There are many villages in the Cerknica field in southwestern Slovenia. One of them is Dolenje Jezero. That’s where the local Vekoslav Kebe opened the museum about the largest intermittent lake in Slovenia. The museum, which has been open for twenty years, is the only place where a live model of Lake Cerknica can be seen. Kebe offers guided tours of the museum and explains exactly how the lake works. Lake Cerknica fills in after the autumn rain and in spring when the snow melts. It dries in May or June and sometimes even in winter.
The lake is an important wildlife resort, especially as a nesting place for many bird species. Botanically, it is distinguished by amphibious plants.
Kebe has been closely monitoring the lake and its features for over thirty years. He is a meticulous observer and a critical native, who has published a publication about field and lake and is an expert in intermittent lakes. In recent years he has noticed that the lake dries up more often.
This is important because the habitats of endangered animals and plants that are already on the verge of extinction are changing or disappearing.
“Order is important.” Large water (lake), small water (when water is in riverbeds) and dry field (when water is only underground). “The order is small water – big water – small water – dried lake,” said Kebe. Plants and animals are adapted to such a sequence of water status.
People began to change order already in the 19th century, wishing that the field was flooded for a longer time. Over the past 30 years, the fishing family has started to make artificial barriers. There is now an 8m high barrier in Rešeto and the lake does not dry there. The fish retreat with water, but if not, the fishing family rescues them. “Pit for pit, section by section, they carry them behind that barrier,” said Kebe. This gave the fish a larger and longer-lasting habitat, but it was taken away from non-aquatic plants and animals. At that time, they began to transform the natural image and natural flow of the Karst field.
In order to protect the environment and the plants and animals in it, they established Notranjska Regional Park. But this, according to the locals, only made the situation worse. Previously, the field was mowed by farmers who cleaned the grass behind them, now the park managers are hiring people for mowing. They come with large tractors and attachments and mow part of the field. They leave the cut grass there. It then rises with the water in the rain and clogs the drains on the other side of the field. Machines scare away the birds, drive over their nests that are in the grass, and crush their eggs. “There are no birds and no other animals since they appeared,” he said.
There are many endangered animals and plants in the Cerknica Lake area, including those that live only here and are not found anywhere else in the world. Wetlands are rich in life and difficult to maintain. There must be at least some water throughout the year for adapted living beings can live.
Various projects are regularly underway in the field. The LIFE Stržen project is currently underway to extend and dig in the river bed of the Stržen stream, which is one of the main watercourses of the lake. Kebe said that the project is well-designed, but he cares because it means even more heavy machinery and encroachment on nature.
In the scope of the project, they will fill up the channel, which has been dug with the goal of cutting off the flow of water to the natural course of Stržen. This project intervention will restore the riverbed into its original double meander. Irena Likar, project manager, said that: “the living conditions in the area are then improved, especially for aquatic and riparian species.” During dry season, this will increase the chances of survival of water-related organisms, such as crustaceans, fish, amphibians, birds.
Likar claims, that they are restoring a part of Cerknica Lake to the state it was in before human intervention and adds that they affect the lake, affect the wettability during the driest period. When the lake is flooded it will have no effect, but in the dry season, when the water is solely in riverbeds, there will be more water for these aquatic organisms. Because the water stays in a longer channel than it currently was.
Kebe does not agree with the performance, as he believes that the machines will leave an irreparable seal on the lake. “Any encroachment on the lake is meaningless, without effect, a big nonsense, we destroy nature, we throw money away!” he added. He says they will move the lake a little higher when there is less water. The big water fills the whole core anyway, but when the water is low it will stay in the meander.
Global warming on the lake has not yet had a major impact. Kebe says it only reflects in infrequent rainfall and very dry summers. More decisive is the human factor, which in the past has significantly changed the image of the Cerknica field and thereby the lake. Kebe hopes that once the Stržen project is completed, no one will interfere with this part of nature anymore, since “it has its own laws that flow without people”.
Slovenia is full of diverse nature, and there are few corners such as Cerknica Field. Since the amount of water is constantly changing over the seasons, people should adapt to it as well. But they did not. They preferred to change the environment.
Vekoslav Kebe is sorry about how we work with our nature. He lives his own way, protects and nurtures nature, presents its story and function in the museum, and thus inspires his visitors. He advocates the survival of endangered species, “not by machines, but by letting nature take its course”.