Great Basin National Park

Cave Management
Gorp.com
Underground Vocabulary

Cave: a natural underground chamber open to the surface
Karst: an irregular limestone region with sinks, underground streams, and caverns
Source: Webster's New Collegiate Dictionary

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I listened to the familiar sound of mechanical ascenders rhythmically clinking as I ascended the static nylon rope. In the dark, somewhere behind me, I could hear water dripping and splashing off a ledge. The yellowish beam from my headlamp illuminated a small circle of the cave wall directly in front of me. Suddenly, my light revealed a bat in torpor, snuggled underneath a small ledge. I stopped and took a closer look, without shining my light directly on the hibernating bat. I looked just long enough to see the long ears curling backwards over its head and then I continued upward. This bat brought the total number of hibernating Townsend's big-eared bats in the cave to nine. I chuckled when I realized that I was actually starting to see bats as cute creatures. This transformation has come about as education replaced the old wives tales I had grown up with—such untruths as bats are blind, they get tangled in your hair or they are all dirty and carry rabies—have fallen by the wayside as I have had an opportunity to work with bat biologists.

As I climbed, the temperature rose and the smell of the outdoors became stronger. Pretty quickly, I entered the twilight zone, where daylight filtered downward into the darkness of the cave. Looking up, I could see a few wispy clouds floating across the blue circle of sky overhead. I reached up and switched my headlight off, climbing the rest of the way in semi-darkness. As I arrived at the lip of the pit, I unhooked my chest roller and brought my knees up towards my chest. Using my knees to push against the limestone walls, I forced the rope away from the padded edge. After I had raised the rope four inches off the rock, I slid my upper hand-held ascender up the rope as high as I could reach. I then climbed over the lip, squinting in the October sunlight. After unhooking my ascenders, I called down to my companion below that I was off rope, but not too loudly, as I did not want to wake the bats. Bundling my ascenders up in, my arms, I waddled up to the lip of the sinkhole and unhooked my gear, stashing it in my pack.

Pulling my notebook out, I quickly marked the location of the last bat on a copy of the cave map, noting the species in the margin. As the cave management specialist at Great Basin National Park, I was completing a bat survey in one of the wild caves in the park. This survey is an attempt to determine what type of bats use which caves and how they use them. Are they single bachelors, maternity colonies or hibernating colonies? Because bats are easily disturbed, we won't return to this until the hibernation season is over. If I had prematurely awakened a bat from its hibernation, it would have slowly started shivering to warm itself up, then it would have flown around until I left. However, that disturbance would have caused the bat to burn off two to four weeks of its fat supply and it could starve to death before the insects come out in early spring. I'm going to recommend that this particular wild cave remain closed from mid-October to April each year so that the hibernating bats won't be disturbed by cavers.

Stopping the significant population decline we have witnessed in bats over the last three years at Great Basin National Park has become a priority. In some colonies, we have seen a 50 percent reduction during this short time period. These declines worry us for many reasons. Bats can eat tons of insects a night in a given area, some of which are pests that plague farmers. The little brown bat can eat as many as 600 mosquitoes in an hour. Because the loss of bats could cause a greatly increased demand for chemical pesticides and would harm human economies, we have ample reasons to protect this small flying mammal.

Doing bat surveys is just one of my duties. Much of my work centers around Lehman Caves, where I try to offset the impacts of the public visiting the delicate, nonrenewable cave environment. Each visitor to the cave brings foreign material into this easily impacted resource, such things as lint, dust, hair, skin flakes, and shoe rubber. Even the Park's development of the cave causes impacts, with algae growing around artificial lights and damage to the cave when we replace burned-out bulbs in remote spots. To eliminate these impacts on the cave, we are considering a new lighting system for the cave. One proposal is to install a new low voltage cave lighting system that would consist of two separate systems. One part is a trail lighting system to improve visitor safety. The second part is a feature-based lighting system. This system would be designed in such a way as to light individual features, to provide better ranger programs and visually appealing scenes. By careful wattage selections and light placement and using specially-designed shrouds, we could eliminate algae growth and limit the impact on the cave from routine maintenance of lights. This system would incorporate the intrinsic nature of caves into its design and combine contrast, texture and color into eye-catching scenes. By highlighting individual formations, the ranger could better explain the cave's origin and history.

You might see a party of cavers cleaning algae or lint in the cave. These groups will stand out with their helmets, helmet-mounted lights, coveralls and gloves. Their love for the underground world will also be evident. They are all volunteers in the park and members of the local Grottos or chapters of the National Speleological Society. Their contribution to cave management at Great Basin is invaluable.

Cave management is a new discipline, one that is constantly evolving as we learn more about the interaction of the surface and subsurface worlds. We are learning that caves are not isolated features, but are integrally tied to the surface. We are learning just how easily their delicate ecosystems are impacted and the effects those impacts have upon us. Nationwide, about 25 percent of our fresh water comes from cave-rich areas, which are easily polluted by septic tanks, trash dumps and chemical spills. Caves are proving to be an important source of information about past climates, flora, fauna, and evolutionary processes, and they have become a target of groundbreaking biomedical investigations. With the passing of the Federal Cave Resources Protection Act of 1988, we now have a tool to better manage cave and karst resources at National Park Service sites across the country. Not only does this act mandate that we inventory and manage cave and karst resources, but it provides stiff penalties for the thoughtless cave vandal.

Cave management is rapidly progressing at Great Basin National Park, with several projects currently underway. We have installed a bat gate on the natural entrance of Lehman Caves. This gate has restored natural airflow patterns and allowed bats to come and go as they wish. We have also created a wild caving permit system, are writing a cave management plan, have documented all the known wild caves in the park, discovered two new caves and are starting to survey and inventory each identified cave.

See you underground!


Published: 29 Apr 2002 | Last Updated: 15 Sep 2010
Details mentioned in this article were accurate at the time of publication

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