Balancing Human Impact on UNESCO Natural Cave Sites: A Glimpse into the Carlsbad Caverns
When tourism resumes after the coronavirus pandemic, the caretakers of natural sites will have to contend with renewed impact from human activity. This topic is not unique in regard to World Heritage sites, but natural sites are especially at risk due to their delicate ecosystems. Such is the case for Carlsbad Caverns in the state of New Mexico. How have visitors impacted this site and what measures are being taken to preserve this delicate natural site?
The UNESCO World Heritage Website describes Carlsbad Caverns as a karst landscape comprised of over a hundred caves and counting, which was formed as part of a fossilized coral reef from the Permian era known as the Capitan Reef formation (UNESCO). Carlsbad Caverns was added to the UNESCO World Heritage List in 1995, stating that the site is of Outstanding Universal Value based on its exceptional and geological features, unique reef and rock formations, and containment of major cave formations. The reef formation is rich in sea fossils over millions of years, created a massive limestone formation. Several deep canyons in the Capitan Reef formation reveal cross-sections of other formations that have been exposed within the Carlsbad Cave system, including one of the most notable caves in the park, Lechuguilla Cave, which had only been discovered as of 1986 according to the NPS and is currently the deepest and the third longest limestone cave in the site and is home to the largest collection of natural hydromagnesite, helictite, and calcite formations (UNESCO). Carlsbad Caverns continues to form new structures and serves as a highly valued space for scientific research on the geological and biological systems of the park.
Regarding visitors, Carlsbad Caverns receives ~500,000 annually and according to the National Park Service, tourism to Carlsbad Caverns creates about 30.2 million dollars for local businesses near the park (NPS, 2020). These factors highlight the amount of people that come to this World Heritage site, which ties into the impact that the park caretakers must combat.
According to the NPS and US Geological Survey, direct human impact in Carlsbad Caverns includes graffiti, touching of stalactites, off-trail exploring and pollution of cave pools by throwing of coins or litter (USGS.gov). Signage and stricter rules have helped ease this issue even though it occasionally continues. However, indirect means of human impact seemed to have left the most damage on the natural site. One such example is lint accumulation in the caves, which has led to discoloration of the speleothems, which are the structures formed in the cave by the deposition of minerals from water such as stalactites and stalagmites (Jablonski, et al., 1993). This accumulation consists of lint, clothing fibers, skin, and hair left behind by cave visitors. During a lint cleanup in 1991, volunteers who cleaned the lint off the speleothems noted that the calcite beneath the lint was deteriorating and dissolving as a result of microbes feeding on this organic material brought by visitors. As of this study, park rangers installed rock walls along the main trail of the Cavern that can be cleaned via vacuuming or manual treatment.
A second indirect issue is the human impact on the microbe ecosystem in Lechuguilla Cave. Lechuguilla Cave currently has restricted access and is only available for park rangers, scientists, researchers, and cave explorers. Unfortunately, those who had access to the cave inadvertently carried outside bacteria that would outcompete the native bacteria in the Lechuguilla Cave (USGS, 2016). As of this discovery, even stricter preventative measures have been enforced such as the use of sanitized clothing and usage of coverings for all actions done in the cave such as eating and sleeping for those staying overnight.
The most recent issue to come up against this heritage site is the threat of White Nose Syndrome on the Mexican Free-tailed bats that roost in the caverns. Though the disease is not known to directly affect humans, it has been associated with the deaths of millions of bats since it was first identified in 2006. The fungus invades areas of the bat’s body with no fur such as the face, which gave rise to the name. The fungus attacks during the hibernation process and will disrupt the bat’s equilibrium, thus causing starvation or dehydration. The fungus that causes this disease is potentially present in New Mexico and though no trails on the site lead to colonies of bats, the park caretakers have taken preventative measures such as walking on a bio-cleaning mat after leaving the caves or decontamination of visitors going to multiple caves.
This glimpse into the Carlsbad Caverns shows that the visitor impact on Natural Heritage cave sites are a continuous challenge, especially if they hold a strong value to those within and outside the scientific community. With the potential impact of returning visitors once it is considered safe to return to public sites, it is even more important to consider the precautions being taken to protect delicate sites of natural heritage like caves, as they are irreplaceble and essential to our environmental heritage.
RESOURCES:
“Interesting Facts About Carlsbad Caverns.” National Parks Service. U.S. Department of the Interior. Accessed April 28, 2020. https://www.nps.gov/cave/learn/news/interesting-facts-about-carlsbad-caverns.htm.
Jablonski, P., Kraemer, S., and Yett, W., 1993, Lint in Caves, in Pate, D.L. (ed), National Cave Mangement Symposium, 9th, Carlsbad, New Mexico, 1993, Proceedings: Carlsbad, New Mexico, National Cave Mangement Symposium Steering Committee, p. 73–81.
“Tourism to Carlsbad Caverns National Park Creates $34 Million in Economic Benefits.” National Parks Service. U.S. Department of the Interior. Accessed April 28, 2020. https://www.nps.gov/cave/learn/news/tourism-creates-34-million-in-economic-benefits.htm.
USGS, and U.S. Geological Survey Office of Groundwater. “Using Science to Change Management Perspectives at Carlsbad Caverns National Park.” USGS. United States Geological Survey, 2016. https://water.usgs.gov/ogw/karst/kigconference/pab_usingscience.htm.
UNESCO World Heritage Centre. “Carlsbad Caverns National Park.” UNESCO World Heritage Centre. UNESCO. Accessed April 28, 2020. https://whc.unesco.org/en/list/721.
UNESCO World Heritage Centre. “19 COM VIII.A.1 — Decision.” UNESCO World Heritage Centre — Decision — 19 COM VIII.A.1. Accessed April 28, 2020. https://whc.unesco.org/en/decisions/3072.
“White-Nose Syndrome and Carlsbad Caverns.” National Parks Service. U.S. Department of the Interior. Accessed April 28, 2020. https://www.nps.gov/cave/learn/white-nose-syndrome-and-carlsbad-cavern.htm.
