Pancharevo Lake is a reservoir built along Pancharevo Gorge on the Iskar River (Danube River basin), between the mountains Vitosha and Lozenska Planina. It is located in western Bulgaria, nearby Sofia City, at an altitude of 600 m a.s.l. It has a length of 3 km, width up to 700 m, and depth of 20 m. The reservoir is used for drinking and industrial water supply, for sport and recreation activities. The region is characterised with high species richness and habitat diversity. The eastern lake shore is occupied by fragments of native oak forests and pine plantations, the slopes descending steeply to the water, somewhere ending with screes. Some rare plants as orchid species are found in this area. The lake ecosystem supports a great variety of aquatic plants, invertebrates, fish and birds. The Iskar River flowing into the lake is inhabited by fauna typical to the downstream part of the upper reaches as trout, barbel, chub, schneider, gudgeon, and minnow. Specific feature of the region are its thermal springs. The beautiful nature of the lake and its proximity to the capital make it a favorite place for vacation and recreation of Sofia citizens and tourists. The western shores of the lake are urbanised and densely populated (Pancharevo and Kokalyane villages). There are several recreation areas and facilities at the shores, including spa, sports, aquaculture and tourist facilities, providing possibilities for amateur and professional swimming, surfing, water skiing, rowing, angling, hiking and other activities. One of the consequences of this growing pressure of human activities is the introduction and spread of alien and invasive alien species in the region.


How to participate

The BioBlitz will be conducted on 20–22 May 2022, at the region of Pancharevo Lake, Sofia Municipality.

BioBlitz participants are invited to go out and by using the phone applications ‘Invasive Alien Species in Europe’ and ‘iNaturalist’ to take photos and record observations of alien species to collect data for the region.

The participants’ observations will help our efforts to document alien and invasive alien species (IAS) of plants and animals of concern to European Union, Bulgaria and the Danube River basin. According to their interests, participants can select and join a field team, focusing on a particular taxonomic group of organisms (plants, terrestrial invertebrates, aquatic animals). The field teams will be led by experts who will help to sample and identify the target species if necessary, but an active contribution by the participants is expected.

For the purpose of recording their observations, the participants will need a phone or tablet. For registration to participate in the BioBlitz and to receive further detailed information please contact us at: E-mail:


The BioBlitz is organised by:

- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences (IBER-BAS), and University of Forestry (UF)

In the frame of the COST Action CA17122 ‘Increasing understanding of alien species through citizen science’ (Alien CSI), co-funded by the National Science Fund of Bulgaria under the following projects:

- Increasing understanding of alien species through citizen science (Alien CSI): Approaches to citizen science, data management and standards in Bulgaria (No КП-06-COST-13) (2019–2022), coordinated by IBER-BAS

- State and perspectives of citizen science for invasive alien species in Bulgaria (No КП-06-COST-14) (2019–2022), coordinated by UF.

Project funded by:

COST Action CA17122: increasing understanding of alien species through citizen science.