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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Australian study into how seals react to boats prompts new ecotourism regulations

Australian fur seals alert to the presence of the potential danger. Photo: Julia Back

Unable to differentiate between a predator and a tourist boat carrying humans curious to view a colony of seals while resting in their natural habitat, pinnipeds are quick to react defensively as soon as they sense what they perceive as a potential life threat. The closer the vessel approaches, the more likely it is for the animals to rush into the sea in an attempt to escape and the greater the risk of injury and even death in the event of a stampede, or predation once they are in the water. In fact, just the act of remaining alert comes at potentially high energetic costs for the animals.

“Although the purpose of ecotourism is to give patrons the opportunity to observe animals in the wild engaging in typical behaviors, ecotourism-based human interactions may instead alter pinniped behavior by initiating responses indicative of predation avoidance,” explain the scientists.
“The periods fur seals spend ashore at colonies are particularly important for resting, evading predators, molting, breeding and rearing young. Fleeing behaviors in themselves expend energy, and time spent in the water as a result of flight responses can also be energetically costly,” they add.

Australian fur seals begin to flee into the water as a boat approaches Kanowna Island. Photo: Julia Back

To provide recommendations for appropriately informed management guidelines, so that ecotourism does not clashes with the animals’ welfare, the Australian research team of Julia Back and Prof John Arnould of Deakin University, Dr Andrew Hoskins, CSIRO, and Dr Roger Kirkwood, Phillip Island Nature Park, observed the response to approaching boats of a breeding colony of Australian fur seals on Kanowna Island in northern Bass Strait, southeastern Australia. Their study is published in the open-access journal Nature Conservation.

A female Australian fur seal calling for her pup.  Photo: Andrew Hoskins

Whenever a seal detects a threat while onshore, they first change posture, watch the object and remain alert and vigilant until the danger is gone. In the field survey, such a response was triggered when the research boat approached the colony at a distance of 75 m. Interestingly, this reaction would be more pronounced in the morning (the researchers would normally visit the colony twice a day), while in the afternoon the seals would demonstrate a reduced response. Why this is so, remains unclear.

When there was only 25 m between the seals and the boat, the scientists observed many of the animals fleeing to the safety of the water. This kind of reaction is particularly dangerous for the seals and especially their young, as these animals tend to perceive risk based on the responses of the individuals around them. In such a cascading response, a large-scale stampede is likely to occur, where pups could easily get trampled to death or fall from cliffs.

“While the infrequency of these events suggests they are unlikely to have population-level effects, such disturbance impacts are in violation of state and federal regulations protecting marine mammals”, note the authors, citing the International Union for Conservation of Nature.

As a result of the study, the management guidelines were updated, so that they currently restrict boat approaches to 100 m at Kanowna Island from March through October, when the rearing of the pups takes place. During the breeding period, vessels need to keep a distance of at least 200 m, as previously.

In conclusion, the authors also note that their findings are limited to a single colony and are therefore insufficient to make any generalisations about other species or even other Australian fur seal populations.

Australian fur seals begin to flee into the water as a boat approaches Kanowna Island. Photo: Julia Back

 

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Original source:

Back JJ, Hoskins AJ, Kirkwood R, Arnould JPY (2018) Behavioral responses of Australian fur seals to boat approaches at a breeding colony. Nature Conservation 31: 35-52. https://doi.org/10.3897/natureconservation.31.26263