PoLJUBA - Obnovitev in ohranjanje mokrotnih habitatov na območju Ljubljanskega barja

The main purpose of the PoLJUBA project was to restore and preserve wetland habitats in the Ljubljana Marshes area. The project activities were therefore focused on the preservation of three disappearing habitat types: meadows with a dominant purple moor-grass, lowland extensive cultivated meadows and basophilic fens, and the improvement of the status and protection of endangered species that inhabit wetland habitats. These are the rare fen orchid and seven animal species: the false ringlet and scarce large blue butterflies, the migratory meadow bird corncrake, the stone ornate bluet damselfly, the only Slovenian indigenous freshwater turtle the European pond turtle, the hermit beetle and the amphibian yellow-bellied toad. For many of these species, the Ljubljana Marshes are one of the last remaining habitats not only in Slovenia, but also in Europe. The PoLJUBA project was therefore perhaps one of the last opportunities for their preservation.

Colleagues from ZRC SAZU participated in the project as external contractors as part of several professional research tasks:

1. Increasing the population size and improving the conservation status of the false ringlet in the Ljubljana Marshes through supplementation and reintroduction of specimens.

Task leader: Dr. Tatjana Čelik

Some highlights of the results:

• In three ex situ cultivations of Coenonympha oedippus (2019/2020, 2020/2021, 2021/2022), 18 fertilized females were taken from the original population (Mostišče), which were returned to the original population after being kept in cultivation insectaries for 2–4 days (for the purpose of oviposition). With three translocations (2020, 2021, 2022) of reared specimens to the original population (Mostišče; 64 specimens) and to the reintroduction area (NR Iški morost; 398 specimens), we transferred 460 reared specimens into the wild.
• Taking into account the success rate of butterfly hatching from pupae in the wild (NRIM, Mo), we obtained 363 butterflies from 18 fertilized females.
• We completed the project with promising results: the reintroduced population showed an 87% growth rate, while the original population showed a 79% increase after the last supplementation.

More about the results in the final report (in Slovenian). We published a scientific article (In English) about the false ringlet rearing protocol and the results of supplementation and reintroduction, and reported at the international symposium "Conserving Lepidoptera in a Changing World" in England. The project manager also wrote about the importance of conservation translocations and the project in two professional articles in the magazines Alternator (in Slovenian) and Svet ptic (in Slovenian).

2. Initial, intermediate and final vegetation survey in areas of individual methods of controlling species from the genus goldenrod (Solidago sp.) in the Iški morost Nature Reserve within the framework of the PoLJUBA project, no. OP20.02644

Task leader: Dr. Urban Šilc

Some highlights of the results:

• As part of this project task, in 2019, 2020 and 2021, we conducted vegetation surveys in areas of controlling invasive alien species of goldenrod (Solidago spp.) in the Iški morost Nature Reserve (NRIM) in the Ljubljana Marshes. The coverage of invasive alien species from the genus Solidago decreased significantly during the project due to active removal. The sharp decline in coverage was especially seen in the third year, when goldenrod appeared with greater coverage only in two plots (NRIM 7 and 9), and even then only 10-15%. The removal can be considered successful provided that it continues in the future.

More about the results in the final report (in Slovenian).

3. Initial and final vegetation survey, initial and final assessment of the conservation status of the target HT 7230, initial and final assessment of the fen orchid population status, and initial and final vegetation survey in the habitat area of ​​the scarce large blue with initial and final assessment of the habitat status of the scarce large blue in the areas of the PoLJUBA project number 7 (Strajanov breg) and in the area number 4

Project leaders: Dr. Branko Vreš, Dr. Tatjana Čelik

Some highlights of the results:

• By comparing the state of vegetation between 2015 (project LJUBA) and 2019 and 2021 (project PoLJUBA), we find that after the implementation of measures to improve the conservation status (i.e. project activities) in most sample plots with fen vegetation (HT7230), the conservation status is slightly improving. The differences in changes in vegetation stands are small, but due to the (too) short period of vegetation monitoring, we cannot (yet) confirm with certainty that the changes are mainly due to nature conservation project activities or are just a reflection of varying annual climatic conditions in the area.
• The size of the fen orchid population in the Strajanov breg project area has been stable in the last six years (2015–2021). The average population density of the fen orchid in the Strajanov breg project area was lower in 2019 and 2021 than six years ago, but the population populated a larger area (larger number of populated VC) than in 2015.
• No butterflies of the species scarce large blue were observed in plots where Sanguisorba officinalis is not present. As follows from the low cover of Sanguisorba officinalis, the cover of this species alone in a certain period cannot be the (only) indicator for the suitability of a plot for the presence of the large blue. The optimal time for vegetation survey and the phenological development of the Sanguisorba officinalis do not coincide.

More about the results in the final report (in Slovenian).