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Plants form the basis of nearly all terrestrial systems because they form the first link in the food web. Whenever a plant community is affected, it affects every level of an ecosystem, from the bottom to the top. Control weeds in order to maintain the ecology of the area. Reduced biodiversity occurs when Invasive species outcompete other species. When the exotic species are plants, they can affect all other levels of the ecosystem including vertebrates such as birds, mammals, and reptiles and invertebrates such as insects and spiders, and even microbes and fungi. Reduction in food and habitat can even lead to extinction if the organism is endemic to the affected area. In addition to direct effects, exotic species impact ecological and environmental processes. For example, salt cedar (Tamarix sp.) lowers water tables in the desert and cheatgrass (Bromus tectorum) in the Great Plains increases wild fire frequency and intensity. Some weeds can also spread diseases to other plants, such as Japanese barberry (Berberis thunbergii), which is a host to oat rust and Dame's rocket (Hesperis matronalis) which is an alternate host for a virus that attacks a wide range of agricultural plants. The only way to prevent these ecological impacts is to prevent weed infestation followed by proper restoration to maintain an ecosystem function. Exotic species provide more niches and increase biodiversity. An alternative view to the ecological disaster described above is that exotic species increase biodiversity and provide new resources for native species. For example, forests tend to have more bird species than prairie and honeybees (Apis melifera) increases pollination success of both exotic and native species apparently without reducing native pollinator populations. Although invasive species should be controlled, the majority of introduced species do not spread and do not cause problems in the ecosystem. See also the Role of History Back to the ethics page The 6th letter of the password - U |
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