Talk:Invasive species

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Contents

1 Writing texts and listing invasive species: requests: 2 Wanted! 3 discussions 4 economic not the only harm 5 rollback

Writing texts and listing invasive species: requests:

When writing a text about a species that is invasive somewhere, please ALWAYS discuss the species from its native standpoint first, before discussing the species from the viewpoint of it as an invasive exotic. Remember that your invasives are someone else's valued natives. Thanks, MPF

Remember also, that there is an article at Introduced species—this article (Invasive species) is limited to those species listed by government agencies somewhere as problem species (officially invasive) - Marshman 17:08, 28 Mar 2004 (UTC)

Wanted!

More information on invasive species outside the US would be useful here. moved the page to a much more common word

But one with a slightly different meaning. See Talk:Introduced species - Marshman 01:07, 10 Jan 2004 (UTC)

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The Eucalyptus tree is an invasive species in the United States. But I don't know enough about it to write anything. Kingturtle 09:04 Apr 20, 2003 (UTC)

discussions

OK Pollinator! And we probably can find another picture for the Introduced species page. I'll look around - Marshman 01:07, 10 Jan 2004 (UTC)

Got photos of Phragmites, purple loosestrife, Japanese knotweed (and probably some others if I look through my files). I'm not sure these are on the US list of invasives, but think they are both on some state lists. How best to use them? Pollinator 01:17, 10 Jan 2004 (UTC)

Well, any picture on a naturalized introduced species NOT considered a pest would be useful to replace the mosquito photo on the Introduced species page. - Marshman 02:20, 10 Jan 2004 (UTC)

No, I meant on the invasive page...have to think about the other, although you sounded like you might have something...Pollinator 02:34, 10 Jan 2004 (UTC)

No, nothing I was planning on. But there are lots of invasive plants here (like cattail) and I have plenty of photos. I would suggest first getting your pictures into an article on the species (or genus, or family), at the least just to make them known and available. I also want to change the species list of invasives that is misnamed; I'm waiting for comments back on the talk page. That article could use photos too - Marshman 02:56, 10 Jan 2004 (UTC)

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Here's a thought about redeeming features of some invasives. I'll just leave it here rather than sticking it on the page:

The common cat-tail (Typha latifolia) is being crowded from its habitat in many areas by two introduced marsh plants, the common reed (Phragmites australis) and purple loosestrife (Lythrum salicaria). Phragmites establish a complete natural monospecific environment with very little resources to support any other life, while purple loosestrife, because of its abundant nectar and pollen, tends to increase insect biodiversity. Pollinator 01:17, 10 Jan 2004 (UTC)

Funny you mention that. I was thinking of adding a brief word on how the cattail is one of the few species considered a pest (I guess not invasive by definition) in its own native range - Marshman 02:17, 10 Jan 2004 (UTC)

I had never heard of cattail being considered a pest. They were once widely used as a food crop. Poison ivy is a native that can be a noxious weed -not introduced but could be considered invasive. Ribes such as blackberry are also native but considered invasive by some. (Being a beekeeper, I always liked large acreages of blackberries)...Pollinator 02:34, 10 Jan 2004 (UTC)

Remember, when you talk about "native" it does not mean the same to me here in Hawaii. Cattail is an invasive here; and considered a pest by many managers of wetlands on the mainland. There is always lots of chatter on wetlands talk groups about eradicating cattails from managed and constructed wetlands. - Marshman 02:59, 10 Jan 2004 (UTC)

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http://www.invasivespecies.gov/ Pollinator 01:17, 10 Jan 2004 (UTC)

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becomes capable of establishing a breeding population in the new location without further intervention by humans, and subsequently
is troubling me if set in the definition of the word. It may sound obvious, but it is not given in official definitions.

Sure it is. If you mean "not worded just that way" in an official definition, you are right. But this is Wikipedia, not some official source. Why would you be troubled by restatements that are accurate? - Marshman 17:53, 11 Jan 2004 (UTC) And without it, things like cattle are possible to define as "invasive" - Marshman 18:02, 11 Jan 2004 (UTC)

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Although an invasive species is usually an introduced species, this is by no means always the case. A species that is long-established and native to a particular area can, under the influence of human modification to the environment, increase in numbers and become as invasive as an introduced species. The Pied Currawong of south-east Australia is an example: as a result of human changes to the landscape, Pied Currawongs increased greatly in range during the 20th century and have caused substantial declines in the populations of the smaller birds they prey on the nestlings of.

Tannin ~ This is an important concept, but has nothing to do with invasive species that are BY DEFINITION non-native. This has to do with human impact on natural ecosystems and unintended consequences - Marshman 04:48, 20 Jan 2004 (UTC)

economic not the only harm

Certainly "harm" is vague, but executive order 13112 gives not one, but three kinds of harm that define an invasive species:

Economic harm

Environmental harm

Harm to human health

Any one of these qualifies. While economics is certainly important, a species that lowers biodiversity would certainly be causing environmental harm without necessarily affecting the economy in any quantifiable way. WormRunner 07:06, 17 Feb 2004 (UTC)

I agree. I think the definition should be left more open than to just consider "economic harm". But consider this argument (moved here from my talk page):

....think about the definition: You know what is happening with the lumbricid fauna, but you are biased, because you have interest and knowledge. And that would be true for any biologist seeing their speciality over-run by introduced species. So if it is always true ecologically, then "invasive" and "introduced" are basically describing the same thing. But when that point was raised a month or so ago, there was an outcry (to wit: "I and every other biologist know what invasive is, and it is not the same as introduced"). Environmentalists use "invasive" because it has greater emotional appeal than "introduced". But when it comes down to actually defining the difference, the only thing I could find that made much sense is the "economic" issue. If USDA (or some other gov't entity) says the introduced species is causing great harm (usually measured in dollars somehow) then it is invasive; otherwise it is introduced.

Clearly there is some attempt being made by CEQ to indicate a matter of degree. As a biologist/ecologist I'm not certain that is possible. So do we just have two articles (introduced species and invasive species)that are essentially redundant; or can we find a way to differentiate these terms? Would you say, economics aside, that the introduced earthworms are now a pest species in their new range? And step back from your love of the natives, and answer this from the perspective of the ordinary citizen, farmer, etc. - Marshman 19:18, 17 Feb 2004 (UTC)

Well, I would say there are species which are "introduced", but do not qualify as invasive. For example, in the earthworm arena Dendrobaena octaedra is now found almost everywhere, but in low numbers and not transforming the ecosystem. Lumbricus terrestris on the other hand, makes major changes in soil profile, and where it moves in, even in relatively natural forest, the natives disappear entirely. From an earthworm perspective, it is like a functional equivalent of kudzu. I don't have it before me right now, but an article came out a while ago about introduced earthworms (lumbricidae) in Canada destroying formerly good soil structure. I will hunt it up for a reference. I think these things qualify. A local earthworm species Driloleirus macelfreshi (the Oregon giant earthworm) is possibly extinct, basically through competition with Lumbricus terrestris and other lumbricids. This has gotten the Department of Fish and Wildlife interested enough to fund surveys into the matter. Weyerhauser corp. is funding survey work to establish its presence or absence on their land. Certainly the disappearance of a local species is of interest to many ordinary people of the area who have told me of past sightings. But getting back to "invasive", I think we should look at the general english usage of words, not their definition by the US government. A List of species defined as invasive by the USDA would be a reasonable article, but people in Britain or South Africa might not find it as useful. The executive order is a good place to start but not to quit. I think the fundamental characteristic of an invader is that of taking over a system and changing it. There is a difference between becoming part of an ecosystem and displacing the previous inhabitants of it, although it may take some time before the difference is apparent. That would magnify the "invasive" category from the purely economic one, but it would still be a subset of "introduced". WormRunner 22:15, 17 Feb 2004 (UTC)

I would not disagree with you on qualification. After all ecologists and others quible about definitions CONSTANTLY. My challange to you and others is to develop the lucid counter-arguements in a way that the lay reader can understand: NOT, what the definition means according to ME, BUT what the issues are in trying to come to a meaningful definition. The consequence of not doing so is that ecologists and then most people will simply dismiss anyone that uses such a loaded and imprecise term as "using a loaded and imprecise term" -- this can already be seen in the ecological literature.

And right, definitely not a place to quit (use of CEQ definition). Your fundamental characteristic is correct but still weak. I'm not trying to argue a purely economic line has to be crossed. I'm thinking maybe the term "pest" says it better than "economic damage". I'd certainly favor an ecological definition over either an economic or a government one. But what to do? - Marshman 23:13, 17 Feb 2004 (UTC)

A native species most certainly can become invasive. There seems to be a push to define this term very narrowly according to one particular act in the United States. This is a global encyclopedia, and the fact that one particular US government agency uses one particular narrow meaning for a term does not invalidate standard usage. Tannin 20:53, 17 Feb 2004 (UTC)

Interesting point. But I think by definition a native species cannot become invasive (read definition). That is a different ecological phenomenon and the reason for having definitions in the first place (if by "standard" you mean "common", no one should be afraid to declare the common wisdom flawed; we have Wikipedia to educate and clarify; not to further common thinking where flawed). If you can come up with literature on the concept you espouse (or even a lucid discussion), it certainly would be worth including on the invasive species page. I think there is probably a better term, however. There is nothing narrow about the CEQ definition of the term. I think there you are trolling instead of reading. Try and define invasive unique from introduced. You think you know the difference, but all I am doing is challanging you and others that leap to that conclusion with coming up with a practical, applicable definition. I did. I used the literature.

And of course, every country has its equivalent to USDA, the responsibility of that country's agency being to declare which non-native species it regards as pest species and therefore exerts some control over. These declarations are a very practical way to define invasive. I suppose it is possible (and then worth mentioning) that declaration of a native species as a pest should be included here somehow. - Marshman 23:03, 17 Feb 2004 (UTC)

As always, I have no idea from what knowledge base you (Tannin) are making your arguments from. I know nothing of the Pied Currawong. But your write-up says this: "[it] increased greatly in range during the 20th century" Now, if it moved from an area where it was native into areas (even nearby areas) where it never was (in modern times) native, because humans made that new place suitable for it, then is this not an example of an invasion of a non-native species? We may be arguing the wrong thing here. The "area" in which a species is native is not the same thing as an "area" according human social and political boundaries; i.e., I doubt the Pied Curawong is native to ALL of Australia. A native species from California could become invasive in Florida. Both are part of the U.S. but many California species are not really native to the U.S.—they are native (endemics) to a certain geographical range. Indeed, a species from the California Coast Range could theoretically become invasive in the Sierra Nevada only a 100+ miles eastward, if that "invasion" were mediated somehow by man. - Marshman 23:58, 17 Feb 2004 (UTC)

rollback

I reverted text by anon contributor because it was redundant and poorly written. I think you meant Phragmites and your point was already covered in the first paragraph under "Introduction". If you wish to read the article and then improve on it, I'm not trying to be mean. - Marshman 04:40, 11 Feb 2005 (UTC)