Project KRAS.RE.VITA – »Improvement of the state of the most important nature-conservation parts of meadows and bog surfaces at Lake Cerknica and Planinsko Polje.
The aim of the project was to improve conservation status of target habitat types and species in the Natura 2000 site called the Notranjska Triangle, which covers the areas of Lake Cerknica and the Planina Plain in Slovenia.
Lake Cerknica is one of the largest intermittent lakes in Europe. Every year, it appears on the karst plain, trapped between the Javorniki hills on one side and the Bloke plateau and Slivnica on the other. During the dry part of the year, the lake disappears, so that in one year you can row, fish, walk, and mow the grass in the same place.
The lake usually remains in the Cerknica plain for about nine months a year. The water usually spreads over an area of 20 km2, but when the water level is at its highest, the lake covers an area of almost 26 km2. When full, Lake Cerknica is the largest lake in Slovenia.
Lake Cerknica was first mentioned in ancient times and has appeared on maps of Europe since the 15th century. Janez Vajkard Valvasor was the first to study its functioning, which earned him membership in the Royal Society in London. The importance of the intermittent Lake Cerknica therefore extends far beyond the borders of Slovenia. Today, Lake Cerknica, together with Rakov Škocjan and Križna Cave, has been declared an internationally important wetland – a Ramsar site – and, due to its importance for endangered birds, a Natura 2000 site.
Here, you can observe 276 species of birds, which is half of all European species, and 45 species of mammals, which is half of all European mammal species. There are 125 species of butterflies in the Cerknica Lake area, which is just under a third of all European species. There are also 15 species of amphibians, almost a quarter of all European amphibian species – the biodiversity of this area is truly exceptional.
Humans have always been connected to the intermittent Lake Cerknica. With its abundance of fish and game, the lake has attracted and sustained people since the Stone Age. Generations of hard-working hands have shaped the distinctive landscape of the lake’s wet soil and, by maintaining the floodplain meadows, continue to provide a habitat for endangered plants and animals.
Planina Plain is one of the typical karst fields formed in the Notranjska Basin. It is part of the karst basin of the Ljubljanica River and is also the most northwestern in the series of karst fields in its system. Planina plain, “locus tipicus,” defines the concept of karst polje, which is also established in professional karst terminology. It covers an area of around 11 km² and connects the municipalities of Logatec, Postojna, and Cerknica, lying at an altitude of around 450 m.
The Unica river flows through the field, emerging from Planina cave and slowly winding its way to the sinkholes on the other side of the field. The river occasionally overflows its banks, flooding meadows and fields, and during major floods, it also floods the road connecting the villages on both sides of the field. Floods occur several times a year, more frequently in late autumn and early spring, and last from a few days to two months. The highest water level reaches 10 m above the field level, and then 40 million m³ of water floods 10 km² of land. Due to its appearance, which changes with the seasons, the Planinsko Polje is interesting for anyone who enjoys nature. The most popular recreational activities are walking, running, cycling, horse riding, and ice skating in winter. The Unica River offers numerous water sports, including swimming, fishing, and boating during the flood season.
Although the Planina Plain is a karst field, there are no fields on it. The fields and settlements are located on a narrow edge of the plain, which is slightly elevated above the floodplain. During the dry season, the locals made good use of the grassy areas by mowing them. Extensive mowing in the field led to the development of meadows with communities of marsh vegetation. This is the northwesternmost habitat of the Amethyst meadow squill (Sciila litardierei), which is an endangered plant, typical for karst landscapes. The following birds nest here: the corncrake (Crex crex), the barred warbler (Sylvia nisoria), the red-backed shrike (Lanius collurio), and the kingfisher (Alcedo atthis).
Throughout history, there have been several attempts to prevent flooding, which has destroyed the natural channel of the Unica River and sinkholes at the edge of the field in several places.
The aim of this project was renaturation of both karst fields, by implementing various project activities:
- improvement of conditions directly in the field and revitalisation of 232 hectares of land,
- restoration of the double meander “Stržen” and “Beli Breg”, which had been regulated in the past on Cerknica Plain,
- filling in a drainage ditch and excavation of a previously filled-in natural depression on Planina Plain,
- improvement of conservation status of the habitat type intermittent lakes and of the species Ferruginous duck (Aythya nyroca) and Little crake (Zapornia parva),
- establishment of regular management of agricultural land, thereby ensuring the conservation of habitat types such as wet meadows with Molinia caerulea, alkaline fens, and Hydrophilous tall herb fringe communities, as well as habitats for animal species such as corncrake (Crex crex), barred warbler (Curruca nisoria), great crested newt (Triturus carnifex), and plant species such as Amethyst meadow squill (Scilla litardierei),
- arrangement of a karst pond to improve the habitat of the yellow-bellied toad (Bombina variegata),
- measure of guano cleaning and establishment of easier access to the maternity colony of the Greater mouse-eared bat (Myotis myotis)
- relieving the most sensitive parts of the project area from visitor pressure through the establishment of entry points, educational trails, birdwatching hides, canoe entry points, and visitor parking areas,
- raising nature conservation awareness among the local and wider public through concrete field activities and communication actions.
More info about the area and the project:
Notranjska Regional Park: https://notranjski-park.si/en/
KRAS.RE.VITA project website: https://www.kras.notranjski-park.si/