Mojave National Preserve - Nonnative Species

Non-native species are species that are not native to, or originally from, a region. Non-native species are also called introduced, alien, or exotic species. Most non-native species in the United States are cultivated plants (both food crops and ornamentals) and domesticated animals. The tomato, which is native to western South America, is an example of an important crop species that is not native to the United States. Non-native species are not necessarily a concern. Invasive species, however, are a special case.

Invasive species are non-native species that escape cultivation and displace native species, disrupting the natural ecosystem of an area. These species are a problem in part because of the lack of predators, diseases, and other natural forms of population control in the invaded area. In the past, invasive species were sometimes introduced intentionally because the plants or animals were thought to have some useful purpose. It was not known at the time that these particular species would grow "out of control". The increase of global trade and travel has contributed to many accidental introductions in recent years.

Invasive species are a problem everywhere, and Mojave National Preserve is no exception. There are seventy-five non-native species documented in the Preserve but not all of them may be considered invasive. Species such as the California fan palm ( W. filifera ) and Senegal date palm ( Phoenix reclinata ) may be found as cultivated ornamentals at the Zzyzx Desert Studies Center, but these species pose no risk of escaping into the wild. Plant species which are of great concern include tamarisk ( Tamarix ramosissima ), Russian thistle ( Salsola paulsenii and S. tragus ), cheatgrass ( Bromus tectorum ), and Asian mustard ( Brassica tounefortii ). Plants are not the only species that can be invasive. The Preserve has designated the elimination of the burro ( Equus asinus ) from within its boarders as a top resource management priority.