Knowledge is power: How can we make cave tourism more environmentally friendly?

A new study in Nature Conservation presents a literature-based dataset on the ecological status of 265 show caves in 39 countries across the world.

Throughout history, people have used caves for a number of reasons: as shelters, places for rituals, food storage, and, in more recent times, as touristic attractions.  In these so-called show caves, visitors can experience the natural beauty of caves, usually by following a guide on constructed, artificially lit trails.

But caves are also very fragile ecosystems, bursting with underground life. They are home to numerous invertebrate and bat species, including ones that are threatened or endemic. The human disturbances caused by the changes in the infrastructure and environment, coupled with the influx of tourists, often affect the ecological processes and, consequently, these organisms. But how much do we know about the influence of tourists on cave ecosystems?

According to a new study in the open-access journal Nature Conservation, not enough.

Apart from affecting subterranean invertebrates, the artificial lighting and noise related to tourist visits may also affect the life of bats, making it harder for them to reproduce or overwinter in caves.

Going through more than 1,000 scientific papers, an Italian team of scientists, led by Marco Isaia and Elena Piano from the University of Torino, prepared a literature-based dataset relative to the knowledge on the ecological status of 265 show caves in 39 countries across the world. Their database includes a georeferenced set of show caves, where researchers have evaluated a number of environmental indicators that help monitor the impact of tourism and its related activities on subterranean ecosystems. They also list cave characteristics for each cave, including its natural heritage that attracts tourists.

There are many ways in which tourism can disturb life in a cave. For example, the presence of visitors may help increase cave temperature, which, combined with the increase of CO2 air concentration caused by tourists’ breath, may enhance carbonate dissolution, damaging geological formations. Moreover, tourists can carry pollutants and propagules of microorganisms into the cave through their clothes and hands, which then land on geological formations, in the water, in the air, and on the ground. Apart from affecting subterranean invertebrates, the artificial lighting and noise related to tourist visits may also affect the life of bats, making it harder for them to reproduce or overwinter in caves.

The dataset published in Nature Conservation set a baseline towards the integrated and multidisciplinary study of the impacts caused by tourism on these fragile ecosystems, but the research team points out that much remains to be done. For example, they found out that there wasn’t enough research on show caves outside of Europe, or on the possible impacts of tourism on the subterranean fauna in the context of climate change.

Ultimately, the data in this study can help managing authorities come up with guidelines that will allow a sustainable touristic development of show caves, not only from an environmental perspective, but also from an economic and social point of view.

“Overall, this data paper could fill the lack of awareness towards the fragility of the natural heritage of show caves to favour a sustainable touristic use that would guarantee their preservation for future generations as well as the economic development of local communities”, the authors conclude.

Research article:

Piano E, Nicolosi G, Mammola S, Balestra V, Baroni B, Bellopede R, Cumino E, Muzzulini N, Piquet A, Isaia M (2022) A literature-based database of the natural heritage, the ecological status and tourism-related impacts in show caves worldwide. Nature Conservation 50: 159-174. https://doi.org/10.3897/natureconservation.50.80505

All images are from Bossea show cave in Italy, by Simone Marzocchi.

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Ice Age survivors or stranded travellers? A new subterranean species discovered in Canada

The discovery of a new to science species of rare and primitive arthropod from the depths of a cave that was covered by a thick ice sheet until recently is certain to raise questions. In their study, published in the open-access journal Subterranean Biology, entomologist Alberto Sendra and local caver Craig Wagnell describe a new species of cave-dwelling, insect-like campodeid dipluran from the island of Vancouver (Canada) and discuss its origin.

According to the study, the dipluran’s presence could either mean that terrestrial arthropods have indeed been able to survive within the deep subterranean habitats during the Last Glacial Maximum period some 26,500 years ago or it is the result of related species having dispersed to the area during the deglaciation, making their way from as far as Asia.

Contrary to most people’s expectations, the new creature was discovered only an easy hike away from the nearest town of Port Alberni (Vancouver Island, British Columbia). There, cavers Craig Wagnell, Tawney Lem and Felix Ossigi-Bonanno from the Central Island Caving Club, together with Alberto Sendra, Alcala University (Spain), reported a remarkable, previously unknown species of dipluran from a couple of caves recently unearthed in the small limestone karstic area.

The exit of the Kiku Pot cave (Vancouver Island, British Columbia, Canada).

Named Haplocampa wagnelli, the new species pays tribute to co-author Craig Wagnell, “who has dedicated many years sampling and exploring in Vancouver Island caves”.

Unlike most cave-adapted campodeid diplurans, whose bodies and appendages are characteristically elongated and slender – a “trademark” feature for strictly underground arthropods – the new species has only slightly elongated antennae and legs and a thicker body. This is the reason why the researchers conclude that the species is not exclusively subterranean and is likely to also be present in soil habitats. On the other hand, its North American sister species seem to be even less adapted to life underground.

Interestingly, the scientists note close relationships between the genus (Haplocampa) of the new species and three others known from the two sides of the north Pacific Ocean: Pacificampa (Japanese Islands and the Korean Peninsula), Metriocampa (Siberia) and Eumesocampa (North America). According to the team, this is evidence for dispersal events where populations would cross over the old Bering Land Bridge, which used to connect America and Asia.

Furthermore, the new species is also one of the most northerly cave-adapted dipluran species, found at a latitude of 49º north. Some 26,500 years ago, its modern habitat would have been located underneath the Cordilleran Ice Sheet, part of the Late Wisconsinan North American ice sheet complex.

Felix Ossigi-Bonanno and Craig Wagnell at the entrance of the Kiku Pot cave after their successful discovery (Vancouver Island, British Columbia, Canada). 

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Original source:

Sendra A, Wagnell C (2019) The cave-dwelling dipluran (Diplura, Campodeidae) on the edge of the Last Glacial Maximum in Vancouver Island caves, North America (Canada). Subterranean Biology 29: 59-77. https://doi.org/10.3897/subtbiol.29.31467