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The Impact of Invasive Species on Ecosystems

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Influence on ecosystems range from human causes like the bulldozing of a forest to natural causes like a fire or a flood. In recent times, the introduction and spread of invasive species has transformed native communities rapidly and, in some cases, created irreversible damages. In the Earth’s history, changes have often occurred in the ecosystems. For example, glaciers and the retreat of glaciers cause wide-spread changes. However, although change is a constant in ecosystems, animals and habitats often cannot adapt to the rapid alterations of non-natural stresses. Harm to the environment from the introduction of invasive species occurs through changes in the habitat and declines in the native species. Invasive species can make changes in a habitat’s physical structure, hydrology and salinity, productivity, energy flow, and fire cycle. Declines in biodiversity occur through competition, disruption of the food web, and genetic hybridization. These habitat and species modifications could create an irreversible shift in the ecosystem, creating an altered, stable state.

While invasive species cause damage in many ways, one of an invasive specie’s most devastating effects is habitat modification. Once a habitat is physically altered, even if the invader is removed, it becomes difficult or impossible to reverse the effects. In Life Out of Bounds, author Chris Bright describes the cycle of degradation (1998). As local creatures disappear, the loss weakens the strength of their ecosystem. An artificially simplified community is more likely to break down and the effects of disturbances, such as fire or flood, are likely to be more intense, leaving the area open to more invasions. According to Bright, as ...

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