Arizona Wildlife Conservation Strategy

Lower Sonoran Desertscrub

Lower Sonoran desertscrub is the most arid habitat found in Arizona. The vegetation community is dominated by drought-tolerant, low, open stands of creosote bush and white bursage. Winter annuals make up the bulk of the remainder of the vegetation and their blooms can be surprisingly colorful in wet years. Columnar cacti, ocotillo, and cholla, although present, are less abundant than in the neighboring Upland Sonoran desertscrub. Larger trees, such as ironwood, palo verde, and mesquite are largely confined to washes and other drainages (Brown et al. 2017). 

The basin and range landscape is typically comprises of broad, relatively flat valleys separated by scattered, small mountain ranges (Dimmitt 2015). These xeric mountain ranges provide habitat for desert bighorn sheep and Sonoran desert tortoises. Stabilized and active dunes are present throughout this habitat which support a variety of dune and sand-specialist species of plants and animals such as ajo lilies, desert sandfood, flat-tailed and Goode’s horned lizards, Yuman desert and Mojave fringe-toed lizards, and sidewinders. LeConte’s thrasher, round-tailed ground squirrel, desert kangaroo rat, and kit fox are also present in this habitat type (Turner 1994).

The lower reaches of the Colorado and Gila rivers flow through this dry desert region providing a variety of important aquatic and riparian habitats for many fish and wildlife species. Additionally, these riparian areas provide water for agricultural and municipal uses. At least 21% of this habitat type has been lost due to development and agriculture. Approximately 45% of lower Sonoran desertscrub is federal land, including Barry M. Goldwater Range, Yuma Proving Ground, and Cabeza Prieta and KOFA National Wildlife Refuges. Because of this ownership, opportunities may exist to protect and restore large tracts of land in this region.

Significant Habitat Features

The following describes habitat features or microhabitats that are unique to this habitat type and are of particular importance to certain species:

Riparian areas, such as the Gila, Bill Williams, and Colorado Rivers, are important for wildlife and support the only cottonwood and willow forest in lower Sonoran desertscrub. This riparian forest and associated marshlands provide critically important habitat for a variety of species, including Yuma Ridgway’s rail, California black rail, southwestern willow flycatcher, western yellow-billed cuckoo, and northern Mexican gartersnake. Additionally, these river systems provide some of the only perennial water found in these hyper-arid areas.

  • Stabilized and active dune systems are unique to lower Sonoran desertscrub habitat in Arizona. These sandy areas provide habitat for a variety of sand-specialized species such as several desert fringe-toed lizard species, flat-tailed horned lizards, Mojave and resplendent shovel-nosed snakes, sidewinders, and desert kangaroo rats. A variety of dune and sand specialist plants can also be found in these areas, including ajo lily, scaly-stemmed sand plant, sandfood, Gander’s cryptantha, tansy spectaclepod, desert twinbugs, saw-toothed ditaxis, galleta grass, Emoryi’s indigobush, Schott’s wire-lettuce, and fanleaf crinklemat (Felger et al. 2003).

  • Ephemeral washes and pools are important breeding habitats for a variety of desert anurans, including Sonoran green toad, Sinaloan narrow-mouthed toad, lowland burrowing treefrog, and Sonoran desert toad (Brennen and Holycross 2009). Washes, despite their ephemeral nature, support higher densities of mesquite and ironwood compared to the surrounding plains. These linear woodlands serve as nesting sites for birds, provide browse and cover for ungulates, and act as movement corridors for a variety of wildlife species.

  • Bedrock tinajas are small rain-filled pools that develop in bedrock depressions created by wind and water erosion found in the Cabeza Prieta, Gila, Kofa, and Tinajas Altas mountains. These features collect water during rare periods of rain and are vital sources of water for desert bighorn sheep and other montane species.

  • Bajadas are the coalescence of alluvial fans along a mountain front where fine sediment is deposited at the end of dry washes and other drainages. Because of this soil composition, these slopes can host a greater diversity of vegetation and more complex vertical structure compared to surrounding areas.

  • Saguaro cacti are a keystone species in the Sonoran desert, providing a variety of resources for desert fauna. Saguaros provide nectar, pollen, and fruit for two species of SGCN nectivorous bats, as well as a host of other pollinator species that occur across much of southern Arizona. Saguaros also provide cavities for nesting avian species such as cactus ferruginous pygmy owl and western screech owl. Invasive buffelgrass — which outcompetes native flora and provides fuel for wildfire — is a major threat to these iconic keystone species.

Strategy Species

The following list represents SGCN in this habitat type that AZGFD actively manages or are watching closely due to some level of concern:


Sonoran Green Toad, Sinaloan Narrow-mouthed Toad, Lowland Burrowing Treefrog, Sonoran Desert Toad


Costa's Hummingbird, LeConte's Thrasher, Bendire's Thrasher, Verdin, Western Screech-Owl, Bald Eagle, Golden Eagle, Loggerhead Shrike, California Black Rail, Southwestern Willow Flycatcher, Ridgway's Rail, Western Yellow-billed Cuckoo


Phoenix (Squaw Peak) Talussnail, Eastern Desertsnail


Sonoran Pronghorn, Harris's Antelope Squirrel, Antelope Jackrabbit, California Leaf-nosed Bat, Lesser Long-nosed Bat, Mexican Free-tailed Bat, Western Red Bat, Greater Western Mastiff Bat, Pocketed Free-tailed Bat


Goode's Horned Lizard, Flat-tailed Horned Lizard, Yuman Desert Fringe-toed Lizard, Mohave Fringe-toed Lizard, Mohawk Dunes Fringe-toed Lizard, Sonoran Collared Lizard, Speckled Rattlesnake, Sonoran Coralsnake, Three-lined Boa, Sonoran Desert Tortoise, Arizona Mud Turtle, Gila Monster

Sensitive Plant Species

The following list represents plant species that are known to occur in this habitat type:

scaly sandplant, sandfood

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.


Couch's Spadefoot


Black-tailed Gnatcatcher, Lesser Nighthawk, Gambel's Quail, Mourning Dove, White-winged Dove

Invasive Plants

Stinknet, Giant Salvinia, Tamarisk, Sahara Mustard


Desert Bighorn Sheep, Mule Deer, Desert Cottontail, Pallid Bat, Western Yellow Bat, Cave Myotis, Canyon Bat


Desert Iguana, Sidewinder, Common Chuckwalla, Resplendent Shovel-nosed Snake, Mohave 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.

1. Agriculture

1.1: Annual and perennial nontimber crops
1.3: Livestock farming and ranching
Historical and current overgrazing on the landscape has affected native plant populations. With overgrazing and drought prevalent, non-native plant species have taken over areas once dominated by native vegetation. Agriculture operations in a drought-driven environment have contributed to a decreased water table, exacerbating the difficult balance between wildlife conservation and working lands.

2. Biological Resource Use

2.1: Unlawful take of terrestrial animals
2.2: Unlawful take of terrestrial plants
Unlawful take of terrestrial animals or plants can be detrimental to populations that have slow recruitment. Excess harvest can substantially impact species with small populations and reduce their ability to recover from stochastic events, such as drought or wildfire.

3. Climate Change and Severe Weather

3.1: Habitat shifting and alteration
3.2: Droughts
3.3: Temperature extremes
3.4: Storms and flooding
Warmer ambient temperatures may surpass species’ temperature tolerances, causing local extinctions or changing the distribution of less heat-tolerant species. Altered precipitation patterns may affect hydrological regimes (more droughts and floods) which can adversely influence terrestrial plant and wildlife distributions.

4. Residential and Commercial Development

4.1: Housing and urban areas
4.2: Commercial and industrial areas
4.3: Tourism and recreation areas
With the human population increasing in Arizona, habitat loss is becoming more widespread due to the rate of housing and commercial development. Additionally, unlawful/unmanaged recreational use by OHV users may degrade habitats, leading to increased levels of soil erosion, vegetation loss, and habitat degradation.

5. Disease, Pathogens, and Parasites

5: Disease, Pathogens, and Parasites
With the increase in transport of both people and wildlife, emerging infectious diseases are being spread to naive wildlife populations. Infectious diseases have been linked to wildlife declines throughout Arizona and the rest of the United States. In many cases, wildlife populations are unable to adapt immune or behavioral defenses to these diseases to avoid severe population declines. Populations then face genetic bottlenecks and decreased population connectivity, further impacting their ability to recover.

6. Energy Production and Mining

6.2: Mining and quarrying
6.3: Renewable energy
Many areas within lower Sonoran desertscrub have been utilized both historically and contemporarily for mineral extraction. Many of these mines are still in operation and can have major impacts on the habitat. A major increase in solar energy development throughout the southwestern portion of the state is impacting large swaths of habitat previously available for wildlife use.

7. Human Intrusions and Disturbance

7.1: Recreational activities
7.2: War, civil unrest and military exercises
Poorly-managed recreational activities, such as illegal OHV use, can degrade desertscrub habitats by damaging habitats, increasing erosion, harming delicate vegetation, and altering wildlife behavior. Military installations and the resulting activities can impact wildlife habitats and populations. Fortunately, many of these lands have robust conservation measures to avoid and mitigate for these activities. Recent border wall construction has also severely impacted many critically-important habitats along the southern border.

8. Invasive and Other Problematic Species

8.1: Invasive non-native species
Invasive and introduced species may compete with native fauna, over-utilize native species, affect native species populations through hybridization, and cause habitat damage. Invasive species, such as salt cedar (tamarisk), reduce habitat diversity in the delicate riparian habitats found in upper Sonoran desertscrub.

9. Natural System Modifications

9.1: Fire and fire suppression
9.2: Dams and water management
Many invasive plant species are adapted to wildfire regimes. Post-fire, invasive species such as buffelgrass may outcompete native species and quickly displace native communities. Meanwhile, fire suppression can allow for the establishment of woody plants, such as mesquite, that can greatly alter the desertscrub community. Dams and water management activities convert lotic systems into lentic systems, and alter or completely dry downstream lotic stretches of waterways.

10. Pollution

10.1: Household sewage and urban waste water
10.2: Industrial and military effluents
10.3: Agricultural and forestry effluents
10.4: Garbage and solid waste
Pollution can lead to habitat degradation, behavioral modification from noise, direct mortality/reduced fecundity, and loss of food and water. Sources of pollution include leaking septic and fuel tanks, untreated sewage, oil or sediment on roads, lawn and agricultural fertilizers and herbicides, illegal dump sites, mine tailings, roadside litter, construction-site debris, military effluents, and solid garbage and waste.

11. Transportation and Service Corridors

11.1: Roads and railroads
11.2: Utility and service lines
The creation of new roads, as well as current travel corridors, can be both a direct and indirect threat to species in the area. Vehicle traffic can create noise and visual disturbance, altering the behavior of wildlife species and leading to direct mortality due to vehicle strikes. Road construction and maintenance may result in the direct loss of habitat and disrupt migration corridors.

Conservation Actions

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.

1. Land and Water Protection

1.1: Site/area protection
1.2: Resource and habitat protection
  • Identify wildlife corridors essential to the movement of species between high-quality habitat blocks. (Threats 4.1, 4.2)
  • Engage communities to incorporate natural resource values and open spaces into long-term planning. Acquire land and water rights, pursue conservation agreements and easements, especially in critical wildlife corridors. (Threats 4.1, 4.3, 6.2, 6.3, 7.1)
  • Continue maintenance of wildlife waters to mitigate drought and the effects of temperature extremes. (Threats 3.2, 3.3)

2. Land and Water Management

2.1: Site/area management
2.2: Invasive/problematic species control
  • Implement projects focused on improving the quality of altered systems creating suitable habitat and/or habitat features for wildlife. Actively seek opportunities to partner with Arizona agricultural producers, private landowners, and land management agencies on a variety of habitat enhancements that benefit both livestock and wildlife. (Threats 1.1, 1.3, 3.1, 4.1, 4.2, 4.3, 6.2, 6.3, 7.1, 7.2, 9.1)
  • Continue disease monitoring efforts for impacted species. Avoid inadvertent spread of disease by following the proper disinfectant protocols. (Threat 5)
  • Conduct monitoring and targeted removal efforts to limit establishment and spread of invasive species, especially in COAs or other important wildlife areas. Continue removal activities for trespass livestock, burros, and feral horses on managed lands. (Threats 1.3, 8.1, 9.1)

4. Education and Awareness

4.2: Training
4.3: Awareness and communication
  • Engage communities to incorporate natural resource values and open spaces into long-term planning. (Threats 1.1, 1.3, 4.1, 4.2, 4.3, 6.3, 7.1, 10.1, 10.2, 10.3, 10.4, 11.1)
  • Conduct emerging disease education and outreach to user groups who potentially come into contact with affected species. Provide education on methods for avoiding the spread of diseases, pathogens, and parasites into novel populations of wildlife (i.e. bats and white-nose syndrome). (Threat 5)
  • Provide extensive educational outreach through public events, social media messaging, billboards, and partnering with AZ State Parks, OHV dealers, OHV rental companies as well as off-road clubs and organizations. Educate new outdoor enthusiasts on safe, ethical practices and proper behavior in natural settings and in proximity to wildlife. (Threats 4.3, 7.1, 11.1)
  • Work with developers, federal permitting agencies, the Arizona Corporation Commission (ACC), and state and local governments to raise awareness of impacts to wildlife and habitat from renewable and nonrenewable energy development. (Threats 6.3, 11.2)
  • Develop outreach programs for the public on impacts to wildlife, agriculture, and recreation from introduced species. Incorporate citizen science programs to identify distribution of invasives (such as (Threat 8.1)

5. Law and Policy

5.2: Policies and regulations
5.4: Compliance and enforcement
  • Conduct statewide law enforcement patrols targeting illegal OHV use as well as targeted saturation patrols in areas identified as critical habitat that are being adversely impacted by OHV and other recreational activities. (Threat 7.1)
  • Inform federal and state agencies of critical need for wildlife movement across the international border with Mexico, and help design any necessary border barriers to allow wildlife movement. (Threat 7.2)
  • Conduct statewide law enforcement patrols targeting illegal take of wildlife, especially during scheduled hunts. (Threat 2.1)

6. Livelihood, Economic and Other Incentives

6.2: Substitution with environmentally-friendly goods and services
6.3: Market forces
  • Collaborate with the development and renewable energy industries to incorporate BMPs and other measures to reduce impacts to wildlife and habitats. Identify ways for incentivizing incorporation of recommendations. (Threats 4.1, 4.2, 6.3)
  • Work with local governments to incorporate wildlife protections and habitat connectivity into general plans. (Threats 4.1, 4.2, 6.3)
  • Share information and discuss the benefits of participating in species recovery programs such as Safe Harbor Agreements, Habitat Conservation Plans, Candidate Conservation Agreements with Assurances, and Candidate Conservation Agreements with interested landowners. (Threats 1.1, 3.1, 1.3, 7.1)

7. External Capacity Building

7.2: Alliance and partnership development
  • Collaborate with partners across different geographies (e.g., statewide, regional, national and international) to develop and implement management plans, conservation agreements, recovery actions, research, management recommendations, and to determine the effectiveness of specific management efforts for long-term conservation of SCGN wildlife. (Threats 3.1, 3.2, 3.3, 3.4, 5, 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).

  • Encourage and facilitate strategic planning for the renewable energy industry.

  • Identify and improve the connectivity of natural landscapes to better link wildlife populations and allow for range shifts.

  • Identify populations that could benefit from assisted migrations and/or translocation.

  • Implement long-term monitoring protocols for vulnerable species and habitats to inform adaptive management.

  • Establish new wild and/or captive populations of climate-vulnerable SGCN.

  • Maintain existing and identify new wildlife waters for drought mitigation.

  • Monitor and mitigate for introduced/invasive species.

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.
  • Implement conservation actions to promote populations of SGCN species.
  • Collect specimens or samples for taxonomic analysis, genetics, research, and/or disease testing.
  • 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.

Conservation Opportunity Areas (COAs)

The following represents identified COAs where conservation efforts would benefit wildlife and their habitats.

Potential Partnerships

The following is a list of the organizations and agencies that AZGFD regularly partners with on conservation efforts in this habitat type:

Important Conservation Resources

The following are relevant conservation agreements, plans, and other documents or particular interest regarding wildlife in this habitat type: