Improvement of Natura 2000 statuses with renaturation of Stržen's riverbed on intermittent Cerknica Lake (LIFE)

Background

The natural water dynamics of the intermittent Lake Cerknica, admired for centuries for its unique features, were compromised during the 20th century by ‘improvements’ intended to drain the area to maximise its potential for agricultural use. The current hydro-dynamics are the major threat to the favourable conservation status of the temporary lake, and the habitat type, Turloughs, which is listed as a priority for conservation in Annex I of the Habitats Directive. Furthermore, a number of negative impacts have been recognised in the lake that adversely affect the breeding success of Eurasian bittern (Botaurus stellaris), a species listed in Annex I of the Birds Directive.

Objectives

The main objective of the LIFE STRŽEN project was to improve the conservation status of the Habitats Directive priority habitat, Turloughs, by restoring the former Stržen riverbed. The watercourse was prolonged by 1.5 km. This had several positive effects, including an increased saturation of soil with water that improved conditions for characteristic species of fish, invertebrates, birds and mammals. The project also aimed at reducing the negative impact of visitors on the restored riverbed area and establishing quiet zones in the breeding habitat of the Eurasian bittern (Botaurus stellaris) to improve its breeding success. A further aim was to gain long-term support for its conservation actions among the general public, and a positive change of attitude among key stakeholders. Thus, the objectives were strongly linked to the EU Habitats and Birds Directives, Biodiversity Strategy 2020, and Water Framework Directive.

Results

Reactivation of the former Stržen riverbed substantially improved the conservation status of Natura 2000 sites “Notranjski trikotnik” and “Cerkniško jezero”. By prolongation of riverbed for 1,5 km with redirection to its original 2.1 Km long meander both structure and function of the target habitat types were improved, and they established conditions for improved conservation status of priority habitat type Turlough (HT 3180*) on at least 60 ha of the lake.

A “quite zone” for nesting the Botaurus stellaris was established on 219 ha (100 ha foreseen), which improved nesting conditions for Bittern and other red-listed bird species. Overall, the project measures indirectly affected positively other 14 Natura 2000 bird species, aquatic invertebrates, mammals and fish, as shown in the monitoring campaigns. The pressure of scattered visitors was reduced almost by 80%. The project also increased awareness of the importance of the lake, especially among the locals. 500 persons were directly influenced via dissemination or other awareness raising activities. The project web site reached more than 350,000 views plus more than 219,000 views of the project blog.

Networking with all relevant local and regional stakeholders (hunters, anglers, farmers, tourist workers, schoolchildren, and police) was excellent, which is very good for the acceptance of people for conservation of the area and their active involvement. The project has reached all its objectives in full and reached the foreseen figures, with significant overachievement in many aspects. The project was among the 10 finalists for the “Natura 2000 award”.

Project web page: http://life.notranjski-park.si/en