Bird Conservation Plan Chapter 2

Chapter 2     The Planning Unit

2.1   New Mexico Geography, Biogeography and Climate

Because of its size, geographic location, and topographic variation, New Mexico includes portions of several distinct biogeographic regions and contains a diversity of habitat types. Included within its borders are the southern terminus of the Rocky Mountains, the western edge of the Great Plains, the northern portion of the Chihuahuan Desert, the northern extension of the Sierra Occidental, and the southeastern edge of the Great Basin. It includes habitats ranging from Chihuahuan desert to alpine tundra, at elevations ranging from 2,800 to just over 11,000 feet.

The New Mexico landscape includes several distinct upland regions. To the north, the Sangre de Cristo Mountains represent the southernmost extension of the Rocky Mountain chain and contain the state’s highest peaks. Moving south from the northwest “Four Corners” area, middle-elevation forests and cold desert uplands of the Colorado Plateau give way to the higher montane region of the Mogollon Rim along the south-central portion of New Mexico’s border with Arizona. Included in this area are the San Francisco and Mogollon ranges, and the large Gila/Aldo Leopold Wilderness complex.

Perhaps New Mexico’s most distinctive upland areas are its isolated “sky island” mountain ranges. Characteristic of the state’s basin-and-range topography, these ranges extend from the Sandia Mountains and Mount Taylor southward in a widening band to (and up to 100 miles beyond) the Mexican border. The sky island ranges represent stepping stones of montane habitat linking the distinct biological regions of the Sierra Madre Occidental to the south and the Rocky Mountains to the north. The lower-elevation grassland and shrubland areas from which they arise constitute the only significant break in the continental mountain chain extending from the volcanic belt of southern Mexico to northern Canada. Important sky island ranges (moving generally north to south) include the Sandia, Manzano, Magdalena, San Mateo, Sacramento, Animas, and Peloncillo ranges.

The Mogollon Rim and sky island regions of central and southern New Mexico are particularly significant to avian biogeography. A large number of species reach either their northern or southern range boundary in this area, and bird communities may include unusual assemblages of species not normally found together. A second important biogeographic divide exists where the varied mountain and desert topography of the western two thirds of the state gives way to the southwestern portion of the Great Plains, in areas east and north of the Pecos River. Here, a number of species reach the eastern or western extent of their distribution.

Lowland areas (mostly plains, desert grassland, or shrubland) occur in all parts of New Mexico except for the north-central mountains and highland areas of the Mogollon Rim. Some, such as the Tularosa Basin near Alamogordo or the Jornada del Muerto north of Las Cruces, are closed basins. The Rio Grande, New Mexico’s largest river, divides the state from north to south and, with its associated floodplain of riparian, wetland and agricultural habitat, serves as an important migration corridor. Two other major river systems, the Pecos and the San Juan, also drain extensive areas and contain broad floodplains. Other important drainages include the Canadian and Dry Cimarron rivers in the east, and the Mimbres, Gila, and San Francisco rivers in the southwest.

Latitudinal and altitudinal variation produces a varied climate. Most annual precipitation is associated with the southwest monsoonal pattern and arrives in the form of local, high-intensity storms from late June through September. Mountain snows are delivered by frontal storms during the winter months, and snowfall plays a critical role in maintaining flows in the state’s major river systems through the spring and early summer. Average rainfall statewide is about 15 inches, though some areas receive considerably less. Precipitation increases at higher elevations and is somewhat higher in the eastern plains than to the west (Dick-Peddie 1993).

Rain and snowfall patterns can be erratic geographically and from year to year, and are influenced by larger-scale climatic patterns. A major cause of yearly climatic variation is the El Niño – Southern Oscillation (ENSO) phenomenon, a periodic pattern of ocean warming and cooling across the central tropical Pacific which influences climate in many parts of the world. Studies using both meteorological records and tree-ring data spanning over 2,000 years have demonstrated a strong correlation between ENSO patterns and climate in the southwestern United States. ENSO effects in New Mexico are most significant during the winter months, with precipitation often 50 percent above long-term averages during an El Niño (or warm) phase, and a similar amount below normal during a La Niña event (Sevilleta LTER Research Report 1999). Tree-ring data also reveal a long history of wet and dry periods of varying magnitude and periodicity. Following decades of high precipitation during the 1980’s and 1990’s, New Mexico may currently be in the early phases of an extended drought, such as occurred across much of the southwestern United States in the 1950’s (Grissino-Mayer 1995).

The yearly number of frost-free days varies from over 200 in the southwest, portions of the southeast, and along the lower Rio Grande Valley, to 100 around Taos and Tres Piedras. Summer high and winter low temperatures span a wide range from north to south and, to a greater degree, across local altitudinal gradients (Dick-Peddie 1993).

2.2   History of Land Use

The history of land use in New Mexico is a vast and complex topic (Crawford et al. 1993, Dick-Peddie 1993, Scurlock 1998), and only a very brief outline of changes to major habitat types is presented here. Native Americans have resided in New Mexico for centuries. Large population centers were established by “Anasazi” and ancestral Pueblo peoples for commerce and protection as early as 800 A.D., primarily in the western and northern portions of the state. Archaeological evidence indicates that terraced farming was practiced as early as 1000 A.D., and beams for buildings were cut in forests and hauled tremendous distances, as evidenced by the ruins at Chaco Canyon. However, these ancestral Pueblo communities were often abandoned after several hundred years, and most were deserted by around 1300 A.D., probably due to a combination of demographic pressures and prolonged drought.

At approximately the same time, the current Pueblo settlements began along the middle Rio Grande Valley, making this one of the oldest continuously inhabited areas of the United States. Prior to the arrival of Europeans, Pueblo farmers practiced floodwater agriculture relying on overbank flows and surface run-off, and also limited diversions for irrigation. When Coronado’s expedition reached the Middle Rio Grande in 1540, it is estimated that 25,000 acres of land were under cultivation. The Spanish colonial period, beginning in the late 1500’s, brought more intensive cultivation based on ditch irrigation and floodplain clearing. Wood cutting and livestock grazing expanded throughout the colonial period, and in subsequent centuries, the grazing of large numbers of sheep, goats and cows has had a transformative effect on the New Mexico landscape.

Over the past two centuries, a combination of natural factors and increasing human impacts has greatly altered New Mexico’s natural vegetative communities. Drought has been a recurrent fact of life in New Mexico since the last ice age. Tree-ring records reveal that cycles of moderate to severe drought have occurred regularly, at intervals of 2-3 decades, for centuries. Impacts of land use practices on forests, grasslands, and riparian areas are often compounded by drought.

Riparian areas in New Mexico have been greatly impacted by livestock grazing, groundwater withdrawals, and various surface water management practices. Along the state’s three major river systems, the San Juan, Pecos, and Rio Grande, natural hydrological cycles have been disrupted over the 20th century by the construction of flood control dams, agricultural diversions, storage reservoirs, and levee systems. Lack of regular flooding along the Middle Rio Grande in central and northern New Mexico has inhibited the regenerative capacity of this area’s signature cottonwood “bosque” habitat.

Since the 1900’s, forests in New Mexico have been reshaped by a combination of factors including fire, fire suppression, grazing, and logging. Naturally occurring fire has played an important role in the ecology and evolution of forests in New Mexico. Low-intensity fires burned historically every 2-10 years in ponderosa and in lower elevation mixed-conifer forests, sparing the larger trees and clearing accumulations of dead wood and understory growth. Prior to European settlement, regularly occurring fires maintained healthy open stands of larger trees with a grass understory. Hotter, stand-replacing fires occurred with less frequency, mostly in denser forest types such as spruce-fir. Fires occurred more frequently during drought years, and were most severe when the drought was preceded by abnormally wet years, which resulted in a build-up of fuels.

Extensive commercial logging began in the early 1900’s, and coincided with a decrease in fire frequency. Low-intensity, largely grass-fed fires had already become less frequent due to overgrazing in the 1890’s. Fire suppression also began around this time, and by the 1940’s, full fire-suppression become a statewide forestry practice. This combination of factors effectively eliminated much of the park-like forest habitat that had been the historical norm. Older and commercially valuable trees were removed, and mature forest habitat was replaced by dense thickets of young trees and extensive underbrush. High fuel loads made these areas subject to catastrophic, stand-replacing fires, which then reinitiated the cycle of dense, even-aged forest growth. Full-scale fire suppression lasted until the mid-1980’s when policies of prescribed burning and thinning began to be applied.

Cattle and sheep grazing began to affect New Mexico’s grasslands and forests in 1820. By 1890, very large-scale and non-sustainable grazing was common, especially in the southern half of the state. Grazing has since tapered off, but the legacy of historical grazing practices remains, particularly in the conversion of former grasslands to shrublands. Dick-Peddie (1993) notes that “reduction in grassland in New Mexico has been so pronounced that some people today question if it was ever very extensive.” He goes on to cite numerous historical accounts attesting to vast and high quality grasslands extending across much of southern New Mexico in the early and mid-19th century. Grassland reduction in the last 150 years has resulted primarily in an increase in desert shrub and juniper savannah habitats.

Cities and towns in New Mexico did not experience significant growth until the 1950’s. Since then, however, population centers have shown varying but consistent growth patterns. Significant population growth occurred throughout the 1970’s, 1980’s, and 1990’s, a period of abundant rainfall by historical standards. This growth, in combination with recent drought conditions, has placed enormous pressures on the state’s surface and ground water resources, and conflicts over water use and rights (including water to maintain riparian habitats and endangered species) have become common. Urban and suburban development, both around existing population centers and in rural areas, continues to eat away at remaining pieces of natural habitat. According to 2005 population estimates from the U.S. Census Bureau, the largest population centers in New Mexico are the Albuquerque area (over 600,000 people, including adjacent Rio Rancho and the North and South Valleys of Bernalillo County), Las Cruces (over 80,000 people), and Santa Fe (over 70,000 people).

2.3   History of Avifaunal Studies and Conservation

Due to its wide diversity of habitats, New Mexico has recorded the second highest number of bird species of any non-coastal state in the U.S. More than 280 species of birds breed in New Mexico, and its extensive grasslands are important areas for wintering birds. The Rio Grande serves as an important flyway for migrants. In the east, the Playa Lakes region is one of the most significant wetland habitats in the southern quarter of the Central Flyway for migrating and wintering birds.

However, not all of New Mexico’s bird species have flourished. Sharp-tailed Grouse and Sage Grouse, once a part of New Mexico’s breeding avifauna, were hunted by settlers and miners. By the early 1900’s, both were extirpated from the state. The Aplomado Falcon, once regular throughout the Chihuahuan Desert grasslands, experienced steep population declines in the 1920’s and 30’s. Buff-breasted Flycatchers were also recorded with some frequency in the southwestern forests until the 1940’s, when they disappeared. Only since the 1990’s have these two species sporadically reappeared in New Mexico. The reasons for their declines are poorly understood but may reflect the changing landscape in the state or elsewhere on the continent.

New Mexico has a long history of ornithological study. Twenty-nine species of birds have been identified in late prehistoric kiva (Native American religious buildings) murals. Spanish expeditions recorded large numbers of cranes, geese, turkey, quail, prairie-chickens, and grouse. Anglo explorers also remarked upon these same birds. Army doctors, first attending expeditions in the 1850’s, and then stationed at established forts, were the first to systematically report on and collect birds from the state.

Ornithologists Woodhouse, Henry, and Kennerly all recorded over 170 species of birds in the state during the mid-1800’s, along with seasonal occurrence data. (Scurlock 1998). Frances Merriam Bailey began ornithological study in the early 1900’s while traveling with her husband. In 1928, she published her first book – Birds of New Mexico – on the state’s avifauna. J. Stokely Ligon, after several decades of work in the state, published New Mexico Birds and Where to Find Them in 1961.

Following Ligon, John P. Hubbard wrote A Checklist of the Birds of New Mexico in 1970 and revised it in 1978. Important advances in the knowledge of and/or changes in bird distribution have occurred since then, yet the Revised Checklist remains a standard of knowledge for bird distribution and abundance.

Several inventories and long-term monitoring projects have taken place throughout the state. A list of some of the larger studies and monitoring projects is provided in Appendix B.

2.4   Land Ownership and Management

New Mexico totals nearly 122,000 square miles, or about 78 million acres. Approximately 34 percent of this land is managed by the federal government. The two largest management agencies, the Bureau of Land Management (BLM, over 12 million acres) and the U.S. Forest Service (USFS, over 9 million acres) together manage the majority of public lands, covering over a quarter of the state. BLM lands occur throughout New Mexico but are concentrated in the northwest and the southern third of the state. New Mexico’s five largest National Forest areas include the Carson and Santa Fe National Forests in the north, the Cibola National Forest in the central part of the state, and the Gila and Lincoln National Forests in the south. Military reservations managed by the Department of Defense (DOD) constitute the majority of the remaining federally managed lands. Federally managed lands also include National Parks and Monuments managed by the National Park Service (NPS), National Wildlife Refuges managed by the U.S. Fish and Wildlife Service (USFWS), and lakes and waterways managed by the Bureau of Reclamation (BOR) and the Army Corps of Engineers (ACE).

Major federal land management units include the following:

  • BLM: Carlsbad, Farmington, Las Cruces, Rio Puerco, Roswell, Socorro, and Taos Districts; and Kasha Katuwe Tent Rocks National Monument
  • U.S. Forest Service: Apache, Carson, Cibola, Coronado, Gila, Lincoln, and Santa Fe National Forests; and Kiowa National Grassland
  • U.S Fish and Wildlife Service: Bitter Lakes, Bosque del Apache, Grulla, Las Vegas, Maxwell, San Andres, and Sevilleta National Wildlife Refuges
  • National Park Service: Aztec Ruins, Bandelier, Capulin Volcano, El Malpais, El Morro, Fort Union, Gila Cliff Dwellings, Petroglyph, Salinas Pueblo, and White Sands National Monuments; Carlsbad National Park; and Chaco Culture and Pecos National Historical Parks
  • Department of Defense: Cannon, Hollomon, and Kirtland Air Force Bases; White Sands Missile Range; Fort Bliss Military Reservation (administered by BLM and the U.S. Army); and Melrose Air Force Range

New Mexico State Trust lands form a network covering almost 12 percent of the state, or over 9 million acres. State Parks and Monuments add another (relatively small) amount of state-managed land.

State land management units include the following:

  • State Parks: Bluewater Lake, Bottomless Lakes, Brantley Lake, Caballo Lake, Cimarron Canyon, City of Rocks, Clayton Lake, Conchas Lake, Coyote Creek, Eagle Nest Lake, Elephant Butte Lake, El Vado Lake, Fenton Lake, Heron Lake, Hyde Memorial, Leasburg Dam, Living Desert Zoo and Gardens, Manzano Mountains, Mesilla Valley Bosque, Morphy Lake, Navajo Lake, Oasis, Oliver Lee Memorial, Pancho Villa, Percha Dam, Rio Grande Nature Center, Rockhound, Santa Rosa Lake, Storrie Lake, Sugarite Canyon, Sumner Lake, Ute Lake, Vietnam Veterans Memorial, and Villanueva
  • State Wildlife Areas – Barker, Cimarron, Milnesand, and Mescalero Sands.

Native American lands comprise approximately 10 percent of the state, or over 7 million acres. The Navajo Nation owns much of the northwestern quadrant, especially along the Arizona border. The Jicarilla and Mescalero Apaches own land in the north and southeast, respectively. Other Native American landowners include nineteen Pueblos, mainly located along the northern half of the Rio Grande: Acoma, Cochiti, Isleta, Jemez, Laguna, Nambe, Picuris, Pojoaque, San Felipe, San Ildefonso, San Juan, Sandia, Santa Ana, Santa Clara, Santo Domingo, Taos, Tesuque, Zia, and Zuni.

The remaining 44 percent of the total New Mexico land area is privately owned (Deason 1998, Public Lands Information Center).

2.5   Physiographic Areas

Many Partners in Flight Bird Conservation Plans (BCPs) are written for Physiographic Areas, which represent broad-scale units of biological and ecological similarity. While this concept works relatively well for the eastern and central portions of the U.S., it is not practical in the mountain West where topography is highly variable and patches of similar biological assemblages are separated by large expanses of land. For this reason, BCPs for the western states are generally organized by habitat type within state boundaries, rather than by Physiographic Areas.

Within New Mexico are portions of six Physiographic Areas, with acreages shown below:

1)   Mexican Highlands (3.5 million acres)

2)   Chihuahuan Desert (15 million acres)

3)   Mogollon Rim (7 million acres)

4)   Colorado Plateau (40 million acres)

5)   Pecos and Staked Plains (11 million acres)

6)   Southern Rocky Mountains (6.5 million acres)

2.6   Bird Conservation Regions

Bird Conservation Regions (BCRs) are ecologically distinct regions in North America with similar bird communities, habitats, and resource management issues. A BCR mapping team comprised of experts from the United States, Mexico, and Canada assembled at the first international North American Bird Conservation Initiative workshop in 1998 to develop a consistent spatial framework for bird conservation in North America. Since their initial development, BCRs have become in important and dynamic tool for coordinating and implementing integrated, all-bird conservation.

The primary purposes of BCRs, as proposed by the mapping team in 1998 and approved in concept by the North American Bird Conservation Initiative (U.S. Committee) in 1999, are to:

  • Facilitate communication among the bird conservation initiatives, including Partners in Flight and national and regional shorebird, waterbird, and waterfowl conservation plans
  • Systematically and scientifically apportion the U.S. into conservation units
  • Facilitate a regional approach to bird conservation
  • Promote new, expanded, or restructured partnerships
  • Identify overlapping or conflicting conservation priorities.

As integrated bird conservation progresses in North America, BCRs should ultimately function as the primary units within which biological issues are resolved, the landscape configuration of sustainable habitats is designed, and priority conservation projects originate. (For more information on BCRs see http://www.nabci-us.org/bcrs.html).

New Mexico contains portions of four BCRs, each of which extends into other states and/or Mexico. Descriptions and in-state acreages are provided below:

BCR 16 — Southern Rocky Mountains (132,694 square kilometers, 32.8 million acres).

This is New Mexico’s largest BCR segment, covering most of the northern and western two-thirds of the state. This topographically complex region includes the north-central mountains, Colorado Plateau, and central sky island ranges. Various coniferous forest types interspersed with aspen dominate higher elevations. These are replaced by pinyon-juniper woodlands on the lower plateaus. Important birds also segregate into elevational bands: for example, Brown-capped Rosy-Finch and White-tailed Ptarmigan in alpine tundra; Flammulated Owl, Williamson’s Sapsucker and Lewis’ Woodpecker in coniferous forest; Virginia’s Warbler in montane shrub; and Gray Vireo and Pinyon Jay in pinyon-juniper. High arid shrublands and dry upland shortgrass prairies provide critical breeding areas for Mountain Plover and Ferruginous Hawk.

BCR 18 — Shortgrass Prairie (67,266 square kilometers, 16.6 million acres).

This BCR generally coincides with the boundary of New Mexico’s eastern plains, roughly the eastern quarter of the state. It includes extensive grasslands and shrublands, and important playa wetland areas. The Shortgrass Prairie lies in the rainshadow of the Rocky Mountains, and arid conditions greatly limit the stature and diversity of vegetation. Some of the continent’s highest-priority birds breed in this area, including the Mountain Plover, Long-billed Curlew, Ferruginous Hawk, and Lesser Prairie-Chicken. Playa Lakes habitat consists of numerous shallow wetlands that support many wintering ducks, migrant shorebirds, and some important breeding species, such as Snowy Plover.

BCR 34 —  Sierra Madre Occidental (27,852 square kilometers, 6.9 million acres).

Located in the southwest quadrant, New Mexico’s smallest BCR segment includes the Mogollon Rim and “bootheel” mountain ranges. Southeastern Arizona and southwestern New Mexico contain only the northernmost portion of the BCR, which extends south to central Mexico. The region is characterized by a complex topography, with the presence of oak-pine, pine, and fir forests along the mountain ranges, and semi-arid scrub habitats at lower elevations. Mountain and riparian areas host a number of species at the northern limit of their distribution and are extremely important to New Mexico’s avian biodiversity. In upland habitats, species of highest importance include Montezuma Quail, Elf Owl, Elegant Trogon, Strickland’s Woodpecker, Grace’s Warbler, Black-throated Gray Warbler, Red-faced Warbler, and Black-chinned Sparrow. Arizona Grasshopper Sparrow and wintering Baird’s Sparrow and Sprague’s Pipit are present in grassland and scrub habitats. Riparian areas in lowlands support many in-transit migrants, as well as breeding Thick-billed Kingbird, Southwestern Willow Flycatcher, Bell’s Vireo, and Abert’s Towhee.

BCR 35 —  Chihuahuan Desert (87,216 square kilometers, 21.6 million acres).

This BCR covers a large area in the southern half of the state, including desert scrub and grassland, a number of isolated mountain ranges including the Sacramentos, and important riparian and wetland areas along the Rio Grande Valley. In desert scrub and grassland habitats, species of highest importance include Aplomado Falcon, Prairie Falcon, Scaled Quail, Bendire’s Thrasher, and wintering Sprague’s Pipit and McCown’s Longspur. In montane areas, species of highest importance include Mexican Spotted Owl. In riparian areas, species of highest importance include Southwestern Willow Flycatcher, Bell’s Vireo, and Lucy’s Warbler.

2.7   Habitat Types

New Mexico Partners in Flight defines 20 separate habitat types within the state, based on both bird assemblages and vegetative associations. In many respects, these coincide with the principal vegetative cover types recognized by Dick-Peddie (1993). These are broad divisions, within which a number of different sub-types may be present. Because these habitat types do not entirely coincide with any existing scheme of land cover classification, exact areas are not known. Estimated areas are provided here to reflect the overall relative distribution of habitats in the state, but may be inaccurate for some types.

The 20 habitats comprise six major categories: Grasslands, Shrublands, Non-riparian Woodlands, Forests, Wetlands, and Other.

2.7.1   Grasslands

Chihuahuan Desert Grassland

Chihuahuan Desert Grassland covers roughly the southern third of New Mexico and is found only in the Chihuahuan Desert Physiographic Area. This habitat extends along the southern border of the state; north to Hobbs and Roswell in the Pecos Valley; Carrizozo, and White Sands Missile Range in the Tularosa Basin; and San Acacia in the Middle Rio Grande Valley. It occurs north to Hillsboro (excluding the Plains of San Agustin) and west to the Gila River on the Arizona border. Elevations range from 2800 to 5500 feet.

Little of this habitat remains intact in the United States due to persistent, large-scale impacts, primarily grazing. It may be the most endangered biome type in North America (W. Whitford pers. comm.). Small fragments of this habitat may exist on military reservations, such as Fort Bliss in southern New Mexico, but are unlike the major expanses of this habitat that existed before the advent of grazing (W. Whitford pers. comm.).

Continuous grazing has altered the historical composition of this habitat from primarily perennial bunch grasses to low-growing sod grasses in many areas, or where summer rainfall is low, to annuals (Brown 1982). Historically, black grama (Bouteloua eriopoda) was the dominant grass of this habitat, but it is probable that blue grama (B. gracilis) is currently more prevalent (W. Whitford pers. comm.). Other grasses include dropseeds and other Sporobolus spp., gyp grasses, and vine mesquite (Panicum obtusum). Major grass species include tobosa (Hilaria mutica), bushmuhly (Muhlenbergia porteri), burrograss (Scleropogon brevifolius), and side-oats grama (B. curtipendula). 

Most major shrub species in Chihuahuan Desert Grassland are also major species of the Montane and Chihuahuan Desert Shrub types. Some of the more common shrubs include Acacia spp., Agave spp., false mesquite (Callianndra eriophylla), feather peabush (Dalea formosa), sotol (Dasylirion wheeleri), broom snakeweed (Gutierrezia sarothrae), longleaf jointfir (Ephedra trifurca), chollas (Opuntia spp.), and littleleaf sumac (Rhus microphylla). Associations of black grama and side-oats grama (B. curtipendula) with Chihuahuan Desert or Montane Shrub species, as shrub dominants, may be examples of climax desert grassland type (Dick-Peddie 1993).

The condition of these grasslands is a result of the combined effects of several forces. Soil, topography, drought, fire, and grazing history are the main factors. Shrubs tend to occur on sites where the soil is calcareous, where grazing history has been relatively intense, and/or where there has not been an intensive fire regime. Sites that are in good condition contain more grass and fewer shrubs (Dick-Peddie 1993). 

Shrubby habitat (usually mesquite or yucca) is now extensive due to overgrazing. A combination of urban development, lack of fire, oil and gas development, drought, and poor soil resulting from the conversion of grassland to cropland have led to dense brush encroachment; fragmentation of contiguous areas of grasslands; and a reduction in grass stem density, height, and/or alteration of species composition.  

These grasslands were an important breeding area for the Aplomado Falcon prior to the 1930’s. The last recorded breeding of this species in the southwestern United States was at Deming in 1952 (Clark and Wheeler 1987, Hubbard 1978). There have been a number of recent sightings in the Chihuahuan Desert Grasslands; this species may recolonize areas in southern New Mexico. Management for this species may be most appropriate in the Tularosa Basin.

During migration and in winter, these grasslands are used by large numbers of birds, particularly sparrows, meadowlarks, and mourning doves, but also raptors and other species. Three wintering species have been identified as a high priority: Sprague’s Pipit, Baird’s Sparrow, and McCown’s Longspur. 

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.

An increasingly critical threat facing a large portion of the range of grassland species is the conversion of grassland to ranchettes and other suburban developments. Contiguous grassland areas have become fragmented and grassland species composition has been altered as a result. By providing information to land owners and developers, and establishing private land partnerships, large areas of native grasslands could be protected or restored. Vegetation buffers (green belts) could be placed to reduce impacts to nestling grassland bird species in cooperative management efforts.

This habitat is comprised of government-managed and privately-held lands. Most of the habitat east of the Guadalupe Mountains is privately owned in the north and managed by the BLM or the Department of Energy in the south. Much of the land in the south is leased to private oil and gas companies. The Tularosa Basin, west of the Guadalupe Mountains, is primarily under military management. In the Rio Grande Valley, most of the land north of Elephant Butte Lake is BLM-managed. The Hatch, Mesilla, and Las Uvas Valleys, and the Deming-Columbus corridor are predominantly private agricultural lands. Lands west of there, and along the Mexican border, are primarily BLM lands.

Plains and Mesa Grassland

This is the most extensive grassland in the state (Dick-Peddie 1993), this habitat type comprises two distinct regions: the Eastern Plains and Great Basin grasslands. 

The Eastern Plains start along the Texas border and run west to the bajadas of the Sangre de Cristo Mountains in the north, the Sandia and Manzano Mountain ranges in central New Mexico and the Sacramento Mountains in the south, excluding the Pecos Valley below Roswell. Great Basin grasslands, or Mesa Shortgrass areas, are found in the northwest quadrant of the state and the Rio Grande Valley. These include the Plains of San Agustin and mix with Plains grassland over a large area of northwestern and north-central New Mexico (Brown 1994). 

In climax condition, these grasslands are composed almost entirely of grasses. The few shrubs and forbs constitute less than 10% of the vegetation. The transition area from grassland to grassland-scrubland ecotone is often subtle and extensive. Blue grama (Bouteloua gracilis) is the most common component of these grasslands in New Mexico. It co-dominates with buffalo grass (Buchloe dactyloides) in the northeast and east-central plains and with western wheatgrass (Agropyron smithii) or galleta (Hilaria jamesii) on northern mesas. On fine-textured soils in the north, indian ricegrass (Oryzopsis hymenoides), New Mexico feathergrass (Stipa neomexicana), and needle and thread (Stipa comata) may be important components/co-dominants. Other areas may be dominated by threeawns (Aristida spp.) or side-oats grama (Bouteloua curtipendula). Tobosa (Hilaria mutica) swales occur within this type of grassland. These are dominated by Hilaria spp. and, in some areas, alkali sacaton (Sporobolus airoides). Galleta and indian ricegrass are the primary grasses in the northwest.

Shrubs often occur where the soil is calcareous. Shrubs that may occur scattered through eastern shortgrass communities are soapweed yucca (Yucca glauca) and fringed sage (Artemisia frigida). Winterfat (Ceratoides lanata) and bigelow sage (Artemisia bigelovii) can be found in western areas. Broom snakeweed (Gutierrezia sarothrae) increases in overgrazed areas in eastern grassland, as do clumps of low-growing honey mesquite (Prosopis glandulosa) and chollas (Opuntia spp.). Rabbitbrush (Chrysothamnus spp.) and sagebrush (Artemisia spp.) replace broom snakeweed in the declimax communities caused by overgrazing in Great Basin Grasslands. Livestock grazing in the early part of the century resulted in extensive and rapid succession of these grasslands toward shrubland. Great Basin grasslands tend to be more arid than Plains Grasslands and mix with Great Basin desert shrub at lower elevations. 

In the past, high temperatures and summer winds contributed to lightning-set grass fires where grasses from prior growing seasons provided ample fuel. A natural succession to climax grass-forb associations followed. As a result of grazing in most areas, less residual grass is available for fuel, and the incidence of fire is less frequent. Natural successions are now usually arrested and replaced by fire declimax associations of shrubs.

In healthy grasslands, fire will suppress mesquite and other shrubs. Areas with little grass initially, sometimes as a result of overgrazing, lack sufficient fuel to carry a fire. Fire is often prescribed in eastern New Mexico, mostly in swales. Fire is being reintroduced into the Middle Rio Grande Valley at Sevilleta National Wildlife Refuge and the Kiowa National Grasslands in eastern New Mexico (Mike Means pers. comm.). 

Ford (1999) resummarizes several studies on grasses and response to fire, which have been used to promote fire suppression in shortgrass prairies. Upon reanalysis, Ford concludes that “Most of the literature … reviewed was primarily interested in the use of fire as a tool to increase the forage value of the grassland vegetation. Perception and the value of fire in shortgrass steppe may have been colored by a desire for rapid recovery or for increases in grassland productivity to benefit domestic livestock.” Ford continues, “the use of fire in shortgrass steppe need not be perceived in a negative light. Regardless of fire type, buffalograss and blue grama response to fire was predominantly neutral or positive, and it depended largely on precipitation and possibly season of fire.”

Ford and McPherson (1996) state “there is general agreement that fire is necessary (though usually not sufficient) to control the abundance of woody plants and maintain most grasslands”. However, there is some disagreement about the succession of shrubs in healthy non-burned grasslands. Bahre (1991 in Ford and McPherson 1996) concluded through the use of historical accounts that “fire size and frequency have diminished greatly in desert grasslands since the 1880’s”.

In a summary of grassland fire studies, Ford and McPherson (1996) state that many macroarthropod herbivores increase after fire, as well as soil-dwelling microarthropods. Other reported effects of fire include increased habitat heterogeneity. 

“Fires … affect [bird] population levels indirectly by altering habitat structure, abundance of competing species, and food levels (Bock and Bock 1992, Dickson 1981, Rotenberry et al. 1995 in Ford and McPherson 1996). In shrub-grass complexes, bird diversity and abundance are enhanced if shrub cover and nesting sites are interspersed with open grassy areas maintained by fire (Baldwin 1968, Kramp et al. 1983, Pulliam and Mills 1977 in Ford and McPherson 1996) … Many bird species that inhabit grasslands have been documented to increase habitat use in shrublands or grasslands after fire.” They include American Kestrel, Scaled Quail, Mourning Dove, Greater Roadrunner, Eastern Kingbird, Western Kingbird, Loggerhead Shrike, Horned Lark, Sprague’s Pipit, Lark Bunting, Savannah Sparrow, Baird’s Sparrow and Western Meadowlark. “Far fewer bird species are reported to be negatively affected by fire. These species are generally closely associated with shrubby habitat, and [are] more abundant in unburned areas (Ford and McPherson 1996).” 

“Summer fires can stimulate seed yields of native grasses more than fires in winter or early spring (Biswell and Lemon 1943, Paton et al. 1988). … In general, plant species in semi-arid grasslands are more strongly influenced by fire season and frequency than fire behavior (intensity, percent of area burned, fuel consumption) (Steuter and McPherson 1995; Ford and McPherson 1996)”. “Plant growing season and fire season, along with other biotic and abiotic environmental variables, including grazing and rainfall, are important factors in determining the response of plants to disturbance by fire. (Ford 1999)”

Shrubby habitat (usually mesquite in the east) is now extensive due to grazing that generally took place in the last century. A combination of overutilization, changes in fire frequency, and poor soils has contributed to the current abundance of shrub habitat. It should be noted that shrub encroachment dynamics in northeast New Mexico, north of the mesquite range, may differ from areas south of the Canadian Escarpment (Dick-Peddie 1993).

There is clearly a dynamic balance between the distribution and abundance of grass and shrub conditions in eastern New Mexico. Grass conditions are suitable for Grasshopper Sparrow and other grass-preferring birds. Shrub conditions are more suitable for Cassin’s Sparrow and Loggerhead Shrike.

The vast majority of eastern plains lands are privately owned. Some areas near Clayton, comprising the Kiowa National Grasslands, are managed by the U.S. Forest Service. Three National Wildlife Refuges are in this habitat: Grulla (near Portales), Las Vegas and Maxwell. Of the privately owned lands, most are ranches rather than agricultural lands. A high proportion of agricultural lands exist around Clovis/Portales, the Tucumcari Basin to the Texas border, along the Texas border near Clayton, and the Estancia Valley.

Many portions of western grasslands are managed by the Bureau of Land Management: the majority of the Plains of San Agustin and grasslands further north, including the Bisti/De-na-zin Wilderness areas. Chaco Canyon National Monument, managed by the National Park Service includes small areas of this habitat, as does Sevilleta National Wildlife Refuge. A large area of former grassland has been converted to agriculture at the Navajo Agricultural Products area south of Farmington. Other portions are privately owned. 

Most all the areas of Mesa-Plains grassland in New Mexico have been affected by grazing and fire suppression. This is one of the most critical communities for grain of domestic livestock. With the continuous heavy grazing many grasslands have become seriously degraded. Palatable bunch grasses tend to decline first, and often completely disappear. Unpalatable woody species (exotics) tend to either increase, move in, or replace native grasses. In areas of heavy grazing, native grasses are gradually replaced by shrubs from nearby shrublands, or become dominated by weedy invasive shrubs such as snakeweed and rabbitbrush.

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.

Urban sprawl and the conversion of grasslands to ranchettes and suburban developments have major potential effects on this habitat. Contiguous grassland areas have become fragmented and grassland species composition has been altered as a result. By providing information to land owners and developers, and establishing private land partnerships, large areas of native grasslands could be protected or restored. Vegetation buffers (green belts) could be placed to reduce impacts to nestling grassland bird species in cooperative management efforts.

Wet Meadow and Montane Grassland  

Wet Meadows in New Mexico generally consist of high-elevation grasslands and sedge (Carex sp.) meadows at elevations of roughly 7500 feet to treeline. They are characterized by dense grasses and sedges growing in wet soils with the water table at or just below the soil surface. Varying amounts of forbs may be interspersed throughout. Depressions in the ground are often occupied by plants typical of standing shallow water, such as cattails (Typha sp.) and rushes (Juncus sp.). 

Wet meadows are few and far between in New Mexico and have generally been heavily impacted by human activities. They are primarily found in the Sangre de Cristo and San Juan Mountains, with lesser amounts also present in the Jemez, Zuni, and Sacramento Mountains, and mountains of the Mogollon Highlands. Many of the meadows have been drained and converted to agriculture or are extensively grazed during the summer months. A few are threatened by development of residential or resort areas near some of the state’s more popular ski resorts.

Although limited in extent, wet meadows support several species of birds that nest in no other habitat in New Mexico (see Table 1). New Mexico tends to be at the periphery of the breeding ranges for these species due to the limited and unpredictable availability of this habitat within the state. As such, the future of these species as breeders in the state depends upon conservation of the existing meadow ecosystems and feasible restoration of those that have been drained, aided by years of higher than average rainfall that produces temporary wet meadows within grasslands that are dry more often than not.

Alpine/Tundra

Alpine tundra occurs on isolated mountain summits above timberline from 12,499 to 13,156 feet (Brown 1994). In New Mexico, this community extends from the Colorado border south to areas northeast of Santa Fe. It also includes the summits of Sierra Blanca, Mt. Taylor, and South Baldy in the Magdalena Mountains.

This habitat is an extension of the extensive Rocky Mountain alpine tundra found further north. The vegetation includes lichens (various genera), mosses (various genera), sedges (Carex spp.), low-growing shrubs, and herbaceous plants. Elfin growth forms of conifers (krummholz) are sometimes included. All vegetation is adapted to short growing seasons, extreme cold temperatures, drought, and isolation (Brown 1994). Predominant grasses include: tufted hairgrass (Deschampsia cespitosa), alpine fescue (Festuca brachyphylla), bluegrasses (Poa spp.) and spike trisetum (Trisetum spicatum spp. spicatum). This area includes other grass-like plants such as rushes (Juncus spp.). Common low forbs consist of avens (Geum sp.), yarrow (Achillea sp.), Erigeron simples, Hymenoxys brandegei, cinquefoil (Pontentilla sp.), Saxifrage spp., and clovers (Trifolium spp.).

Currently there is little concern about habitat deterioration in New Mexico. However, it is easily damaged by continued pressure from hikers and livestock. If the vegetation is broken, the soil below rapidly erodes. This process is difficult to stop due to severe climate and the freeze-thaw cycle of the soil. Due to the scarcity of wood and the slow growth of krummholz, campers using wood for fires can quickly deplete the wood resources in this habitat (Dick-Peddie 1993).

All alpine tundra in the Sangre de Cristo Mountains is managed by the United States Forest Service, as is Mt. Taylor and South Baldy. Sierra Blanca is owned and managed by the Mescalero Apache.

2.7.2   Shrublands

Chihuahuan Desert Shrub

This shrubland occurs solely within the Chihuahuan Desert Physiographic Area, which roughly covers the southern third of the state. This habitat extends across the southern border of the state east through southern Lea County. In the Pecos Valley, it extends north to Roswell; in the Tularosa Basin, north to White Sands Missile Range and to San Acacia in the Middle Rio Grande Valley. The Sierra-Socorro County line, west to the Gila River on the border with Arizona defines the northwestern area. It spans elevations from 2800 to roughly 5000 feet.

Much of this habitat consists of creosotebush (Larrea tridentata) and tarbush (Flourensia cernua). In some zones, whitethorn acacia (Acacia constricta, A. neovernicosa) co-dominates. Mesquite (Prosopis glandulosa) dominates in other areas. These zones may be quite organized and consistent within the overall desert habitat, depending on elevation and soil composition. In general, areas dominated by whitethorn acacia are characterized by a high diversity of shrubs, while grasslands that have converted to mesquite contain the lowest diversity of plants. 

Other Chihuahuan Desert shrubs such as cacti (various spp.), squawbush (Condalia spathulata), allthorn (Koeberlinia spinosa), fourwing saltbush (Atriplex canescens), lechuguilla (Agave lechuguilla), and ocotillo (Fouquieria splendens) are found scattered or in local patches (Dick-Peddie 1993). On rocky hillsides, little-leaf sumac (Rhus microphylla) may be found.

Chihuahuan Desert Shrub occurs in basins, outwash plains, low hills, and bajadas (Brown 1982). This habitat may be relatively secure and expanding as a result of desertification. Overgrazing in grassland areas may allow invasion of shrubland species. Where shrubs and cacti dominate, grasses are sparse or patchy. It is difficult for fire to spread, especially in creosote-dominated areas. 

Creosotebush is used rarely by Chihuahuan Desert birds for nesting (Anderson and Anderson 1946). The presence of other shrubs such as cacti, yuccas (Yucca spp.), mesquite, javelina bush (Condalia warnockii), white-thorn acacia and Ephedra spp., however, will increase usage by birds in this habitat (Naranjo and Raitt 1993, Kozma and Mathews 1997). The Black-throated Sparrow, in particular, nests where grasses and other small shrubs are found near the base of creosote.

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 dry between rains. 

Chihuahuan Desert Shrub is characterized primarily by desert willow (Chilopsis linearis) and honey mesquite. Occasionally additional shrubs co-dominate, especially where arroyo beds widen. These include burrobrush (Hymenoclea monogyra), Apache plume (Fallugia paradoxa), littleleaf sumac, and brickellia (Brickellia laciniata). Other shrubs may include torrey yucca (Yucca torreyi), javelina bush, catclaw acacia (Acacia gregii), iodinebush (Allenrolfea occidentalis), arrowweed (Pluchea sericea), and seepwillow (Baccharis glutinosa).

In the Chihuahuan Desert of Fort Bliss in south-central New Mexico, Kozma and Mathews (1997) found that the nesting density of breeding birds in arroyos was greater than twice the density of nests on surrounding uplands. Of breeding neotropical migrants, 33% nested more frequently in arroyos. However, of the non-migratory birds, 62% nested equally or more frequently in arroyos. Peak nest initiation for all species occurred between 18 and 24 May in each of the three years of the study.

Kozma and Mathews found that littleleaf sumac, mesquite, desert willow, and javelina bush were preferred for nesting in this habitat, even though these shrubs were less abundant overall, relative to other species. They concluded that desert birds may be strongly influenced, when selecting nest sites, by shrubs that are denser, have spines, have more foliage, and are larger with stiff branches. This may be because they offer greater protection, provide shade, and protect from heat generated by the soil.

Another structural component of arroyos are the walls comprising the edges. These walls can provide important nesting areas in the form of cavities for such species as Rock Wren, American Kestrel, Burrowing Owls and even Barn Owls.

Desert Shrub habitat occurs within a matrix of government-managed and privately held lands. Most of the lands east of the Sacramento Mountains are privately owned. Land east of the Guadalupe Mountains is managed by the BLM or the Department of Energy. Patches of this habitat may be leased to oil and gas companies. Habitat in the Tularosa Basin is primarily located on military lands. In the Rio Grande Valley, most of this habitat north of Elephant Butte Lake is BLM managed, while lands in the Hatch, Mesilla, and Las Uvas Valleys, as well as the Deming-Columbus corridor are primarily private. Agricultural lands are intermixed with this habitat in these areas. Much of the land west of Deming and Columbus is BLM managed.

Plains-Mesa Sand Shrub

This habitat type includes two distinctive vegetation types: sand shinnery and sand sage shrub.

Sand Sage shrub occurs north of the Chihuahuan desert in the Rio Grande Valley to Espanola and north of the White Sands Missile Range to areas south of Santa Fe, east to Nara Visa.

Sand sage habitat is dominated by sand sagebrush (Artemesia filifolia) in combination with other shrubs such as fourwing saltbush (Atriplex canescens), Mormon tea (Ephedra torreyana) , squawbush (Condalia spathulata) and yuccas (Yucca spp.). Grasses and forbs may occur within this type and include many of the common species of the Plains and Mesa Grassland, including blue grama (Bouteloua gracilis), sand dropseed (Sporobolus cryptandrus), and buckwheats (Eriogonum spp.).

Sand shinnery habitat is found solely within the Pecos and Staked Plains Physiographic Area. This habitat transitions from Chihuahuan Grasslands or Desert Shrub in the southeastern corner of the state. It extends along the uplands east of the Pecos River Valley to Roswell and northeast to the Texas border near Portales. 

This habitat type is found mostly within woodland, savanna, and grassland vegetation and is characterized by sandy areas (dunes). Major deep, sandy areas are found on the shoulder of the floodplains of the Pecos and its tributaries. The vegetation is co-dominated by shin-oak (Quercus havardii) and sand sagebrush. Other common shrubs include broom snakeweed (Gutierrezia sarothrae), a half-shrub; honey mesquite (Prosopis glandulosa); and soapberry (Sapindus saponaria var. drummondii). Succulents may include yuccas (Yucca spp.) and pricky pears (Opuntia spp.). Major grasses include sand bluestem (Andropogon hallii) and big bluestem (Andropogon gerardii), purple three-awn (Aristida purpurea), hairy grama (Bouteloua hirsuta), fall witchgrass (Digitaria cognata), little bluestem (Schizachyrium scoparium), and sand dropseed (Sporobolus cryptandrus). The most common forbs are annual buckwheat (Eriogonum annuum), annual sunflower (Helianthus annuus), western ragweed (Ambrosia psilostachya), sand verbena (Abronia angustifolia), and Texas croton (Croton texensis).

Annual plants are more abundant in shrublands than in any habitat type. Cheatgrass, russian thistle, and filaree are common non-natives that aggressively invade these habitats. Cryptobiotic soils are common. Mosses, lichen, and blue green algae also occur on these arid soils.

Land uses primarily include livestock grazing and to a lesser extent hunting and agriculture. With irrigation, cropland, and dense settlement developed in scattered locations. In a few areas coal mining and petroleum development has, also, occurred. Livestock grazing and over-grazing has altered the amount and composition of the vegetative communities. Where patches of native grasses have died out, cheatgrass and halogeton, two of the undesirable species, have invaded. Wildfires tend to be devastating, killing off large expanses of shrub cover (Whisenant 1990).

Arroyos and Dry Washes

Arroyos and dry washes occur in areas that receive periodic, concentrated pulses of water due to heavy rainfall events. Between rains these habitats are dry. Water is intermittently present following rainfall events.

Arroyo riparian associations are usually dominated by desert willow (Chilopsis linearis), honey mesquite (Prosopis glandulosa) and/or, in more northerly areas, rabbitbrush (Chrysothamnus sp.). Other vegetation is similar to that of the surrounding lands. 

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

The walls of arroyos and dry washes can provide important nesting areas in the form of holes, for such species as Rock Wren, American Kestrel, Burrowing and Barn Owls. In the area around Albuquerque in central New Mexico, arroyos can be quite large. The soil is also loamy. This provides excellent banks for the burrows of Bank Swallow, especially in areas within 1.2 mi (2 km) of the Rio Grande. While this species requires areas near water, large arroyos or banks, are also critical for nesting in New Mexico.

The Lesser Prairie-Chicken is the highest priority bird in this habitat type according to NM PIF. Numbers were estimated in the millions in the last century. However, hunting and the Dust Bowl of the 1930’s decimated the population (Rakestraw 1995). Numbers have continued to decline probably due to habitat destruction. During drought periods, these birds lek and attempt to breed, but they are often unsuccessful (K. Johnson pers. comm.). During wet years numbers may increase significantly. This species has become a priority in the last few years; the last four years have been low rainfall years in the eastern plains of New Mexico (written in 2001).

Agriculture in sand shinnery habitat is more prevalent than in sand sage habitat, especially in Curry and Roosevelt counties. Flattening sand dunes for dairy production and peanut farming has resulted in irreversible loss of habitat type.

Impacts to this habitat include 1) grazing, 2) herbicide use for shrub control, 3) fire, 4) agriculture and dairy production, and 5) oil and gas development. 

Much of the sand shinnery habitat in New Mexico is managed by the Bureau of Land Management. The state also owns several parcels of this type of habitat in the southeastern quadrant of the state. While sand sage habitat is managed primarily by the Bureau of Land Management or U.S. Fish and Wildlife Service in the Rio Grande Valley, the majority of this habitat, especially in the north and east is under private ownership, as are small portions of shin-oak/sand sage.

Montane Shrub

This habitat type is found throughout much of New Mexico in small areas between other types of habitat. It extends from southern New Mexico in the Guadalupe Mountains and Foothills west to the Arizona border and north to the Colorado border. Very little of this habitat exists in the Pecos and Staked Plains Physiographic Area. 

This habitat type often constitutes a patch or a strip within other more extensive types of vegetation. These areas represent conditions where there is less available moisture than surrounding areas, such as a high, rocky, windswept knoll, southwestern facing slope, or an escarpment of exposed rock. The dominant plant of the montane shrub type is mountain mahogany (Cercocarpus montanus). It shares dominance with serviceberry (Amelanchier sp.) and cliffrose (Cowania stansburiana) in the northwestern part of the state; with skunkbush (Rhus trilobata) and/or shrub oak (Quercus sp.) in the north-central portions of the state; and with redberry juniper (Juniperus coahuilensis) and desert ceanothus (Ceanothus greggii) in the southeast, occasionally with Texas madrone (Arbutus xalapensis). In the San Andres Mountains of south-central New Mexico, it occurs with buckbrush (Ceanothus greggii), skunkbush, shrub live oak (Quercus turbinella), winterfat (Ceratoides lanata), feather indigobush (Psorothamnus schottii), algerita (Berberis haematocarpa), agave (Agave spp.), and buckbrush at upper elevations; and at lower elevations with resinbush (Viguiera stenoloba), algerita, shrub live oak (Quercus turbinella), sacahuista (Nokina macrocarpa), sotol (Dasylirion wheeleri), ocotillo (Fouquieria splendens), and banana yucca (Yucca bacata). In southwestern New Mexico, other co-dominants include mock orange (Philadelphus microphyllus), and buckbrush. Other species found here are hoary yucca (Yucca schottii), century plant (Agave palmeri), shrubby senna (Cassia wislezeni), border pinyon (Pinus discolor), toumey oak (Quercus toumeyi), and Arizona madrone (Arbutus arizonica).

Many of the dominant shrubs of the higher montane shrub vegetation are also found as members of the shrub layer in montane coniferous forests and woodland vegetation. Some of these include bigtooth maple (Acer grandidentatum), silverleaf oak (Quercus hypoleucoides), manzanita (Arctostaphylos pungens), buckbrush, snowberry (Symphoricarpos sp.) and currants (Ribes spp.). Many dominant plants of lower montane shrub are also members of the desert grassland vegetation. Examples include sotol (Dasylirion wheeleri), century plant, banana yucca, and sacahuista. Some semi-riparian species are also important in this type. For instance, Apache plume (Fallugia paradoxa), chokecherry (Prunus virginiana), and hoptree (Ptelea angustifolia).

Arroyos and Dry Washes

Arroyos and dry washes are established in areas that receive periodic, concentrated pulses of water due to heavy rainfall events. Between rains these habitats are dry. Water is present intermittently, following rainfall events.

Arroyos in this habitat are generally small and graduate into other habitats. In mountainous areas, arroyos derive their vegetation from surrounding areas. However, due to larger amounts of water in the arroyos, shrubs may reach greater heights and be denser. Another structural component of arroyos are walls comprising the edge. These walls can provide important nesting areas in the form of cavities for such species as Rock Wren and American Kestrel.

Much of this habitat is managed by the federal government: U.S. Forest Service, Bureau of Land Management, National Park Service, and U.S. Fish and Wildlife Service. Various tribal governments, mainly the Navajo Nation, Jicarilla Apaches, and Mescalero Apaches, own other portions of this habitat. Some privately managed lands exist as well. 

Great Basin Desert Shrub

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. Various authors have referenced this community type as Cold Desert (Arizona PIF plan), Great Basin-Colorado Plateau Sagebrush Shrubland, and Semi-desert Shrubland (Colorado PIF Plan) in regional plant community classifications (Brown 1982, Lowe 1964, West 1983, Arizona PIF plan 1998).

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).

Immense stands of sagebrush interspersed with small openings of native bunch grasses formerly covered hundreds of thousands of hectares in the west (Vale 1975). Little is known about the natural disturbance regimes that shaped this plant community. Although pre-settlement sagebrush shrublands probably experienced at least occasional wildfires, sagebrush has a slow post-fire recovery rate and does not resprout after fire, but must come back from seed; a process that can take 15-30 years. Wildfires probably sculpted a landscape of sagebrush stands of varying age interspersed with grassy open areas on the scale of tens to thousands of hectares.

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 co-dominate. 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 sub-habitat. 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.

Land uses throughout the range of this habitat have been agricultural in nature and include primarily livestock production. Crop production does not occur in those areas conducive to dry farming or irrigation. Other uses include winter range for big game, recreation, and land development (West 1983). Historically large expanses of sagebrush have been cleared to increase foliage and allow a higher stocking rate of domestic animals or to support more grazing wildlife. Heavy grazing in some sagebrush areas has led to the elimination of native perennial grasses that have been replaced by exotic annual grasses, especially cheatgrass. In some cases, the herbaceous cover has been lost completely and replaced by shrubs. Sagebrush shrublands that are converted to another cover type have limited potential to revert to sagebrush. Factors such as increased frequency of fire, excessive distance to seed sources, loss of symbiotic mycorrhizal fungi, and competitive exclusion by other plants combine to maintain the new cover type.

The ecological integrity of sagebrush shrublands has been widely compromised by the invasion of exotic (e.g. cheatgrass) or native (e.g. juniper) plant species; conversion to agriculture, residential, or other land types; and changes in the natural fire regime. Grazing is widely considered to have altered the amount and composition of the various plant components (West 1983). The presence of the non-native cheatgrass has made some areas susceptible to wildfire. In some regions, fires tend to be a stand replacing phenomena, and therefore have become a management concern of considerable importance (Whisenant 1990). Though this does not appear to be the case in New Mexico. Other impacts outlined in Paige and Ritter’s (1998) “Birds in a Sagebrush Sea” include: Prairie dog control, invasion of non-native grasses, water development, spraying, recreation, mining and/or 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 a “checkerboard” due to the complex mix of landowners for individual sections and quadrangles. Landowners/managers include the Navajo Reservation, private landowners, the Bureau of Land Management, the U.S. Forest Service, and New Mexico State Lands.

Bird diversity and density is typically low in this plant community (Wiens and Rotenberry 1981). This is most likely due to its structural and floristic simplicity (MacArthr and MacArthur 1961, Rotenberry 1985, Wiens and Rotenberry 1981, Willson 1974). Usually a given stand will support three to six species of breeding birds. Species that are typical of this habitat include Sage Thrasher, Sage Sparrow, and Brewer’s Sparrow. Sagebrush birds evolved in this mostly contiguous habitat, where openings were comparatively small. Much of this contiguous habitat has been fragmented by removing sagebrush and leaving small stands separated by large openings. This habitat fragmentation could be a factor, not yet studied, in potentially higher rates of predation and nest parasitism in certain sagebrush bird species.

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.

2.7.3   Non-riparian Woodlands

Pinyon-Juniper Woodland

This important habitat contains two distinct sub-groups: Juniper Savanna and Pinyon-Juniper (P-J) woodlands. These areas are widely scattered throughout the state. They occur to a lesser extent in the eastern plains and the Mexican highlands. In the Mogollon Rim and the Mexican Highlands, this forest has a larger oak component. In the very southern mountains, savanna may actually be composed of oak rather than juniper (Dick-Peddie 1993).

Juniper Savanna and Pinyon-Juniper occur above desert or grassland vegetation and below pine forest (Peiper 1977). The elevation of this habitat type ranges from 4650-7130 feet, with extremes between 3255 and 7700 feet (Brown 1994). As elevation increases, pinyon dominance often increases, juniper density decreases, total tree density increases, and trees become larger in stature (Peiper 1977, LaRue 1994). Although soils underlying P-J vary, they are often shallow, rocky, low in fertility, and are derived from a wide range of parent material including granite, basalt, limestone, sandstone, and shale (Pieper 1977).

Pinyon-Juniper habitat is a cold-adapted, evergreen woodland that is characterized by varying codominance of juniper (Juniperus spp.) and pinyon (Pinus spp.). Junipers are often the most abundant of the two dominant species, but pure stands of either species may occur. The most common juniper in New Mexico is one-seed juniper (Juniperus monosperma) . It may share dominance with Rocky Mountain juniper (J. scopulorum) and/or Utah juniper (J. osteosperma) in the north, and alligator juniper (J. deppeana) and/or redberry juniper (J. erythrocarpa) in the south. The most common pinyon is Colorado pinyon (Pinus edulis), while border pinyon (P. discolor) also occurs. Oaks may form a larger component of P-J woodland in southern mountain areas. These can include Gambel (Quercus gambelii), gray (Q. grisea), and Arizona white (Q. arizonica) oak. The understory varies from completely open to very dense, especially where sagebrush (Artemisia spp.) is present. Understory species include those of Montane or Great Basin Shrubland and of Chihuahuan and Plains and Mesa Grasslands.

The stature of Pinyon-Juniper rarely exceeds 39ft (12m) in height. Typical P-J habitat exhibits an open woodland arrangement with well-spaced trees. In lower elevation P-J woodland, trees are widely spaced with a grass understory. In general, these trees are all one species of juniper. If fewer than 130 trees per ac (320/ha) are present, this is referred to as Juniper Savanna (Dick-Peddie 1993). The Savanna is an ecotone between woodland and grassland. As the elevation rises within this habitat, trees become more dense and moisture more abundant, resulting in Pinyon-Juniper woodland, which may form a closed canopy forest at its upper boundary. In northern portions of the state, densities can reach 280 48 trees per acre ( 690 120 per hectare) (Moir and Carleton 1987).

Junipers have encroached upon large areas that were once grassland. Encroaching junipers are usually found at a lower elevation than pinyons. There is no evidence that P-J woodlands, with mature pinyon trees 100-200 years old, were formerly grasslands that have been invaded by trees (Little 1977). 

Wide-scale conversion of P-J woodland to grassland for cattle forage began after World War II. Conversion was accomplished by various methods including cabling, bulldozing, hand chopping, grubbing and burning. An anchor chain dragged between two tractors was frequently used to remove trees. Seeding with grass, especially crested wheatgrass, followed. This conversion occurred in two types of habitat: areas of grasslands, mostly at low elevations where juniper, but not pinyon, had invaded due to overgrazing and lack of fire, and in areas of natural pinyon-juniper woodlands. In the southwest, conversion of P-J to grassland has included destruction of mature pinyon trees on greater than a few hundred thousand acres (Little 1977). Widespread conversion has decreased primarily due to the low cost-benefit ratio and also because of destruction to archaeological sites (Lanner 1981, H. Schwartz pers.comm.).

Conversion of natural P-J woodlands to grassland for forage production and big-game values has resulted in ambiguous results. Seeding to improve forage has generally proved unsuccessful over large areas (Gottfried et al. 1994). In one study, an undisturbed Pinyon-Juniper stand had greater cover of grasses and forbs than a cabled area after 20 years (Gottfried et al. 1994). The impact of P-J conversion on native wildlife has been documented (Swenson 1977 and others). Mule deer and elk use was highest on undisturbed Pinyon-Juniper. Natural P-J has greater bird species diversity and higher numbers of individuals (with the exceptions of wintering flocking species) than converted areas (Swenson 1977).

Historic grazing practices have also had an effect both adjacent to, and within, the P-J woodland matrix. These practices have resulted in soil and vegetation degradation. Soil compaction contributes to or causes increased soil erosion, decreased water infiltration, and reduced soil fertility. In one study, bare ground increased from 8% on a relict, undisturbed site to 65% on a continuously grazed site (Swenson 1977). Browse species became heavily used, contributing to hedging and an increase in less desirable species. While cool season grasses covered 65% of the ground on an undisturbed site, they were completely eliminated on a continuously grazed site (Swenson 1977). A rest-rotation grazing system in place for 15 years appeared to produce a situation intermediate to the undisturbed and grazed sites: 35% cool season grasses and 35% bare ground (Swenson 1977). 

The loss of a continuous herbaceous cover, especially in adjacent grasslands, due to overgrazing, has produced a situation where P-J stands do not have enough fuel to carry fire and eliminate young trees. Fire suppression has also contributed by allowing small trees to successfully outcompete grasses for water, nutrients and light. Grazing and erosion cause drier surface soils, which favor deep-rooted species rather than grasses (Gottfried et al. 1994).

Brown-headed Cowbird parasitism rates on Pinyon-Juniper sites may play a significant role in songbird breeding success. Goguen and Mathews (1996) found that three species (Plumbeous Vireo, Blue-gray Gnatcatcher and Western Tanager) in northeastern New Mexico were parasitized in excess of 75% on both grazed and ungrazed plots. Other species also suffered from parasitism, including Virginia’s and Black-throated Gray Warbler.

Pinyon-Juniper is important as a seasonal habitat for elk and mule deer. P-J is also used for firewood, pinyon nuts, fence posts, charcoal, railroad ties, mining timbers, and livestock forage (Tueller 1979). Increasingly, Pinyon-Juniper is valued for its aesthetic and cultural values, as well as for providing habitat for threatened and endangered species and management species of concern. It should be noted that the western United States has a global responsibility for this unique habitat.

Several rural and indigenous populations including the Navajo, Zuni and Ute have spiritual connections with Pinyon-Juniper woodlands. They derive food, plant and animal products for ceremonies, etc. from Pinyon-Juniper. In addition, Pinyon-Juniper contains many prehistoric and historic archaeological sites.

Although bird assemblages in Pinyon-Juniper vary with stand characteristics, 73 bird species are reported to breed in P-J (Balda and Masters 1980). However, not all of these species will occur at any one site. Only a few bird species are considered obligates or semi-obligates of this habitat. These include: Gray Flycatcher, Ash-throated Flycatcher, Western Scrub-Jay, Pinyon Jay, Juniper Titmouse, Bushtit, Bewick’s Wren, Gray Vireo, Black-throated Gray Warbler and Lark Sparrow. In one study of Pinyon-Juniper birds, 87% of the foliage nests and 87% of the cavity nests were located in juniper (LaRue 1994). Total breeding density increases as total tree density increases (Balda and Masters 1980, La Rue 1994). As pinyon density increases, densities of Gray Flycatcher, Mountain Chickadee and Black-throated Gray Warbler increase (La Rue 1994). Large annual fluctuations in breeding densities may occur (LaRue 1994). Juniper seeds, when present in winter, are an important food source for a variety of thrushes.

Impacts to this habitat include: 1) fuelwood cutting, especially older, mature trees 2) development, which contributes to habitat fragmentation, 3) mistletoe, 4) high intensity grazing, 5) fire suppression, 6) catastrophic fire, and 7) P-J conversion to grassland.

Madrean Pine-Oak Woodland

Peloncillo Mountains in Hidalgo County. It is part of the “Madrean Sky Islands” and corresponds to the habitat of the same name in Arizona (AZ PIF).

This habitat is defined by Chihuahua pine (Pinus leiophylla) and Arizona white oak (Quercus arizonica). Mean annual precipitation is 22 inches per year. Mean annual temperature is 52 degrees. Elevations range from 5000 to 7000 feet.

Associated trees in this type include emory (Q. emoryi), netleaf (Q. rubosa) and silverleaf oak (Q. hypoleucoides). Associated conifers include border pinyon (P. discolor) and alligator juniper (J. deppeana). Some common shrubs are manzanita (Arctostaphylos pungens), yuccas (Yucca spp.), agave (Agave spp.), beargrass (Nolina microcarpa) and wright silktassel (Garrya wrightii). Herbs include bullgrass (Muhlenbergia emersleyi), mutton grass (Poa fendleriana), sedge (Carex sp.), beggartick grass (Aristid orcuttiana), pinyon ricegrass (Piptochaetium fimbriatum), bluestems (Schizachyrium spp.), and pennyroyal (Hedeoma spp.)

Principal influences in this habitat are fire, grazing, fuelwood cutting, road-building, and mining. Fire has been largely suppressed since the 1880’s, concurrent with the advent of large-scale grazing. A study of this type of forest in Arizona concluded that low intensity fires had burned some part of a 215-acre forest plot in 67 different years over a hundred-year period (Ganey et al. 1996 in Ffolliott et al. 1996). Fires can be expected to encourage oak and juniper growth and enhance germination of such shrubs as manzanita and deerbrush (Ceanothus sp.). Chihuahua Pine, in particular, is a fire-adapted species and shows shade tolerance in an understory of oaks and junipers (Dick-Peddie 1993). It appears that the presence of Chihuahua pine signifies a climax forest. Long-term, year-long and rotation-pasture grazing has reduced the palatable herbaceous component and favors poisonous or thorny understory species such as sages (Artemisia spp.), broom snakeweed (Gutierrezia sarothrae) and catclaw mimosa (Mimosa sp.). A change to these species’ dominance in the understory may have influenced the production of less palatable plants and mat-forming, low grasses such as blue grama (Bouteloua gracilis) (Neilson 1986). 

The Buff-breasted Flycatcher was historically a breeding species in this type of New Mexico woodland. Prior to the 1990’s, it was last definitely sighted in the state in 1929. The last recorded nest was reported in 1887 (Hubbard 1978). However, this species has been recently documented in this habitat in the Peloncillo Mountains several times. This species would be considered a priority species if it were to be found breeding again in the state.

The Buff-breasted Flycatcher breeds in wide mountain canyons with open growth of pines and/or oaks. Its habitat usually contains an open understory of grasses and small trees or burned forest with patches of living pines. Nesting has been documented in Arizona between 6400 and 9400 feet. Optimal habitat has a gradual slope and canopy cover of about 20% above 33ft (10m) and <10% cover below 16ft (5m). Typical canopy trees are pines of medium-age or older. The understory should have 198-210 small oaks per acre (80-85 per hectare). These forest patches should be >492ft (150m) wide (Bowers and Dunning 1994). Management for this species may return it to the regular breeding avifauna of the state.

Additionally, the Gould’s subspecies of Wild Turkey resides in the Peloncillo Mountains. This New Mexico state Threatened and Endangered Species is found nowhere else in the state. The population currently appears stable.

This habitat is managed or owned by private land-owners in the Animas Mountains, primarily by the Animas Foundation. Portions of the Peloncillo Mountains are also managed by the Animas Foundation. Other sections are managed by the U.S. Forest Service or by other private land-owners.

2.7.4   Forests

Ponderosa Pine Forest.  

This pine-dominated forest is found in northern New Mexico, south to the Sacramento and Guadalupe Mountains in the east, and west to the Mogollon Rim. Elevations of this habitat extend from 6000 to 9000 feet. 

Ponderosa pine (Pinus ponderosa) is the dominant tree in this forest. It may share dominance with pinyon pine (P. edulis) and gambel (Quercus gambelii), gray (Q. grisea) and wavyleafed oak (Q. undulata). Other common associated trees include one-seed (Juniperus monosperma), alligator (J. deppeana), and Rocky Mountain juniper (J.scopulorum). New Mexico locust (Robinia neomexicana) or sumac (Rhus spp.) may also be found. A variety of plants may share the understory including Arizona fescue (Festuca arizonica), mountain muhly (Muhlenbergia montana), screwleaf muhly (M.virescens), skunkbush (Rhus trilobata), pine dropseed (Blepharoneuron tricholepis), mutton grass (Poa fendleriana), squirreltail (Sitanion sp.), Kentucky bluegrass (Poa spp.), little bluestem (Schizachyrium scoparium), deervetch (Lotus wrightii) and sedges (Carex spp.). Sites with a higher gravel content may have snowberry (Symphoricarpos oreophilus) and wood rose (Rosa woodsii). Higher areas may have kinnikinnik (Arctostaphylos uva-ursi) and common juniper (J. communis) (Dick-Peddie 1993).

Succession in the grassy pine forest habitat has been thoroughly documented. Recurrent, low-intensity fires occurred at 2-10 year intervals prior to about 1900, when fires suppression actions were taken. These fires helped maintain open, parklike vistas, with small patches of tree regeneration or small grassy openings (Cooper 1960 in Scurlock 1998). Since about 1900, most fires have been put out. As a consequence, there is increased density of pine regeneration, often in dense thickets, abundance of dwarf mistletoe (a tree parasite), and suppressed herbaceous understory (Dick-Peddie 1993).

Juniper or oak can dominate for a period of time in a successional pine forest, especially after a severe disturbance. This is often because a stand-replacing fire or clear-cutting occurred on the site. Ponderosa pine eventually shades out these trees relegating them to an understory shrub. Small tracts of oak in a pine forest have important wildlife value. If pines do not regenerate quickly, oak or pinyon-juniper forests can replace ponderosa.

Allen and Breshears (1998) documented the effects of drought on the lower elevational edges of ponderosa pine forest. Their study area in north-central New Mexico suffered a prolonged drought in the 1950’s. In less than five years, at the end of this extended drought, a large-scale die-off of ponderosa was noted. Ponderosas at lower elevations were affected at a greater proportion than those at higher elevations. In their place a pinyon-juniper woodland dominated and the shift from ponderosa to pinyon-juniper has remained for forty years. Not all the ponderosa died off, but where there were large patches of ponderosa, the habitat has become fragmented. Allen and Breshears attribute this rapid change primarily to the combined effects of drought and fire suppression. Fire suppresion had allowed pinyon-juniper to invade pine forest before the drought occured.

The vast majority of these lands are managed by the U.S. Forest Service. Also portions of this habitat are owned by the Jicarilla and Mescalero Apaches and the Navajo Nation. Private land-owners own a small percentage, mostly in the Mogollon Rim Physiographic Area. 

Impacts to this habitat type include 1) fire and fire suppression, 2) grazing, 3) logging, 4) development, and 5) recreation.

Mixed Conifer Forest.  

Mixed Conifer type habitat is found roughly from 8000 to 10,000 feet in New Mexico.  It covers portions of the all higher mountain ranges, including the Mogollon Rim, the Sacramento Mountains, and the Animas Mountains in Hildalgo County.

These forests contain Douglas-fir (Pseudotsuga menziesii) and white fir (Abies concolor), blue spruce (Picea pungens), aspen (Populus tremuloides) and several pine species including southwestern white (Pinus strobiformis), ponderosa (P. ponderosa) and limber pine (P. flexilis). Warm mixed conifer forests are found in the Animas, Sacramento, San Francisco and Mogollon Mountains and some of the Black Range. They contain forests of Douglas-fir and netleaf (Quercus rugosa) or silverleaf oak (Q. hypoleucoides). 

This habitat type can contain other tree species including bristlecone pine (Pinus aristata), Englemann spruce (Picea engelmannii), corkbark fir (Abies lasiocarpa), big-toothed maple (Acer grandidentatum), Rocky Mountain maple (Acer glabrum), Gambel oak (Quercus gambelii), pinyon pine (Pinus edulis) and occasionally alligator juniper (Juniperus deppeana). These habitats often contain a profusion of shrubs and herbs including skunkbush sumac (Rhus trilobata), mountain mahogany (Cercocarpus montanus), oceanspray (Holodiscus dumosus), wax currant (Ribes sp.), ninebark (Physocarpa monogynus), New Mexico locust (Robinia neomexicana), creeping mahonia (Berberis repens), wood rose (Rosa woodsii), snowberry (Symphoricarpos oreophilus), huckleberry (Vaccinium sp.), forest fleabane (Erigeron eximius) and common juniper (J.communis). Common herbs are thimbleberry (Rubus parviflorus), forest ricegrass (Oryzopsis asperifolia), fringed brome (Bromus ciliatus), pale geranium (Geranium richardsonii), mutton grass (Poa fendleriana), mountain trisetum (Trisetum spicatum), parry oatgrass (Danthonia parryi), Arizona fescue (Festuca arizonica), mountain (Muhlenbergia montana) and longtongue muhly (M. longiligula), meadowrue (Thalictrum fendleri), yarrow (Achillea sp.), and groundsels (Senecio spp.)

The Animas Mountains in the southwestern corner of the state, along with the Chiricahua Mountains in Arizona, contain the only United States mixed conifer breeding habitat for the Mexican Chickadee. Additionally, the Yellow-eyed Junco nests only in the Animas Mountains and a few mountain ranges in Arizona. While populations of these two species appear to be stable, New Mexico has a high responsibility for them.

The vast majority of these lands are managed by the U.S. Forest Service. Portions are owned by the Jicarilla and Mescalero Apaches and the Navajo Nation. Private land-owners own a small percentage. The Animas Mountains are owned by a private non-profit organization, the Animas Foundation.

Impacts on habitat include: 1) recreation, 2) grazing, 3) fire and fire suppression, and 4) logging.

Spruce-Fir (Subalpine) Forest 

There is relatively little of this type of forest in New Mexico, compared to other states. The largest areas of this type are in the Sangre de Cristo Mountains, with smaller areas in the San Juan and Jemez Mountains. Outside of these ranges, there are small areas in the Chuska, Sacramento, Mogollon, San Mateo, Magdalena and San Francisco Mountains. The Black Range and Mt. Taylor also have this forest type. It occurs roughly from 9500 feet to treeline.

These are cold forests with short growing seasons. Dominant species are Engelmann spruce (Picea engelmannii), and corkbark fir (Abies lasiocarpa). Other trees include the bristlecone (Pinus aristata) and limber pine (P. flexilis), Douglas-fir (Pseudotsuga menziesii) white fir (A. concolor) and aspen (Populus tremuloides). Important shrubs include rocky mountain maple (Acer sp.), common juniper (Juniperus communis), forest willow (Salix scouleriana), myrtle huckleberry (Vaccinium myrtillus), thimbleberry (Rubus parviflorus), Canada buffaloberry (Shepherdia canadensis), bearberry honeysuckle (Lonicera involucrata) and mountain lover (Pachistima myrsinites). Grasses can include thurber (Festuca thurberi) and forest fescue (F. sororia), fringed brome (Bromus ciliatus), mountain trisetum (Trisetum spicatum), bluegrasses (Poa spp.), forest ricegrass (Oryzopsis asperifolia) and foeny sedge (Carex foenea).

Disturbances include timber harvesting, especially in the early part of the twentieth century, and catastrophic fires. Early logging often removed only old-growth forest. Fire suppression began with the advent of logging. However, fire does not appear to have played as great a role in these habitats as in lower elevation forests. Dick-Peddie (1993) suggests that fires burned through these forests infrequently “on the order of decades”. When they did occur, they were erratic, i.e. crown fires in some places and ground fires elsewhere. However, as fuel levels rise, the possibility of catastrophic fire increases. Other sources claim that stand-replacing fires burn through an area every 250-500 years but are essential to reinvigorate these high elevation forests and are especially important for maintaining an aspen component (M.Orr pers. comm.).

The impacts of elk grazing at higher elevations in this habitat may be a more significant issue than cattle grazing (NM PIF).

These lands are primarily managed by the U.S. Forest Service. Parcels located in the Chuska and Sacramentos are owned by the Navajo Nation and the Mescalero Apache tribal governments. Some small areas are privately owned.

Impacts on this habitat include: 1) grazing, 2) logging, 3) fire, 4) blowdown, and 5) recreation.

2.7.5   Wetlands

Southwest Riparian

These riparian woodlands occur solely in the southwestern quadrant of the state, from the Arizona and Mexican border north to the San Francisco drainage and east to a few drainages on the east slope of the Black Range, such as Las Animas Creek in Sierra County. It is roughly defined by the presence of Arizona sycamore. However, an area lacking Arizona sycamore may be classified as Southwestern Riparian if it is within the boundaries described above and has some of the southwestern priority species listed below, e.g. San Simon Cienaga. Elevations range from 4000 – 7000ft.

Tree- and shrub-dominated habitat along lower streams or rivers requires permanent water or a consistently high water table. Southwestern riparian woodland is generally dominated by Arizona sycamore (Platanus wrightii), and/or cottonwood (Populus spp.). Goodding willow (Salix gooddingii) may be a codominant, often with fremont cottonwood. Other trees may include netleaf hackberry (Celtis reticulata), boxelder (Acer negundo), Arizona alder (Alnus oblongifolia), velvet ash (Fraxinus pennsylvanica), walnut (Juglans spp.), screwbean mesquite (Prosopis pubescens), honey mesquite (P. glandulosa) and western soapberry (Sapindus saponaria). Non-native trees and shrubs include russian-olive (Elaeagnus angustifolia) and salt cedar (Tamarix spp.). Understory vegetation may include New Mexico olive (Forestiera neomexicana), skunkbush (Rhus trilobata), rabbitbrush (Chrysothamnus spp.), sandbar willow (Salix sp.), seepwillow (Baccharis glutinosa), false indigo (Amorpha fruticosa), coyote willow (S. exigua), arrowweed (Pluchea sericea), silvery buffaloberry (Shepherdia argentea), and Parthenocissus creepers.

Gallery forests are important components of Southwestern Riparian Woodlands. In these forests, shade-tolerant species replace pioneering species, which require more open conditions. There is more available moisture in these forests as a result of reduced soil temperatures beneath the canopy. Mature forests resist flooding, resulting in reduced erosion and bank containment, except in extreme cases (Dick-Peddie 1993). 

These riparian areas are the most species-rich in New Mexico. They support a higher percentage of breeding species than any other habitat due to their complex structural components, the continual presence of water, and their location in close proximity to Mexico. Marshes and other wetland habitats are created by widening river valleys or through the creation of oxbows. Stoleson and Finch (1998) have studied breeding bird density in six areas along the Gila River in southwestern New Mexico. They have documented some of the highest breeding bird densities north of Mexico.

The Gila River remains the only large, undammed river in New Mexico. Natural flooding regimes on this river, as well as the Mimbres, maintain the dynamic nature to which this habitat is adapted.

Impacts to habitat include: 1) habitat loss due to development or agriculture, 2) overgrazing, 3) recreation and off-road vehicle use, 4) lack of regeneration of cottonwood and willow due to altered flood regimes 5) lower water tables 6) water diversion or damming, 7) poor in-stream flow management, and 8) invasion of exotic weeds and grasses.

Several New Mexico high-priority species regularly breed only in Guadalupe Canyon in Hidalgo county. These are Broad-billed Hummingbird, Violet-crowned Hummingbird, and Thick-billed Kingbird.

Owners/managers of these lands include the US Forest Service, the state, and private land-owners.

Middle Elevation Riparian

Middle Elevation Riparian Woodlands are found throughout the state, excluding most of the southwest, from just below 3000 feet in the lower Pecos Valley to 7500 feet or higher in some areas. These habitats are found primarily on the Rio Grande, Pecos, San Juan, Canadian, and Dry Cimmaron Rivers and their tributaries. Other riparian woodlands occur in canyons within the smaller mountain ranges.

This habitat is characterized by tree- and/or shrub-dominated areas along streams, primarily in canyons or valleys associated with permanent water or a consistently high water table. In these canyons, the surrounding upland vegetation consists of oak/pinyon-juniper and ponderosa pine (Pinus ponderosa). In valleys, the uplands are grasslands or shrublands. Middle Elevation Riparian woodlands are generally dominated by Fremont cottonwood (Populus fremontii), or at higher elevations lanceleaf cottonwood (P. acuminata). South of Fort Sumner along the Pecos River and in other river valleys, salt cedar (Tamarix spp.), an exotic species, dominates. Codominants can include peachleaf willow (Salix amygdaloides) in the north and Goodding willow (S. gooddingii) in southern areas. Other trees include Arizona walnut (Juglans major), New Mexico locust (Robinia neomexicana), New Mexico olive (Forestiera neomexicana) and Gambel oak (Quercus gambelii) along with Russian-olive (Elaeagnus angustifolia), another exotic. Shrubs found in these areas include bluestem willow (S. irrorata), coyote willow (S. exigua), southwest rabbitbrush (Chrysothamnus pulchellus), silvery buffaloberry (Shepherdia argentea), wright silktassel (Garrya wrightii) and skunkbush (Rhus trilobata).

Riparian areas are the among the most species-rich habitats in New Mexico. They support a higher percentage of breeding species than other habitats due to their complex structural components and the continual presence of water. Marshes and other wetland habitats are created by widening river valleys or through the creation of oxbows. Additionally, these areas provide water for many species found in adjacent habitats not normally associated with riparian woodland. In Southwestern Riparian Woodland, Stoleson and Finch (1998) have studied breeding bird density in six areas along the New Mexico portion of the Gila River. In these areas, they have documented some of the highest breeding bird densities north of Mexico. While these high densities may not translate exactly to Middle Elevation Riparian Woodland it indicates the importance of riparian habitats to New Mexico birds.

Historically, natural flooding maintained the dynamic nature to which this habitat is adapted. Currently, flooding regimes in this habitat have been drastically altered by dams and the draw-off of water for agricultural, industrial, and municipal use.

Gallery forests are important components of woodlands along the Rio Grande and several other rivers, excluding the Pecos River south of Fort Sumner. In these forests, shade-tolerant species replace pioneering species that require more open conditions. There is more available moisture in these forests as a result of reduced soil temperatures beneath the canopy. Mature forests resist flooding, resulting in reduced erosion and bank containment, except in extreme cases (Dick-Peddie 1993). 

Brown-headed Cowbird parasitism may be an increasing problem. Mehlman (1995) documents elevated cowbird numbers, concurrent with broadening distribution, based upon New Mexico BBS routes from 1968 to 1994. During that period, cowbird occurence increased from 50% to 90% of New Mexico routes. Average cowbird numbers have increased by almost 100% since 1968. Mehlman notes that these birds may already have a substantial impact on populations of species like Willow Flycatcher, Bell’s Vireo, and Yellow Warbler. Parasitism is a symptom of overall habitat changes, and not the ultimate cause of population declines. However, with the advent of cattle grazing in the southwest, regular feeding stations in an area allow the constant presence of cowbirds which have been documented traveling up to 12 miles (20km) or more, from foraging areas in search of nests to parasitize (Goguen and Mathews 1997).

Impacts to habitat include: 1) habitat reduction through development or for agriculture, 2) overgrazing 3) off-road vehicle use, 4) lack of cottonwood and willow regeneration due to altered flow/flood regimes, 5) lowered water tables, 6) water diversion or damming, 7) poor instream flow management , and 8) fire (a significant threat in the middle Rio Grande Valley).

Managers of these lands include the Army Corps of Engineers, Bureau of Land Management, National Park Service, Bureau of Reclamation, U.S. Forest Service, U.S. Fish and Wildlife Service, Pueblo and other tribal governments, the state, private land-owners and a few Spanish land-grant holders.

Montane Riparian

This habitat is characterized by trees or large shrubs associated with permanent water or a consistently high water table. It occurs at elevations where the dominant vegetation is mixed conifer, spruce-fir, or alpine vegetation. Alpine riparian vegetation is not included in the following discussion. These riparian woodlands generally occur from 7500 feet to treeline and are located in the Mogollon Highlands, the Chuskas, and the Southern Rocky Mountain chain including the Sacramentos, Manzanos, Jemez, Sangre de Cristos, and San Juan mountains, as well as other isolated peaks and ranges. 

Narrowleaf cottonwood (Populus angustifolia) is the primary overstory species in this habitat. Other dominants include blue spruce (Picea pungens) and cottonwood (Populus spp.). Other species present include aspen (P. tremuloides), water birch (Betula occidentalis), bigtooth maple (Acer grandidentatum), New Mexico locust (Robinia neomexicana), Arizona alder (Alnus oblongifolia) and boxelder (A. negundo). Lower elevation species may include black cherry (Prunus serotina) and sandbar willow (Salix sp.). Shrubs include bebb (S. bebbiana), scouler (S. scouleriana), and yellow willow (S. lutea), mountain alder (A. tenuifolia), mountain maple (A. glabrum) and red ozier dogwood (Cornus stolonifera). California bricklebush (Brickellia californica) and false indigo (Amorpha fruticosa) are characteristic shrubs at lower elevations. In west-central New Mexico, blue spruce associations occur at lower elevations. These woodlands have an understory layer dominated by Gambel (Quercus gambelii) or Arizona oak (Q. arizonica) (Dick-Peddie 1993).

Impacts on this habitat include: 1) recreation, 2) grazing, 3) fire, and 4) logging.

The manager of the majority of these lands in New Mexico is the U.S. Forest Service. The remaining owners/managers of this habitat are tribal governments, the state and private land-owners.

Emergent Wetlands and Lakes

Eastern Playas

This habitat is located within the Llano Estacado, south of the Canadian River, covering most of Quay, Curry, Roosevelt, and Lea counties in the Pecos and Staked Plains Physiographic Area. Playas are part of a larger wetlands system that covers five states in the southern Great Plains. Approximately 85% of the playas in these five states are in New Mexico and Texas (Haukos and Smith 1997). In New Mexico, there are estimated to be from 1700 playas (Nelson et al.1983) to about 2460 (Guthery et al. 1981), mostly in the Llano Estacado (Haukos and Smith 1997).

Playas are shallow, closed systems, generally with clay bottoms. Historically, they received water only from rain and surrounding rainfall runoff. Tailwater from surrounding irrigated agricultural lands is currently an additional water source. This may cause playas to flood more frequently than prior to initiation of agriculture (Haukos and Smith 1997). 

While playas occupy only about 2% of the land, they collect flood waters from approximately 90% of the region and are important for storm water catchment in urban areas. Few playas are directly connected to groundwater but are critical recharge points to the southern portions of the Ogallala Aquifer, filtering and recharging 20-80% of collected water to the aquifer (Haukos and Smith 1997).

Playas are characterized by the ephemeral nature of rainfall in this area, averaging about 14-16 in (36-41 cm) per year (Jones 1996). During wet periods, vegetation characteristic of permanent ponds and marshes develops. When this occurs, playas become an important stopover point for migrating waterfowl and shorebirds, as well as a water source for all birds in the area. Playas with moist soil, but no standing water, develop vegetation that is dominated by forbs. This may produce seeds important to migrating sparrows and finches. Playas that remain mostly dry develop vegetation similar to that of the surrounding grasslands. Playa vegetation is dependent upon the wet and dry cycles for rejuvenation. A decrease in vegetative diversity will result in a corresponding decline in wildlife diversity. For groundwater recharge and bird value, playas should be allowed to function naturally within an agricultural landscape (Haukos and Smith 1997).

Historically, this area contained short- and mid-grass prairie. Cattle grazing began here in the 1870’s. Agricultural cultivation began around the 1920’s. The advent of irrigation in the late 1940’s allowed a larger percentage of land to be farmed (Haukos and Smith 1997). 

Sedimentation from cropland has been identified as a major threat to playas. Sediment fill results in increasingly xeric conditions. Other threats include pesticide and herbicide runoff. One study (Price et al. 1989) found that applying tebuthiuron at higher levels than 1.9 lbs/ac (2.2kg/ha) on rangelands adversely affect playa algal communities. Dumping of contaminated water from oil field operations has killed large numbers of birds (Nelson et al. 1983). Construction of irrigation pits within playas changes the natural wet cycles and the surface area, and affects plant communities. Edges become more xeric with prairie vegetation dominating, while the pit becomes more perennial with concurrent permanent marsh vegetation. Overgrazing of playas reduces plant diversity and increases species such as buffalo grass (Buchloe dactyloides), cockleburr (Xanthium strumarium), and burr ragweed (Ambrosia grayi) (Guthery et al. 1982). Elimination of grazing around playas increases habitat for waterfowl and shorebirds and reduces the encroachment of less desirable vegetation, erosion, increased turbidity, and sedimentation (Guthery et al. 1982).

Over 99% of playas are privately-owned (Haukos and Smith 1997). Therefore, education about the benefits of playas is highly important.

Alkali Lakes and Closed Basins

These lakes, also commonly called playas, are shallow, closed basins that receive water from rainfall. They are more common within the Chihuahuan Desert and Colorado Plateau Physiographic Areas in New Mexico, although a few occur in the Mogollon Rim and on the Pecos and Staked Plains. 

They function in a similar manner to the playas described above. Average yearly rainfall is generally from 8 to 12 inches. Because these lakes and basins are not normally associated with agricultural areas, agricultural tailwater rarely affects these areas. They are usually filled with water less often than non-saline playas.

Ground cover is sparse in alkali lakes. Often, there is enough standing water to prevent perennials from taking hold. Burrowgrass (Scleropogon brevifolius) and occasionally forbs, usually from the surrounding grassland, occupy the edges. In the northwestern quadrant, fourwing saltbush (Atriplex canescens) and shadscale (Atriplex confertifolia) codominate and ground cover may be higher than in southern areas. Most of the forbs belong to the goosefoot family, Chenopodiaceae. If the southern lakes’ edges are sandy, shrubs may include mesquite (Prosopis sp.) or soaptree yucca (Yucca elata). Annuals, such as bitterweed (Hymenoxys odorata), often form pure stands on the dried playa beds. If edges are not sandy, tarbush (Flourensia cernua) may dominate. Sacaton associations are often found in transition zones to surrounding grasslands (Dick Peddie 1993). 

Large areas with dense stands of fourwing saltbush are typical of closed-basin vegetation. Occasionally, pale wolfberry (Lycium pallidum) is a codominant. Common forbs are red sage (Kochia americanca), Atriplex patula, and A. corrugata. Greasewood (Sarcobatus vermiculatus) can be found dominating upper portions of the basins. On the closed basins near White Sands, Reid (1980) found large areas dominated by Coldenia hispidissimus, with scattered allthorn (Koerbelinia spinosa) and squawbush. Forbs in these areas, especially in south-central and southeastern New Mexico, are gypsum-soil adapted, including gyp moonpod (Selinocarpus lanceolatus), gyp grama (Bouteloua breviseta), gyp dropseed (Sporobolus nealleyi), and the mustard Nerisyrenia camporum (Dick-Peddie 1993). Trees are rare in these areas although salt cedar (Tamarix spp.) can be found, sometimes in great abundance. 

Lakes, Ponds, and Marshes

Vegetation does not generally differ from small seeps to large lakes, except with increased water depth. Therefore, all are included in this section. Additionally, this vegetation may occur in playas and alkali lakes if water is present for long enough periods of time to allow emergent growth. Generally, cattails appear first, followed by bulrushes, rushes and sedges (Dick-Peddie 1993).

In wetland areas, vegetation in shallow water or very moist soil consists of grasslike plants such as sedges (Carex spp., etc.), bulrushes (Scirpus spp.), rushes (Juncus spp.), and cattails (Typha spp.) along with nongrasslike forms such as water plantain (Alisma sp.) and arrowhead (Sagittaria sp.). Floating-leaf plants, such as water shield (Brasenia sp.), pondweed (Potamogeton sp.), water fern (Azolla sp.), duckweed (Lemna sp.), watercress (Rorippa sp.), and smartweed (Polygonum sp.), develop as water becomes deeper. Floating algae (phytoplankton) may also be present. These two associations of plants comprise the majority of marsh vegetation. If deeper water is present, submersed plants including milfoil (Myriophyllum sp.), waterweed (Elodea sp.), hornwort (Ceratophyllum sp.), stoneworts (Chara spp. and Nitella spp.), bladderwort (Utricularia sp.) and fixed algae (various genera) occur (Dick-Peddie 1993). 

Considerable variation exists in dominant species. Some lakes naturally do not contain all associations. Many man-made lakes maintain relatively stable water levels and support two or more associations of aquatic vegetation. Some man-made lakes are subject to large and rapid changes in water levels and rarely have stable plant communities. The vegetation that occurs in unstable lakes contains fewer plant species than in lakes with stable water levels (Dick-Peddie 1993). These are the larger reservoirs found along the San Juan, Rio Grande and Pecos Rivers. 

Non-riparian wetlands are used by breeding, long-legged waders, waterfowl and shorebirds. Use of these wetlands by these species is dependent on the amount of vegetation and water depth rather than elevation or location. Exceptions are Snowy Plover and Least Tern, which must have relatively level, alkali flats, free of vegetation near the water.

These wetlands serve as a source of water for all birds in the surrounding areas. In addition, these wetlands are extremely important for migrating and wintering birds. Waterfowl and Sandhill Cranes depend on wetlands at Bosque del Apache National Wildlife Refuge near Socorro. Larger reservoirs, built for water storage rather than flood control, are important for piscivorous waterbirds such as loons, grebes, some ducks and cormorants. The headwaters of Elephant Butte and Caballo lakes are a breeding area for many colonial waterbirds.

The shorter rush and taller grass areas bordering these wetlands are important breeding areas for smaller ducks such as Cinnamon and Blue-winged Teal and rails, such as Sora. Currently, these birds are not considered at risk and, therefore, this habitat niche is not specifically addressed in the following sections. Western and Clark’s Grebe are considered together in this plan due to a lack of information about differences in their breeding habitat and because there are instances of interbreeding in New Mexico.

Impacts to these habitats include 1) grazing, 2) draining, 3) water diversion, 4) agricultural, urban and industrial runoff and waste, and 5) upslope development for housing or industrial use.

These lands are owned and managed by a variety of private landowners, Native American jurisdictions, and state and federal agencies. Some of the most important wetland areas are managed by the National Wildlife Refuge System and include Bitter Lake, Bosque del Apache, Las Vegas and Maxwell National Wildlife Refuges.

 

2.7.6   Other

Cave/Rock/Cliff

Cliff/Cave/Rock habitat is probably better described as a sub-habitat. It occurs wherever rock is found, throughout the state. Areas above treeline are excluded from this designation and included under alpine tundra. 

Small caves are found throughout the state. Large cavern openings are rare and are mainly found in the Guadalupe Escarpment, especially at Carlsbad Caverns National Park in Eddy County. Carlsbad Caverns provide nesting habitat for the majority of the state’s Cave Swallows. Rocky outcroppings may exist anywhere and even small areas may provide habitat for breeding Rock Wrens. In northern New Mexico, these areas are often free of snow in winter, providing foraging areas for species such as longspurs in rocky portions of grasslands. Cliffs need not be very tall for birds such as Canyon Wrens. Rocky cliffs near or in riparian areas are also included. Black Swifts use cliffs in and around waterfalls. Golden Eagles may nest at 180 ft. or higher above the ground (Hawks Aloft, unpub. data). Steep-sided cliffs with ledges for nest sites or scrapes that allow little or no access from the ground are key components of raptor nesting cliffs. 

Owners/managers of these habitats constitute almost all types in the state.

Impacts to these habitats include 1) mining operations, 2) development and 3) disturbance through recreation such as rock climbing.

Agricultural Lands

Occurs primarily in association with the major river valleys of New Mexico, the Rio Grande, Pecos, Gila, and San Juan drainages. Also occurs in the eastern grasslands north to Roswell, Clovis, Clayton, and in the Estancia valley north along the eastern edge of the Sangre de Cristo mountains. Prevalent on the Navajo Agricultural Products, Inc. in San Juan County and the Deming-to-Columbus corridor in Luna County. Elevations range from 3500 to 7500 feet.

This habitat includes a variety of differing agricultural landscapes and scales. Many types of fields exist from alfalfa fields which may support large numbers of birds to cotton fields which are generally avoided by birds. Orchards are also included in this category, including both fruit and pecan orchards. Recently, Yellow-billed Cuckoo and Eastern Bluebird have been found breeding in these types of orchards in southern New Mexico.

Flooded agricultural fields may provide foraging habitat for many shorebirds and waterfowl during migration. Agricultural fields often support large numbers of wintering birds.

Irrigation ditches (“acequia’s” in northern New Mexico) are also considered agricultural in nature and can provide habitat for birds. Thompson et al. 1996 found that during migration, ditches which had not been scraped of vegetation supported higher numbers of migrant birds than either agricultural fields or orchards. While these areas do not serve as a replacement for riparian habitats they can be viewed as a good addition to riparian habitats in the state.

“Clean farming” replaces biodiversity with monoculture and can reduce critical habitats for wildlife, including hedgerows and roadside vegetation. Soil erosion, and the resultant sedimentation, can reduce cropland capability for the production of plant and animal biomass. This can impact the quality and quantity of aquatic habitat (Bolen and Robinson 1999).

Impacts to this habitat include: 1)noxious plants and weeds, and 2)pesticide use.

Urban

This habitat includes urban and suburban areas where native vegetation has been removed, as well as golf courses.

Link to Chapter 3;

Chapter 3     Avifaunal and Habitat Analysis