Although metallic and industrial mineral mining have a long history in Arizona, the state lacks major fossil fuel resources and has never been a leading producer of oil or natural gas. Only moderate amounts of coal have been extracted from the state’s two coal fields and with the 2006 Renewable Energy Standard set by the Arizona Corporation Commission (ACC), the closing of the Navajo Generating Station in 2019, and Arizona Public Service’s (APS) commitment to source 100% clean energy by 2050, coal production in Arizona is likely to decrease in the coming years.
In contrast, Arizona continues to take advantage of the state’s plentiful renewable energy resources including solar, wind, and hydroelectric energy. In 2018, renewable energy provided about 13% of Arizona's electricity net generation (U.S. Energy Information Administration 2020). In 2017 solar energy surpassed conventional hydroelectric energy as the dominant form of renewable energy produced in Arizona (U.S. Energy Information Administration 2020). Arizona currently ranks second in the nation in solar energy production, bringing significant benefits to Arizona’s economy, the country, and the environment.
Renewable energy is an important strategy to reduce our dependence on foreign oil, carbon emissions, and the release of other pollutants associated with fossil fuel generation. The Renewable Energy Standard and Tariff (REST) rule approved by the ACC in 2006, which requires 15% of the state’s energy to come from renewable energy resources by 2025, indicates Arizona’s commitment and support for this strategy. The manner in which the renewable energy industry plans for, develops, and operates utility-scale facilities can have significant implications for wildlife and natural resources. Disturbance and habitat loss associated with land use change and development go beyond the main facility footprint. The construction of new or expansion of existing substations, new transmission lines, and associated access roads and other infrastructure also result in habitat loss and fragmentation, and wildlife mortality (e.g., when bird and bat species come into contact with transmission lines or wind turbines). The addition of roads such as service roads increases the spread of invasive plants, and the construction of additional solar facilities increases water demands. Opportunities to reduce impacts exist, however, appropriate project siting at the early stages of project development is one of the most effective ways to minimize these negative effects. Although only of small benefit to wildlife, some solar companies are now allowing native vegetation to reestablish within the solar facilities providing suitable habitat for smaller wildlife species that can negotiate the perimeter fencing.
Like solar facilities, mineral and rock mining can have negative impacts resulting from construction, drilling, and reclamation activities. Associated water use and potential contamination are also concerns because riparian areas are critical habitat for many native species. Exploratory drilling and new mining site proposals in Arizona must go through a comprehensive permitting process, including environmental compliance assessments and must adhere to health and safety regulations to minimize negative impacts to people and the environment. During early stages of project planning, it is important to coordinate with land, water, and wildlife managers so that siting and design stages incorporate conservation practices specific to the project area. This not only minimizes negative impacts to natural resources, but also reduces the risk of costly mitigation and/or redesign at later stages for the project proponent.
There has been a major push for large utility-scale solar facilities throughout the western United States in recent years. In 2013, the Arizona BLM initiated the Restoration Design Energy Project (RDEP), which identified 192,100 acres of BLM-managed lands that may be most suitable for the development of renewable energy. Areas identified are near transmission lines or designated energy transportation corridors, close to population centers or industrial areas, and in areas where impacts on water usage would be moderate.
While there is clearly a need for renewable energy development, and great potential for solar energy in Arizona, it can have negative effects on wildlife and natural communities. Impacts from solar energy development can include habitat loss from the construction of large-scale facilities and new or expansion of existing substations, new transmission lines, and associated access roads. These structures will also increase habitat fragmentation and have the potential to negatively-impact wildlife movement. In addition, utility-scale solar facilities generally have large impervious surface areas which block or reroute surface flows, and they may use significant amounts of groundwater if using wet-cooled systems. The resulting changes in drainage patterns, storm water runoff, and depth to groundwater could result in significant negative impacts to wildlife and their habitats.
Strategic siting of solar facilities to avoid known wildlife movement corridors and sensitive habitat such as riparian areas is an important step the industry can take to reduce environmental impacts of utility-scale facilities. In order to protect Arizona’s natural resources while still fostering growth of the solar industry, AZGFD has developed recommendations and protocols to reduce the impact of solar energy development on wildlife, which can be found in Guidelines for Solar Development in Arizona.
Wind energy facilities are not yet widespread in Arizona. However, as demand for alternative sources of energy increases and the technology improves, there is potential for more wind-energy sites to be developed within the state. Wind-generated electrical energy is a viable source of clean, renewable energy that is generally supported in the conservation community. Climate adaptation strategies identify the need for more environmentally friendly energy sources that do not create air-polluting and climate-modifying emissions. However, wind turbines and their construction can adversely affect wildlife and habitats. Wind turbine towers in particular have been associated with mortality of large numbers of bats and birds (including raptors) when they are struck by moving blades (Kunz et al. 2007).
Effects of utility corridors include habitat fragmentation and disturbance from authorized and unauthorized use of access roads and pads, wildlife mortality due to collision with infrastructure, creation of new electrical transmission corridors, and the introduction of non-native plant species due to the disturbance of soil and native vegetation during construction and maintenance (Parendes and Jones 2000).
When wildlife needs and critical habitat areas are considered in project siting and design, many of the negative effects can be greatly reduced. Another AZGFD-produced guidebook, Guidelines for Reducing Impacts to Wildlife from Wind Energy Development in Arizona, which provides general guidance to project proponents on how to minimize or avoid impacts to wildlife and their habitats. However, for project-specific recommendations, it is important to coordinate with appropriate agencies including AZGFD.
Industrial minerals such as sand and gravel, clay, cement, and gypsum, and metallic minerals including copper, gold, silver, and uranium are mined throughout Arizona. Types of mining operations range from large-scale, open pit copper and uranium mines to small, abandoned hard rock mines. According to the USGS, Arizona produced $7 billion worth of minerals in 2021 (USGS 2021). Copper is the most abundant and valuable of Arizona’s metallic minerals and accounts for almost 74% of the domestic copper production in the United States (USGS 2021). Of the approximately 27 major mines currently operating in Arizona, 10 are copper mines, eight of which are in the southeastern portion of the state (UA Superfund Research Program). While state and federal regulatory agencies, including the ADEQ, ADWR, and EPA, ensure operations meet environmental standards, there is still significant impact to the land, water, and wildlife in the vicinity of the mining sites.
Processing plants and the infrastructure associated with large-scale mining, as well as resulting waste, have the potential to permanently alter the immediate and surrounding environment, and can contaminate surface and groundwater. Also of concern is the considerable quantity of water required to operate the mines and process minerals. The water is typically sourced from a combination of underground aquifers, surface streams, and water provided through the Central Arizona Project (CAP; Singh, 2010). Mining operations within Active Management Areas (AMAs) where reliance on groundwater is especially high, such as for the Tucson AMA in southeastern Arizona, are particularly concerning. Riparian habitats in these areas can be impaired by increased water consumption, erosion, and contamination.
Wildlife impacts from mining include habitat fragmentation and loss when land is cleared and roads are built to support the operation, and ongoing disturbance from lighting, noise, and maintenance activities. Surrounding areas can also be impacted if invasive species are not controlled within the disturbed area of the mining site. It is recommended that each mine’s general plan of operations should include a soils and vegetation management plan that acknowledges potential impacts and identifies measures to minimize and avoid negative effects. Mitigation measures and adjustments to mine operations may reduce negative impacts to wildlife and sensitive habitats, or provide mitigation measures to restore or enhance suitable habitat in nearby areas. Once the mine ceases operations, the reclamation process — during which adverse environmental effects are minimized and the mined area is returned to beneficial use — might restore habitats to conditions suitable for some wildlife (Jansen et al. 2006). However, long periods of operation and/or abandoned operations with no reclamation still pose a significant negative impact.
Several species of bats actually benefit from the excellent habitat provided by abandoned, underground mines. Managing mines for bats across Arizona has become an important conservation tool. The partnership between AZGFD, BLM, and the Arizona State Mine Inspector, has installed more than 125 gates at abandoned mine sites throughout the state which serve multiple purposes. The gates ensure public safety by restricting access to the site, while still allowing bats to enter and exit freely. The gates not only protect people from a serious hazard, they also protect bats from human disturbance.