Explain how an accidentally or purposely introduced non-native plant or animal can have?

Question

Explain how an accidentally or purposely introduced non-native plant or animal can have an adverse impact on an ecosystem. Give examples.

Answer 1

I'll do you one even better: look up "kudzu."
You'll get everything you need...

Answer 2

Any number of different things can go wrong. Here are some very different examples:

* A plant that spreads out of control. Kudzu is the best example of this. Japanese knotweed, or Purple Loosestrife are all classic examples.

* A species that hybridizes with a native species, diluting the genetics of the original population in irreversible ways. An example of this is the white mulberry, introduced from China, that hybridizes with the red mulberry native to the U.S.

* A species can be a host to a disease or parasite that kills off other native species. An example of this would be dutch elm disease, brought over through elm bark beetles, or the chestnut blight, brought from Chinese chestnuts (which are unharmed by the blight and may actually have a symbiotic relationship with the fungus that causes it).

* Some plants produce toxic chemicals which kill other plants. Since plants in their native environment are not exposed to these chemicals, the plants in the new environment are more susceptible. A classic example of this is Ailanthus altissima, the "Tree of Heaven".

* Introduced birds can aggressively displace native birds from their nesting sites. An example of this would be European Starlings or House Sparrows, both introduced from Europe.

* Introduced animals can devastate ecosystems by eating things to the point of destroying them. Some different examples would be sheep being introduced to islands, where they strip the vegetation, or the mute swan being introduced to the chesapeake bay, where it pulls vegetation up by the roots (the native one cuts it off so it can grow back), or any of the predatory mammals introduced to New Zealand, which are killing native birds and other native animals at alarming rates.

* Some species can quietly change the structure of an ecosystem, how it stores and cycles nutrients. For example, norway maples are displacing sugar maples in many forests in the U.S. The norway maple leaves are much slower to decompose and create a different environment, less rich in nutrients and less hospitable to native plants. Or, some introduced plants will have shallower roots than native plants, and thus result in soil loss from erosion.

Answer 3

If the alien species manages to survive, it is because it has found an environment that offers conditions for its survival. The problem generally occurs when the environment did not evolve with that species and, therefore, it finds no natural predators or competitors that can limit their population growth. The effect is that this species can dominate completely the environment and bring drastic changes to it. The most annoying example of this in an urban area is probably the Florida "lovebug disaster".

Answer 4

Big problems include; the introduction of diseases to which the native population have no resistence (Europeans introducing smallpox to North America), no natural predators (cane toads in Australia) or being able to outcompete native species (grey squirrels in the UK)

Answer 5

Kudzu is the prime example, also try "Johnny Weed". Apparently Johnny Appleseed also spread a few other plants that were less well received than apple trees.

Answer 6

Cane toad