Before now I have been focusing on the detrimental aspects of invasive species, but what most people do not know is that the effects of invasive species are not always negative. There are some benefits provided by the introduction of a new species.
One such benefit is outlined in a paper by Sax et al. (in Links: Species invasions and extinctions: The future of native biodiversity on islands). In it, Sax et al. claim that though invasive animals almost always lead to extinctions of other species,
invasive plants can be beneficial on islands. They go on to include data from the International Union for Conservation of Nature's databases, showing the significant difference between vertebrate, invertebrate, and plant extinction patterns over the past 500 years. Finally, they analyze the ratio of native and naturalized plant species (invasive species that have been in the ecosystem for a good deal of time) on oceanic islands. While the level of biodiversity of plants is high on land-bridge islands, it is found to be greatest on oceanic islands. Sax et al. showed that there is a one-to-one ratio of native and naturalized plant species and that over the years, the number of naturalized species has increased on six islands near Australia and New Zealand over the past 160 years. Basically, what this paper is showing, is that with more invasive species on islands, you only get more plant biodiversity. It appears as if the new species may be filling slightly different niches than the native plants and that they are able to live cooperatively successfully. Beyond that, increased biodiversity is very desirable for other reasons, such as maintaining natural processes, air quality, water quality, etc. For a list of reasons for the importance of biodiversity, see the corresponding link in Links.
Invasive species may have certain economic benefits as well, for some perform jobs more effectively than native species. For example, the Asian oyster has been considered for introduction into the Chesapeake bay to help improve the water quality. Asian oyster are more adept filters than the native oysters, and they also have thicker shells and are less prone to acquiring disease. Another potential benefit that is being looked into is the use of algae for biofuel. Some scientists and corporations believe that algae is a much better alternative to biofuel produced by corn. Further research is being done and there is little conclusive evidence, but if this ends up being the case, then explosive populations of invasive algal species such as the green algae in the Mediterranean could be used as a primary fuel source in lieu of oil and natural gas.
Finally, several scientists are coming to believe that rather than a direct causality between native species loss and exotic species increase, invasive species are merely taking the available space left over after the ecosystem has been altered. Didham et al. specifically, in his paper (in Links: Are invasive species the drivers for ecological change) asks whether the invasive species are drive changes in an ecosystem or if they are merely 'passengers on the ride'. In his paper he states that rather than invasive species causing the loss of biodiversity it is more anthropogenic changes that alter ecosystems. Didham claims that human industries cause other problems, such as carbon dioxide increases in the atmosphere, altered landscapes, and changing the biogeochemical cycles, and these drive global warming, which is the main cause of biodiversity loss. Invasive species are just Nature's way of filling in the holes to ensure all the niches are filled.
One such benefit is outlined in a paper by Sax et al. (in Links: Species invasions and extinctions: The future of native biodiversity on islands). In it, Sax et al. claim that though invasive animals almost always lead to extinctions of other species,
invasive plants can be beneficial on islands. They go on to include data from the International Union for Conservation of Nature's databases, showing the significant difference between vertebrate, invertebrate, and plant extinction patterns over the past 500 years. Finally, they analyze the ratio of native and naturalized plant species (invasive species that have been in the ecosystem for a good deal of time) on oceanic islands. While the level of biodiversity of plants is high on land-bridge islands, it is found to be greatest on oceanic islands. Sax et al. showed that there is a one-to-one ratio of native and naturalized plant species and that over the years, the number of naturalized species has increased on six islands near Australia and New Zealand over the past 160 years. Basically, what this paper is showing, is that with more invasive species on islands, you only get more plant biodiversity. It appears as if the new species may be filling slightly different niches than the native plants and that they are able to live cooperatively successfully. Beyond that, increased biodiversity is very desirable for other reasons, such as maintaining natural processes, air quality, water quality, etc. For a list of reasons for the importance of biodiversity, see the corresponding link in Links.Invasive species may have certain economic benefits as well, for some perform jobs more effectively than native species. For example, the Asian oyster has been considered for introduction into the Chesapeake bay to help improve the water quality. Asian oyster are more adept filters than the native oysters, and they also have thicker shells and are less prone to acquiring disease. Another potential benefit that is being looked into is the use of algae for biofuel. Some scientists and corporations believe that algae is a much better alternative to biofuel produced by corn. Further research is being done and there is little conclusive evidence, but if this ends up being the case, then explosive populations of invasive algal species such as the green algae in the Mediterranean could be used as a primary fuel source in lieu of oil and natural gas.
Finally, several scientists are coming to believe that rather than a direct causality between native species loss and exotic species increase, invasive species are merely taking the available space left over after the ecosystem has been altered. Didham et al. specifically, in his paper (in Links: Are invasive species the drivers for ecological change) asks whether the invasive species are drive changes in an ecosystem or if they are merely 'passengers on the ride'. In his paper he states that rather than invasive species causing the loss of biodiversity it is more anthropogenic changes that alter ecosystems. Didham claims that human industries cause other problems, such as carbon dioxide increases in the atmosphere, altered landscapes, and changing the biogeochemical cycles, and these drive global warming, which is the main cause of biodiversity loss. Invasive species are just Nature's way of filling in the holes to ensure all the niches are filled.
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