Friends,
While I am devoted to all the plants, of course, sometimes vilifying
invasive plants is the right thing to do. For example, we need to
vilify the strawberry guava (Psidium cattleianum) in Hawaii that
displaces native forests across watersheds
(http://www.fs.fed.us/psw/programs/ipif/strawberryguava/). And, of
course another one to vilify is Miconia calvescens. Unfortunately,
this horrible invasive species was used as the lead photo in that
Nature comment, just above text that advocated for less concern about
the spread of alien weeds. That mismatch was really unfortunate
because M. calvescens has displaced a huge fraction of native forest
in Tahiti, where it is known as the "green cancer" and threatens to
create the same ecodisaster in Hawaii, where it is known as the
"purple plague". http://en.wikipedia.org/wiki/Miconia_calvescens .
Another really clear case of an invasive plant to be vilified is the
Giant Hogweed (Heracleum mantegazzianum), which is expanding its
range across NE and NW US and Canada and can cause blindness, burns
all over the body and death, because its sap triggers extreme and
persistent photosensitivity.
http://en.wikipedia.org/wiki/Giant_Hogweed There are several
fascinating and creepy videos on YouTube about it! e.g.,
http://www.youtube.com/watch?v=LTktmNiMRxI&feature=fvsr or
http://www.youtube.com/watch?v=KaV2jwNT0MQ . For those who love
awesome music, there is an 8 minute classic song by Genesis about it
(http://www.youtube.com/watch?v=7j6fr4TQzMg ) It would be wrong to
use that Nature Comment to justify diverting resources away from
important work controlling the spread of invasive species. The weak
arguments in that Comment have to be balanced against the consensus
of the thousands of others who have justly advocated for the
preservation of native-dominated ecosystems and for targeting
invasive alien species (see e.g., the Millenium Ecosystem Assessment)
so we can leave the earth in as good condition as we found it, or better.
Lawren Sack
UCLA
At 06:20 PM 6/11/2011, David Duffy wrote:
Matt Chew has presented an interesting perspective on how the Nature
editorial (Davis et al. 2011, Don't judge species by their origins)
came into being. I have significant concerns about the paper, which
while certainly interesting and provocative, does not live up to the
standards of Nature. While this may be in part a product of the
editing process and limitations that Matt described, responsibility
for the commentary remains with the authors.
Nature informed me that the piece was not peer-reviewed. While peer
reviewing would not be appropriate for the message of any editorial,
it should help ensure that facts are correct and interpretations are
fairly presented. I won't comment here (until the bottom) about the
message, but I will comment about facts and what is best described
as unfortunate presentation that should have received the attention
of an editor or the self restraint of the authors, assuming they all
read the final product.
This is a scientific commentary. Words like "vilified" and "beloved
`native' species", "pervasive bias", "apocalyptic" and "rightful"
are best left to bodice rippers or American talk radio.
"Classifying biota according to their adherence to cultural
standards of belonging, citizenship, fair play or morality does not
advance our understanding of ecology." It does seems to be
advancing an argument that plants have a consciousness that makes
them capable of culture and ethics. Tomkins (1973: The Secret Life
of Plants) advanced this hypothesis but it has not really received
scientific support until this editorial in Nature. Poor editing or ?
Six of ten references are by co-authors. There is a near absence
of literature from the "invasive species biology" that they are
commenting on, the sole exception being a 1998 paper, while all the
others are from 2009-2011. Fairness should have called for citing
one or more current references about how invasive species biology
and management are actually practiced, rather than presenting their
one sided picture. Again poor editing?
They give an example of a long term eradication effort in Australia
involving devil's claw plant (Martynia annua). They claim "There is
little evidence that the species ever merited such intensive
management", quoting a paper by one of the co-authors (Gardner et
al. 2010. Rangeland J. 32: 407-417). In reality, this species is
considered a pest because of its "clawed fruits cause injury and
discomfort to animals having been know to work their way into soft
body parts" (Smith 2002, Weeds of the wet/dry tropics of Australia,
Environment Centre NT.) and Gardner wrote that it is "of moderate
annoyance to the cattle industry" (Gardner et al. 2010). As we know
from the Yellowstone/Montana wolf situation, what is "little
evidence" to academics but a moderate annoyance to cattlemen can
trigger control and eradication efforts.
The authors ask whether the "effort is worth it?" for this
eradication effort. They ignore the conclusion of co-author Gardner
(et al. 2010), that the effort was a valuable training exercise for
200 or 400 participants (both are given), especially for 82
"Aboriginal Rangers" from "Traditional Owners" of the land who
subsequently took over management of the area. Did Gardner actually
read the final draft or did the other authors not read Gardner's paper?
Similarly for tamarisk in the western U.S., the three references
are problematic. Two are by co-authors. In the third, they
reference Aukema et al Bioscience 60: 886-897 in support of their
statement that "Tamarisks. . .arguably have a crucial role in the
functioning of the human modified river bank environment".
Unfortunately Aukema et al wrote on the historical accumulation of
nonindigenous forest pests in the Continental United States and I
can find no reference to tamarisk, much less documentation for the
statement. Finally, tamarisk management is not settled science in
the West, so a more balanced selection of literature might have been helpful.
The reference to the number of successful plant eradications in
Galapagos has no citation. The authors cite the Ring-necked Pheasant
as one among "many of the species that people think of as native are
actually alien." It isn't clear who "the people" are. Most
ecologists know the pheasant is introduced if they work in the area.
In any event the pheasant is irrelevant. It is managed as a game
bird, not controlled as an invasive species, unless there are local
efforts which the authors do not mention. Editing should have
removed this whole section.
Finally, the authors use straw dog arguments which, while
effective propaganda, are poor writing.
Claiming that the "native versus non-native dichotomy in
conservation is declining and even becoming unproductive" they cite
Flieschman et al. (Bioscience 61) as proof that "many
conservationists still consider the distinction a core guiding
principle". The paper in question lists 40 top priorities for
science to inform management. As Davis et al. admit, invasive
alien species can have negative effects, so it is a straw dog to
complain that these principles actually consider the impact of
non-native species. A better reference might prove their point, or
not. Better editing or better writing might have helped.
Here are the priorities that mention non-natives:
35. How will changing levels of human activity in the Arctic that
are enabled by climate change affect Arctic ecosystems? Cli-
mate change has already resulted in the relocation of native
villages along the Arctic coast and will enable expansion of
human activities, such as transportation (van Loon 2007)
and development of energy sources, in terrestrial and
marine ecosystems in the Arctic. Unintended movement of
nonnative species also is likely to increase.
31. How will changes in land use and climate affect factors that
facilitate the spread of nonnative species? Changes in land use
and climate will affect modes and rates of introduction of
nonnative species, which may complicate efforts to achieve
ecological and agricultural targets. Among the many fac-
tors likely to increase rates of pathogen transmission and
colonization by nonnative species are increases in air travel
and increases in sea traffic in Arctic regions (facilitated by
melting of sea ice). The introduction and spread of nonna-
tive species may require developing and implementing new
strategies for screening imports, assessing the potential for
ballast water and hull fouling on ships to introduce species,
detection, rapid response, and restoration.
25. At what threshold values of abiotic or biotic attributes do ecosys-
tems change abruptly in response to species extirpations or species
introductions? Changes in species composition affect ecosys-
tems at multiple levels, from mutualisms or predator-prey
relations to disturbance regimes. For example, the invasion
of nonnative annual grasses has changed fire dynamics across
the western United States (Knick et al. 2005). Few methods
exist to detect impending threshold events. Knowledge of
thresholds at which changes in ecosystems are irreversible
would help prioritize responses to declines or introductions
of species by management agencies.
9. How do population dynamics respond to the independent and
interactive effects of multiple Stressors? The responses of
particular species to a given Stressor, such as habitat loss,
drought, invasion of a nonnative species, or harvest, often
are fairly well known. By comparison, mechanistic under-
standing of how species respond to the cumulative effects
of multiple Stressors and their interactions is limited. Lack
of knowledge constrains robust assessments of cumulative
effects required under policies such as the National Environ-
mental Policy Act (NEPA) and the Endangered Species Act
(ESA) for public and private organizations.
Another straw dog: "Clearly natural resource agencies and
organizations should base their management plans on sound empirical
evidence and not on unfounded claims of harm by non-natives." Do
they really think managers would knowingly base their efforts on
unsound empirical evidence? Of course if we scientists haven't
provided any such evidence, managers just have to muddle through.
And "We must embrace (more bodice ripping -DCD) the fact of "novel
ecosystems" and incorporate many alien species into management
plans, rather than try to achieve the often impossible goal of
eradicating them or drastically reducing their abundance". Isn't
that what we call agriculture, a field where which invasive species
biology springs, in part? Good editing might have produced a little
less high horse and a bit more dirt under the fingernails.
In sum, this commentary could have used a good edit and the
authors should have exhibited some professional restraint, in the
absence of peer review.
****
Now I going to make my own comments about the content of the paper,
as opposed to its presentation, facts and writing. I suspect this
commentary will appear to managers of real time/real world
situations as yet another demonstration that academic science is
about publishing papers, not about actually helping. Given limited
resources, managers prioritize constantly, so telling them to start
doing so is more than a bit fatuous. Given the frequent absence of
scientific studies about a particular species, managers will
continue to make the best decisions they can with the information
they have. Being lectured to by academics, managers will be less
likely to listen in the future. Of course this will give future
academics the chance to publish a similar commentary in a decade or
so, but meanwhile the same problems will continue.
Finally good science in alien species biology or whatever the
authors wish to call it will be futile in terms of the real world
unless it considers people. People decide if species are a problem,
and science is only part of that decision. The tamarisk issue is
probably more about visions of what the West should be, or value
judgments about native plants versus Willow Flycatchers, than about
water flow. The devil's claw eradication effort appears to have
always been more about culture and education (and, yes, winning a
case of beer!) than about concerns over nutrient cycling.
Commentaries like this that lambast the real world for not living
up to the authors' scientific standards are the proverbial one hand clapping.
To be blunt, often the best thing we academics could do is sit
down, shut up, share a beer with a manager, and listen. And yes I
too need to follow my own advice.
David Duffy
University of Hawaii
David Cameron Duffy Ph.D.
Professor/PCSU Unit Leader/CESU Director
PCSU/CESU/Department of Botany
University of Hawaii Manoa
3190 Maile Way, St John 410
Honolulu, HI 96822 USA
Tel 808-956-8218, FAX 808-956-4710
http://www.botany.hawaii.edu/faculty/duffy/
----------------------------------------------------------------------------------------------
Lawren Sack
Associate Professor
Department of Ecology and Evolutionary Biology
University of California, Los Angeles
621 Charles E. Young Drive South
Los Angeles, CA 90095-1606 USA
Tel: 310-825-6525
Fax: 310-825-9433
Email: lawrens...@ucla.edu
http://www.eeb.ucla.edu/Faculty/Sack
