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| The most isolated Island in the world - Bouvet Island (Photo: Dolph kessler) |
Basically all habitats are endangered by the introduction of species but in fact there are some which are more fragile.
Islands - Generally, islands species have limited population because of the island capacity, the geographic distribution is also limited and these species are less adapted to new predators. In result of that, these vulnerable species have more chance to extinction (Vitousek, 1997).
In islands the species evolved extreme vulnerable habits without presence of predators. The introduction of common predators such as snakes, cats, lizards or rats can result in extinction of species as happened in Fernando de Noronha where the endemic Noronhomys vespuccii was extinct by invasive species.
Rivers and Lakes - The introduction of exotic animals in rivers or lakes can result in catastrophes. The introduction of Lates niloticus in Victoria's lake in Africa to develop the fishing industry had catastrophic results. Approximately 70% of native species in the lake were extinct or close to be extinct. In consequence of this, the main source of protein and food to those communities around the lake there is no longer (Ogutu- Ohwayo, 1990; Kaufman, 1992).
Rivers and Lakes - The introduction of exotic animals in rivers or lakes can result in catastrophes. The introduction of Lates niloticus in Victoria's lake in Africa to develop the fishing industry had catastrophic results. Approximately 70% of native species in the lake were extinct or close to be extinct. In consequence of this, the main source of protein and food to those communities around the lake there is no longer (Ogutu- Ohwayo, 1990; Kaufman, 1992).
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| Fishing at lake Victoria in Africa. |
Works Cited:
KAUFMAN, L. Catastrophic change in species-rich freshwater ecosystems: the lessons of Lake Victoria. BioScience, v. 42, p. 846, 1992.
OGUTU-OHWAYO, R. The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile perch, Lates niloticus, and the Nile tilapia, Oreochromis niloticus. Environmental Biology of Fishes, 27, p. 81–96. 1990.
VITOUSEK, P. Diversidade e invasões biológicas de ilhas oceânicas. In: E. O. Wilson (Ed.), Biodiversidade. Rio de Janeiro: Nova Fronteira. 1997.
Hi. I liked this post. Especially when you talked about Fernando de Noronha. Do you know which invasive species caused the extinction of Noronhomys vespuccii?
ReplyDeleteCertainly, besides introduction of species cause ecological disturbances it affects humans themselves, as seen in Victoria's lake.
Very interesting. =D
As I said in the first topic that was about Vespuccii's rats, the introduction of cats, others rats species and other domestic animals maybe resulted in their extinction.
DeleteIsland ecosystems are complex systems and, as you so aptly show, fragile. The fragility of these ecosystems should be of high conservation concern. I was intrigued that you also showed how fragile other ecosystems can be. Is Bouvet Island also under similar threat from invasive species?
ReplyDeleteIn a fast research I didn't find data about invasive species there, in some works that I read they say that any exotic invasive specie are known there.
DeleteBut, humans bring with them a lot of species, sometimes domestics, others not... so we can conclude that there is some invasive species (Such as dogs, cats or even rats)
It's always astounding to me how short-minded humans are when it comes to introducing fish into new areas with the idea of setting up a fish industry. I know this practice has been quite common, clearly still happening in the 80's and 90's, but do you happen to know if introducing large edible fish stocks into foreign ecosystems is still happening more recently? I feel as though at some point humans would realize it's not working.
ReplyDeleteUnfortunately, this still happening in poor/developing countries. Sometimes the idea and hope of a better future in difficult times added with poor knowledge leads these people to look for a new perspective. However, there are many projects around the world which are going each time more deeply in the countryside bringing awareness and knowledge to them.
Deletelove this post.I knew that humans had an effect on the natural ecosystems but i never really understood how extensive that impact really is.
ReplyDelete