ACEC Information

ACEC Information

 Area of Critical of Environmental Concern

Area of Critical of Environmental Concern (ACEC) are special management areas designated by BLM to protect significant historic, cultural, or scenic values; fish and wildlife resources; natural process or systems; and/or natural hazards that:

• have more than locally significant qualities which give it special worth, consequence, meaning, distinctiveness, or cause for concern, especially compared to any similar resource;
• have qualities or circumstances that make it fragile, sensitive, rare, irreplaceable, exemplary, unique, endangered, threatened, or vulnerable to adverse change;
• has been recognized as warranting protection in order to satisfy national priority concerns or to carry out the mandates of Federal Land Management and Practices Act (FLMPA);
• has qualities which warrant highlighting in order to satisfy public or management concerns about safety and public welfare; and/or
• poses a significant threat to human life and safety or to property.

The Las Vegas Field Office maintains 18 ACECs and the Pahrump Field Office three ACECs. These ACECs are situated in remote and relatively pristine areas of the Mojave Desert, encompassing significant and/or unique biological and cultural resource values. Since 1998, these ACECs have seen increased use, owing to population increases in Clark County and Pahrump and an increase in tourism to southern Nevada.

The BLM is required by four laws (Antiquities Act of 1906, National Preservation Act of 1966, Archaeological Resources Protection Act of 1979, and Federal Land Policy and Management Act) to protect historic properties on BLM managed public land. Under these laws, 12 ACECs protect and preserve irreplaceable significant cultural resource sites that include prehistoric rock art sites, prehistoric village and habitation sites, and historic mining, town, railroad, and trail sites. These sites are either eligible for, or are on the National Register of Historic Places (NHRP). These sites are invaluable to the general public and federally recognized Native American tribes located in or near the Southern Nevada District.

 

ACECs are designed to protect multiple attributes of cultural resource sites including the physical site, site integrity, setting and feeling that contribute to the site significance and eligibility for the NRHP. Setting and feeling includes the viewshed and association with other sites and the environment. In essence, setting and feeling refers to how a person can stand at the site and get a feeling for what it would have been like to have been living at the time the site was occupied and participating in the same occupations as the original inhabitants. 

 

One ACEC protects significant scenic values adjacent to Lake Mead National Recreation Area.

 

Biologically, the ACECs are endowed with quality habitat for many plant and wildlife species. Ten of the ACECs were established to protect wildlife habitat, six of which were allocated to safeguard designated critical habitat for the following federally listed threatened and endangered species: desert tortoise; southwestern willow flycatcher; woundfin and Virgin River chub in the Virgin River; and numerous listed species that occur in Ash Meadows.

 

Eight ACECs contain a natural process or system including listed and rare plant species, riparian plant communities, and unique and rare geologic features. These resources include desert wetlands, mesquite woodlands, rare plant populations, relict plant communities located on a sky island, rare geological features including an unconformity and a desert sinkhole, a candidate area for a geologic stratotype section, and paleotological resources. The sinkhole also qualifies as a natural hazard.

By creating these ACECs based on public input, the BLM has promised the American People to protect and preserve wildlife, their habitat, important natural systems, and historic properties located within their management boundaries. Thus, the BLM ensures protection of their biological, cultural, scientific, historic, and archaeological values through limits on highly destructive activities in these ACECs, in compliance with the scope and scale of BLM’s goals, and their legal and regulatory framework.
Amargosa Mesquite ACEC

This ACEC is located in Nye County south of State Highway 95 west of Lathrop Wells. This ACEC was designated to protect approximately 1,700 acres of mesquite woodland important for neotropical bird species. In a landscape dominated by desert shrublands, these patches of woodland serve as important breeding, foraging, and resting places for many avian species. This mesquite woodland occurs in association with a sand dune system, offering protection from weather and predators, and provides a location where birds can find shelter to help them conserve energy in an extreme environment. Desert woodlands comprise a small percentage of the total vegetation in the Southwest, but support greater densities of birds than surrounding desert habitats. Woodland patches scattered throughout the desert may play an important role in the successful migration of birds attempting to cross large ecological barriers such as deserts, as they provide important stopover sites.

 

Arden Historic Townsites
This ACEC is located in the southwestern corner of the Las Vegas Valley. It was designated to protect historic railroad construction and mining sites.

 

Arrow Canyon ACEC

Arrow Canyon ACEC is located at the northern end of the Arrow Canyon Mountains northwest of Moapa and south of Pahranagat Wash within the Arrow Canyon Wilderness. The ACEC features a canyon measuring 20 feet across at its narrowest, 200 to 400 feet deep and several miles long with sheer walls that hosts prehistoric rock art. These and other cultural resources found within the canyon contribute to its eligibility to the National Register of Historic Places. The canyon is also significant for paleontological resources, including Miocene aged fossilized bird tracks, coral, brachiopods, and fossilized mollusks in limestone sediment. Vegetation consists predominantly of creosote-bursage scrub with mesquite and acacia in the washes.
Ash Meadows ACEC

The Ash Meadows ACEC is located in the Amargosa Valley in southern Nye County between Death Valley National Park and the town of Pahrump. Ash Meadows is a desert wetland ecosystem containing spring-fed wetlands and alkaline desert uplands that provide habitat for at least 25 species found nowhere else in the world. Thirteen species are endangered or threatened and most depend on the isolated springs and wetlands found there. This concentration of native species is considered to be the greatest of any local area in the United States. The 36,910-acre Ash Meadows ACEC surrounds the 23,000 acre Ash Meadows National Wildlife Refuge, including all lands identified in the Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada as essential habitat for the recovery of the listed species. Species receiving protection through the special designation include:

 

Endangered fish species:

1.       Devil's Hole pupfish

2.       Ash Meadows Amargosa pupfish

3.       Warm Springs pupfish

4.       Ash Meadows speckled dace

 

Endangered plant species, the Amargosa niterwort.

 

Threatened plant species:

1.       Ash Meadows milk-vetch

2.       spring-loving centaury plant

3.       Ash Meadows sunray

4.       Ash Meadows ivesia

5.       Ash Meadows gumplant

6.       Ash Meadows blazing star

 

Threatened aquatic beetle species, the Ash Meadows naucorid.

 

Mesquite and ash groves flourish near wetlands and stream channels. Saltbush dominates dry areas adjacent to wetlands and creosote-bursage scrub habitat occurs in the drier elevated areas. The area around Ash Meadows was intensively farmed prior the establishment of the National Wildlife Refuge. During the 1960s and early 1970s in particular, irrigated row crops, grazing, and development took a heavy toll on the area's natural resources. Plants, fish, and wildlife declined as pumping and diversion of spring channels, development of roads, large scale earth moving, and introduction of more than 100 non-native plants and animals. The Carson Slough, a portion of which is located in the northern portion of the ACEC, was historically the largest wetland in southern Nevada. The slough was drained and mined for its peat in the 1960's.

 

Big Dune ACEC

Big Dune ACEC is located in the Amargosa Valley of Nye County off Valley View Road south of State Highway 95. It is a 1.5 square mile complex star sand dune that reaches 2,731 feet above sea level. It is managed to protect habitat for four sensitive beetle species, three which are endemic to this single dune complex and are found nowhere else in the word. Big Dune is one of only three dune systems in the planning area. Giuliani’s big dune scarab beetle (Pseudocotalpa giulianii) was proposed for listing as a threatened species under the Endangered Species Act in August 1978 with the entire Big Dune Complex proposed critical habitat for the species. Off-road vehicle use and mining were identified as the largest threat to the species at the time. Three other sensitive beetle species can also be found at Big Dune:

 

·         Large Aegialian Scarab Beetle (Aegialia magnifica)

·         Rulien’s miloderes weevil (Miloderes rulieni)

·         Big Dune aphodius scarab beetle (Aphodius sp.)

Vegetation around and on the dunes includes creosote bush (Larrea tridentata), sandpaper plant (Petalonyx thurberi), prickly poppy (Argemone corybosa) and astragalus (Astragalus lentiginosus var. variabilis). These plants and the dune itself are very important for survival of these rare beetle species. All four Big Dune beetle species rely on dune plants for survival. The plants provide food and mating sites and, when covered with sand, shelter and food for their larvae. The beetles also burrow into the harder layers of sand below the loose, windblown dune surface when they are inactive.

Crescent Townsite ACEC

This ACEC is located east of the town of Nipton on Crescent Pass. It was designated to protect historic railroad construction and mining sites.

 

Devils Throat ACEC

This ACEC located 7.25 miles south of Whitney Pockets off the Gold Butte Backcountry Byway protects a natural hazard area within Gold Butte, a 100-foot wide by 100-foot deep sinkhole. This is an active geologic feature that enlarges regularly from erosion. Its formation is poorly understood, but is believed to be caused by dissolution in the subsurface or erosion by groundwater flow (piping). Some visitors have stated that Devil's Throat reminds them of the Gypsum Sinkhole of Cathedral Valley in Capitol Reef National Park.
Desert Tortoise ACECs

The Desert Tortoise Recovery Plan (USFWS 1994) directs land management agencies to protect reserves for desert tortoises measuring 1,000 square miles (640,000 acres) each. When undeveloped habitat of that size does not exist, multiple smaller, more intensively managed reserves should be established with a combined total of at least 1,000 square miles. The Las Vegas Field Office has protected 1,097 square miles (702,160 acres) of desert tortoise critical habitat in desert tortoise ACEC reserves. The majority of this habitat is within the Northeastern Mojave Recovery Unit (NEMO RU), with 190,000 acres in the Eastern Mojave Recovery Unit (EMO RU). Each recovery unit is considered a distinct population in which the U.S. Fish and Wildlife Service tracks the species progress towards recovery of the species. The ACEC boundaries were established to match the boundaries of desert tortoise critical habitat where the habitat was largely intact and where tortoise populations were highest. Boundaries differed in some locations to exclude degraded habitat and to add habitat outside critical habitat designated areas to make up for the degraded areas.
Coyote Springs ACEC

Coyote Springs ACEC is located north of Las Vegas along US 93. The ACEC is comprised of a broad alluvial valley that lies between the Sheep Range to the west and the Arrow Canyon and Meadow Valley Ranges to the east. The northern boundary is Lincoln County and State Route 168, and the southern boundary is the Apex Industrial Park. The ACEC's configuration is intended to provide functional corridors of habitat between tortoise recovery units in order to enhance long term persistence of the species. It consists of the western portion of the Mormon Mesa Critical Habitat Unit, protecting moderate to high densities of desert tortoises between the Desert National Wildlife Refuge, the Arrow Canyon Wilderness, and the Mormon Mesa ACEC.

This area supports three vegetative communities, creosote-bursage scrub, Mojave mixed scrub, and blackbrush. These plant communities provide diverse habitats for many species including desert bighorn sheep.

Gold Butte ACECs

Gold Butte ACEC is located south of Mesquite along the Arizona border between Grand Canyon-Parashant National Monument and Lake Mead National Recreation Area. It is characterized by isolated, rugged terrain and an extensive network of braided shallow washes. In addition, it has several well developed springs.

Gold Butte ACEC is managed as three separate ACECs. Gold Butte, Part A covers the portion that is designated as critical habitat for the desert tortoise. Gold Butte, Part B lies to the south and is managed to protect a number of biological resources including habitat for sensitive plants, desert bighorn sheep, and desert tortoise. Gold Butte, Part C is located near the peak of the Virgin Mountains, protecting unique high elevation habitats including relict forest stands and habitat for desert bighorn sheep. Part C is also classified as a Clark County Natural Area and an Instant Study Area managed under Interim Guidance for Wilderness Study Areas.
Mormon Mesa ACEC

The 149,000–acre Mormon Mesa ACEC is located along the Clark and Lincoln county line. The ACEC is composed primarily of creosote-bursage scrub and mixed Mojave shrub communities. Mormon Mesa has expansive bajadas considered to be prime tortoise habitat as well as steep mountain ranges located in the Mormon Mountains and Meadow Valley Mountain Wilderness Areas. The ACEC connects with three ACECs totaling 203,670 acres of habitat in the Ely Field District: Mormon Mesa, Kane Springs, and Beaver Dam Slope ACECs. It is separated from the Coyote Springs ACEC by US 93 and State Route 168, and the Coyote Springs development.

 

Piute/Eldorado ACEC

Piute/Eldorado ACEC is located in the Piute and Eldorado Valleys between Boulder City and California and surrounds the communities of Searchlight and Cal Nev Ari. It measures approximately 328,242 acres and contains 286,541 acres of designated desert tortoise critical habitat. The ACEC represents the largest area of high density desert tortoise habitat known in Nevada. This population is contiguous with a large high density area in California. It spans the boundary between the NEMO RU and the EMO RU. Approximately 190,000 acres of the ACEC beginning just north of Searchlight and extending south through Piute Valley is located with the EMO RU. The desert tortoises in this portion of the ACEC share genetic markers with those in California to the south. The remaining ACEC (approximately 138,000 acres) is located in Eldorado Valley within the NEMO RU to the north with desert tortoises sharing genetic markers with those found in the Las Vegas Valley and areas to the northeast.

The area consists primarily of rolling valleys and bajadas with creosote-bursage scrub, shadscale scrub, blackbrush and pinyon-juniper woodland. It marks the transition between Mojave and Sonoran desert vegetation. Habitat quality ranges from fair to good across low to moderate elevation flats and slopes. The ACEC is bisected into four parts by US 95 and State Route 164.

The diverse topography and vegetation may offer opportunities for desert tortoise populations to survive should climate changes occur. Approximately 828 miles of roads are designated within this ACEC, in addition to the highways. Human uses affecting habitat quality include unauthorized cross country OHV use, highways, mining, utility corridors, and historic grazing activities. Invasive weeds and grasses are becoming and increasing concern.
Gold Butte Townsites ACEC

The Gold Butte Townsites ACEC is located on the Gold Butte Backcountry Byway north of Cedar Basin in the Gold Butte Part B ACEC. This is the location of the historic mining town of Gold Butte.

 

Hidden Valley ACEC

Hidden Valley is located within the Muddy Mountains Wilderness. The valley contains prehistoric habitation and rock art.
Keyhole Canyon ACEC

Keyhole Canyon is located on the east side of the Eldorado Valley in the Nelson Hills. The canyon contains prehistoric habitation and rock art.

 

Rainbow Gardens ACEC

This ACEC is located on the east side of the Las Vegas Valley next to the Sunrise Mountain Township. The ACEC is managed to protect the geologic, scientific, scenic, and cultural resources and sensitive plants. It contains the Great Unconformity, a location where there are missing intervals of the geologic record. In this case, a surface of rock was exposed and then covered with a much younger layer of rock so there is approximately 1.2 billion years of geologic time missing in the local geologic record.

Rainbow Gardens ACEC contains a scenic mountain and canyon landscape similar to those found in more remote locations of southern Nevada, but unique in its close proximity to the city, allowing people a wilderness experience within a few miles of their homes.

Unique cultural resources can be found in Rainbow Gardens. Gypsum cave has been nominated to the National Register of Historic Places based on its traditional importance to Southern Piute and Chemehuevi tribes, its importance to the early history of North American archaeology through the work done at the cave in the 1930s by archeologist Mark Harrington, and the information it has provided and will continue to provide concerning the archaeological and natural history of the region.

Rainbow Gardens ACEC contains deposits of gypsum and sandy soils that support sensitive plant species including the Las Vegas bearpoppy. Commonly referred to as “badlands” by locals, these areas have historically been used as OHV play areas throughout the planning area. These soils are very friable when disturbed, and the cyptobiotic surface is easily damaged. The ACEC protects a portion of this habitat.

 

Red Rock Spring

Red Rock Spring is located in Gold Butte Part A in a drainage north of the Gold Butte Backcountry Byway. This location contains prehistoric habitation sites and rock art.

 

River Mountains ACEC

The River Mountains ACEC is located on the east side of the Las Vegas Valley east of the City of Henderson. The ACEC is managed to protect habitat for the River Mountains desert bighorn sheep herd and to protect the scenic viewshed for Henderson and Boulder City. This ACEC contains rough, rocky and steep terrain, broken up by canyons and washes which provides the steep slopes where the bighorn sheep can escape from predators. This ACEC shares an eastern boundary with lands managed for the herd in Lake Mead National Recreation Area. This herd has suffered from loss of habitat due to increasing urban development in its range from expansion of Boulder City and Henderson and widening of US 95.

 

Stump Spring ACEC

Stump Spring is located in Pahrump Valley just east of the Nye County line. This spring site is the location of a prehistoric camp and historic trail and camp.

 

Virgin River ACEC

The Virgin River ACEC is located in northwest Clark County just south of the City of Mesquite. It protects the river’s wild and scenic character and riparian habitat. The Virgin River flows within the tri-state area of Utah, Arizona, and Nevada. Portions upstream have be inventoried and determined to have wild and scenic character. The ACEC designation protects those characteristics present within the planning area. In addition to wild and scenic character, the ACEC contains portions of designated critical habitat for two endangered fish species, the Virgin River chub and woundfin, and one endangered bird species, the southwestern willow flycatcher. The ACEC also supports habitat the listed Yuma clapper rail and the yellow-billed cuckoo, a candidate for listing. The riparian habitat type is extremely limited in this eco-region, making this habitat important to maintain species diversity and to support bird migration.

Whitney Pocket ACEC

Whitney Pocket is located in Gold Butte Part A ACEC at the intersection of the Gold Butte Backcountry Byway and the Whitney Pass Road. It is a cluster of sandstone outcrops with cultural resource sites including prehistoric habitation and rock art.