Monitoring bat populations during seasonal migrations
17/11/2023
In April and May 2023, the company Geonatura d.o.o. conducted monitoring of the bat population during the seasonal migration period throughout the area of Krka National Park, in the underground shelters Miljacka II, Velika pećina Kaočinka cave and Topla pećina cave, Čikola River
These activities were the continuation of multi-year research and monitoring of bats in the park territory and its surroundings. The field research was performed in accordance with the guidelines of the International Convention to Protect European Bat Populations (UNEP\EUROBATS) and the national bat monitoring programme in the Republic of Croatia. The research was aimed at collecting data on bat populations that inhabit these shelters during the period of the seasonal migrations, and data on the species composition and their abundance. Based on the field observations, possible threats to shelters were analysed and recommendations given for further activities.
A total of eight bat species was recorded: Rhinolophus blasii (Blasius’ horseshoe bat), R. euryale (Mediterranean horseshoe bat), R. ferrumequinum (greater horseshoe bat), Myotis blythii (lesser mouse-eared bat), M. emarginatus (Geoffrey’s bat), M. capaccinii (long-fingered bat), Eptesicus serotinus (serotine bat) and Miniopterus schreibersii (common bent-wing bat). All the recorded species, with the exception of Eptesicus serotinus (serotine bat), are included in Annex II of the Habitat Directives, i.e., the List of plant and animal species of significant to the European Union and requiring protection.
The Velika pećina Kaočinka cave primarily serves as a transitional shelter. Its importance was observed for the first time as part of this study, when larger colonies of R. euryale and R. ferrumequinum were recorded during field surveys in September 2023. The Miljacka II cave is also an important summer shelter, while the Topla pećina cave was also found to be an important transitional shelter during research in 2023, though confirming its status as a summer shelter requires further monitoring. Due to the small number of surveys and the often-questionable reliability of data obtained, it was not possible to learn more about these bats, and so regular monitoring of the state of populations of these bats during the seasonal migrations is necessary.






Monitoring
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