User:Lee yun betty/sandbox/threats

Invasive Species
According to the national wild life federation, "An invasive species can be any kind of living organism—an amphibian (like the cane toad), plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs—that is not native to an ecosystem and causes harm. They can harm the environment, the economy, or even human health. Species that grow and reproduce quickly, and spread aggressively, with potential to cause harm, are given the label “invasive.”"(National Wildlife Federation)

One of the biggest invasive species in the Arizona Uplands region is:

Buffelgrass
Bufflegrass is the enemy of the Sonoran Desert. This invasive grass cause significant damage to the native ecosystem. Buffelgrass is native to Africa, Asia, and the Middle East. This grass was brought to the U.S int the 1930s for cattle forage and erosion control but ended up being a big mistake. Buffelgrass (Pennisetum ciliare), is a fire adapted, perennial bunch grass introduced from the African savannah. Buffelgrass grows in dense stands, producing large quantities of seed that readily germinate and is able to invade both disturbed and undisturbed desert sites. It is spreading rapidly across Arizona's deserts, threatening the ecological integrity of the Sonoran desert ecosystems and public as well as private lands.(U.S. Department of the Interior) The African buffelgrass (Pennisetum ciliare) has been identified as the most serious ecological threat to the paloverde-saguaro-ironwood desertscrub in the Arizona Upland (AZU) subdivision of the Sonoran Desert. This scenic vegetation is protected in Arizona in Organ Pipe Cactus National Monument, Saguaro National Park, Ironwood Forest National Monument, Sonoran Desert National Monument, Tucson Mountain Park (Pima County), etc., where it is in excellent condition and relatively little impacted by grazing, wood cutting, and recreational activities. However, the introduction of buffelgrass either through pasture development as in Sonora or dispersal along roads and wind-blown seed as in Arizona is a very serious threat to natural communities because it also introduces fire as a new ecological process (Figure 1). Few if any Sonoran Desert or northern Neotropical plants have any adaptations to recurrent fires. In time, buffelgrass fires could convert the Arizona Upland into a savanna-like landscape as saguaro (Carnegiea gigantea), foothill paloverde (Parkinsonia microphylla), ironwood (Olneya tesota), organ pipe cactus (Stenocereus thurberi), etc. are killed. (Devender, Dimmitt) Buffelgrass is a threat to the arizona uplands region because it grows densely and crowds out native plants of similar size. It competes for water can weaken and kill larger desert plants. Dense roots and ground shading prevent germination of seeds. It appears that buffelgrass can kill most native plants by these means alone.

Another close simialar species to the Buffelgrass is the Fountaingrass.

Fountaingrass
Fountaingrass is a large grass that produces lots of seeds that can spread rapidly spreads from cultivation into nearby disturbed areas, and eventually into natural habitats. It often forms dense stands and aggressively competes with native species, especially perennial grasses and seasonal annuals, for space, water, and nutrients. It is a perennial bunch grass with attractive purple or green flowers. It is an ornamental plant that is still sold in nurseries. Although some nursery varieties are considered "sterile", no varieties are recommended for planting and landscaping. Choose other attractive native grass alternatives for your landscape, like sacaton (Sporobolus wrightii), or rabbit-resistant deer grass (Muhlenbergia regens). Threats from fountaingrass fires are most serious in natural riparian habitats in scenic mountain canyons. In the Tucson area, it has invaded the rocky canyons in Finger Rock, Pima, Sabino, and other Canyons in the Santa Catalina Mountains and King Canyon in the Tucson Mountains. Fountaingrass is less of a threat in desert grassland or chaparral above 3500 feet where fire is a natural process. Fountain grass can form dense stands with several undesirable effects. It provides a large amount of fuel for hot fires that can destroy native plants and animals. It displaces native grasses, blocks the natural flow of water in washes, and alters the habitat for animals, particularly frogs and toads that are sensitive to such changes.

Fountain grass occurs mainly in the washes in the Park, but has also been found on steep slopes. It grows rapidly on hillsides, along roadsides, and in washes all around Tucson.

Population Increase


Human impact is one of the biggest threats of the environment in general. Because of that population increase is directly related to being a threat to the environment. An increase in population means an increase in resource depletion, an increase in deforestation, mining, and a decrease in biodiversity.

References 1) “Invasive Species.” National Wildlife Federation, www.nwf.org/Educational-Resources/Wildlife-Guide/Threats-to-Wildlife/Invasive-Species. 2) Devender, Thomas R, and Mark A Dimmitt. “Final Report on ‘Conservation of Arizona Upland Sonoran Desert Habitat. Status and Threats of Buffelgrass (Pennisetum Ciliare) in Arizona and Sonora. Project #2004-0013-003)’.” Desert Museum, 25 May 2006, www.desertmuseum.org/programs/buffel_survey_report.pdf. 3)“War on Buffelgrass.” U.S. Department of the Interior, 23 Apr. 2016, www.doi.gov/ocl/hearings/111/WarOnBuffelgrass_041010. 4)"Invasive Species in the Sonoran Desert Region" mpasz.org [] 5)“Fountain Grass.” National Parks Service, U.S. Department of the Interior, www.nps.gov/sagu/learn/nature/fountain-grass.htm.