The floodplain forests of the Hungarian Lower-Danube-valley are the largest ones in Europe and they are threatened by intensive sylviculture (plantation of non-native tree species and clear-cuts).
During our project intensive faunistic surveys were conducted along the Hungarian parts of the Danube and in the mountains of Hungary to gather as many pond bat occurrence data as possible. We obtained data with mist-nettings, automatic ultrasound loggers and winter censuses. As a result of our program, we proved that the pond bat can be found all over the Danube in Hungary. Many other strictly protected bat species were found which helped us to directly save forest stands from clear-cuts.
With ultrasound loggers we compared the importance of different tree species for the hunting of bats. The results were a bit surprising because most of the species or species groups used the black nut stands the most. The second most used were the oak-ash stands, except in one case. Myotis species used the oak stands more intensively in comparison with the other tree species. Oak-ash stands are denser than black nut and clone poplars, this is why fast flying aerial hawking bat species (Barbastella barbastellus, Nyctalus noctula, Nyctalus leisleri and Pipistrellus pygmaeus) preferred the latter two stand types. Myotis species prefer foraging under and in the canopy. Myotis species are rarer than the other species groups, so the importance of oak stands is unquestionable.
Radio-tracking of barbastelle and pond bat revealed a high number of important information. As in mountainous areas, barbastelle occupied crevices under loosing bark and frequently changed their daily roost. We have found 53 new roosts, most of them in oak trees. Pond bats used mostly trees (oak) for roosting, but a large colony, with over 350 specimens was found in a bridge. All of the roosts were saved from forestry disturbance.
We took a trip to southern countries to find the southern border of the distribution area of pond bat. We proved the existence of a reproducing population of the species in Serbia. The pond bat was found along the Serbian part of the Danube. Other rare species (greater horseshoe bat, Savi’s pipistrelle) were found in Serbia and in Romania.
We developed and published
a little brochure in Hungarian which draws attention to the conservation of bats in forests and the proper management of protected woodlands.
A help of many volunteers was essential during our project. Also, the protection of bats cannot be achieved without public awareness, so we gave radio interviews and presentations .