What is biodiversity?
Biodiversity can be seen right outside of your window. Notice the differences between the trees, flowers, and birds. Each of these different coexisting species represents biodiversity in our environment.
We all learned about the “web of life” in school –– it’s the link between all organisms on Earth, binding each one into an interdependent ecosystem in which all species have their role. Each member is important for the survival of the others. The next time you see a bird making its home in a tree, or a butterfly landing on a flower, you will see this complex system in action.
Biodiversity is not only beautiful, but it is also essential for life. It’s the resource upon which families, communities, and future generations depend. Earth’s natural assets are made up of plants, animals, land, water, and the atmosphere. Together, we all form the biosphere.
Nature powers human endeavors by supporting everything we need to survive. If there is a biodiversity crisis, our health and livelihoods are at risk too. Our economies, food security, health and quality of life all rely on a healthy and functioning biosphere.
Biodiversity in Arizona
All over the world, biodiversity loss on the scale we are experiencing today has one common denominator: human activity. We are exploiting nature faster than it can replenish itself.
The impacts of human activity on an ecosystem greatly depend on the resources, species, and geography of the location in question. The focus of this article is on the contributing factors to biodiversity loss and potential solutions specifically relating to Arizona.
At the junction of several great arid ecoregions, Arizona’s species richness is dominated by desert-adapted plants and animals. Several desert regions call Arizona home: the Sonoran Desert in the southwest, the Mojave Desert in the northwest, and the Colorado Plateau in the northeast. Each brings a unique suite of arid land species. With nearly 3,500 species of plants, 500 species of birds, and 1,000 species of bees, the Sonoran is the most biodiverse desert on Earth.
A state-wide elevation difference of 12,563 feet provides Arizona with remarkably high ecological diversity. Within this wide range of elevation, arid deserts and canyonlands, semiarid shrub, grass-covered plains, woodlands, shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated peaks, and river alluvial floodplains can all be found. In addition to elevation, rainfall patterns are another key to this incredible biodiversity.
Biodiversity Loss in Arizona
The impacts of climate change and human activity are significant in these regions. Average global temperatures have already risen about 1.5 degrees Fahrenheit compared to the mid-twentieth century. By the end of this century, temperatures are expected to rise at least another 2.5 to 8.5 degrees — the result depending on the global response to emissions.
Arizona is already in the grip of a major drought: much of the Sonoran Desert has seen a 25% to 40% drop in precipitation over the past 50 years. Projections indicate that the region will continue to be drier than average, and with temperatures soaring above 90 degrees Fahrenheit for over half the year, prolonged water stress will be devastating to many species.
Several species of animals have already been greatly impacted, including the Sonoran Pronghorn, Desert Tortoise, Cactus Ferruginous Pygmy-Owl, Sonora Tiger Salamander, and our Border Cats (Ocelots, Cougars, etc.). Each of these species play an important role within our desert ecosystem and are suffering from environmental factors like climate change and regional human activity. As they become extinct, our local ecosystems will change forever.
Biodiversity loss, including the loss of these species, reduces the efficiency by which ecological communities capture biologically essential resources, produce biomass, decompose, and recycle biologically essential nutrients. Through time, the stability of ecosystem functions will decrease as biodiversity is increasingly threatened.
Threats to biodiversity in Arizona include mining, population increase, urbanization, recreation, high per-capita consumption, water diversion and impoundment (damming), and animal agriculture.
In addition to species being lost, new invasive species are finding their way into Arizona’s ecosystems. Intentionally planted exotic species and invasive species of plants are becoming increasingly common in our ecosystems, and this problem will only grow worse as the climate continues to change. Representing one of the most serious threats to natural ecosystem integrity, invasive species fragment native ecosystems, displace native plants and animals, and alter ecosystem functions.
AZSA volunteers removing invasive species at Indian Bend Wash Greenbelt
So, what can we do about it?
Similarly to how human activity can threaten biodiversity, we can also take action to protect it. By incorporating sustainability in our decision making, we can protect species, genetic resources, and critical habitats to influence both the rate of biodiversity loss and the final levels of diversity that survive.
By planting native shrubs, flowers, and trees, the residents of Arizona can contribute to preserving the natural biodiversity of their area. In addition to adding ecologically appropriate species of plants, we can also remove invasive species. The Adopt-a-Park pillar within AZSA brings together volunteers monthly to remove invasive species. If you’d like to get involved, click this link to access our volunteer onboarding form.
Biodiversity isn’t the only thing impacted by planting native species. By planting desert-adapted trees like Eucalyptus, Desert Willow, and Palo Blanco, we can increase our carbon capture, decrease the heat island effect (lower temperatures), and create a sanctuary for the beautiful birds that call our state home.
In Phoenix, a recent study led by the USDA Forest Service and Arizona State University found that although the presence of bird species, bird abundance and the number of bird species all decreased over time, in areas where homeowners provide more areas with desert-like plantings, some desert specialist birds such as verdin and cactus wren could still be found.
The Urban Forestry pillar within the AZSA plants trees in cities around the valley and provides education to Arizonans about the benefits of urban forestry. We are currently developing tree-planting projects in Apache Junction, Guadalupe, and the West Valley. If you would like to volunteer with, donate to, or learn more about the Urban Forestry pillar, you can visit our page here.
Note: Learning about biodiversity loss can be emotionally taxing. If you find yourself experiencing climate grief or eco anxiety, make sure that you take steps to prioritize your mental health. One of the best ways to do this is to get involved with environmental volunteering –– planting trees with like-minded individuals can be very therapeutic. You can find the link to our volunteer onboarding page here.
Written by Deanna Pratt for the Arizona Sustainability Alliance
References
Cardinale, Bradley J., et al. “Biodiversity Loss and Its Impact on Humanity.” Nature News, Nature Publishing Group, 6 June 2012, www.nature.com/articles/nature11148.
“Climate Change and the Sonoran Desert Region.” Defenders.org, defenders.org/sites/default/files/publications/climate_change_and_the_sonoran_desert_region.pdf.
“Climate Change in the Sonoran Desert (U.S. National Park Service).” National Parks Service, U.S. Department of the Interior, www.nps.gov/articles/climate-change-in-the-sonoran-desert.htm.
Hope, Diane, et al. “Socioeconomics Drive Urban Plant Diversity.” PNAS, National Academy of Sciences, 22 July 2003, www.pnas.org/content/100/15/8788.
“How Does Biodiversity Loss Affect Me and Everyone Else?” WWF, wwf.panda.org/our_work/biodiversity/biodiversity_and_you/.
Lathrop, Janet. “Phoenix Is Losing Birds, but Desert Plants Provided by Homeowners Offer Habitat for Desert Species.” Phys.org, Phys.org, 12 Mar. 2019, phys.org/news/2019-03-phoenix-birds-homeowners-habitat-species.html.
“Mojave Desert.” Biologicaldiversity.org, www.biologicaldiversity.org/programs/public_lands/deserts/mojave_desert/index.html.
Nabhan, Gary. “Biodiversity: The Variety of Life That Sustains Our Own.” Arizona-Sonora Desert Museum, www.desertmuseum.org/books/nhsd_biodiversity.php.
Nolan, Connor, et al. “Past and Future Global Transformation of Terrestrial Ecosystems under Climate Change.” Science, American Association for the Advancement of Science, 31 Aug. 2018, science.sciencemag.org/content/361/6405/920.
“Sonoran Desert Network Ecosystems (U.S. National Park Service).” National Parks Service, U.S. Department of the Interior, www.nps.gov/im/sodn/ecosystems.htm.
Sonoran Desert, www.biologicaldiversity.org/programs/public_lands/deserts/sonoran_desert/index.html.
