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Great Basin Desert Shrub
Description, importance and conservation status:

Great Basin Desert Shrub occurs in northwestern New Mexico from western Bernalillo and Sandoval counties to the Colorado border in the north and the Chuska Mountains along the Arizona border. It also occurs in western Taos and eastern Rio Arriba Counties.

Shadscale is the best indicator of Great Basin Desert Shrub (Dick-Peddie 1993). Other major shrubs include big sagebrush (Artemisia tridentata), shadscale (Atriplex confertifolia), greasewood (Sarcobatus vermiculatus), and four-wing saltbush (Atriplex canescens). Big sagebrush has increased dramatically as a result of heavy grazing. Its expansion from desert into grassland and woodland has been extensive throughout the intermountain West. Sagebrush stands with some grass are often believed to indicate disturbance conditions. In New Mexico, most areas are currently dominated by big sagebrush on sites that were grassland or savanna in the middle of the last century (Gross and Dick-Peddie 1979 in Dick-Peddie 1993). Big sagebrush communities with significant grass cover are considered to be part of the Great Basin vegetation type. Big sagebrush communities usually occur at higher elevations than saltbush communities. Tree junipers (Juniperus spp.) may also occur here. Other sagebrush species that occur with big sagebrush include black sage (Artemisia arbuscula) and bigelow sage (Artemisia bigelovii).

Arroyos and Dry Washes

Arroyos and dry washes are established in areas that receive periodic, concentrated pulses of water due to heavy rainfall events. These habitats are usually dry between rains.

In the northwest quadrant of the state, arroyo riparian associations are usually dominated by greasewood (Sarcobatus vermiculatus). Rabbitbrush (Chrysothamnus sp.) is another common arroyo codominante. Other vegetation is similar to that of the surrounding lands. The walls of arroyos and dry washes can provide important nesting cavities, for such species as Rock Wren, American Kestrel, and Barn Owl.

These habitats can be important because plants may be denser or taller than those of surrounding uplands. In the Chihuahuan Desert in New Mexico, these habitats support twice the breeding bird nest density of surrounding habitats (Kozma and Matthews 1997). Though studies have not focused on arroyos in this habitat, it is likely that arroyos in Great Basin Shrub are equally important to breeding birds.

Urban

Urban areas exist within this habitat and are considered to be a subhabitat. This section is being developed and will appear in a later version of this Bird Conservation Plan.

Sage Grouse was once a breeding species in this habitat in north-central New Mexico. However, this species has now been extirpated from the state. Reintroduction efforts have failed.

Impacts outlined in Paige and Ritter (1998) "Birds in a Sagebrush Sea" include fire, grazing, prairie-dog control, invasion of non-native grasses, water developments, spraying, recreation, mining and oil/gas development, habitat fragmentation, and residential development.

These areas are under a mosaic of ownership. In Taos county, land is either managed by the Bureau of Land Management or privately owned. Land in the northwestern quadrant of the state is referred to as "Checkerboard" due to the complex mix of land owners for individual sections and quadrangles. Land owners/managers include the Navajo Reservation, private landowners, the Bureau of Land Management, the U.S. Forest Service, and New Mexico State lands.

Physiographic Areas covered: Colorado Plateau

Associated priority species from Appendices B and C:

Great Basin Desert Shrub Table 1.

Highest Priority	Priority	High Responsibility
Loggerhead Shrike Sage Thrasher Bendire's Thrasher Sage Sparrow	Green-tailed Towhee	Scaled Quail Burrowing Owl Ash-throated Flycatcher Rock Wren Black-throated Sparrow
Additional Representative Species: Brewer's Sparrow

Bird Habitat Requirements, Population and/or Habitat Objectives:
(in taxonomic order)

Loggerhead Shrike _{(Yosef 1996)}

Associated Species: Scaled Quail, Mourning Dove, Ash-throated Flycatcher, Sage Thrasher, Green-tailed Towhee, Black-throated Sparrow

shrub component within a grassland complex critical
shrubs with spines, or barbed wire fenceline, critical for impaling prey before eating
nests often found in shrubs, usually thorny or dense shrubs
in Idaho, has nested in sagebrush, bitterbush and greasewood; in Colorado has nested in Russian olive (Elaeagnus angustifolia)
nest height above ground depends on shrub height
diet includes birds, insects, and small mammals

Distribution: Found statewide.

Population and/or Habitat Objectives:

in NM, T = -5.9%, p = 0.001, N = 49, RA=3.72 (Sauer et al. 1997)
stabilize BBS trends in the state
maintain or enhance grassland areas with large shrub component
From anecdotal information, this species appears to be secure in the state. However, current BBS trends in New Mexico are showing a decrease. This species is of intense interest in Canada, as well as in many areas of the United States. New Mexico currently has a large breeding population and, therefore, may be extremely important to this species.

Sage Thrasher _{(Yanishevsky and Petring-Rupp 1997)}

Associated Species: Scaled Quail, Loggerhead Shrike, Brewer's Sparrow, Vesper Sparrow, Sage Sparrow, Horned Lark

uses sage-dominated grasslands and shrubby arid lands; considered a sagebrush obligate and prefers dense sagebrush
closely tied to big sagebrush in New Mexico
nests built near trunks or in branches of sage averaging 0-3ft (0-0.9m) high, generally near the center of the shrub rather than the edge. Little if any, surrounding bare ground
prefer nesting substrates at least 27in (70cm) high
nests placed in areas of dense shrubland, often with a concealing vegetative canopy. There is some thought that these birds actually construct an overhang. Canopy depth averages 23in (58cm). These birds may select nest sites from the top downward, based on vegetative volume or density

Distribution: Occurs in the northwestern quadrant of the state from Cebolla north to the Colorado border and east to Taos, and in the West, north from Mt. Taylor and west to the Arizona border.

Population and/or Habitat Objectives:

in the Colorado Plateau, T = -4.0%, p = .10, N = 26, RA=2.68 (Sauer et al. 1997)
stabilize populations based on BBS trends in New Mexico
closely monitor this species
maintain areas of sagebrush grassland where large, dense sage (>27in/69cm high) occurs

Bendire's Thrasher _{(England and Laudenslayer 1993)}

Associated Species: Mourning Dove, Burrowing Owl, Bewick's Wren, Northern Mockingbird, Sage Thrasher, Black-throated Sparrow

relatively open grass-shrubland with scattered shrubs or trees. May use fringes of dense vegetation, such as riparian woodland or desert washes
large shrubs must be present. May breed in degraded desert-grassland and desert shrublands supporting various xereophytic microphyllous shrubs with little grass
uses cholla in the north
nest placed in semi-dense shrubs, cacti or trees typically 2.5-5ft (0.7-1.5m) above the ground but can be as high as 21ft (6.5m)

Distribution: Especially prevalent in degraded grasslands of northwestern New Mexico. Also found from juniper savanna areas around Corona north to the Caja del Rio west of Santa Fe, and in the Chihuahuan Desert from Deming west to the Arizona border.

Population and/or Habitat Objectives:

in NM, T = -7.1%, p = 0.19, N = 14, RA=6.80 (Sauer et al. 1997)
stabilize then reverse current BBS trend in New Mexico
maintain continued presence at known nesting areas
maintain edge habitat with a grass component in shrubland
NOTE: little is known about managment for this species and, given the trend, is of high concern

Green-tailed Towhee _{(Dobbs et al.1998)}

Associated Species: Rock Wren, Brewer's Sparrow, Vesper Sparrow, Blue Grosbeak, Western Meadowlark

habitat varies with elevation: at low elevations uses more mesic areas with a high diversity of shrub species, including sagebrush, greasewood or pinyon-juniper, at high elevations uses more xeric shrub areas.
nests in areas of high shrub density
average height of nest above ground is approximately 2ft (0.6m)

Distribution: Breeds in mountains south to the Sacramento and Mogollon Mountains and in Great Basin shrub in the northwest quadrant of the state.

Population and/or Habitat Objectives:

in NM, T = 1.3%, p = 0.55, N = 15, RA=1.79 (Sauer et al. 1997)
maintain population trends in New Mexico using BBS routes
maintain or enhance shrubby greasewood areas especially near water or washes

Brewer's Sparrow _{(Yanishevsky and Petring-Rupp 1997)}

Associated Species: Rock Wren, Sage Thrasher, Green-tailed Towhee, Vesper Sparrow, Sage Sparrow

prefers sagebrush habitat; may also breed in mountain mahogany, rabbitbrush and other shrubs
prefers 0-30% degree slopes with well-drained soils and tall woody shrubs
frequents more open and less regularly spaced shrubs
abundance is negatively correlated with percent cover of grass and litter, shrub species diversity, and rocky substrates
average canopy cover is 53% in Montana
locates nest near edge of shrub averaging 6.5-11in (16.5-28cm) above ground, with high nest canopy concealment

Distribution: found in the northwestern quadrant of the state from El Rito north to the Colorado border and east to Taos, and in the West, north from the Plains of San Agustin, west to the Arizona border. (May also breed in the Estancia Valley south to the Willard area.)

Population and/or Habitat Objectives:

in the Mogollon Rim, T = 3.4%, p = 0.67, N = 26, RA=0.12; in the Colorado Plateau, T = -2.9%, p = 0.57, N = 28, RA=3.54 (Sauer et al. 1997)
maintain current population trend in Mogollon Rim
maintain more open, shrubby areas, especially in the northwestern quadrant of the state

Sage Sparrow _{(Martin and Carlson 1998)}

Associated Species: Sage Thrasher, Brewer's Sparrow, House Finch

prefers semi-open habitat with evenly spaced shrubs 3-7ft (1-2m) tall
closely associated with big sagebrush, either pure stands or interspersed with butterbrush, saltbush, shadscale, rabbitbrush or greasewood; occasionally in sagebrush-juniper
prefers taller shrubs with larger canopies and 75% live material for nesting, nests within or under shrubs, where shrubs are interspersed with open areas

Distribution: Breeds in the northwestern quadrant of the state from El Rito north to the Colorado border and east to Taos, and in the West, north from Mt. Taylor and west to the Arizona border.

Population and/or Habitat Objectives:

in Colorado Plateau, T = 0.2%, p = 0.96, N = 22, RA=3.79 (Sauer et al. 1997)
maintain populations based on BBS trends in New Mexico
maintain evenly spaced sagebrush from 3-6 ft (10-20m) high
maintain a high percentage (>75%) of live sage within stands of sagebrush

Overall Habitat Strategies:

NM PIF recommendation to be added later. See also management recommendations within Paige and Ritter's 1998 "Birds in a Sagebrush Sea: Managing Sagebrush Habitats for Bird Communities".

Research and monitoring needs:

1. Monitor for continued presence of Loggerhead Shrike in shrublands throughout the state. Determine limiting factors.

2. Survey for Bendire's Thrasher throughout New Mexico. Determine habitat requirements for Bendire's Thrasher in northwestern New Mexico. Determine microhabitat for nesting Bendire's Thrasher. Determine reason for suspected population decline in New Mexico.

3. Determine dynamics of sage invasion of grasslands in northwestern New Mexico.

4. Determine effects of exotics, particularly grasses, on Great Basin Desert Shrub in New Mexico.

Additional species for which monitoring is recommended:

Scaled Quail

Burrowing Owl

Black-throated Sparrow

Table 2. Great Basin Desert Shrub: Priority Species Habitat Factors

Species	Vegetation Composition/ Structure	Abiotic Factors	Landscape Factors	Special Factors
LOSH	shrubs intermixed with grasses; nests can be in sagebrush, bitterbush or greasewood			needs thorny shrubs for impaling vertebrate prey in order to eat
SATH	big sagebrush dominated grasslands; prefers dense sagebrush; 27in or higher for nesting
BETH	shrubland or juniper savanna; must be relatively open with shrubs averaging 2-5ft in height		grasslands surrounding shrubs are often degraded
GTTO	shrublands with high diversity; high density shrubs; average height of nest 2ft			Low elevation: uses more mesic areas
BRSP	sagebrush, mountain mahogany, rabbitbrush or other shrubs; openly and less regularly spaced	flat areas preferred; well-drained soils		negatively correlated with percent cover of grass and litter, shrub diversity and rocky substrates
SGSP	big sagebrush with bitterbrush, saltbush, shadscale, rabbitbrush or greasewood, occasionally juniper; semi-open habitat with evenly spaced shrubs 3-7ft high; taller shrubs with larger canopies preferred