39,131 bats of 11 species – this is the result of the 24th international bat count in the Międzyrzecki Fortified Region in the Lubusz Voivodeship. This is one of the largest Polish wintering grounds for these flying mammals. Scientists point to the adaptability of these animals to climate change.
The annual event took place last weekend and brought the second record result in its history. Since 1999, more bats have been counted only in 2020, when there were 39,658 individuals. In January 2024, 36,653 bats representing nine species were counted in the Międzyrzecki Fortified Area.
The most numerous, as every year, are the large and red bats. These the first ones were counted about 28.5 thousand, and the second ones – about 5.8 thousand. At the other extreme, there are Bechstein's bats – 13 and calf-haired bats – 16 individuals.
The number of bats is stable
Once again, the leading topic of the counting was the impact of climate change on the environment and bats, which scientists have been researching at MRU since 1999 as part of an international program coordinated by the University of Life Sciences in Wrocław. Due to their life cycle, these mammals are considered a barometer of climate change.
– Since 2021, despite ongoing climate changes, the number of bats in the MRU has been stable, which proves the adaptive abilities of these animals, but also the effective protection of their habitat, which is carried out by the Regional Directorate for Environmental Protection in Gorzów Greater Poland. The basements are properly secured and for three consecutive years we have not found any illegal visits by outsiders, said Dr. Tomasz Kokurewicz from the Wrocław University of Environmental and Life Sciences.
He added that evidence of bats' adaptation to changing climatic conditions is clearly visible in the behavior of cold-loving species, which are hibernating in increasingly large numbers in bunkers above ground from much warmer undergrounds than before. This mainly applies to mops.
Bats were counted in the Międzyrzecki Fortified AreaPAP
– It is possible that soon it will be necessary to think about better protection of these facilities against human access, so that they do not disturb the bats during the hibernation period. Waking up by people is very dangerous for these animals, because the energy used may not be enough until spring. However, for several years we have had a problem with the underground drying out, which is unfavorable for bats – added Dr. Kokurewicz.
Over 60 people penetrated the underground corridors and rooms as well as the above-ground bunkers of the former German fortifications: scientists, PhD students and students from Poland, the United States, Serbia, Bosnia, Georgia, Germany, the Netherlands, Belgium, Ireland, Great Britain and Italy.
“A business card on the international arena”
Monitoring the number of bats in MRU facilities, carried out since 1999, is one of the elements of the program for the protection of this naturally priceless wintering site. They are supervised by the Regional Directorate for Environmental Protection in Gorzów Wlkp. – From the perspective of 25 years of research, it can be said that effective protection of bats in one of the largest wintering grounds in the EU is our showcase on the international arena – said a specialist from the Wrocław University of Environmental and Life Sciences. Poland is obliged to submit a report to the European Commission every six years on the state of valuable natural habitats and species protected within Natura 2000 areas, and one of them is the MRU complex, most of which also has the status of a nature reserve (Nietoperek reserve).
Perfect conditions for bats
The basement of the “Nietoperek” nature reserve and free-standing structures in the Nietoperek Natura 2000 area cover the central part of the Fortress Front section of the Odra and Warta Arc, popularly known as the Międzyrzecki Fortified Area (MRU). It is a system of corridors, tunnels and chambers (over 30 kilometers long) and above-ground bunkers, built by the Germans in the 1930s and during World War II.
Bats from the Lubuskie, West Pomeranian and Greater Poland voivodeships, as well as from eastern Germany (Brandenburg and Mecklenburg), find winter shelter in the MRU. Some of them travel 260 km to reach MRU. The constant temperature and humidity there create optimal conditions for bats to hibernate.
Main photo source: PAP