In Arizona, Chihuahuan desertscrub covers only a relatively small area southeast of Tucson around Duncan, San Simon, and the San Pedro River Valley at elevations of approximately 3,500 to 5,000 feet above sea level. Chihuahuan desertscrub is more widespread in neighboring regions covering most of north-central Mexico, portions of West Texas, and southern New Mexico.
Chihuahuan desertscrub in Arizona typically receives less than nine inches of precipitation annually, mainly in the summer months (Brown 1994). Creosote, tarbush, and whitethorn acacia are characteristic shrubs. Additional characteristic plant species include ocotillo, mesquite, desert zinnia, agave, and yucca (Brown 1994). Trees are rare throughout this habitat type. The extent of Chihuahuan desertscrub in Arizona has expanded due to conversion from grasslands in areas experiencing suppression of natural fires and high grazing pressure combined with drought (Gori and Enquist 2003). This habitat type generally occurs on relatively flat areas of less than 10% slope making it attractive for agriculture operations and development. Several SGCN species occur in Chihuahuan desertscrub, including Gila monster, Harris’ antelope squirrel, and banner-tailed kangaroo rat. However, no SGCN are limited to only this habitat type (AZGFD 2012).
Significant Habitat Features
The following describes habitat features or microhabitats in this habitat type that are of particular importance to certain species:
Springs act as important water sources in an arid environment and often support endemic species that require aquatic habitats to support their life cycle, such as San Bernardino springsnail, Chiricahua leopard frog, and lowland leopard frog.
Ephemeral washes and pools are critically important breeding habitats for a variety of desert anurans, including plains spadefoot, green toad, and Sonoran Desert toad (Brennen and Holycross 2009). Washes, despite their ephemeral nature, support higher densities of mesquite and ironwood than the surrounding plains. These linear forests serve as nesting sites for birds, provide browse and cover for ungulates, and act as movement corridors for a variety of wildlife species.
Riparian areas, such as the San Pedro River and Ciėnega Creek, are important for wildlife. These waterways can support cottonwood and willow forests and provide critically-important habitat for a variety of species, including southwestern willow flycatcher, western yellow-billed cuckoo, and northern Mexican gartersnake. Besides providing some of the only perennial water in the region, these lush areas also act as important corridors for seasonal and annual movements for wildlife.
The following list represents SGCN in this habitat type that AZGFD actively manages or are watching closely due to some level of concern:
Chiricahua Leopard Frog, Lowland Leopard Frog, Plains Leopard Frog, Sonoran Desert Toad
Black-capped Gnatcatcher, Cassin's Sparrow, Chihuahuan Raven, Golden Eagle, American Peregrine Falcon, Scaled Quail, Southwestern Willow Flycatcher, Western Burrowing Owl, Western Yellow-billed Cuckoo
Antelope Jackrabbit, Banner-tailed Kangaroo Rat, Black-tailed Prairie Dog, Cave Myotis, Greater Western Mastiff Bat, Harris's Antelope Squirrel, Hispid Pocket Mouse, Lesser Long-nosed Bat, Northern Pygmy Mouse, Western Red Bat, Yellow-nosed Cotton Rat
Gila Monster, Mexican Gartersnake, Ornate Box Turtle
Sensitive Plant Species
The following list represents plant species that are known to occur in this habitat type:Cochise pincushion cactus, San Pedro River wild buckwheat, Arizona eryngo, Bartram stonecrop, Huachuca water-umbel, lace-leaf rockdaisy
Additional Influential Species
The following are other wildlife species, native and non-native, that can have particular influence in this habitat type. Influential species can affect SGCN and their habitats directly and indirectly, for example altering predator/prey interactions, overgrazing, outcompeting natives, creating microhabitats, and others.
Green Toad, Plains Spadefoot
Curve-billed Thrasher, Gould's Turkey, Greater Roadrunner
Banner-tailed Kangaroo Rat, Desert Cottontail, Kit Fox, Mule Deer, Western Yellow Bat, White-nosed Coati
Checkered Gartersnake, Greater Earless Lizard, Mexican Hog-nosed Snake, Mohave Rattlesnake, Round-tailed Horned Lizard, Texas Horned Lizard, Western Diamond-backed Rattlesnake
The following describes the primary threats facing this habitat type, adapted from Salafsky et al. (2008). First-level threats (i.e. Agriculture, Climate Change) represent broad categories while second-level threats reflect more specific stressors to the system. For detailed information on threats to this habitat type and conservation actions being taken, see Chapter 8: Threats and Conservation Actions.
3. Climate Change and Severe Weather
6. Energy Production and Mining
7. Human Intrusions and Disturbance
8. Invasive and Other Problematic Species
9. Natural System Modifications
11. Transportation and Service Corridors
The following describes specific conservation actions that can be taken to reduce or eliminate threats to this habitat type, adapted from Salafsky et al. (2008). Level 1 conservation actions (i.e. Land and Water Protection) represent broad categories of potential actions, while the Level 2 conservation actions (i.e. Resource and habitat protection) are more specific.
2. Land and Water Management
- Maintain native desertscrub through chemical and manual treatments of invasive and problematic species; protect native flora through appropriate stocking rates and to address soil erosion from grazing. (Threats 1.1, 1.3, 8.2)
5. Law and Policy
- Work with federal and state agencies to address the critical need for wildlife movement across the international border with Mexico, and help design any necessary border barriers to allow wildlife movement. (Threat 7.3)
6. Livelihood, Economic and Other Incentives
- Partner with agricultural producers and private landowners on a variety of habitat enhancements that benefit both livestock and wildlife. (Threats 1.1, 1.3, 4.1)
- Perform outreach with interested landowners on species recovery programs such as Safe Harbor Agreements, Habitat Conservation Plans, and Candidate Conservation Agreements. (Threats 1.1, 1.3, 3.1, 8.1)
Conservation in the Context of Climate Change
The following describes some of the conservation strategies that may mitigate the effects of a changing climate for this habitat type. Strategies have been adapted from guidelines by the Association of Fish and Wildlife Agencies (AFWA 2009).
Conserve a variety of habitats that support healthy populations of wildlife as the climate changes.
Conduct research targeting species and habitat types likely to be vulnerable to climate change impacts.
Monitor and mitigate for introduced/invasive species.
Maintain existing and identify new wildlife waters for drought mitigation.
Identify and improve the connectivity of natural landscapes to better link wildlife populations and allow for range shifts.
Other Conservation Actions
The following describe other routine or on-going conservation actions AZGFD regularly performs in this habitat type:
- Conduct surveys and monitor populations of SGCN as specified in work plans and job statements.
- Survey other influential species within the habitat to inform adaptive management strategies in order to minimize negative impacts to habitat and associated species.
- Fund or work with partners to conduct conservation-related species research.
- Manage recreational activities and OHV use of desertscrub habitat to minimize negative impacts to habitat and associated species.
- Collect specimens or samples for taxonomic analysis, genetics, research, and/or disease testing.
Conservation Opportunity Areas (COAs)
The following represents identified COAs where conservation efforts would benefit wildlife and their habitats.
- Chiracahua Mountains
- Dos Cabezas
- Gila Box
- Leslie Canyon NWR
- Little Dragoons
- Lower San Pedro River
- Mule Mountains
- Peloncillo Mountains North
- Peloncillo Mountains South
- San Bernardino National Wildlife Refuge
- San Pedro Riparian National Conservation Area
- Tucson Sky Islands
The following is a list of the organizations and agencies that AZGFD regularly partners with on conservation efforts in this habitat type:
- BLM Safford Field Office
- BLM Tucson Field Office
- Malpais Borderlands Group
- Borderlands Restoration Network
- The Nature Conservancy
- Arizona Field Ornithologists
- Sonoran Joint Venture
Important Conservation Resources
The following are relevant conservation agreements, plans, and other documents or particular interest regarding wildlife in this habitat type: