Both temperature and precipitation define the environmental and hydrological conditions that determine vegetation composition and distribution at large scales, and water availability is the primary factor limiting plant growth in dryland areas such as the southwestern United States. As temperatures rise, rates of evapotranspiration (water losses from both plants and land surfaces to the atmosphere) increase, resulting in reduced plant growth and favoring drought- and heat-tolerant species. Boundaries between terrestrial habitat types have already shifted. In northern New Mexico, there are sites where piñon (Pinus spp.)-juniper (Juniperus spp.) has replaced ponderosa pine (Pinus ponderosa) following severe drought and ponderosa pine mortality. Additionally, creosote (Larrea tridentata) and honey mesquite (Prosopis glandulosa) shrubs have spread into grasslands in central and southern New Mexico, respectively. In the future, grasslands may decline significantly, especially in central New Mexico. Shrublands may increase in some areas, including continued expansion into grassland habitats. Alpine (above tree line) habitats are likely to shrink as mid- and lower-elevation forests and woodlands move upslope. Tree stress and mortality, along with associated insect and disease outbreaks and wildfire, are likely to increase as evapotranspiration rates and drought length and severity increase. Rising temperatures may enhance survival of bark beetles (Ips confusus), to which species such as piñon pines (Pinus edulis) are particularly susceptible. Many forested and woodland areas may ultimately be converted to grass and shrub-dominated communities, in some cases facilitated by high severity wildfires.

Aquatic and riparian habitats are also likely to be impacted by a changing climate. Reduction in stream flow associated with reduced snow pack and increased spring-summer drying trends, along with potential mismatching in timing between earlier spring runoff and seed dispersal, are likely to reduce the abundance of native riparian vegetation. Water tables may be lowered by increasing aridity and groundwater extraction. These trends favor deeper-rooted and more drought-tolerant woody species, such as non-native tamarisk (Tamarix spp.) and Russian olive (Elaeagnus angustifolia), over native cottonwoods (Populus spp.) and willows (Salix spp.). Availability of high-quality perennial cold and warm water stream habitat, suitable for associated aquatic species, is likely to decline. As stream flows decline, water will warm more quickly in response to increasing air temperatures and may increase thermal stress, create migration barriers, fragment habitat, and reduce reproductive success of native species adapted to cold water. Non-native aquatic species and some warm-water species may be favored by higher water temperatures in streams, lakes, and reservoirs. Warm waters in particular may be susceptible to increases in salinity and algal growth, with impacts on available oxygen levels and local fish populations. Wetlands are threatened by drought and are sensitive to climate fluctuations. Many wetlands may ultimately transition from permanent to ephemeral (temporary) aquatic habitats. Some current ephemeral wetlands and catchments, including playas, may disappear. Montane wetlands may be especially vulnerable to projected shifts in climate.

Climate change presents a substantial threat to the conservation of wildlife diversity. Climate-related change in extinction risk varies by species, taxonomic group, and region, and species that are already at risk of extinction may be particularly vulnerable to the impacts of climate change. Species in mountainous regions and in wetland, riparian, and aquatic habitats, as well as species that are specialized, narrowly-distributed, or have limited movement capabilities, are likely to be particularly vulnerable to the effects of climate change. As winter temperatures warm, cold-blooded organisms, such as fish, reptiles, amphibians, and invertebrates, may extend their active seasons and require additional energy during winter months, when food resources are limited. Migratory species may be impacted by climate-driven mismatches between life history events and resource availability. Detailed information is not available for all SGCN, but climate-related declines have been observed or projected for multiple taxonomic groups and based on climate vulnerability analyses performed for the 295 vertebrate SGCN, fish and amphibians are especially vulnerable to climate change. Climate refugia analyses for New Mexico indicate that mountainous regions, especially in the Arizona/New Mexico Mountains and Southern Rocky Mountains ecoregions, are likely to help buffer birds and mammals against changing climate conditions. Similarly, portions of the Rio Grande and Pecos River valleys may help buffer amphibians and reptiles against climate change.

Climate change can aggravate current threats and produce new impacts, complicating the actions of conservation practitioners. Information on why a species is vulnerable to climate change can be used to direct management actions. General recommendations for coping with climate change include: 1) increase the robustness of SGCN populations by reducing pressures from factors other than climate change; 2) enhance the ability of natural systems to resist immediate effects of climate change; 3) use longer-term strategies that enhance species and ecosystem resilience to and adaptive capacity in the face of climate-related stressors (e.g., conservation of genetic diversity, protection of climate refugia); 4) accommodate future native species range shifts by maintaining connectivity between protected areas and future suitable habitats; 5) consider the timing of species management actions and perform them when conditions are most favorable for native species; 6) prepare for long-term conservation of SGCN to necessitate intensified efforts, innovative approaches, and flexibility; and 7) implement monitoring programs to assess population trends and evaluate success of climate-related management actions.

Conservation actions related to climate change in the SWAP focus on the following: 1) determining how climate change will affect SGCN, vegetation patterns, and community and ecosystem processes and dynamics; 2) identifying climate change or disturbance refugia; 3) implementing actions to mitigate the effects of climate change on SGCN and their habitats; 4) promoting the conservation and restoration of corridors that allow animals to move as climate conditions change; 5) developing recovery plans that consider future conditions for species and their habitats; 6) informing the public about the adverse impacts of climate change on SGCN and their habitats; and 7) monitoring SGCN to determine trends that correlate to ecosystem dynamics and habitat changes.