The Midden Summer 2022 Issue

Summer 2022 Volume 22 Issue 1
View of Lehman Caves area in 1940
View of Rhodes Cabin in 1940 before Lehman Caves Visitor Center was built. Note the amount of pinyon-juniper.

NPS Photo

Thinning Project Outreach

By Julie Long, Supervisory Biological Science Technician and Bryan Hamilton, acting Integrated Resource Management Program Manager

In October 2021, fire crews began work on the 65-acre Boundary Thin. This is one of several projects the park is working on to reduce fuels, protect life and property, and restore plants and animals. Based on questions and comments from the community and visitors, we wanted to provide more information on this project.

View of extensive pinyon pines and juniper near lehman caves visitor center
2022 View of Lehman Caves parking lot and beyond; note the change in tree cover

NPS Photo

Why Were Trees Cut? Trees were cut to protect buildings from fires. For the past 100 years, land managers excluded wildfires from the park. But scientific research has shown that this policy has made fires larger and more dangerous. Without fires, trees have expanded, creating dense areas of heavy woody fuel. Compare the images to the right. Pinyon pine and juniper trees have increased over 150% in the Great Basin since European colonization, increasing high intensity, catastrophic fires. These megafires are deadly. They devastate landscapes, destroy homes, and create flooding. Cutting trees provides a fuel break between the park and private residences, to slow down or stop a fire moving up or down the Lehman Creek drainage.

Why Should You Care? Tree removal is good for plants and animals. Pinyon and juniper trees compete with grass and sagebrush for water and sunlight. Without fires, trees crowd out sagebrush and grasses. Sage grouse depend on sagebrush habitat and are also declining due to tree encroachment. Tree removal projects like the Boundary Thin are used by biologists to restore native plants and animals, like sage grouse and pygmy rabbits. Historically, low intensity fires burned frequently, holding back tree encroachment, and favoring sagebrush and grasses. These fires, ignited by lightning or Native Americans, are sometimes called good fires. Tree removal is an important first step in reintroducing natural, good fires to the park.

Let’s Keep the Conversation Going! If you have other questions, please contact Bryan Hamilton, acting Integrated Resource Management Program Manager email: e-mail us; phone: 775.234.7563

Additional Information
song sparrow
Song sparrow on a snow-covered branch.

Photo by Joey Danielson

Results of 2021 Christmas Bird Count

By Gretchen Baker, Ecologist

It was another year of dancing with ‘rona, but we managed to have an excellent turn out at the Snake Valley Christmas Bird Count on December 15, 2021 with 18 participants.

This year we had the added challenge of a huge snowstorm the day before, which closed roads and made for difficult travel. Nonetheless, all the Ely and St. George participants showed up and helped with the effort. We even had enough people to duplicate parts of routes, which always yields more birds.

The grand total was 55 species and 2538 birds seen on count day. Another 5 species were seen during count week. A couple standout bird species were 1) American Pipits—one team spotted 26 of them! They had only been counted on one count day and one count week previously and 2) a Snow Goose, previously a one-time count week bird, seen on a local pond north of the Great Basin Visitor Center, observed by another team.

Every route (except one) had at least one species that was not seen on any other route. The most counted birds were mallards (211), pinyon jays (184), dark eyed juncos (184), European starling (158), and common raven (97).

The Snake Valley Christmas Bird Count is an example of great volunteer involvement and interagency cooperation. Thanks to Utah Division of Natural Resources, Nevada Department of Wildlife, Ely Bureau of Land Management, Nevada Department of Conservation & Natural Resources, local volunteers, University of Nevada-Reno, and park staff for combining forces to get such good results.
person reaching out towards bat flying
A person points out a bat flying in the twilight. A recent paper about Mexican free-tailed bats shows that a huge roost near a large-scale wind energy facility contains many reproductive females and juveniles, which came as a bit of a surprise.

Photo by Joey Danielson

Bats in Spring Valley

By Bryan Hamilton, acting Integrated Resource Management Program Manager

Joey Danielson, Kelsey Ekholm, and I recently had a paper published in the peer reviewed journal Population Ecology on Mexican free-tailed bats. These bats are one of the most abundant mammals on earth. They consume vast quantities of insects and provide $23 billion dollars annually in economic benefits to agriculture in the United States. A single colony in Texas was valued at over $3,000,000 in annual pest insect suppression services. But like many common species, Mexican free-tailed bats are often ignored by conservationists and biologists. A major emerging threat to Mexican free tailed bats is wind energy development.

Millions of bats are killed worldwide by wind energy facilities each year. Migratory, high flying, open foraging bat species, such as Mexican free-tailed bats, are at high risk for wind turbine strikes and barotrauma. Two studies quantifying bat mortality at wind energy facilities near large roosts or in greater concentrations of this species found most fatalities (85% and 94%) were Mexican free-tailed bats (Miller, 2008; Piorkowski & O'Connell, 2010).

Mitigating wind energy mortality requires data on biology of the affected populations. But often these data are not available, especially for common species like Mexican free-tailed bats. To address this, we collected data on Mexican free-tailed bats at a large roost in eastern Nevada. Two million bats use this roost. Did I mention the roost is 6 km from a 152-MW industrial wind energy facility?

We used a harp trap to capture 46,353 Mexican free-tailed bats over 5 years. Although just over half of the bats were nonreproductive adult males (53.6%), 826 pregnant, 892 lactating, 10,101 post-lactating, and 4,327 nonreproductive adult females were captured. Juveniles comprised 11.5% of captures.

Roost use by reproductive females and juvenile bats demonstrates this site is a maternity roost, with significant ecological and conservation value. To our knowledge, no other industrial scale wind energy facilities exist in such proximity to a heavily used bat roost in North America.

Given the susceptibility of Mexican free-tailed bats to wind turbine mortality and the proximity of this roost to a wind energy facility, we need to continue work at this site. We need more information on bat mortality and the effects of mitigation. Pattern energy has been an excellent partner and works hard to protect bats at their facility. I hope we can publish the results of this work soon.

Surprisingly, we have almost no information on migration patterns of Mexican free-tailed bats in the southwest and California in particular. We hope to use the MOTUS network to understand these migration patterns. This information would allow much more precise siting of wind energy facilities and help with local mortality mitigation.

Read the paper here:
man brushing cave surface in purple light
A long-time lint camp attendee uses a blacklight to find lint.

NPS photo Gretchen Baker

Lint Camp Recap

By Gretchen Baker, Ecologist

Who likes spring cleaning? Fifteen volunteers came from Baker, Ely, Reno, Salt Lake City and the Wasatch Front, Bend, Oregon and southern California to spend two days helping restore Lehman Caves during the annual lint camp on March 2 & 3, 2022. About half of the attendees were returning lint camp pickers, while the remaining half were new. In addition, about half were cavers from grottos, while the other half were general public.

Lint Picking We started off lint picking in the Lodge Room area using only blacklights as our light sources. These make the cave look really different, plus the lint pops out in bright colors making it more visible to remove. Later we moved into the Grand Palace, where the amount of lint was indeed grand.

Cave Restoration In the afternoon of the first day, we had some folks ready to tackle rediscovering the natural cave floor. We worked in areas near the Queen’s Bathtub and the Inscription Room, digging out old sand and dirt that had been brought into the cave for the original trail. Popcorn floors, rimstone dams, and more can now be seen.

Trail Cleaning We just couldn’t ignore the numerous large lint balls in the exit tunnel any longer. Using a broom and vacuum, the area was cleaned up in less than two hours filling a gallon Ziploc bag with lint. We had a couple volunteers bring a portable power washer, and they worked with some others on the slope going down into the Grand Palace, marked with a slippery sign. With a tarp, scrub brushes and sponges, the crew was able to remove quite a bit of caked on mud, gum and other man-made debris with 5 gallons of water, which was all retrieved and carried out of the cave. This should make the trail safer for both visitors and staff.

Algae Spraying Algae grows near many of the cave lights, sometimes so abundantly it looks like a mini-forest. We had less algae than normal due to the lights being turned off in the cave for over a year while the cave was closed for COVID. The crew found algae at only 10 lights from the Entrance to the Lodge Room. About half the lights in the Grand Palace had some algae near them. As we got closer to the Exit Tunnel, where the lights are left on longer, we found more algae. We sprayed the algae with a 10% bleach solution, which isn’t so good for cave life, so the more we can reduce algae by other means (such as keeping lights off as much as possible), the better.

Carbide Removal In the 1890s, the carbide lamp was invented, and miners soon were using it through the Great Basin. The lamp can be mounted on a helmet. The bottom portion holds carbide powder. Water is added, a spark lights the output, a chemical reaction occurs which creates a flame illuminating the area ahead. Eventually the carbide powder is burned out and needs to be replaced with fresh carbide. There are several areas in Lehman Caves with carbide dumps, or places where this spent carbide was disposed. We focused on two of those sites, the Sunken Gardens and Talus Room. Experimenting with a variety of techniques from brushes to tweezers to vacuum, we removed about half of a 5-gallon bucket of spent carbide from the cave. The fine white carbide powder is toxic to cave biota.

Final Thoughts As a thank you to attendees, we showed the National Geographic movie The Rescue about the 2018 Thai Cave rescue and also did a tour through the Talus Room and West Room. Many attendees say they don’t need a thank you, just knowing that they are helping make the cave a better place is thanks enough. We are so lucky to have such dedicated volunteers! We suspect that we’ll be able to continue to fill lint camps quickly, especially if we adopt what one participant suggested as the new lint camp motto, “You missed a spot.”

night photo of a mountain lion
A wildlife camera captured a photo of this mountain lion.

NPS photo

Mountain Lions are Keystone Species

By Bryan Hamilton, acting Integrated Resource Management Program Manager

Mountain lions are keystone species. Through interactions with their prey, mountain lions create “top down” effects that regulate prey abundance and behavior, reduce herbivory, invasive species, and disease transmission, while increasing soil fertility and biodiversity (Beschta and Ripple, 2009). These predator induced trophic cascades can restore and maintain healthy ecosystems (Fraser et al., 2015).

However, predator management is a polarizing issue. Despite the positive effects of predators on ecosystems, mountain lions can be viewed unfavorably, particularly in rural areas.

Further complicating predator management is the rural urban divide. Mountain lion conservation is widely supported in cities and suburbs, but mountain lion habitat is mostly in rural areas on federally managed lands in Nevada. Rural communities that co-exist directly with mountain lions often hold fundamentally different views on wildlife management and unlike urban dwellers, may not support predator conservation (Manfredo et al., 2021).

National Parks find themselves in the middle of this controversy. The mission of Great Basin National Park is to protect its resources and ecosystem processes “unimpaired for future generations”. Apex predators are valued as an integral component of the faunal community but most national parks are not large enough to protect intact predator populations. Large-bodied obligate carnivores like mountain lions must leave the sanctuary of parks, where conflicts between lions may arise. Cooperative conservation is the only effective management strategy for large animals, like mountain lions, which must be managed at landscape scales, across administrative boundaries (Elbroch, 2020).

Cooperative conservation recognizes that wildlife management is a human endeavor. Without community support, dialogue, and engagement, conservation falls flat and difficult problems become more difficult. Despite this reality, most agencies and conservation biologists fail to acknowledge the importance of social differences and human behavior in managing predators.

To improve mountain lion management, Great Basin National Park has applied for Southern Nevada Land Management Act funding to implement the cooperative conservation model. This project will use mountain lion research and management as tools for outreach and community engagement. Mountain lions will be captured and fitted with satellite linked GPS collars. When the GPS locations become tightly clustered, this often means the lion is feeding on prey. After the lion leaves the kill, citizen scientists and school groups will investigate those kills and collect information about patterns of mountain lion predation. The project will also hold regular meetings in Baker and Ely, connect students from urban areas with landowners and livestock producers around the park, and provide training in wildlife techniques. Using these data, scientists can determine the home ranges, abundance, diet, and habitat use of mountain lions. Ultimately this project will improve predator management, ecosystem health, and human well-being through mountain lion research and community engagement.

Beschta, R. L., and W. J. Ripple. 2009. Large predators and trophic cascades in terrestrial ecosystems of the western United States. Biological Conservation. 142:2401-2414.

Elbroch, M. 2020. The Cougar Conundrum: Sharing the World with a Successful Predator. Island Press, Washington.Fraser, L. H., W. L. Harrower, H. W. Garris, S. Davidson, P. D. N. Hebert, R. Howie, A. Moody, D. Polster, O. J. Schmitz, A. R. E. Sinclair, B. M. Starzomski, T. P. Sullivan, R. Turkington, and D. Wilson. 2015. A call for applying trophic structure in ecological restoration. Restoration Ecology. 23:503-507.

Manfredo, M. J., R. E. Berl, T. L. Teel, and J. T. Bruskotter. 2021. Bringing social values to wildlife conservation decisions. Frontiers in Ecology and the Environment. 19:355-362.

Rominger, E. M., H. A. Whitlaw, D. L. Weybright, W. C. Dunn, and W. B. Ballard. 2004. The Influence of Mountain Lion Predation on Bighorn Sheep Translocations. The Journal of Wildlife Management. 68:993-999.
one person holding a scale, the other balancing a tube in a wintery scene with an orange snow survey sign in the foreground
Weighing a snow tube at a snow course marker to determine the snow water equivalent, or amount of moisture that's in the snow.

NPS photo Gretchen Baker

Changing Faces: A Recent History of Snow Surveys in GRBA

By Gretchen Baker, Ecologist and Meg Horner, Biologist

One of the oldest datasets in the Park is the Baker Creek Snow Survey, with three snow courses located in the Baker Creek watershed. Since 1941, the snow has been measured in late February and late March every year (and in some years also late January and late April).

Snow survey data is managed by the Natural Resources Conservation Service (NRCS). When I (Gretchen) started at GRBA in 2001, the surveys were run by two NRCS employees, including Curt Leet, with help from Rob Ewing (GRBA LE) and volunteers Jeff Woodruff and John Woodyard. I heard stories of how hard it was and was a bit intimidated. The 300% snowpack in 2005 resulted in them being dropped off by helicopter high up in the Baker watershed and skiing downhill so they wouldn’t have to break trail uphill through such deep snow. That sounded super cool, but also beyond my rudimentary cross-country ski level.

Around 2010, Law Enforcement staff changed, and Jacob Wahler was sent out to assist. He had never even been cross-country skiing. He survived, so I decided I would give it a try in 2011. It wasn’t easy, but with skins to help me get extra traction on the snow, I had enough control to make it doable and fun.

Jacob left the park, and no other law enforcement staff wanted to continue, so park resource management stepped in to assist , particularly Meg Horner and Ben Roberts. NRCS staff retired and moved, and a few years later Nicole Bolton started working for the NRCS in Ely. She quickly learned to cross-country ski and started helping with surveys.

The Baker Creek snow course has three sites: one just above the trailhead at about 8,200 feet elevation, another about 2 miles up the trail, and a third about 3 miles up the trail at 9,500 feet elevation. If we can get to the trailhead by driving or UTV, that means we can do the snow survey in about 8 hours. Otherwise, it is a long day lasting 10 or more hours. The best conditions are when we have good snowpack and recent snowfall. In years with minimal snowpack, we must take off our skis multiple times to avoid lots of obstacles.

When we get to each of the three snow courses, we assemble the three snow tubes, measure the distance to each of the five sites where we sample the snow, and drive the tube into the snow. We read snow depth, the length of the snow core in the tube, and then weigh the tube and snow in the tube to get the Snow Water Equivalent, or SWE. The SWE basically represents how much water would be covering the area if all the snow melted.

Thanks to all who have helped with snow surveys. Over the past 15 years that includes (in alphabetical order): Gretchen Baker, Joanie Bernardi, Nicole Bolton, Chandra Conrad, Joey Danielson, Meg Horner, Nancy Herms, Bryan Hamilton, Jenny Johnson, Curt Leet, Julie Long, Greg Moore, Mark Pepper, Ben Roberts, Brooke Safford, Peter Super, Andrea Wagner, Jacob Wahler, Jeff Woodruff, Liz Woolsey, and John Woodyard.

If you’d like to learn more about the science behind snow surveys, plus great tips for staying safe in the backcountry in the winter, you can check out the online snow survey training:

Selected Publications about the Park

  • Bentz, B. J., Millar, C. I., Vandygriff, J. C., & Hansen, E. M. (2022). Great Basin bristlecone pine mortality: Causal factors and management implications. Forest Ecology and Management, 509, 120099. Link
  • Danielson, J. R., Williams, J. A., Sherwin, R. E., Ekholm, K. L., & Hamilton, B. T. (2022). Seasonal variation in age, sex, and reproductive status of Mexican free‐tailed bats. Population Ecology. Link
  • Schoettle, A. W., Kegley, A., Sniezko, R. A., Burns, K. S., Vogler, D., Bovin, P. P., & Baker, G. (2022). Preparing for Invasion: Rust Resistance in Limber, Great Basin Bristlecone, and Rocky Mountain Bristlecone Pines. H5II Conference Proceedings. Link
  • Schook, D. M., Friedman, J. M., Hoover, J. D., Rice, S. E., Thaxton, R. D., & Cooper, D. J. (2022). Riparian forest productivity decline initiated by streamflow diversion then amplified by atmospheric drought 40 years later. Ecohydrology, 15(3), e2408. Link

Upcoming Events

  • June 22-24: Forest Health BioBlitz Get ready for the 14th annual BioBlitz, with an array of experts coming. Check the BioBlitz page for more info.
  • August 6: Centennial of Lehman Caves National Monument Dedication. Check the Centennial page for a schedule of events.
  • September 22-24: Astronomy Festival. Check the park website for details.
packrat with headlamp and backpack reading a paper
This woodrat knows of the many treasures to be found in middens!

Illustration by Emily Hale

More information

The Midden is the Resource Management newsletter for Great Basin National Park. A spring/summer and fall/winter issue are posted each year. We welcome submissions of articles or drawings relating to natural and cultural resource management and research in the park. They can be sent to: Resource Management, Great Basin National Park, Baker, NV 89311 Or call us at: (775) 234-7331

Superintendent: James Woolsey
Acting Integrated Resource Management Program Manager: Bryan Hamilton
Editor & Layout: Gretchen Baker

What’s a midden?

A midden is a fancy name for a pile of trash, often left by pack rats. Pack rats leave middens near their nests, which may be continuously occupied for hundreds, or even thousands, of years. Each layer of trash contains twigs, seeds, animal bones and other material, which is cemented together by urine. Over time, the midden becomes a treasure trove of information for plant ecologists, climate change scientists, and others who want to learn about past climatic conditions and vegetation patterns dating back as far as 25,000 years. Great Basin National Park contains many middens.
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Last updated: November 2, 2022

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