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 and 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 three years have been low rainfall years in the eastern plains of New Mexico.

Impacts to this habitat include 1) grazing, 2) herbicide use for shrub control, 3) fire and 4) 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.

Physiographic Areas covered: Colorado Plateau, Pecos and Staked Plains

Table 1. Plains-Mesa Sand Shrub Priority Species

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

• uses savannas, with occasional trees, shrubs and brush patches; also occurs in towns, agricultural areas and landscaped areas, such as golf courses
• density decreases with increased presence of grama-buffalo grass
• needs low number of perches (trees, shrubs, fences, wires) ranging from just above ground to 33ft (10m) in height
• nests in isolated trees or shrubs, often honey mesquite [averaged 45ft (13.8m) to next nearest shrub, 45ft (4.7m) in height, and 225 yd; (172m;) in volume in one e. Texas study. Shrubs had less vertical cover from 0-10ft (0-3m) increasing 10-20ft (3-6m)(Nolte and Fulbright 1996 in Regosin 1998).
• needs wide shrubs because nest placement can average 6ft (1.9m) from main stem

Fire - Shinnery shrublands are adapted to fire. While pre-European settlement fire regimes are not known, it is estimated that fires burned through these areas on a regular basis. It is known that the density of shrubs in this habitat is higher and the shrubs are generally larger than recorded in historical accounts. Peterson and Boyd (1998) provide a summary of fire studies conducted on shin-oak vegetation. Burning early in spring, during dry years, may increase grass and forb production. Burning later in spring may actually decrease production. However, during wet years, burning earlier in spring can bring dramatic increases in forb production with some grass increases. Burning later in the spring will bring over 60% more grasses and a slight decrease in forb production. Shin-oak burns readily in spring and often almost 100% of stems above ground are killed. Fire also stimulates vigorous oak resprouting, often to the point that oak occurrence equals that in unburned areas after only eight months. Fall burning tends to reduce cover and increase bare ground.

Research on the effects of fire and its role in maintaining productive habitat is still needed. However, evidence is growing that annual or biennial burning, especially during wet springs may decrease canopy height of shin-oak and increase production of perennial grasses. Managers should strive to maintain grass heights greater than 1.4ft (0.4 m). Over time and a larger landscape, managers should strive to keep an average balance of 60% grasses and forbs, 30% shrubs, and work to maintain no more than 10% bare ground. In more southerly areas where mesquite may be more prominent, maintenance of an average of 10-20% shrubs should be maintained.

Grass canopy cover- An overall canopy of 50-65% should be maintained. In areas where Lesser Prairie-Chickens nest, successful nests have been shown to be in areas of dense grass, surrounded by tall grass. Overhead cover was at least 50% (Haukos and Smith 1989). Bare ground should be kept to a minimum for the majority of grassland species.

Grazing and Grass Cover - While shrub vegetation has evolved with grazing, intense cattle grazing will turn grass-shrub dominated communities to communities dominated by shrubs, annual grasses and forbs. This will replace the more dominant perennial grasses of lightly or ungrazed areas (Lenfesty 1983). Additionally, bare ground can increase dramatically in this situation (Holland 1994). In other fire-adapted communities, grazing limits the fine fuels that spread fires. This is likely to be the case in these shrublands as well.

Rest-rotation or deferred-rotation grazing is recommended for maintaining and possibly improving habitat for ground-nesting birds. Stocking rates may be equally, or more, important for maintaining shrubland health. Lowering stocking rates, especially during drought years, will help to maintain habitat. Overgrazing, especially during drought years, can have dramatic negative effects on Lesser Prairie-Chicken and Scaled Quail numbers (review in Peterson and Boyd 1998).

Herbicide treatment - (generally with tebuthiuron) In general, herbicide control of shin-oak is less cost effective the further west it is performed, where precipitation is lower and wildlife values should be included in the calculation (Peterson and Boyd 1998). Herbicidal control, if necessary, should not be performed during drought years, in areas of large dunes, or where perennial grasses are not as widespread. Treated areas should not be summer-grazed or burned for 2 years following treatment (Doerr and Guthery 1980 in Peterson and Boyd 1998). If treatment is used, then it should be provided in a mosaic of smaller blocks (Davis et al. 1979). Tebuthiuron use should not exceed 0.36 lb per acre for control (Jones and Pettit 1984 in Peterson and Boyd 1998). Fire is a preferred management technique.

In general, Lesser Prairie-chickens do not do well under herbicide treatment. Peterson and Boyd (1998) state that "there is no evidence from Texas or New Mexico indicating that shin(ery)-oak treatment with tebuthiuron benefits prairie-chickens." Studies reviewed in Peterson and Boyd (1998) indicate that small- to medium-sized mammal populations overall will drop due to tebuthiuron treatment Bednarz 1987 in Peterson and Boyd 1998). This will likely result in a decrease of all or most raptor populations, including Swainson's Hawk (Doerr and Guthery 1980 in Peterson and Boyd 1998). Chihuahuan Ravens will reduce nesting starts and Scaled Quail populations will decline (Olawsky et al. 1987 in Peterson and Boyd 1998). Loggerhead Shrike and meadowlarks may increase (Olawsky et al. 1987 in Peterson and Boyd 1998).

Additional species for which monitoring is recommended:

• Burrowing Owl
• Rock Wren
• Curve-billed Thrasher