Thanks for the post David.
As a newcomer to science (working on my Ph.D.), there were some
lingering questions I had while reading Davis et al. and the
responses: Is this how we want to move forward as a science? What
does it mean when we resort to gathering signatures? Is this how our
science should work? What does it contribute? How should we deal with
issues that are debated in a more productive and less polarizing
manner? Personally, I don't think that petitioning changes ecology
nor any other natural phenomena.
I would like to add Peter Kareiva's blog on the matter to be added to
this discussion:
http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/
Opening of the piece: "A famous person once observed that the
signature of a civilized mind is the ability to hold two seemingly
contradictory ideas in one’s head at the same time. This is exactly
what conservation must learn to do when it comes to introduced (or
what we often call “non-native” or “invasive”) species."
Cheers,
Chris
On Jul 6, 2011, at 2:18 PM, David Duffy wrote:
>> Date: Wed, 06 Jul 2011 19:52:27 +0000
>
>
>
>> Forwarded from rom: Shyama Pagad
>> <[email protected]> on Aliens-L list server
>>
>> Correspondence Nature Vol 475 July 7 2011
>>
>> ----------
>> Non-natives: 141 scientists object
>>
>> We the undersigned feel that in advocating a
>> change in the environmental management of
>> introduced species (Nature 474, 153154; 2011),
>> Mark Davis and colleagues assail two straw men.
>> First, most conservation biologists and
>> ecologists do not oppose non-native species per
>> se — only those targeted by the Convention on
>> Biological Diversity as threatening “ecosystems,
>> habitats or species”. There is no campaign
>> against all introductions: scarcity of resources
>> forces managers to prioritize according to the
>> impact of troublesome species, as in the Australian Weed Risk
Assessment.
>>
>> Second, invasion biologists and managers do not
>> ignore the benefits of introduced species. They
>> recognize that many non-native species curtail
>> erosion and provide food, timber and other
>> services. Nobody tries to eradicate wheat, for
>> instance. Useful non-native species may
>> sometimes still need to be managed because they
>> have a negative impact, such as tree invasions
>> that cause water loss in the South African fynbos.
>>
>> Davis and colleagues downplay the severe impact
>> of non-native species that may not manifest for
>> decades after their introduction — as occurred
>> with the Brazilian pepper shrub (Schinus
>> terebinthifolius) in Florida (J. J. Ewel in
>> Ecology of Biological Invasions of North America
>> and Hawaii (eds H. A. Mooney and J. A. Drake)
>> 214230; Springer, 1986). Also, some species may
>> have only a subtle immediate impact but affect
>> entire ecosystems, for example through their effect on soils.
>>
>> Pronouncing a newly introduced species as
>> harmless can lead to bad decisions about its
>> management. A species added to a plant community
>> that has no evolutionary experience of that
>> organism should be carefully watched.
>>
>> For some introductions, eradication is possible.
>> For example, 27 invasive species have been
>> eradicated from the Galapagos Islands,
>> mitigating severe adverse effects on endemic
>> species. Harmful invasive species have been
>> successfully kept in check by biological, chemical and mechanical
means.
>>
>> The public must be vigilant of introductions and
>> continue to support the many successful management efforts.
>>
>> Daniel Simberloff* University of Tennessee, Tennessee, USA.
>> [email protected]
>>
>> *On behalf of 141 signatories
>>
[<http://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdf>http://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdf]
>> (see go.nature.com/f1eqjn).
>>
>> ----------
>> Non-natives: put biodiversity at risk
>>
>> Bias against non-native species is not
>> xenophobic (Nature 474, 153154; 2011) — it has
>> a sound scientific foundation. The non-native
>> status of a species is highly relevant to
>> assessing its potential environmental and
>> economic impact. Unrestrained growth and
>> environmental damage follow when there are no
>> natural enemies in newly colonized areas. This
>> is not necessarily a sign of an invader’s
>> superior evolutionary fitness: it may lead to a
>> population collapse due to overexploitation of resources.
>>
>> Non-native species can increase the variety of
>> species in a community, but it is an
>> oversimplification to equate this with increased
>> biodiversity, of which species richness is only
>> one component. Surviving populations of native
>> species may shrink or become restricted to
>> poor-quality marginal habitats. Such unevenness
>> hardly contributes to a more diverse community.
>>
>> The genetic diversity of invaded communities may
>> decrease because of bottlenecks: native
>> genotypes disappear as populations fall, whereas
>> the invaders originate from very few initial colonizers.
>> Establishment of non-native species inevitably
>> decreases global diversity. Australia, for
>> example, was unique in having no placental
>> mammals; their introduction by humans made the
>> continent ecologically more similar to the rest of the world.
>>
>> Andrei Alyokhin University of Maine, Maine, USA.
>> [email protected]
>>
>> ----------
>> Non-natives: plusses of invasion ecology
>>
>> Contrary to the implications of Mark Davis and
>> colleagues (Nature 474, 153154; 2011), invasion
>> ecology has given us valuable insight into the
>> effects of new species on ecological function
>> and into some of the precipitous changes we may face in the coming
decades.
>>
>> Invasion ecologists generally assert that only a
>> very small fraction of non-native species harm
>> their new ecosystems. This position emerged as
>> early as 1986 and was mainstream in the era that
>> Davis and colleagues claim as the nadir of ecological nativism.
>>
>> It is unfair to characterize any scientific
>> discipline solely by past failures and to ignore
>> its successes. Invasion ecology is making real
>> progress with defining impact and characterizing
>> risk. Let’s not throw up our hands in despair just yet.
>>
>> Julie L. Lockwood Rutgers,
>> The State University of New Jersey, USA.
>> [email protected]
>> Martha F. Hoopes Mount Holyoke College, Massachusetts, USA.
>> Michael P. Marchetti California State University, California, USA.
>>
>> ----------
>> Non-natives: four risk factors
>>
>> Mark Davis et al. set an unrealistically high
>> bar for those making management decisions about
>> exotic species (Nature 474, 153154; 2011).
>> Control is often easier, cheaper and more
>> effective soon after detection (R. A. Haack et
>> al. Annu. Rev. Entomol. 55, 521546; 2010). We
>> agree that research on ecosystem impact is
>> necessary, but such studies can take years.
>> Meanwhile, we suggest that control priorities
>> for potential invasive species could be based on
>> easily available data about natural history and
>> evolutionary ecology. We propose four guidelines
>> for identifying such invasives.
>>
>> An exotic organism may be more likely to invade
>> and cause disruption the greater its rate of
>> reproduction; the greater its dispersal ability;
>> the closer (phylogenetically) its preferred food
>> in its native range is to an abundant taxon in
>> the new range; and the farther away
>> (phylogenetically) its predators and pathogens
>> are in its native range from those in its new range.
>>
>> For example, the red turpentine beetle
>> (Dendroctonus valens) is not particularly
>> disruptive in its native range in North America
>> because it attacks only trees that are already
>> weakened. In China it attacks and kills healthy
>> trees (Z. Yan et al. Biodivers. Conserv. 14,
>> 17351760; 2005). The reasons for this beetle’s
>> success as an invasive include its high
>> dispersal and reproductive rates, its affinity
>> for Chinese pines closely related to those it
>> feeds on ‘at home’, and the lack of predators or
>> pathogens phylogenetically similar to ones found in North America.
>>
>> Manuel Lerdau Xishuangbanna Tropical Botanical
>> Garden, Chinese Academy of Sciences, Menglun,
>> Yunnan, China; and University of Virginia, Virginia, USA.
>> [email protected]
>> Jacob D. Wickham Institute of Chemistry, Chinese
>> Academy of Sciences, Beijing, China.
>
>
> David Cameron Duffy
> Professor of Botany and Unit Leader
> Pacific Cooperative Studies Unit (PCSU)
> University of Hawai`i
Christopher Moore, Ph.D. student
Program in Ecology, Evolution, and Conservation Biology
Department of Biology
University of Nevada, Reno
Office: Fleishman Agriculture Building 140
Webpage: http://www.unr.edu/~cmmoore
Email: [email protected]
