The article is sort of species libertarianism. It suggests that the global mixing around of species is not reducing local biodiversity. The "nothing but kudzu" (Great Lakes version: "nothing but purple loosestrife") fear is dismissed. While the article only manages some dubious spin re introduced animal species, it explicitly claims that introduced plants are on the whole, harmless. "There is no evidence that even a single long term resident species has been driven to extinction, or even extirpated within a single U.S. state, because of competition from an introduced plant species,” Bailey claims.
Well, tell it to the folks at Lake Caddo, is one easy answer. Species don't go extinct easily, but that doesn't mean landscapes can't be ruined.
On the other hand, much of what Bailey says makes intuitive sense to me. The species are all going to get swapped around anyway. There's only so much we can do to protect unique isolated island ecologies. Beyind that, why even try to keep species out? Why I wonder why we don't just stand back and let the species fight it all out. Once climate change kicks in in earnest it's going to be all invasive species, sometimes deliberately introduced. It will be that or nothing, I guess.
I am not making a claim here. I'm asking a question. I asked this question back in the sci.environment days "Hawaii sure doesn't look biologically impoverished" was my politically incorrect utterance. Of course, a fellow (named Alan McGowan) was so horrified at this question that he considered me an agent of the rapacious corporate sector, which people who hate me nowadays may find a headscratcher.
But I never got good answers to these things, and I'm sure, among my readers, there are as good answers as they get.
What, after all, does "ecological services" mean and why can't exotic species provide them?
It's likely I'm terribly ignorant to ask these questions, and I'm not sure I believe Bailey, but, like many intelligent people coming into climate change, I haven't seen an answer I find satsifying.
So where's the IPCC of wildlife ecology?
Update: Received in email:
Please accept my apologies for emailing you directly, but I was trying
to comment on your blog posting regarding the Ron Bailey article, but
Blogger failed me three times.
I am thus emailing you what I wrote, in case you find it of interest
(and also because I hate to have put in the time for nought,
particularly when I should have been working!).
Many thanks, M
Alright, a little bit on plants.
First, if this is the guy I am thinking of, I am a bit dubious based
on what I have heard him say in the past (although I haven't read the
article yet). I remember a talk at my alma mater back in 2004 or so,
given by a chap who works for the Cato Institute and writes for
Reason. I think it might well have been Bailey. Anyway, I remember
asking him a question along the lines of: "what about humans depending
on ecosystems and biodiversity for various services?" (His talk, if I
remember correctly, was about conservation being a nice personal ethic
to have, but it is basically just another belief system). Anyway, to
answer me, he said, 'just look at New York, several million people
live there and they're just fine, and NY doesn't have much in the way
of biodiversity or ecosystem services.' (given the long interval since
then, I paraphrase). He moved on then to the next questioner, but I
remain gobsmacked that he suggested that New Yorkers can survive using
just the resources in their immediate environs, as if their drinking
supply doesn't come from well-forested catchments in the Catskills,
and their food from farmland all over the planet, etc.
Anyway, I say all that because it might give some indication that his
perspectives on ecological matters are rather simplistic. If it's the
On to plants. First, I am not going to give you a documented
extinction, although I have heard that alien plants have caused the
extinction of several plants in South Africa's fynbos biome. If I had
more time I would try hunt down a few references.
Even if it hasn't yet, it is likely only a matter of time in the
aforementioned biome. Fynbos is one of the most endemic-rich biomes on
the planet. There are some species there that are known from only a
handful of very small localities, and there is an enormous invasive
plant problem there. Australian Acacias (such as cyclops, longifolia),
Pinus radiata, and Hakea sericea are a few of them, and they are rife.
Not only do they threaten to over-run the habitat of such isolated
endemics, but they also dramatically alter fire regimes, which in turn
plays havoc with the reproduction of numerous native species that
themselves depend on certain fire regimes for recruitment (this gets
very complicated, and is made messier by the problem of alien ants
(argentine ant) replacing native ants, which affects seed dispersal of
many species that makes the seed less able to survive fires).
So, there is that very real problem. Since many invasions are fairly
young (within the past 50 - 200 years, many of the ones I am familiar
coincide with introductions that occurred during the British empire in
the mid to late 1800s), they are just getting rolling. Just because
there isn't an abundance of documented extinctions doesn't mean they
aren't coming. Saying that an absence of extinctions means that aliens
plants won't cause them is kind of like saying that human population
growth is no worries because Ehrlich's prediction was wrong (which
ignores the fact that we are still expecting another 2-3 billion folks
to arrive in the next few decades).
Last point. Besides extinctions, alien plants cause other ecological
havoc. I return to South Africa, where they take their water resources
very seriously. They have an entire program aimed at removing alien
plants from watercourses (Australian acacias, again, plus Eucalypts)
because they tend to invade down watercourses and such up heaps of
runoff. Some calculations suggest that removing aliens might even
save them from having to build new dams to satisfy growing water
Etc. Anyway, I have certainly gone over my little of forebearance.
Hope this makes some sense.
Like Lyndon I also experience trouble with blogger that precludes me commenting on your site. I thought I'd send you a couple of links to paint a broader picture on the European perspective. Firstly I think you should visit the GB Non-Native Species Secretariat at the link below - they have lots of information that pertains to your question "Are Invasive Species a Threat?"By the way, Blogger actively sucks. Do not start serious blogs here.
A colleague of mine Helmut van Emden always maintains that you don't know how threatening an invasive species is until it has been present for seven years. That is the rough amount of time it takes for the local parasitoids and other potential natural enemies take to adapt to a novel species.
You may also want to get in touch with one of the authors of this paper:
How well do we understand the impacts of alien species on ecosystem services? A pan-European, cross-taxa assessment.
Montserrat Vilà et al 2010 Frontiers in Ecology and the Environment Volume 8, Issue 3
The paper is paywalled but below is some text I culled from a now-defunct Science Daily article about it:
"Invasive species can disrupt natural and human-made ecosystems, throwing food webs out of balance and damaging the services they provide to people. Now scientists have begun to put a price tag on this damage. In a study published the week of April 20 in Frontiers in Ecology and the Environment e-view, ecologists have listed the invasive species that cause the most harm to environment and cost the most money to control.
Vilà and her colleagues produced a list of the top 10 invasive species in Europe by assessing which species had the most impacts in the most categories. Among the top invaders were Canada geese, zebra mussels, brook trout, the Bermuda buttercup and coypu, also known as nutria. Terrestrial vertebrates produced the widest range of impacts, often showing effects in all of the ecosystem service categories.
"Many terrestrial vertebrates are top predators, and their introduction causes cascading effects in the food web," Vilà says.
By contrast, terrestrial invertebrates such as insects and spiders had the narrowest range of effects, but wreaked the most financial havoc. Vilà points out that terrestrial invertebrates cause the most damage to crops and forests, sectors in which there are well-established methods to quantify the costs of food and lumber production. The authors estimate annual crop losses in the United Kingdom due to alien arthropods at €2.8 billion (about $3.7 billion); other studies say that the cost of eradicating the 30 most common weeds could be more than €150 million ($197 million).
The authors also describe the alien species generating the highest reported financial investment, including costs of monitoring, controlling and eradicating the invader, along with environmental education programs. Among the most expensive invaders were water hyacinth (€3.4 /$4.5 million), coypu (€2.8/$3.7 million) and a marine alga (€8.2/$10.9 million)."