| Previous digest | Subsequent digest |
Global Invasive Species Team listserve digest #068
Wed Sep 06 2000 - 12:28:15 PDT
--CONTENTS--
1. More poopy goats (Oregon)
2. Weeds spread by fire teams (Montana)
3. New weed documents available (Nationwide)
4. Invasive species articles (Nationwide)
A) Antidote to claims that introductions decrease biodiversity
B) Magazine articles for kids
C) Coffee-table magazine article on invasive species
D) Scientific journal articles
E) Impact of crossing 'native' species collected from afar on
local population genetics
---------------------------------------
1. More poopy goats (Oregon)
From: Lesley Richman (lesley_richman(at)or.blm.gov)
When goats are eating seeds, it takes 7-10 days for their systems to clear
them. But don't forget that they may be packing the seeds around in their
hair. The best strategy is to use them prior to weeds going to seed and
hope their grazing will prevent seed production. As far as bringing
them onto a site clean, it would be best to feed them a weed free hay
ration for 7-10 days first.
As far as diapers go, maybe that would be practical for a couple of
animals in a limited setting. I used modified cow fecal collection bags
with my goats on a research trial when I was collecting feces for
analysis. Those might work but I can't imagine it being practical on a
large scale.
---------------------------------------
2. Weeds spread by fire teams (Montana)
From: Brian Martin (bmartin(at)tnc.org)
(Brian posted this on the fire listserve---I'm cross-posting it here for
those who might have missed it---Barry)
If you are aware of any local fire engine crews on fires in Montana,
especially in the Bitterroot, expect that they will be transporting
spotted knapweed and sulfur cinquefoil to your neighborhood. The
Bitterroot is dominated by these and other invasive exotics that have
basically destroyed all of the lower elevation grasslands in western
Montana. It would be worth your time to talk to fire crews about
de-weeding their equipment before they start spreading these around. It
is very easy for these weeds to be captured on vehicles.
---------------------------------------
3. New weed documents available (Nationwide)
From: Barry Rice (bamrice(at)ucdavis.edu)
Even more Element Stewardship Abstracts have been placed online by
your faithful Invasive Species Team. Steer your web browser to our site
to see:
New Lonicera (Bush Honeysuckles) Species Management Summary
SEE: http://tncinvasives.ucdavis.edu/esadocs/loni_spp.html
New Ligustrum (Privet) Species Management Summary
SEE: http://tncinvasives.ucdavis.edu/esadocs/ligu_spp.html
New Melia azedarach (chinaberry) Species Management Summary
SEE: http://tncinvasives.ucdavis.edu/esadocs/meliazed.html
New Alliaria petiolata (garlic mustard) Species Management Summary
SEE: http://tncinvasives.ucdavis.edu/esadocs/allipeti.html
---------------------------------------
4. Invasive species articles (Nationwide)
From: John Randall (jarandall(at)ucdavis.edu)
A) ANTIDOTE TO CLAIMS THAT INTRODUCTIONS INCREASE BIODIVERSITY
Angermeier, P.L. 1994. Does biodiversity include artificial diversity?
Conservation Biology 8(2): 600-602.
Angermeier answers the question by clearly advocating the EXCLUSION of
non-native biota from definitions of biological diversity. He points out
that addition of non-native species makes the receiving and donating
systems more alike (they now share a species) and hence reduces global
biodiversity. He also argues that native diversity is inherently more
valuable over the long term than what he terms 'artificial diversity'
(numbers of non-native taxa) which he argues can never be a substitute
for native diversity in terms of societal value or ecological function.
Up to this point I am in total agreement and find the paper useful for
its clear, concise presentation which will help put to rest arguments
that introduced species actually enhance diversity. I'm less convinced
by Angermeier's closing arguments that conservation biologists should
strive to maximize 'ecological integrity' since in my experience this has
been even harder to quantify than biological diversity. But read it for
yourself - I wish I had done so 6 years ago when this first appeared!
B) MAGAZINE ARTICLES FOR KIDS
Odyssey: Adventures in Science, magazine for kids grades 4 (good readers)
and up. Reading level is middle school/jr high, designed for use in the
classroom. The April 2000 issue features articles on Alien Invaders
including: An Ecological Train Wreck: protecting Hawaii's native birds;
Pigs everywhere; Out of Control: the brown tree snake; Trouble in
Paradise: alien plants in our National Parks; Musseling in on the
ecosystem (zebra mussels); The purple plague (purple loosestrife); Wicked
Weeds (with photos by TNC's John Randall). You can order back issues
online at www.cobblestonepub.com, click on catalog, follow directions, and
either enter the article's title in search field or scroll down the
Odyssey back issues. Or call 800 821 0115. single issues are $4.95 +
$2 for shipping and Handling. Class sets (20 or more) $4.50 each plus 9%
shipping and handling. For more about the magazine
check: www.odysseymagazine.com.
C) COFFEE-TABLE MAGAZINE ARTICLE ON INVASIVE SPECIES
Green Raiders: weeds in the global garden. Plateau (land and peoples of
the Colorado Plateau) Summer 2000. reprint of John Randall's
introductory chapter from the book 'Invasive Plants: weeds of the global
garden'. Includes several color photos of invasive weeds not included in
the book.
D) SCIENTIFIC JOURNAL ARTICLES
Simberloff, D. and B. Von Holle. 1999. Positive interations of
non-indigenous species: invasional meltdown? Biological Invasions 1:
21-32.
Review article that points out that introduced species frequently
interact with one another and that these interactions often promote one
or more of the invaders. In particular, they note that mutualisms
between plants and animals that pollinate them or disperse their seeds
and the modification of habitats by introduced plants and animals are
often important in facilitating other invasions. On the other hand so
far there is little evidence that interference among introduced species
impedes further invasions. The authors conclude that syntergistic
interactions among invaders may accelerate negative impacts on native
species - a positive feedback, invasional 'meltdown' process.
I.M. Parker, et al. 1999. Impact: toward a framework for understanding
the ecological effects of invaders. Biological Invasions 1: 3-19.
Too little attention has been paid to clearly determining how invasive
species impact native species, communities and systems. The authors note
that this has impeded efforts to develop ecological theory about
invasions and that it forces conservation workers to set priorities for
preventing and controlling invasion without knowing how much damage the
species in question actually cause. They argue that impacts include
three fundamental dimensions: range, abundance, and per capita or per
biomass effects of the invader. They suggest ways in which field work
and models could provide a more comprehensive understanding of the
impacts of invaders and urge researchers to take on this task.
E) IMPACT OF CROSSING 'NATIVE' SPECIES COLLECTED FROM AFAR ON LOCAL
POPULATION GENETICS
Keller, M., J. Kollmann and P.J. Edwards. 2000. Genetic introgression
from distant provenance reduces fitness in local weed populations.
Journal of Applied Ecology 37(4): 647-659.
The authors studied the performance of the offspring of three ruderal
species native to Switzerland that were intentionally crossed with pollen
from populations native to distant parts of Europe. Most of the first
generation crosses exhibited improved performance in terms of biomass
and/or seed size relative to to that of both parents when grown in common
plots (heterosis, aka hybrid vigor). However, the second generation
backcrosses (native Swiss plants crossed with pollen from the F1s) almost
all showed reduced performance in terms of biomass and survival relative
to both parents. Analysis of the data indicated the reduction in
performance was due to the breakdown of adaptive gene complexes which
were apparently present in individuals from the native population and
which wree disrupted by outbreeding with individuals from other
populations. The authors point out where reduced performance is the
result of certain poorly adpated genes from the ditant populations these
genes will be selected against and so the damage seen will decrease with
each backcross. On the contrary, where the reduction in performance is
due to the breakup of co-adapted gene complexes from the native
population the damage is likely to increase with each backcross for at
least several generations. The authors discuss the implications of these
findings and other studies for the use of plants, seed and pollen
collected from distant sites for restoration projects, noting that small
native populations are especially vulnerable to 'genetic assimilation'.
However, they are unable to come up with general guidelines regarding
what is an acceptable distance from which native plants can be introduced
since population genetics vary so widely between the few species and
populations that have been carefully studied so far.