Second field trip to Brijuni National Park
After three weeks on Mljet, it was time to visit Brijuni once again! The same team as on Mljet headed to the northern Adriatic to continue research in the National Park. Like last time, we were initially greeted by rain, low temperatures and wind, but that didn’t stop us from getting down to business. Since we had already researched which meadows might be suitable for studying the behaviour of Messor wasmanni in April, we were able to continue to the next step.
The selected meadows contained a large number of Messor wasmanni colonies (sometimes up to 100), so we had to narrow down the selection to those most suitable for monitoring behaviour and studying thermal heterogeneity. We found colonies in a variety of microclimate conditions – from those at the edge of the meadow surrounded by tall grass, to those with bare soil, and colonies sheltered in the shade of trees. A compromise between a drone, a handheld thermal camera, and a regular camera made our choice easier, and after a few days, we decided which colonies we were going to focus on.
In parallel with the heterogeneity research, we also started standardised sampling in a transect on Veliki Brijun. We visited open habitats of Mediterranean grasslands, as well as shaded macchia and got to work. With an ant aspirator, we collected various species, and also encountered numerous other invertebrates that inhabit the surface soil layer – for example, termites in the photo. We spent some days in the pleasant shade of the macchia, and others in the sun surrounded by the prickly Echinops plant, ticks, and peacocks.
In addition to Veliki Brijun, we visited the islands of Mali Brijun, Galija, Gaz, and Vrsar, where we also conducted transects. In addition to ants, we most often encountered seagulls, which were not happy to see us since it’s their nesting season, but we tried not to distract them. At all locations, we also collected specimens for testing critical thermal minima and maxima, so our evenings were spent at the accommodation, working with the dry thermal baths.
Unlike Mljet, Brijuni NP has large populations of deer, rabbits and peacocks, so before each implementation of the protocol for investigating thermal heterogeneity and monitoring behaviour, we checked the equipment installed. This was a good reminder of the charms of field research, but fortunately, all thermocouples remained functional, and we were able to carry out the protocol to the end without any problems.
With our return from Brijuni, we closed the field season until September, when we will go back to the National Park with new knowledge and plans. Until then, we would like to thank the excellent team of Brijuni National Park, who provided us with everything we needed to conduct the field and transported us to various islands!
