (eDNA) - particles of this substance left in the water by living organisms.

During the project, scientists expect to discover a range of new, interesting research topics and perhaps also new species.

According to Prof. Grabowski, building a reference database of DNA barcodes will not only contribute to a better understanding of the diversity of aquatic fauna of the Lake Skadar basin, but above all, it will provide a tool for fast and effective biomonitoring of its ecological status. "We expect that it will facilitate sustainable development planning for this region of Montenegro, valuable from the natural and tourist point of view, and preventing its exploitative use" - concludes Prof. Michał Grabowski from the University of Lodz.

The project is scheduled to end in 2021.

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