I. PLANNING AREA DESCRIPTION
The Road 18 Caves Environmental Assessment (EA) (hereinafter referred to as the Caves EA) project is designed to analyze effects of humans on wildlife resources (including bat habitat), recreation opportunities, geologic features, native vegetation, and cultural resources at nine caves in regards to past, present and future use. The project includes low and high use caves that were addressed in the Cave Strategy in 1999: Boyd Cave, Arnold Ice Cave, Skeleton Cave, Charcoal Cave, Hidden Forest Cave, Wind Cave, Bat Cave, Deg Cave, and Charlie-the-Cave.
The project is located approximately eight miles southeast of Bend, Oregon, in the northeastern portion of the Bend/Ft. Rock Ranger District of the Deschutes National Forest. The project lies within portions of T19S, R13E; Sections 4, 8, 14, and 27 Willamette Meridian. The area is located east of the Northwest Forest Plan boundary line, and lies outside the range of the northern spotted owl. It is located in the Kelsey Butte/Arnold Subwatershed.
II. MANAGEMENT DIRECTION
The Deschutes National Forest Land and Resource Management Plan (LRMP), as amended in June 1995 by the Decision Notice for the Continuation of Interim Management Direction Establishing Riparian, Ecosystem and Wildlife Standards for Timber Sales (hereinafter referred to as the Interim Management Direction), and Inland Native Fish Strategy, establishes broad direction for the Forest. The analysis conducted for the Caves Planning Area tiers to the LRMP and its supporting documentation. Cultural resources on the Deschutes National Forest are regulated by the guidelines in a 1995 Regional Programmatic Agreement between the USDA-Forest Service, the Advisory Council on Historic Preservation, and the Oregon State Historic Preservation Office. Forest Service Manual (FSM) 2356 also provides direction for the management of caves on National Forest land. The EA would incorporate significance criteria found in the Federal Cave Resources Protection Act (FCRPA) of November 18, 1988.
III. PURPOSE AND NEED FOR ACTION
The primary purpose and need for this EA is to preserve and protect cave resources of the eight caves located within the Arnold lava tube system and Skeleton Cave. The EA addresses emerging impacts of a visitor use philosophy that promotes mostly unrestricted cave access. Management adjustments are designed to reduce or eliminate impacts to caves and cave resources from human use. This approach is designed to provide the Forest Service with a template for uniform and consistent management for each cave discussed in this EA.
The purposes of the FCRPA are: (1) to secure, protect, and preserve significant caves on Federal lands for the perpetual use, enjoyment, and benefit of all people; and (2) to foster increased cooperation and exchange of information between governmental authorities and those who utilize caves located on Federal lands for scientific, education, or recreational purposes." It is the policy that Federal lands be managed in a manner, which protects and maintains, to the extent practical, significant caves (as classified under the act). (102 Stat. 4546; 16 U.S.C. 4301-4309)
Direction from the Forest Service manual states: "Caves are dynamic natural systems affected by surface and subterranean environmental changes. The policy of this manual is to manage caves as nonrenewable resources while maintaining their geological, scenic, educational, cultural, biological, paleontological, and recreational values." It is also the policy to "emphasize wild cave management with few or no facilities to aid or facilitate use."
Currently, all of the caves in the project area qualify as significant caves under the definition of the Act. All activities within significant caves (as defined by FCRPA) have the potential to cause damage to the geology or biota of the caves. This includes but is not limited to, walking, breathing, touching, and adding or removing materials to the cave floor, ceiling, or walls. The extent to which these activities alter or damage the cave resources varies with the type of activity, the location of the activity in reference to important cave resources, the visibility and duration of the activity, and the amount of alteration of the natural condition of the cave that results from the activity.
A Cave Strategy, completed by the Deschutes National Forest in 1999, identified conditions and recommendations related to the cave resources. Some of the identified conditions pose a threat to caves and cave resources and to the quality of the recreation experience of these caves. Generally, the Cave Strategy recognized a need to maintain caves and cave resources through time by reducing, eliminating or changing human use patterns.
Specifically, the Cave Strategy identified the following long-term goals:
IV. EXISTING CONDITION
1. Recreation
Cave resources have deteriorated with increased visitation and recreation
activities over the last five to eight years. With little if any site definition
at the caves (i.e., visitor facilities, designated parking areas, pathways,
etc.), new user-defined parking areas, roads and trails have developed on the
landscape. This has resulted in the loss of vegetation, wildlife habitat and
aesthetic quality, especially at cave entrances.
The more popular caves (Wind, Skeleton, Arnold and Boyd) are accessed from system roads off of Road 18 (China Hat). Parking areas are not well defined on the ground, which has led to vegetation impacts through expansion of the sites by the public. This mostly occurs through the development of more parking and somewhat from the development of campsites (mostly to accommodate camp trailers or large recreation vehicles). None of the interior of the caves in the project is accessible by people in wheelchairs. Though people in wheelchairs cannot access the cave mouths or interiors they can get to the cave entrances and peer in.
With increased uses and visitations, there has been a corresponding increase in dispersed trails, littering, bolting and chalk accumulation in cave ceilings and walls, vandalism and graffiti as well as damage to other cave resources including, but not limited to, loss of wildlife habitat and cultural resources. This increased use has changed this unique habitat and increased disturbance to wildlife as well as changes to traditional, aesthetic, and recreational experiences that people have come to enjoy and anticipate. Such use can also diminish the experience of solitude, quiet, or scenic beauty that people have enjoyed in the past.
In the past, limiting vehicle access to caves has shown to minimize human disturbance as well as to diminish vandalism. However, many of the road closures continue to be illegally breached due (in part) to the loss of vegetation from the Wind and Skeleton Fires, topography (the area is flat with little to no natural barriers), and also a lack of support for the closures from a small segment of the public who use the caves.
There are three basic types of legitimate activities that occur at these caves: sport climbing, bouldering, and spelunking.
a. Sport climbing emphasizes extremely difficult moves and relatively short and uncomplicated approaches and descents while minimizing risk. The climbing experiences at some Road 18 caves are a good example of the diverse climbing opportunities and unique environments that climbers seek in the United States. Several caves offer the opportunity to suspend horizontally from the cave ceiling while sport climbing or bouldering. This area is the only known place in the country where sport climbing in caves on Federal lands is permitted. Despite the fact that the type of climbing found here is technically very difficult, virtually all climbers who have visited the caves believe they offer a unique climbing experience that should be available to the public. The various types of technical climbing are generally defined by the characteristics of the experience.
Bolt anchors and overhanging rock typify climbing areas. Not all sport climbers place bolts; only the first ascent party places bolts, and all subsequent parties use these bolts. Historically, climbers have been responsible for determining when and where to place and replace bolts, modify handholds or place artificial handholds. Climbs generally end at fixed anchors where the sustained difficulty of the climb diminishes or the character of the rock changes. The climber descends by being lowered or rappelling from these top anchors.
b. Bouldering is the term for climbing that concentrates on short sequential moves on rock usually no more than 20 ft. off the ground. Each climbable sequence of moves is called a "boulder problem", and each boulder problem varies in difficulty. Some bouldering is practiced for bigger climbs while others pursue it as a rewarding sport in its own right. Bouldering requires relatively little equipment other than rock shoes, chalk and sometimes the use of a "crash pad". Crash pads (usually 4' X 3' and up to 5" thick) may be placed below climbs to soften falls and lessen risk of injury from accidental bad landings. Bouldering embraces a greater degree of risk than sport climbing and a sense of freedom that derives from the focus on pure movement rather than on equipment.
Sport climbers and boulderers use magnesium carbonate powder (chalk with or without additives) to improve their grip on rock. In steep, technically difficult, humid environments, the use of chalk is widely considered essential to participate in this activity.
The climbing opportunities by cave are summarized as follows:
c. Caving (Spelunking) has been a popular recreation activity for a variety of visitors at these caves for decades. Some come to explore the cave from entry to end, curious about the geology and the cave environment. Others only venture near the entry, as a retreat from the summer heat. Some are family groups, or a few friends out for an afternoon picnic, while others are avid cave enthusiasts that explore caves as part of a formalized club. Other formalized groups, such as the Boy Scouts, have nature study outings to the caves. Overall, the caves provide an opportunity for seclusion, exploration and relaxation for an array of local and non-local visitors.
2. Wildlife Habitat
The following species can be found within and adjacent to caves and cave entrances.
Big Game
This project occurs within Deer Habitat (MA 7) as identified by the Deschutes
National Forest Land and Resource Management Plan (LRMP, 1990), and is subject
to the standards and guidelines described in the LRMP. A small number of elk
also inhabit the project area during the winter months. There is no cooperative
road closure in this portion of the deer winter range so all roads (unless
otherwise noted) are open to vehicle traffic during the winter months. OHV
traffic also occurs during this time. The disturbance from vehicles and OHVs to
big game varies throughout the winter depending on snow depth. This disturbance
is increasing as the population of Bend increases and the number of people
recreating (sightseeing, wildlife watching, OHV trail riding, and caving)
increases within the winter range.
Raptors
There are currently no known raptor nest sites adjacent to the caves within
the project area. Historically, kestrels have been known to nest in the cavities
of trees near or within the sink at the cave entries to Hidden Forest Cave. Some
of these trees have been used for climbing or rappelling, thus likely disturbing
any kestrels that would nest here. With the use at this cave increasing to
climbers, the kestrel's use of this habitat is unlikely.
Raptors are known to drink the melt-water in the cave entry of Arnold Ice Cave.
Woodpeckers
Habitat occurs for several woodpecker species within the project area. There
are a few trees that occur within the sink to Hidden Forest Cave that contain
cavities for woodpeckers and other cavity nesters. Some of these trees have been
used for climbing or rappelling, thus likely disturbing any woodpeckers that
would nest here. With the use at this cave increasing to climbers, woodpecker
use of these trees is unlikely.
Woodpeckers have been known to drink the melt-water in the cave entry of Arnold Ice Cave.
Special Habitat/Ecological Indicators
As of January 1994, cave distribution on National Forest lands in Oregon and
Washington was: 45% of all known caves in Oregon and Washington occur on the
Deschutes National Forest and 75% of caves in Oregon occur on the Deschutes
National Forest (USDA 1997).
Cave entrances are both sensitive and critical to cave ecosystems. Entrances are a focus of biological activity that contributes nutrients to deep cave organisms. The moderating effect of warm moist air creates microenvironments, which promote growth and occupation by unusual plants and animals. It is common, for example, to find plants and animals occurring at cave entrances that are otherwise many miles outside their normal range (Nieland 2000).
Caves share with other discrete habitats vulnerability to trampling and physical disturbance, and because of their conformation, have a much lower human carrying capacity than most surface environments. Cave systems can be disrupted to a much greater degree than most other habitats because of the confined space involved, limited escape routes for species using caves, and the fragile ecosystems within caves. Small passages suffer greater disturbance than large passages because a greater percentage of small passage area is affected (Nieland 2000).
The caves within the project area provide habitat for many vertebrate and invertebrate species. Factors that attract the species include solitude, darkness, stable temperatures, and hydrologic values. The following are species that can be found to utilize the caves that occur within the project area:
Insects - (flies, beetles, etc.) - The majority of cave inhabiting organisms are insects and range from accidental to true troglobites (animals that live in caves and are not found elsewhere). Included in this group would be the fleas associated with mammals and perhaps nests, some flies which have larval stages in animal droppings, other flies with larval stages in decaying bodies, several species of moths which often hibernate near entrances, a variety of fungus flies which swarm at skylights and entrances, a couple of fungus flies which appear to be troglobites with the larvae feeding on mold on the walls, crickets which hibernate in caves or move in and out daily to feed outside, beetles, and finally the grylloblattids, a relatively large wingless predaceous form (USDA 1997). Several of these insect species, especially moths, are an important prey base for bats.
Arthropods - A variety of arthropods are present in caves. Some of these are:
Millipedes and Centipedes - these creatures live primarily in the surface debris on soil and thus are often present in entrances and cave twilight zones.
Arachnids (spiders, mites, ticks, and harvestmen)- Spiders are common in cave entrances and twilight zones where they feed on insects. Mites are commonly found in rodent nests where they feed on the rodent, the debris left by it in and around the nest and on the vegetable matter. Some apparently feed on fungi that might grow on various organic sources including mammal droppings. Hibernating harvestmen are often found near the entrances during the winter.
Reptiles - Resident snakes will enter caves for hibernation in winter but probably tend to use smaller cavities.
Frogs - Frogs and toads are unable to survive long in the dark zones but are encountered in the twilight zone.
Salamanders - Several groups of salamanders are capable of living in caves, primarily in the twilight zone. They can lay eggs in damp debris such as rotting moss-covered logs that are often present in the entrance and twilight zones.
Birds - Great horned owls, red-tailed hawks, kestrels, vultures, wrens, robins, juncos, thrushes, woodpeckers, sapsuckers, flickers, swallows, and ruby crowned kinglets will nest in or near the entrances but are capable of surviving elsewhere. Some owls may hunt bats near cave entrances.
Rodents - Packrats and porcupines may have dens or nests near the entrances but seem to prefer smaller passages and rooms. Chipmunks, golden-mantled ground squirrels and gray squirrels will enter the twilight zones to shell cones. None of these require caves but the litter and droppings they bring into the cave may be a significant input to the energy of a cave. Deer mice and pika are also seen. Snowshoe hares have been known to use them for shelter.
Carnivores - Bobcats, cougars, coyotes and other smaller carnivores use caves for shelter in some areas, but can survive without them.
Bats - Bats include small-footed myotis, long-eared myotis, long-legged myotis, fringed myotis, California myotis, big brown bat, little brown bat, western big-eared bat, and hoary bat. Caves are often used as winter hibernation sites or summer maternity sites. During the summer, some bats may roost in caves during the day and fly outside to feed in the evening. Additional information regarding bats is given in the following section below.
Recreational caving can disturb many of these species. Besides bats, woodrats and pikas will abandon caves if disturbed (Senger and Crawford 1984). The introduction of sport climbing and bouldering at several caves may prevent use by some of these species (including bats at one cave, which is currently closed year around) by disruption of cave walls, ceiling, and floor habitat. Humans have used the caves within the project area for centuries. Habitat has been moved or removed (rocks, logs, vegetation) that some of the above listed species need for their survival. It is unknown what the populations of many of the cave dwellers are, with the exception of bats at each of the caves within the project area. Biological inventories have not been conducted and would be difficult for most species. We can only assume that with the history of human use, and the types of uses that occur within the caves, that these species have been disrupted in some way by disturbance to cave habitat.
None of the bat species that use the caves are Federally designated as sensitive (Region 6), threatened, or endangered. The small-footed myotis, long-eared myotis, long-legged myotis, fringed myotis and western big-eared bat (considered critically sensitive in Oregon, indicating that listing as threatened or endangered may be appropriate if immediate conservation actions are not taken) are all listed as sensitive by Oregon Department of Fish and Wildlife. These same species are also listed by the United States Fish and Wildlife Service as species of concern (SOC). The long-legged myotis has received special habitat protection status on Federal lands in western Oregon in order to prevent population declines. The western big-eared bat was listed as a regionally sensitive species, but was not included in the most updated list dated November 2000. It is recognized as a management indicator species for the Deschutes National Forest. Two other subspecies of big-eared bat, the Ozark big-eared bat and the Virginia big-eared bat, are listed as endangered in the eastern U.S.
Interest in recreational caving is increasing in America. Along with the obvious benefits the educated, conservation minded cavers offer to cave management come the undeniable negative impacts that increased roost visitation has on sensitive bat species. All bats are sensitive to disturbance from humans entering hibernating and maternity colonies. Humans passing under a hibernating group of bats, or spending only a short time in the roost, may not be aware that they have disturbed the animals. Nervous conduction is very much a function of temperature, and bat behaviors that would indicate disturbance to humans (wriggling, scanning, taking flight) may not be evident until the bat has warmed sufficiently to move its muscles. This may take some time and human visitors may leave before agitation is evident. But the warming process is irreversible and will proceed until the bat is fully warm and able to fly, even though the source of the disturbance has disappeared. By simply shining a light on cluster of bats can trigger an awakening response (Twente 1955). Repeated disturbances of hibernacula and the consequential excessive loss of the bats' limited winter energy reserves may result in reproductive failure, abandonment of the site or death due to starvation. Each arousal costs an individual bat 14 to 21 days of stored fat from its vital reserve. Such arousals substantially effect the winter survival of the bat (Senger and Crawford 1984).
Unlike many species, which seek refuge in crevices, the western big-eared bat will form highly visible clusters or roost as single bats on open surfaces, such as domed areas of caves, making them extremely vulnerable to disturbance. This species is highly susceptible to human disturbance and may abandon roost, nursery, or hibernating areas if disturbed (Marshall 1992). The western big-eared bat is a colonial species with relatively restrictive roost requirements. In general, hibernacula for the western big-eared bat in the western United States contain mixed-sex groups that generally are comprised of fewer than 40 individuals, and only exceptionally exceed 200 animals (Dobkin 1992). Western big-eared bat roost fidelity, longevity and low reproductive capability all combine to intensify any negative effects of anthropogenic threats to the species.
Population declines have been documented for the northwest including populations in Oregon (Perkins 1986 and Dobkin 1992). The western big-eared bat was considered common in the 1930's (Marshall 1992). In Central Oregon, oral accounts indicate that more bats hibernated in these caves between 1950 and 1970 (Becker 1995). Based on population counts in hibernation caves between 1970 and 1985, the decline had continued (Perkins 1986). The decline is attributed to several factors: increased human activity in caves, the sensitivity of the bats to human disturbance, the narrow range of temperature and humidity conditions required by bats for hibernation, raising young, and roosting, and forest fires.
Western big-eared bats are insectivorous, feeding primarily on Lepidoptera (Whitaker et al. 1981). They forage in a broad range of forested conditions, from open savanna to fully stocked conifer stands. Prey species are strongly associated with bitterbrush, ceanothus, and other shrub species (Miller 1995). Most foraging is suspected to occur within five miles of their day roosts. Past studies have shown that foraging along forest edges occurred most often, apparently related to availability of prey species (moths) and protective habitat from predation (Clark 1993).
Most caves within the project area provide ideal habitat conditions for the western big-eared bat and several other bat species for hibernation and maternity colonies.
Surveys conducted over the past 15 years have found 2 maternity roosts and 6 hibernation roosts used by western big-eared bats within the project area. All these roosts were burned over in the 1996 Skeleton wildfire. The population is estimated to be 600 individuals in Central Oregon (including the Deschutes National Forest and immediately adjacent areas). The total population in Oregon is approximately 2,300 to 2,600 (Perkins, 1986). About 25% of the known Central Oregon winter population hibernates in the project area; 65% of the winter population hibernates within 1 mile of the project area; and, 10% hibernates about 20 miles southeast of the project area. Maternity roosts have been surveyed for occupancy in 6 of the last 14 years; they have been occupied for 3 of the 6 years. Two other maternity roosts were found about 30 miles southeast of those in the project area. They have been occupied in both years they were surveyed. Population trends for Central Oregon, based on winter counts in hibernacula, have declined about 25% since 1986 (see the attached graphs in Appendix A). The decline is most likely related to increased human activity, disturbance to maternity and hibernating colonies, and the impacts of recent wildfires. Within the project area, surveys between 1990 and 2000 have found as few as 1 bat in the smallest cave to as many as 94 in the largest cave.
The above hibernation roosts are also used by several myotis species. Although populations of myotis remain healthy across the state, disturbance during the hibernation period has negative impacts on their survival also. There is one big brown bat maternity colony within the project area. As few as 1 myotis in the smallest cave, to as many as 31 myotis in the largest cave were found hibernating between 1990 and 2000 surveys.
Recreational use of the caves has been increasing over the past 10 years (see the Recreation Specialist Report in the EA). Contemporary levels of human disturbance and various human activities may be displacing bat species, especially the western big-eared bat. At present, two hibernating caves are open year around to the public, and four have administrative seasonal closures. These closures are continuously ignored by a small segment of the public. Currently, none of the hibernacula caves are 100% secure to protect hibernating bats. In caves and mines in other areas of the U.S. where disturbance has been controlled, the numbers of hibernating bats has increased dramatically within a few years of the closures. This has prompted administrative seasonal closures to several caves to protect roosting bats and evaluate preferred bat use in the absence of human disturbance. These closures are continuously ignored by a small segment of the public, making it difficult to evaluate this habitat.
Besides forest fires, clearly, the single greatest threat to bats is human disturbance. This can come from recreational use and/or intentional harassment. Seasonal closures and gates are needed to prevent disturbance to these bats. Disturbance from human visitation (noise and lights) awakens the bats. To avoid the disturbance, the bats may awaken and fly. The effort causes them to expend energy, which they need to survive the remainder of the winter. Because the bats eat only insects, and insects are not active in the winter, the bats depend on stored fat reserves for energy during hibernation. They lose between 30 to 50% of their weight during winter hibernation. Any extra activity reduces their chances of survival until spring when insects become available again.
Western big-eared bat's sensitivity to human disturbance of roost sites is well documented. Western big-eared bat maternity and hibernation roosts that experience increased visitation rates during critical use periods experience concomitant losses in colony populations. Graham (1966) blamed the abandonment of several maternity sites through the species range to an increase in recreational cave activity. Pierson et. al. (1991) has shown that those colonies with the greatest population declines also experience frequent disturbance. A long-term study of a number of cave roosts in West Virginia (Stihler and Hall 1993) has shown that excluding humans from roost sites by gating or fencing has resulted in an increase in big-eared bat populations. When gates have been breached, populations have dropped precipitously, and been slow to recover. The summer after the cave was illegally entered, the colony numbered only 286, and four years later had only recovered to 40% of its pre-vandalism levels.
The most acceptable method of restricting access is through the use of gates. Gates placed on caves to protect bat species are usually constructed of horizontal angel iron bars, welded to support posts. Bars are spaced (5 3/4 inches) wide enough for bat passage, but narrow enough to block humans.
Many of the caves within the project area occur within habitats that have been impacted by wildfire. The fires killed extensive areas of bitterbrush and sagebrush, and increased grass cover. This has reduced the amount of vegetation adjacent to cave entrances and most likely changed bat prey abundance and species composition. Vegetation surrounding entrances not only provides habitat for bat prey species, but also helps maintain environmental conditions needed by many other animals. Shading, and protection from strong winds, provided by trees, may be essential for maintaining temperature and humidity regimes necessary for bats. Vegetation surrounding roost entrances may also provide protection from predation (Nieland, 2000).
3. Geology
The caves considered in this Environmental Assessment all developed during
volcanic activity and have been affected by subsequent volcanic activity. Though
the source of these lava tubes is not known positively, its thought that most
were formed within lava flows erupted from Lava Top Butte to the south of the
project area sometime between 30,000 and 200,000 years ago. More recent volcanic
eruptions have spread thin layers of ash over the landscape including a one-foot
layer from the catastrophic eruption of Mt. Mazama (Crater Lake) 7,700 years
ago.
The natural features of these lava caves have created a host of microenvironments. The cave entrance allows volcanic ash, soil, water, seeds, pollen, plants, light, animals, and air to enter. Ash and soil accumulate on the cave floor at the entrance and may be spread by water a short distance into the cave. A strong gradient of moisture and light extends from the cool, moist soils of the cave floor at the entrance to the darker and lower moisture areas further into the cave. Many microenvironments exist in this relatively small area. This gradient is modulated by "breathing" of the cave where air constantly moves into and out of the cave as a result of barometric pressure changes. Plants and animals occupying this lighted, dynamic region can be readily affected by human activities.
Deeper in the cave, open spaces in the heavily fractured rock carry water, air, and fine-grained soil. Water from rain and melting snow percolates downward through the cave on its way to the water table hundreds of feet below. Human activities on the surface and in the cave can change the chemistry and particulate material carried in these waters, which can affect cave life and the deposits on cave walls.
Vast amounts of air flow through the caves and all their surrounding fractures every time the barometer changes, which is hundreds of times a year. Smoke, dust, pollen, and anything small enough to be carried by air are spread throughout the cave and its fractures. Dense smoke from human fires in the cave, smoking or from forest fires outside can affect cave life, including bats.
These lava caves are very strong, except at a few places including cave entrances and areas of unstable fractured rock inside the caves. Over geologic time, earthquakes, ice wedging, and accumulated tiny movements from daily heating and cooling of rocks dismantle these caves. New lava flows can bury the caves. Over human-scale time, the influences on these caves are related to people, fires, and climate.
4. Scenic Quality
The Road 18 caves project area is located along a secondary travel route with
close proximity to the urban interface area near the city of Bend, Oregon. Both
humans and animals have used the caves in the past for shelter and recreation
throughout the pre-history and history of Central Oregon. Over the years, these
caves have been used and abused. Intensive recreation, vandalism, graffiti and
unsightly deposit of trash and other remains are a constant concern for land
managers and the general public. Unmanaged foot and vehicular traffic have worn
down the areas around the entrances to these caves area.
Vegetation, such as trees, shrubs, and grass species, have been reduced or eliminated from the immediate area at most caves. Erosion, by both wind and water is a threat to cave and scenic resources.
The current impacts to these caves have altered the existing landscape character from a "natural appearing landscape" into a more altered landscape.
The desired scenic condition for the caves is a "natural appearing landscape" where land management and recreational use would not drastically alter the existing landscape character.
5. Proposed, Endangered, Threatened, and Sensitive Plants (PETS)
a. Vascular plants
The areas close to the caves and above the entrances have a plant association
of bitterbrush, sagebrush, bunch grasses, such as Idaho fescue, and some
ponderosa pines. These potentially offer habitat for the green-tinged
paintbrush, Castilleja chlorotica, although none were located during plant
surveys. The areas at the entrances to the caves are generally lower than ground
level and contain a more diverse flora including Desert-sweet, Chamaebatiaria
millefolium, Giant wildrye, Elymus cinereus, and Ocean-spray, Holodiscus
dumosus.
Although the plant species at the entrances are common plants, it is unusual to
find them in this area of the district and they offer an interesting variety of
flora in these smaller more confined places. Caves within the area of the
Skeleton Fire suffered damage to the plants, but during this year's visits it
was noticed that most plants had recovered and were thriving. Disturbance from
foot traffic is visible at all the caves and there are areas of bare soil. Foot
traffic will continue, but if pedestrians remain on the existing footpaths
further damage to the flora is likely to be minimal.
No proposed Threatened, Endangered, or Sensitive (PETS) species were found at the cave entrances or in the area immediately above the caves.
b. Non-vascular plants
1b. Lichens. There are three types of lichens; crustose, foliose and
fruticose, and representatives of each type inhabit these caves. Crustose
lichens such as Diploschistes spp. Xanthoria spp. and Candaleria
spp. were
common in the entrances and on the rocks outside the caves. Crustose lichens
when dry are, for the most part, fairly hardy. They will, however, be worn away
by constant foot traffic especially when wet. Where trails into the caves go
over the rocks few crustose lichens were seen. In Skeleton Cave, Lepraria spp.
was growing on the rock inside the cave about 20 feet from the entrance to about
60 feet back. This bright green lichen also grows in a small patch near the
entrance on the east side and had some chalk marks on it. Studies that were
begun in the City of Rocks National Monument found that although chalk will
discolor crustose lichens, it will not kill them. Foliose lichens such as
Peltigera spp. were seen growing on many of the rocks in the areas of the cave
entrances and frequently on the rocks above the caves. Foliose lichens are
susceptible to damage by abrasion (foot damage) and are more sensitive than
crustose lichens to changes in air quality. Few were seen in the area of rock
immediately above the entrance to Skeleton Cave. This may be a result of past
campfires in the entrance of the cave. Some fruticose lichens such as Cladonia
spp. were also found in the lower areas outside the caves. The Cladonia spp.
tended to grow in the sheltered area below shrubs, but they too would be
susceptible to foot damage should the shrubs be damaged or removed.
2b. Bryophytes. Mosses are most likely to be rubbed off the rocks by foot traffic and climbing activities, and few were found on the rocks at the cave entrances. Some Rhacomitrium spp. and Grimmia spp. were found growing in a few places in the lower areas outside the caves. Tortula spp. grew where protected either by shrubs or by being in less accessible locations. At Skeleton Cave, there was some damage to the mosses that were growing on the vertical rock wall outside the cave. This appeared to have been caused by climbing on the rocks, but it could have been a natural event.
No Lichens or Bryophytes are listed as Threatened, Endangered, or Sensitive Plant Species on the Deschutes National Forest.
6. Noxious Weeds and Exotic Plants
Cheatgrass, Bromus tectorum, grows near many caves in this project area.
There is a lot of cheatgrass at Boyd, Wind and Skeleton caves. It grows around
the top of Charlie-the-Cave in the disturbed area. It also grows among the
shrubs around the top of Arnold Ice cave and Charcoal and it has been seen along
the trails to these two caves. There was a little cheatgrass in the areas of the
other caves. Although it is not considered a noxious weed, it is a very
aggressive and undesirable non-native. Part of a Russian thistle, Salsola
Kali,
was found near the entrance to Skeleton Cave and some yellow sweet clover,
Melilotus officinalis, was seen along Road 242 near Boyd Cave. No other noxious
weeds have been found close to the caves.
7. Cultural Resources
a. Prehistory
Human occupation of Central Oregon and Deschutes County in particular, spans
at least the last 11,500 years, falling with the recent geologic/climatic period
known as the Holocene. Three historically known Indian tribes inhabited and/or
seasonally used areas within the County, the Northern Paiute, the Tenino/Tygh
(Warm Springs) and Klamath. These tribes represent small bands of hunting and
gathering peoples who were adapted to the high desert (steppe) and
woodland/forest environments of Central Oregon by a nomadic or semi-nomadic
foraging and collecting way of life. Faunal, floral and geologic resources
sustained their economies. Tool kits, such as hunting and gathering implements,
adornments and clothing were also supplied by faunal and floral resources, and
in addition, geologic resources provided tool stone for lithic tools, such as
obsidians, basalts and micro-crystalline silicates, and pigments, such as iron
oxide (red ochre).
The caves are located on the northern flanks of Newberry Volcano, located between likely winter village locations on the middle Deschutes and Crooked River drainages and the rich lithic resource patches, in the form of vast obsidian flows of the volcano's caldera. It is likely that prehistoric Native Americans traveled through this area on the way to procure new tool stones to replenish their supplies. The availability of water, sometimes in the form of ice, would have been the sole source of water in this area, and thus is potentially responsible for the presence of lithic scatter sites. It is also likely that large and small terrestrial game species were also hunted and gathered opportunistically in this area as well. The Native Americans consider the caves in this analysis area a spiritual and sacred area to be protected from damage and defacement. Furthermore, the presence of rock art in the area, indicate both the acquisition and use of mineral pigments for spiritual/symbolic activities in the area, which are generally associated with moderate to intensive prehistoric use or occupation.
b. History
The historic period for Central Oregon began as Euro American explorers
transected the area during the first half of the 19th Century. These expeditions
were associated initially with fur trapping, then military/scientific surveys,
and later, military campaigns against insurgent Indian populations. While these
expeditions left little physical evidence, they did spur later settlement by
providing accounts of the land and resources, such as John C. Fremont's popular
travelogue of his 1843 survey of the Deschutes River with Kit Carson and Indian
guide, Billy Chinook.
The Prineville area was settled after 1870 and by the 1880s pioneer ranchers and settlers were coming to the Arnold Cave system area by wagon and horseback for picnics, overnight camping and recreation. Later the ice caves, such as Arnold, were ice-mined, where blocks were cut and transported out of the cave in chutes and carried by wagons to the community of Bend, which was settled in the early 20th Century, for use in taverns, distilleries and grocery stores. Once Bend was connected to the intercontinental railroad routes in 1911, Central Oregon pine forests were opened up to large scale industrial logging operations, with the establishment of the Brooks-Scanlon and Shevlin-Hixon mills and railroad logging systems. In the early 1920s the Brooks-Scanlon logging operations moved into the Arnold Ice Cave area. Recreation use of the caves increased, particularly following the close of the WWII era, when road access improved, and the local population had more free time and expendable income. That trend of increased use of the caves has been on the rise ever since.
There are few intact historic sites and features within the project area of any significance. Much of the evidence of early 20th Century recreation, ice-mining and logging did not leave any lasting traces, save for the presence of linear features in the form of old trails, road and logging railroad grades. However these linear features have not retained their original integrity due to subsequent uses and natural deterioration.
Caves in central Oregon hold special meaning to the Native Americans whose ancestors used these caves in the past. The increase in recreation use has had an effect on the cultural resources and values of some of the caves in the project area. Loss of materials is due to pot hunting, vandalism, or through the effects of climbing chalk on rock art. An assessment of Hidden Forest Cave was accomplished in summer 2000. It provides a basic condition assessment for the cave, with regard to conservation needs associated with current recreation use and impacts and natural deterioration.
In regards to cultural conditions, hand-drying agents (especially chalk) is of main concern. The primary complaints surrounding the use of climbing chalk in close association with rock art sites are that the chalk residue is unsightly (affecting scenic quality and integrity), it is very hard to remove, and residues contaminate rock art making them impossible to date. Also, if not removed it is likely to become "fixed" in place by any natural mineral accretion activity and the formation of natural weathering crusts, making it even harder if not impossible to remove. The impacts of chalk (either climbing chalk or blackboard/school chalk as both are carbonate based) on the dating of rock art are based on simple chemistry. As the various methods used for the dating of pictographs all rely on a form of radio carbon dating, the presence of carbonates would prevent the use of some methods. The existence of organic binders in the composition of chalk (used to make both types of chalk cohesive and form lumps) would affect the use of all dating methods. Likewise, because the chalk is used to absorb sweat and body oils, the chalk residue is in fact a mixture of processed chalk compounds, binders and other organic matter derived from the user. This provides a source of contamination that renders dating methods unusable. Professor Marvin Rowe, who developed the use of accelerated mass spectrometry for the radio carbon dating of pictographs, reiterated these problems. He also voiced concerns over the introduction of pigments to color climbing chalk. The pigments used are likely to have an organic component, which makes it difficult to see and avoid when sampling pictographs for dating. Organic compounds are also a probable component of antiperspirants now being included in some climbing chalk formulations, and are an additional source of contamination.
In some areas, chalk accumulation from rock climbers has impacted rock art at Hidden Forest Cave. The problems of chalk becoming fixed in place by the natural formation of weathering crusts on rock surfaces has been demonstrated by Professor Ron Dorn, who recently found grains of school chalk (used to highlight a petroglyph) embedded in newly formed desert varnish in a sample taken from a site in Wyoming. The problems of applied materials in general becoming fixed in place are well known and widely observed, with many examples of old vandalism (chalking of glyphs, spray paint, crayon) becoming sealed in place by natural mineral deposition.
The close examination of the residues at Hidden Forest Cave demonstrates the fine size of the chalk particles and their embedded nature filling the tiny depressions and interstices of the rock surface. The smooth appearance of the surface of these accumulations also suggests a certain compaction and burnishing, presumably the result of the repeated action and use of localized points as handholds. Removing this material is not simple. Water introduced onto dry porous surfaces, such as rock, has a tendency to be drawn into the rock by capillary forces, resulting in the transportation of chalk particles even deeper into the rock fabric, rather than washing them out.
V. PROPOSED ACTION
The proposed action (Alternative B) is described on pages 20-23. It was
designed to be consistent with the Forest Plan, existing laws and Forest Service
Manual (FSM) 2356. The purpose of the proposed action is to maintain and restore
a healthy cave ecosystem that includes a range of habitat conditions for biota
and recreation experiences for the public.
1. Decision to be Made
The purpose of this document is to display the effects of the proposed action
and the various alternative methods of addressing the purpose and need and
issues identified for the Caves EA. It documents an environmental analysis of
the alternatives including the no-action alternative. Based on this information
and public comments, the Bend/Fort Rock District Ranger will determine which
alternative will be implemented in the Caves project area and if so, where and
under what conditions. An Interdisciplinary Team (IDT) conducted a site-specific
environmental analysis. The analysis is supported by reports and background
material from resource professionals.
2. Incorporated by Reference
Specialists' reports and their professional references used in the
preparation of this Environmental Assessment are found in the appendices and
incorporated by reference.
GOTO:
Deschutes and Ochoco National Forests Website
http://www.fs.fed.us/centraloregon/manageinfo/nepa/documents/bendfort/caves/chapter1.html
Last Update: 6/6/01
R.A. Jensen