Natural World

Nature & Science

Jewel Cave is the second longest cave in the world. To date, over 140 miles of passages have been explored and surveyed, and airflow studies indicate that most of the cave has yet to be found. Each year, explorers discover and map about two additional miles of the cave.

Jewel Cave is well known for its natural beauty and unusual features. However, there is much more to the Monument than just the cave. Jewel Cave National Monument is also home to a variety of plants and animals, and has a fascinating wildfire history.

Natural Features & Ecosystems

The primary resource of Jewel Cave National Monument is the cave itself. Jewel Cave is a unique world of sparkling calcite crystals, delicate strands of gypsum, and other spectacular cave formations. It contains large rooms strewn with boulders, tight crawlways, and dark fissures leading into the unknown.

Environmental Factors

It might seem that the cave is isolated from the surface world - that the things that happen on the surface would have no effect on the cave. However, that is not entirely true. The changes inside Jewel Cave are usually so slow that the average person would not notice, but changes do occur, especially where moisture is able to seep from the surface into the underlying cave passages.

Increased moisture can cause the formations to grow faster, or it can erode them away. Forested areas above Jewel Cave receive less moisture than open, grassy areas. This is because trees take up much more rainwater than grasses do. When the surface of Jewel Cave was heavily forested with ponderosa pines, less moisture got into the cave. The Jasper Fire killed many of the pine trees, leaving the area open for grassy meadows. As a result, more rain water is expected to enter the cave, causing more changes.

The fire opened up the meadows to native plants such as blanketflowers, purple coneflowers, and western wheatgrass. Unfortunately, the fire-disturbed land also encouraged the growth of exotic plants such as mullein and Canada thistle.

Jewel Cave National Monument employs a "weed crew" to manually remove these unwelcome invaders. This means cutting the plants or pulling them up by their roots. The Monument does not currently use chemical herbicides on the plants because these could filter down along with the water into the cave, and the National Park Service strives to maintain natural water quality.

Many people, even those in big cities, get their drinking water from underground aquifers or rivers. Spraying herbicides or pesticides on the ground, dumping oil onto your driveway, or just pouring out chemicals like used cleaning fluid . . . all of these have the potential to affect the quality of the water you drink.

Fire

A Natural Cycle

Natural wildfires have burned throughout the world for thousands of years. The primary cause of wildfire is lightning. Not every lightning strike will cause a fire, but given the right conditions of heat, wind, and low humidity, a fire can easily ignite and spread.

Cross-sections of cut trees reveal a long history of fire in the Great Plains region. Fire scars are visible in tree growth rings, and can tell scientists how often fires naturally occur. In the Jewel Cave area, major wildfires historically happened on a cycle of at least every ten years. These fires were not usually catastrophic, because they occured so frequently. Frequent fires leave little material behind on the forest floor, and the result is a cooler-burning fire that thins the forest without destroying everything in its path.

The Cost of Suppression

The fear of fire has led to decades of successful fire prevention programs. The result has been a build-up of fuels. "Fuels" are anything that can catch on fire, such as dry pine needles and bark on the forest floor, dead trees, and dry grasses. This means that when a wildfire does start, it now burns with great intensity and is more difficult to stop.

The Benefits of Fire

The fuels consumed by fire don't just vaporize. They add nutrients to the soil that keep plants and animals healthy. Shortly after a fire, bright green grass can be seen poking up through the ashes. Deer and elk are attracted to recently-burned areas by the nutritous plants found there.

Most fires kill only small trees. The rest of the forest is left unharmed, and is actually benefited. When the forest is thinned out, trees are not packed tightly together and do not have to compete with each other for available nutrients. Fire also opens up the canopy, allowing more sunlight to reach the forest floor and stimulate the growth of grasses and wildflowers.

Prescribed Fire

Fire is both beneficial and inevitable. Prescribed fire is used as a tool to reduce fuel loads, manage vegetation, and mimic natural processes. Writing a fire prescription is complex, and takes into account weather, fuel type, fuel moisture, the objectives of land managers, and feasibility. Since fires will happen whether we light them or not, it is best to plan them ourselves, under the right conditions, rather than be surprised by a costly and catastrophic wildfire.

The most recent prescribed fire at Jewel Cave was in the fall of 1999. It burned low to the ground and spread slowly, meeting the fire objectives by removing built-up fuels on the forest floor. Less than a year later, the Jasper Fire started west of Jewel Cave. The area that had been burned in the prescribed fire did not burn as hot as other areas of the Jasper Fire. This slowed the fire's advance toward the visitor center and other park buildings, and very likely helped to save them.

Current Research

There is much that we don't know about Jewel Cave. Ongoing research contributes greatly to our understanding and effective management of the cave.

Airflow Study

For the past three years, a cave climatologist has been conducting a cave airflow study in the Black Hills. He has placed ultrasonic anemometers and temperature loggers in several barometric caves, including Jewel Cave and Wind Cave. 

Ultrasonic anemometers are highly sensitive instruments that can measure not only the velocity of airflow, but also the direction, temperature, and vertical flow component. This study is an attempt to better understand the dynamics of cave airflow, to calculate cave volume, and to determine whether or not the studied caves are connected to each other.

At Jewel Cave, airflow has been measured at the Historic Entrance and at constrictions leading to the eastern and western branches of the cave. Click here to listen to cave specialist Mike Wiles discuss the airflow study.

Microbiology Study

A microbiologist recently began a study of microorganisms found deep inside Jewel Cave.

A pilot study was conducted in 2001 to determine if microbes were present in samples of "corrosion residue," a powdery substance that coats the walls in some cave passages. The pilot study found stalked bacteria, with morphological similarities to organisms found in Lechuguilla Cave, New Mexico.

More samples were collected in 2005, and are currently incubating in glass tubes inside the cave. DNA will be extracted from these samples and compared with sequence databases in order to determine closest relatives. These cave microbes have the potential to be unique species found nowhere else on earth.

Jewel Cave National Monument encompasses 1275 acres of ponderosa pine forest and hosts a rich diversity of native plants. The Monument also contains many introduced non-native plant species. Controlling the spread of invasive exotic species is a primary objective of resource management at Jewel Cave.

Wildflowers

These are just a few of the native flowers that you might see while visiting Jewel Cave National Monument. To learn more, you can get a wildflower list from a ranger at the visitor center. Remember not to pick the wildflowers you find; leave them for others to enjoy!

Pasqueflower (Anemone patens) blooms in late March to early May and is the state flower of South Dakota. This flower is sometimes seen growing through the springtime snow.

Western salsify (Tragopogon dubius), also known as goatsbeard or yellow salsify, flowers in late May to July. It is zealously eaten by wildlife. When salsify gets ready to seed, it looks like a giant dandelion.

Gunnison's mariposa lily (Calochortus gunnisonii) is one of the many species of lily found at Jewel Cave National Monument. They flower in June to early August. The bulbs of this plant were used as food by the Cheyenne.

The pale-purple coneflower (Echinacea pallida var. angustifolia) was often used as an anesthetic by Native Americans. The roots or immature heads were chewed to suppress thirst as well. The flowers bloom in June through July.

Wild bergamot (Monarda fistulosa) is also known as horsemint or beebalm, and blooms in July through August. The leaves of wild bergamot were used by Native Americans in vapor treatments for colds.

Wavyleaf thistle (Cirsium undulatum) is one of the few native thistles at Jewel Cave National Monument. The flowers bloom in June through July, and attract many species of butterflies.

Exotic Plant Management

Invasive exotic plants such as Canada thistle and leafy spurge, if not controlled, can choke out native vegetation. Aggressively invasive non-native plants are known as "noxious weeds."

Jewel Cave National Monument uses an integrated pest management (IPM) approach to control noxious weeds. IPM includes manual / mechanical control (hand-pulling and cutting), chemical control (application of herbicides), and biocontrol (introducing insects which attack the plant).

Jewel Cave relies primarily on manual / mechanical methods to control exotic plants. Hand-pulling removes part of the root system and stresses the plant. Cutting prevents the plant from producing seed.

To prevent contamination of water inside the cave, herbicide chemicals cannot be used in most areas of the park. Biocontrol agents such as Apthona flea beetles are used to control leafy spurge, and have been quite successful where they have been released.

Many animal species make Jewel Cave National Monument their home. Most live in the ponderosa pine forest and open meadows of the surface, but some also live in the cave itself.

Over 1,000 bats use Jewel Cave as a winter hibernaculum, and some stay into the summer. Many packrats also make the cave their year-round home. They can sometimes be seen on the Lantern Tour.

Springtails are small insects that can be found near the historic entrance and around the Scenic Tour route. Deep in the cave, only protozoa and other microbes are able to survive, because of the lack of food. In fact, almost all cave life at Jewel Cave is found near the entrances, because there is no natural mechansim for carrying organic material deeper into the cave.

On the surface, herds of elk pass through the park, grazing on the meadows opened up by the Jasper Fire. These shy animals are rarely seen. Easier to find are white-tailed deer, mule deer, rabbits, red squirrels, and birds.

Bats

Year Round Residents

Bats are one of the most common mammals at Jewel Cave National Monument. Thousands of bats, of nine species, take advantage of the monument's habitat. Five species of Myotis and one species of Corynorhinus use the limestone caves throughout the year. Eptesicus fuscus (Big brown bats) are found at Jewel Cave during the summer months, and a few will hibernate here during the winter.

In late spring, pregnant Myotis are found at the monument, forming nursery colonies in ponderosa pine snags, rock crevices, and sometimes, buildings. Several hundred Myotis and Corynorhinus hibernate within Jewel Cave during the colder months, accessing the cave through the historic entrance.

Each year, the monument conducts a mid-winter bat count in order to monitor population levels. In January 2008, 1,319 bats were counted. There were 877 Corynorhinus, and 442 Myotis. Click here to download this year's bat count report (357 kb PDF).

Fair Weather Friends

Two species of bats reside at the monument only during the warm months. Hoary bats, which are the largest of the local bats, have a heavy coat of fur and roost high in the foliage of trees. Silver-haired bats take advantage of the high number of ponderosa pine snags to establish daytime roosts. They form nursery colonies in cavities created by woodpeckers and under loose, peeling bark. When the weather turns cold, the hoary and silver-haired bats migrate to the southern United States and Mexico.

Unsolved Mystery

Jewel Cave supports one of the largest known hibernating colonies of Townsend's big-eared bats in the world. C. townsendii are not known to migrate great distances, yet only one nursery colony has been located in the Southern Black Hills, despite intensive searches. C. townsendii seem to choose inaccessible caves (and presumably mines) for giving birth and raising young, and tend to choose sites which have little disturbance from humans. A single pregnant female was located at one of the monument's water sources in 1989, suggesting a nursery colony nearby. Information leading to the location of additional nursery colonies could help protect this species.

Beneficial Predators

Vacationers and the local community benefit from the insect control provided by bats. Black Hills bats are insectivorous; they feed on beetles, moths, flies, and mosquitoes. They also eat cockroaches, termites, crickets, katydids, cicadas, and night-flying ants. A single little brown bat (M. lucifugus) can catch hundreds of mosquitoes in an hour. Cucumber and June beetles, stink bugs, and leafhoppers, all well-known pests, are just a few of the many insects known to be consumed by bats. Townsend's big-eared bats are particularly adept at catching moths.

Bats at Risk

Bats are slow-growing and slow-reproducing mammals. On average, bats rear only one young per year. Some bats do not begin reproducing until they are two or more years old. Bats can be long-lived (a little brown bat was documented at 36 years of age), but the average life span of a bat that reaches adulthood is ten years.

Bats sometimes form large colonies, which makes them susceptible to disturbance. A significant portion of a colony can be put at risk each time the colony is disturbed. Because of their reproductive and colony-forming characteristics, bats do not bounce back quickly after significant disturbance.

During winter, many bats enter hibernation, a state characterized by a much lower metabolic rate and a body temperature near that of ambient air, and requiring an insulated, sheltered roosting site. Arousal of hibernating bats results in an increased metabolic rate. Numerous arousals exhaust a bat's energy reserves and might result in the bats lacking sufficient fat and water reserves to survive winter. To protect hibernating bats, no one is permitted to enter the historic entrance of Jewel Cave from October through May. The only exception is for the mid-winter bat count, which is conducted once a year by bat biologists and park managers.

Homeowners who attempt to evict bats from nursery sites might cause the adult females to abandon their young before the young are capable of flying and capturing food. This can result in starvation and the loss of a generation of bats. To avoid affecting the colony, bat exclusion should be accomplished before the bats arrive, or after they leave the roosts in late summer. Homeowners should provide alternate bat roosting sites near their buildings before excluding bats.

Bats are also threatened by predators. They are a food source for owls, hawks, falcons, raccoons, domestic and feral cats, and snakes. A single feral cat once waited outside the historic entrance of Jewel Cave and killed more than 200 bats! If you see a cat anywhere in the monument, report it at the visitor center. Park staff will trap the cat and bring it to a shelter.

Why is Jewel Cave a good hibernaculum?

The historic area of Jewel Cave has many different levels and temperature ranges. It provides a variety of suitable roosting habitats for a diversity of species. For instance, Corynorhinus hang from walls and ceilings at relatively low levels, and are tolerant of climatic fluctuations, while M.thysanodes, M. volans, M. lucifugus and M. septentrionalis hibernate in large rooms in relatively warm and stable environments.

The gated entrance works for bats in two ways. The gate provides protection by preventing unauthorized access, and it has horizontal bars which allow the bats to fly through the gate easily.

Will you see bats during your visit?

You might see bats if you are visiting during the warmer months, and in the evening. The monument bats hunt for insects during the evening and night hours. They have been seen flying over the visitor center parking lot, and entering and exiting Jewel Cave at the historic entrance. If you take the Lantern Tour, you may even see bats inside the cave.

Monument Bat List

Eptesicus fuscus (Big brown bat)

Myotis lucifugus (Little brown myotis)

Myotis volans (Long-legged myotis)

Myotis ciliolabrum (Western small-footed myotis)

Myotis septentrionalis (Northern myotis)

Myotis thysanodes pahasapensis (Black Hills fringed-tail myotis)

Corynorhinus townsendii (Townsend's big-eared bat)

Lasionycteris noctivagans (Silver-haired bat)

Lasiurus cinereus (Hoary bat)

Several of these species have been given special designations. Four species have been designated species of concern by the U.S. Fish and Wildlife Service: M. thysanodes, M. volans, M. ciliolabrum and C. townsendii. Four species are monitored by the South Dakota Natural Heritage Program: M. thysanodes pahasapensis, L. noctivagans, M. septentrionalis, and C.townsendii.

For additional information on bats, contact:

Bat Conservation International

P.O. Box 162603,

Austin, TX 78716

(512) 327- 9721

Reptiles

Below is a list of snakes found at Jewel Cave National Monument. No snakes are found inside the cave.

The list is alphabetical by common name with alternate common names listed after the back slash. Latin names are listed in parenthesis and italicized.

Bull Snake (Pituophis catenifer sayi)

Common Garter Snake (Thamnopis sirtalis)

Eastern Yellow-bellied Racer/Blue Racer (Coluber constrictor)

Milk Snake/Plains Milk Snake (Lampropeltis triangulum)

Plains Garter Snake (Thamnophis radix)

Plains Hognose Snake/Western Hognose Snake (Heterodon nasicus)

Prairie Rattlesnake (Crotalus viridis viridis)

Redbelly Snake (Storeria occipitomaculata)

Smooth Green Snake/Grass Snake (Opheodrys vernalis)

Wandering Garter Snake (Thamnophis elegans vagrans)

Turkey

Wild Turkey

Meleagris gallopavo

Family: Phasianidae (Pheasants, Quail, Peacocks, Turkeys and Chickens)

Benjamin Franklin preferred that the Wild Turkey, not the Bald Eagle, be the national bird. Wild turkeys are found all over the United States. This bird went from a rare visitor before the Jasper Fire to an uncommonly seen resident. Turkeys feed on acorns and nuts from trees, seeds, insects, roots and berries. They forage in open meadows during the day but roost in trees at night. Before the fire, Jewel Cave National Monument was heavily forested with few meadows. There were more than enough areas to roost, but the turkeys would have to fly far to find food. Now that the fire created open meadows where the turkeys can search for food, this bird has returned to the Monument.

Mallard

Mallard

Anas platyrhynchos

Family: Anatinae

This is the most commonly seen duck in the United States. Mallards have a wide variety of habitat. They can be seen on lakes, rivers, streams, ponds, and marshes. They eat a variety of grasses and herbs. The Monument has few suitable habitats for Mallards so it is rare to see one at Jewel Cave.

Great Blue Heron

Great Blue Heron

Ardea herodias

Family: Ardeidae

This is a rare visitor to the Monument. The Great Blue Heron is very water dependent. Its habitat is the shallow waters of marshes, ponds, lakes and tidal flats, even backyard pools and ponds. It wades through the shallows looking primarily for fish, but it also eats a variety of foods from small mammals to insects to other birds. The habitat of the Monument is not suited to Great Blue Herons. They live in the Black Hills but mostly around the artificially created lakes or seasonal marshes found throughout the Black Hills. They can also be spotted raiding backyard ponds that are stocked with fish.

Turkey Vulture

Turkey Vulture

Cathartes aura

Family: Ciconiidae

These huge birds are mainly spotted by the average person soaring magnificently above roads. Their primary habitat is deciduous woodlands and adjacent farmlands or pastures. The dominant tree species of Jewel Cave National Monument is the Ponderosa Pine, a coniferous evergreen so they are an uncommon visitor to the Monument. They are found throughout the Black Hills and adjacent prairie. As the day heats up, columns of hot air, called thermals, rise upward. Turkey Vultures ride these thermals saving themselves an enormous amount of energy by soaring without flapping their wings. The rising columns of air also bring the scent of their food to them. These birds are carrion eaters and can be seen feasting on roadkill.

Birds

The following is a list of birds seen at Jewel Cave National Monument. Not all of the birds listed below are commonly spotted at the Monument; even the rare birds are included. The list is arranged in the order found in most field guides.

Abbreviation code:

Frequency of birds found in the park:

a = abundant, occurs in large numbers

c = common, occurs regularly in moderate numbers

u = uncommon, occurs regularly in numbers in proper habitat

r = rare or accidental

Residency:

R = permanent resident

S = summer resident

W = winter resident

M = migrant, spring and/or fall

Bird (Frequency/Residency)

Great Blue Heron (r/S)

Turkey Vulture (u/S)

Mallard (c/M)

Blue-winged Teal (u/M)

Red-headed Merganser (r/S)

Gadwall (r/M)

Bald Eagle (u/W)

Sharp-shinned Hawk (u/S)

Cooper's Hawk (u/S)

Northern Goshawk (u/R)

Red-tailed Hawk (u/S)

Golden Eagle (u/R)

American Kestrel (u/S)

Wild Turkey (c/R)

Semipalmated plover (r/M)

Killdeer (u/S)

Greater Yellowlegs (r/M)

Solitary Sandpiper (r/M)

Spotted Sandpiper (u/S)

Wilson's Phalarope (r/M)

Franklin's Gull (r/M)

Rock Pigeon (c/R)

Mourning Dove (u/S)

Great Horned Owl (c/R)

Long-eared Owl (u/S)

Northern Saw-whet Owl (u/S)

Common Nighthawk (c/S)

Common Poorwill (u/S)

White-throated Swift (u/S)

Rufous Hummingbird (u/S)

Lewis' Woodpecker (u/S)

Red-headed Woodpecker (u/S)

Downy Woodpecker (u/R)

Hairy Woodpecker (c/R)

Black-backed Woodpecker (u/R)

Northern Flicker (yellow-shafted and red-shafted) (u/S)

Western Wood Pewee (c/S)

Dusky Flycatcher (c/S)

Cordilleran Flycatcher (u/S)

Western Kingbird (u/S)

Eastern Kingbird (u/S)

Loggerhead Shrike (u/S)

Plumbeous Vireo (u/S)

Warbling Vireo (u/S)

Red-eyed Vireo (u/S)

Gray Jay (u/R)

Blue Jay (u/R)

Pinyon Jay (u/R)

Clark's Nutcracker (u/R)

Black-billed Magpie (u/R)

American Crow (c/R)

Tree Swallow(u/S)

Violet-green Swallow (c/S)

Northern Rough-winged Swallow (u/S)

Cliff Swallow (c/S)

Barn Swallow (c/S)

Black-capped Chickadee (c/R)

Red-breasted nuthatch (a/R)

White-breasted nuthatch (c/R)

Brown Creeper (u/R)

Rock Wren (c/S)

Canyon Wren (u/R)

House Wren (u/S)

Ruby-crowned Kinglet (u/S)

Eastern Bluebird (u/S)

Mountain Bluebird (u/S)

Townsend's Solitaire (c/R)

Swainson's Thrush (u/M)

American Robin (c/S)

Cedar Waxwing (u/M)

Tennessee Warbler (r/M)

Orange-crowned Warbler (u/M)

Yellow-rumped Warbler (a/S)

American Redstart (u/M)

Ovenbird (c/S)

MacGillivray's Warbler (u/S)

Common Yellowthroat (u/S)

Yellow-breasted Chat (u/S)

Western Tanager (c/S)

Black-headed Grosbeak (u/S)

Lazuli Bunting (u/S)

Indigo Bunting (r/S)

Spotted Towhee (u/S)

Chipping Sparrow (a/S)

Clay-colored Sparrow (u/M)

Field Sparrow (u/S)

Vesper sparrow (u/S)

Lark Sparrow (u/S)

Lincoln's Sparrow (u/M)

Dark-eyed Junco (c/R)

Red-winged Blackbird (u/R)

Western Meadowlark (u/S)

Brewer's Blackbird (c/S)

Brown-headed Cowbird (c/S)

Northern Oriole (r/M)

Cassin's Finch (u/S)

Red Crossbill (a/R)

Pine Siskin (c/R)

American Goldfinch (u/S)

Geology