The Importance Of Invasive Species In The Mojave Desert

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Invasive species in wetlands of the Mojave Desert negatively affect all aspects of the ecosystem. Invasive species are overtaking most of the wetlands in the Mojave Desert. Wetland areas in the desert are rare and very important sites for desert wildlife and migrating birds. Some of the main species that are invading wetland areas are Salt Cedar (Tamarisk spp.), Russian Knapweed (Acroptilon repens), Pepperweed (Lepidium latifolium), Fivehook Bassia (Bassia hyssopifolia) and Cheatgrass (Bromus tectorum). Invasive plants tend to thrive in wetland environments because of the excess of energy, a higher water table and more fertile soil. When an exotic species invades an area, it takes space, water, nutrients and pollination chances away from the …show more content…
Salt Cedar comes in two main subspecies; ramosissima and chinensis but there are also many forms of hybridized individuals. Tamarisk is a type of dense, shrubby tree that produces tiny pink flowers. Tamarisk trees have taken over 1.5 million acres of wetlands in the western United States (Whitecraft, Talley, Crooks, Boland & Gaskin 2007). They can thrive in a range of soil conditions and tolerate very saline soils. The tree’s tap root will stretch down far enough to tap into the water table, where native plant’s roots cannot reach (Longcore, Rich, & Müller-Schwarze. 2007). Large groves of tamarisk trees can completely drain a wetland system. Tamarisk seeds were brought to the United States from Asia by settlers to provide wind breaks for their crops and water holding ponds. You will frequently see tamarisk planted in a square pattern around old water holding ponds in the Mojave. One mature tree can produce 600,000 seeds in a growing season. The tiny, light seeds are easily dispersed by wind, water or becoming stuck to an animal’s fur. Tamarisk trees are known for displacing native willows and cottonwoods that naturally thrive in wetland …show more content…
This species is not as well-known as the tamarisk, but is making its way around the desert. Knapweed was brought to the United States on accident in animal feed from Eurasia. It is now spreading at a rate of 8%-14% a year (Hultine & Bush. 2011). Russian Knapweed produces purple flowers that look similar to the flower of a thistle plant. The seeds of Knapweed come in very recognizable balls that can be found covering the ground beneath the plant after growing season. The plants are typically 1 to 2 feet tall with small grayish green leaves that are coated with tiny hairs. Once Knapweed begins to grow in an area it will form a very dense patch that will push out all of the native vegetation. It will then spread outward from that patch and overtake the area. The separation of Knapweed from its natural enemies allows for the density to be much higher in non-native habitat as opposed to its native habitat (Callaway, Schaffner, Thelen, Khamraev, Juginisov & Maron. 2012). Because it is so dense and can produce 1600 seeds a year, it is very hard to

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