No matter how many times we see them, the exceptional natural values ​​always leave us breathless. In case of the bat colonies from Huda lui Papară cave, the “breathless” feeling comes because these are the largest bat colonies in Romania. In the country’s chiropterological superlative, bats form living carpets on the ceiling, and are among the largest colonies from Europe.

Of course, connoisseurs remember, or rather can not forget that in Huda lui Papară this feeling of breathlessness is also due to the fact that geting close to bat colonies requires a little bit of swimming in 5 degree celsius cave water, but also climbing some half-frozen waterfalls. Obviously during winter. And in extraterrestrial-type equipment, meaning wetsuits, helmet, strong headlamps and equipment specific for bat monitoring and research. While always keeping an eye on the level and color of the water, due to the danger of flooding.

At the moment we know that Huda lui Papară offers adequate roost for at least 10 bat species out of the 32 from Romania (Bücs et al. 2012, Bücs et al. 2019), all being protected by national and European legislation. No, bat species are protected not only for the sake of protection, but also because throught their existence, bats control the size of insect populations. In other words, bats make our lives are easier, because they consume huge amounts of insects. These insects include mosquitoes, moths, spiders, as well as pest species that are harmful to agriculture and forestry.

From published data (ex. Bücs et al. 2012) we know that in Huda lui Papară the maternity (summer) colony includes 4.000-5.000 bats from three species: the greater mouse-eared bat (Myotis myotis), the lesser mouse-eared bat (Myotis blythii), and bent-winged bat (Miniopterus schreibersii). There are studies from abroad that attest to the fact that a single bat can consume over 2.000-3.000 insects in a single night. Even if we take a much more pessimistic 1.000 insects / night, we realize that this maternity colony in Huda lui Papară eliminates hundreds of thousands, maybe millions of insects from the landscape on each night of the warm seasons. But that’s not all. Because during autumn another 60.000-80.000 hungry bats start to arrive at the cave, dreaming of a belly full of insects, and thus a quiet winter.

The teams of the Center for Bat Research and Conservation (CBRC) have been monitoring the bat fauna from Huda lui Papară only since 2017, but the first observations about the huge winter colonies were made in 1998, by Conf. Dr. Ioan Coroiu (Faculty of Biology and Geology, Babeș-Bolyai University): “After investigations in 1998, we came to the conclusion that the Huda lui Papară Cave is a unique site, both in Romania and in Europe, from several considerations. First of all, it is the largest winter roost (hibernaculum) for bats in our country and in Europe, with multiannual fluctuations between 60.000 and 170.000 individuals. The cave is also a summer shelter (maternity) for several species. It should also be considered as a mirror for the health of the environment and biodiversity in the area, because of the fact that most bats that roost here are sedentary species, coming from a radius of 100-200 km.”

The hibernation colonies of Huda lui Papară are so large that bats cannot even be counted in the classical way, as we do in the case of colonies of only several hundreds of specimens. No, the colonies in Huda lui Papară are so large that we actually have to estimate how many square meters these living carpets occupy on the ceiling of the cave. And multiplying this with the specific number of bats per m2, we obtain a final estimate. For example, 1 m2 of bent-winged bats includes about 2.000 specimens. This species forms the largest living carpets on the ceiling of Huda lui Papară, usually over 15 m2.

In this way the size of the hibernation colonies from Huda lui Papară become simply incredible. In the winter of 2012, 55.200 specimens of bent-winged bats were observed (over 20 m2, Bücs et al. 2012), while in the winter of 2018 the CBRC team observed around 37.000 specimens of pipistrelles (Pipistrellus pipistrellus). To these we can add 3.000-4.500 greater and lesser mouse-eared bats, as well as one of the largest Romanian colonies of the greater horseshoe bat (Rhinolophus ferrumequinum), with over 1.100 specimens (counted in the winter of 2018, Bücs et al. 2019). Putting it all together we reach 76.000-85.000 bats in hibernation, placing Huda lui Papară in the top of European bat caves.

The large difference between the size of summer (4.000-5.000 specimens) and winter colonies (85.000 specimens) in Huda lui Papară indicates that the cave gathers bats from a vaste area of ​​Romania to an ideal hibernation place. Similarly, with the arrival of spring, Huda lui Papară sends these bats back to these areas of origin, to form maternity colonies in those areas and thus to ensure the survival of these populations.

Lucian Macaveiu, former custodian of the Trascău Mountains protected areas, is of the opinion that “based on the international importance it has, and as a habitat for many bat species, the protection of Huda lui Papară is certainly a priority. This cave is the only scientific reserve in the Trascău Mountains, a status that contradicts the idea of modifying it for mass tourism. We understand the importance of using natural locations for tourism, but (also) in this case we must be extremely careful. In fact, national and European legislation also focus on conservation and treas as secondary other interests, when it comes to protected areas.

While the summer colony occupies its usual place in the entrance area of ​​the cave (at a height of over 20 m), hibernation colonies are found along the entire length of the main gallery. Moreover, groups of tens to hundreds of bats are not only located in the ceiling, but also at lower heights, 2-3 m above the water level. In winter any disturbance can awaken bats from hibernation, and thus can contribute to the accelerated consumption of fat reserves, that were accumulated during autumn (yes, those insects that were eaten). This also decreases the chance of surviving the winter period, that is without food resources. Given the fact that, by their location, the hibernation colonies from Huda lui Papară cannot be avoided, not even with the greatest goodwill, they must be completely protected from human disturbance. For this reason and based on current legislation, human activities are restricted during the critical seasons in Huda lui Papară, especially during hibernation (October 15 – April 15)

Based on the importance for the bat fauna, and the existence of huge colonies, the cave benefitted from a protective gate at the entrance, placed during the LIFE+ project “Bat conservation in the Pădurea Craiului, Bihor and Trascău Mountains”. Placed in the period 2011-2012, the gate lasted only a few years, being swept away by a recent flood. These floods are becoming more frequent and unpredictable, so access to Huda lui Papară, in addition to legal permits and appropriate equipment, requires maximum attention. In any case, in order to keep the bat colonies of the cave in the top of Europe, and implicitly, to ensure the continuity of bat populations in a vast region, which goes far beyond the limits of the cave, Huda lui Papară needs maximum protection.

Cited sources:

  • Bücs Sz.L., Jére Cs., Csősz I., Barti L., Szodoray-Parádi F. (2012): Distribution and conservation status of cave-dwelling bats in the Romanian Western Carpathians. Vespertilio 16: 97-113.
  • Bücs Sz.L., Gönczi Vass I., Szigeti M., Jumanca M., Dumbravă AR, Telea A., Crețu G., Csősz I., Jére Cs .: The cave-dwelling bats of Romania: Research and conservation in key European sites. 9th Symposium on Karst Protection, Belgrade, Serbia.

Note: The research and monitoring activities of CBRC teams at the colonies of Huda lui Papară are carried out with the necessary authorizations and approvals, issued by the Romanian competent authorities.