Introduced Species: The Threat to Biodiversity & What Can Be Done
By: Daniel Simberloff
An article from ActionBioscience.org
Copyright 2000
http://www.actionbioscience.org/biodiversity/simberloff.html
Summary
Introduced species are a very big threat to the environment because they can cause many changes, like: overcrowding an area and replacing a native species, costing the economy tons of money by damaging human enterprise, and even placing entire ecosystems at risk by changing the habitat. It has been proven that introduced species are the cause of 49% of species becoming endangered. In addition, the combination of harvest, pollution, and disease isn’t even as much of a threat to biodiversity as introduced species are. Also, the U.S. economy loses 137 billion dollars a year to repair damages introduced species cause.
When a new species is introduced to another environment, there is a lot of competition that goes on between the native and introduced species for things like food and water. An example of this was when the predatory brown tree snake was introduced to Guam from the Admiralty Islands. The human impact on this scenario is the plain fact that they were the ones who brought the snake over (by cargo). This new species has had a major impact on Guam. Ten of eleven native bird species there were wiped out because of the brown tree snake. Another example of the impact of introduced species is when the greedy Nile perch was introduced to Lake Victoria. Since it was first brought over, the Nile perch has eliminated more than one hundred species of cichlid fish native to the area. Finally, red squirrels in Great Britain have almost gone extinct because of the competition between them and the North American gray squirrels for food. The North American gray squirrels are more efficient at searching for nuts, and as a result, they are eating most of the red squirrels’ food before the red squirrels even have a chance to find it.
Often, it is the introduced species who change an entire habitat that are causing the greatest impact. When these species alter a specific place, lots of native species that can thrive only in the particular area become extinct. Species like fungi, trees, and aquatic plants have all proven just how powerful they can be. Other times, invaders can endanger a single species or a group of species without adjusting the environment in any way whatsoever. The brown tree snake and the Nile perch mentioned above are good examples of this. Finally, invasive species do their work sneakily, but it still can cause destruction. When invasive species use a process called hybridization, or cross-breeding, to eliminate a native species, this is an example of their subtle efforts. By breeding with the native species, the invasive species alters the native species’ gene pool, so that the native species develop into a form of the invasive species.
There are three main pathways that aid in the fastest spread of invasive species: wooden packing material, ballast water, and gardening plants. However, invasive species that are discovered early on can be destroyed. Currently, there are several technologies that can greatly help to control invasive species: biological, chemical, and mechanical. When an enemy from the same place as the unwanted pest is introduced to control the invasive species, it is called biological control. Using a pesticide like insecticide or herbicide is an example of chemical control. Finally, when hand pulling or different types of machines are used, it is considered mechanical control. There is a new technology being developed, called ecosystem management, that gives an entire ecosystem a ‘treatment’ (like a simulated fire) regularly. These ‘treatments’ often favor the survival of the native species over the introduced species. While not all these methods are 100% effective, they can help greatly in controlling unwanted pests.
The best solution for addressing the invasive species issue is through international cooperation and management. When the Rio Convention of Biological Diversity acknowledged the situation as a threat and pressed a need for action, there was a great international response. Now, a Global Invasive Species Program formed by international organizations (like the United Nations) is helping out by developing programs to deal with introduced species. It is great that people are finally trying to help out with this serious issue because if no one took action, then the invasive species would most definitely take over.
As you can see, introduced species often have a negative impact on the new place they’re introduced to, and this is the reason why measures need to be taken to prevent this from happening over and over again.
Opinion/Reflection
I can’t believe how much of an impact introduced species can have to a particular environment. Before reading this article I was never aware of just how powerful these species can be, and how humans have no definite way of stopping them. However, it is often the human impact that causes these issues in the first place, by introducing a new species to an area because they believe it will provide some sort of benefit. I find it sad how different species often have to suffer because of human mistakes. Competition goes on between the native species and the introduced species, which is understandable, because the introduced species has different adaptations and body structure than the native species. For instance, in the bird experiment we did in class, the introduced species was adapted to eat all the different kinds of food, whereas the native species could only eat a particular type of food that they could pick up with their beak. Invasive species often win the competition, and the native species begins to die out. Reading this article, I also thought it was clever what the introduced species will do to take over an environment, even if they aren’t introduced by humans. For example, invasive species will use hybridization to get the native species to evolve into something much like themselves. I found this extremely smart.
Ask Questions
1) Do you think humans will be able to stop the spread of invasive species, or at least control it?
2) What are other examples of an invasive species taking over an environment?
3) Do you believe it is ever possible for an environment to benefit from an invasive species?
4) What is your take on how international management will occur? Do you think it will truly be helpful, or will it be done so that particular organizations can look good in front of the public?
5) Of the controlling methods mentioned in the article, which do you think would be the most effective to use on an invasive species? Why?
1) Oh, definitely, we are certainly able. The real question is, are we willing? Many people are actively introducing invasive species, mostly for economic reasons.
ReplyDelete2) Asian carp in the Midwest is one example. Anywhere where there was a major colonization push, such as Hawaii, also have many invasive species because settlers brought the animals and plants they thought they would make the most money with. Business is probably the biggest cause for invasive species introduction.
3) Perhaps in the short term. But in the long run, it would hurt the environment because the biodiversity would take a huge hit.
4) In my opinion, the ONLY solution is international cooperation. However, for international cooperation to work we need at least minimal active participation from every country, and that is not going to happen any time soon. Many developed nations (such as the US) are unwilling to make sacrifices in order to halt/reverse climate change. Many undeveloped countries are unwilling to set aside rapid economic development for more stable, green development. This is not universal of course, but it seems like the agendas of most countries are extremely short-sited. What's the point of having strong economies or Hummers if there is not a planet left to use them on?
5) As I mentioned in my answer to the last question, I beleive full international cooperation is the ONLY answer, not just the best answer. Without everyone's cooperation, the whole undertaking could be ruined by one shady exporter.
And now for something completely different, some additional questions:
ReplyDelete1) Do you think we should bother stopping invasive species, or leave ecosystems to nature and "survival of the fittest"?
2) Do you think stopping the pread of invasive species isactually possible?
3) Do you think stopping the spread of invasive species is possible without international cooperation?
4) What effect do you think stopping the spread of invasive species wil have on international trade?
Reflection
ReplyDeleteVery informative article, Lauren! I was wondering what people do to manage invasive species before I read this and you've answered my question! Great choice to complement what we were learning about in class recently!
Responses
1) I definitely think we could control invasive species, it's only a matter of acquiring the sufficient human and material resources. We'd need to raise awareness before any real change can happen.
2) According to invasivespecies.gov, there's this invasive disease called Sudden Oak Death that can kill a whole lot of other tree species in the U.S. And judging by the name, by the time you realize a tree has it, it's already too late.
3) I do believe an invasive species could be helpful in some rare occasions to control a native species that's taking over its habitat, or to control another invasive species a la the methods Lauren described.
4) I think that international management will have both effects. It will do good, but partially for the wrong reasons. The UN wants to help keep Earth from going to hell in a handbasket, but it also wants to appease its members so that they don't get angry with them and leave.
5) I think unleashing a predator or other species in the same niche will be the most helpful because it doesn't involve direct human involvement, in which there's the possibility for human error. And frankly, I don't think Mother Nature appreciates human error.
My Questions
1) What do you think would be a good way to stop the intentional or accidental introduction of invasive species?
2) What kind of response should come from both the US and other countries on this issue?
3) What's a good way to raise awareness of this issue?
4) How do you think the UN's program will turn out? Will it be a hit or a miss?
1) Humanity is perfectly able to do so but we make it more difficult for ourselves by letting the problem spread to near impossible to contain level such as what happened with Asian carp in the Mississippi river.
ReplyDelete2)As I mentioned above the Asian carp taking over the Mississippi River.
3)Yes but it is extremely unlikely as humanity would probably have to do extensive studying and handpick the species for it to benefit the enviroment it is put into.
4)It could probably help but it is probably just a public image improver.
5)The method which introduces a 'simulated fire' into the enviroment is probably the most effective method.