One side of the argument is that invasive species pose a problem by out-competing native species filled in the same niche. It is widely believed that if an invasive species enters an ecosystem and the job it performs is already filled by a native species, the invasive will typically out-do the native and drive it to the brink of extinction.
One such analytical experiment was performed by Callaway and Aschehoug (in Links: Invasive Plants Versus Their New and Old Neighbors). In it they looked at the effects that Centaurea diffusa, or Diffuse Knapweed, on both the other plants in it's natural habitat and the ones in it's invaded habitat. They showed that this plant had a much greater negative effect on the other weeds in North America (the invaded habitat) than it did on those in its natural area. This is due primarily to the Knapweeds roots, which make it better able to compete for resources. This ties into the idea of evolution, because in the ecosystem where the Diffuse Knapwood evolved, the other species evolved alongside it in order to keep up with its advancements. The plants in North America do not have that advantage, so they have not evolved ways to keep up with the invasive Knapweed. This is generally a basis for the idea that invasive species are problematic; because they did not evolve in the ecosystem which they have invaded, the native species are not equipped to compete with it.
This is explored in a paper by Carol Eunmi Lee (in Links: Evolutionary genetics of invasive species). She claims that the evolutionary genetics of invasive species has not been explored extensively, but it could open up new doors in the science. Recent studies, however, have suggested that the success of some invasions of species has more to do with their ability to withstand natural selection rather than direct competition with native species. Further exploration in this area could demonstrate the importance of evolution in the effects of an invasive species. If the species is completely foreign and the native plants have not had time to adapt to it, then of course the invasive will be in competition with the native species. However, is it possible that if an invasive stayed in an ecosystem long enough, the entire system would evolve with it and create a completely new system?
In the article cited in the first post, we see that there has been a huge influx of tropical species into the Mediterranean sea due to warming of the waters. It is at a peculiar stage at the moment, where the waters are warm enough for the tropical species to thrive but the cold water species are still there. This causes a huge influx of biodiversity, but many scientists believe that this is only because there has not been enough time for the invasive species to exterminate the native ones. In some case studies, this has already happened, with the Red sea species taking the place of the Mediterranean counterparts. One specific example is the rabbitfish, which feeds on algae. So far it has out-competed similar grazing species from the Mediterranean off the coasts of Lebanon, Israel, and Libya, further marginalizing the populations of the native grazers.
Evidently, there is a problem here.
One such analytical experiment was performed by Callaway and Aschehoug (in Links: Invasive Plants Versus Their New and Old Neighbors). In it they looked at the effects that Centaurea diffusa, or Diffuse Knapweed, on both the other plants in it's natural habitat and the ones in it's invaded habitat. They showed that this plant had a much greater negative effect on the other weeds in North America (the invaded habitat) than it did on those in its natural area. This is due primarily to the Knapweeds roots, which make it better able to compete for resources. This ties into the idea of evolution, because in the ecosystem where the Diffuse Knapwood evolved, the other species evolved alongside it in order to keep up with its advancements. The plants in North America do not have that advantage, so they have not evolved ways to keep up with the invasive Knapweed. This is generally a basis for the idea that invasive species are problematic; because they did not evolve in the ecosystem which they have invaded, the native species are not equipped to compete with it. This is explored in a paper by Carol Eunmi Lee (in Links: Evolutionary genetics of invasive species). She claims that the evolutionary genetics of invasive species has not been explored extensively, but it could open up new doors in the science. Recent studies, however, have suggested that the success of some invasions of species has more to do with their ability to withstand natural selection rather than direct competition with native species. Further exploration in this area could demonstrate the importance of evolution in the effects of an invasive species. If the species is completely foreign and the native plants have not had time to adapt to it, then of course the invasive will be in competition with the native species. However, is it possible that if an invasive stayed in an ecosystem long enough, the entire system would evolve with it and create a completely new system?
In the article cited in the first post, we see that there has been a huge influx of tropical species into the Mediterranean sea due to warming of the waters. It is at a peculiar stage at the moment, where the waters are warm enough for the tropical species to thrive but the cold water species are still there. This causes a huge influx of biodiversity, but many scientists believe that this is only because there has not been enough time for the invasive species to exterminate the native ones. In some case studies, this has already happened, with the Red sea species taking the place of the Mediterranean counterparts. One specific example is the rabbitfish, which feeds on algae. So far it has out-competed similar grazing species from the Mediterranean off the coasts of Lebanon, Israel, and Libya, further marginalizing the populations of the native grazers.
Evidently, there is a problem here.
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