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Global Invasive Species Team listserve digest #099
Tue Feb 12 2002 - 14:49:21 PST
--CONTENTS--
1. e-Bay changes policies (Global)
2. Torching multiflora rose (North Carolina, USA)
3. Weed grants (Nationwide, USA)
4. Case statements (Nationwide, USA)
5. Invasive frogs (Colorado, USA)
6. Aquatic invasives on canoes (Wisconsin, USA)
7. Native invasives in sensitive wetlands (Maryland, USA)
8. Weed meeting 26-27 March (Idaho, USA)
9. Cockleburs! (Texas, USA)
10. Proceedings on fire and weeds (Global)
11. Fungal bio-herbicides (Vermont, USA)
12. Eastern Invasives Network (Global)
13. Literature reviews (Global)
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1. e-Bay changes policies (Global)
From: Barry Rice (bamrice(at)ucdavis.edu)
Martha Carver gets three gold stars from the Wildland Invasive Species
Team for pressuring e-Bay not to sell invasive species like purple
loosestrife (Lythrum salicaria). Martha encouraged a number of agencies
and authorities (including WIST) to contact e-Bay. The result? e-Bay has
added a category of noxious and/or banned plants to their prohibited list
of sale items! There are still other web sites selling nasty invasives,
but this is still a great success!
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2. Torching multiflora rose (North Carolina, USA)
From: Margit Bucher (mbucher(at)tnc.org)
I talked with Marshall Ellis who coordinates the management of Natural
Resources for North Carolina State Parks. They are using a propane torch
to treat multiflora rose (Rosa multiflora); so far cutting, then flame
treatment, seems most successful. Does anybody else have similar
observations?
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3. Weed grants (Nationwide, USA)
From: Janet Clark (cipm(at)montana.edu)
The Center for Invasive Plant Management is pleased to announce its 2002
grant program at http://www.weedcenter.org/grants/overview.html. Grants
are available for Restoration Case Studies, Seed Money, Applied Science,
Multidisciplinary Research Planning, Cooperative Weed Management Areas,
and Citizen Involvement. Application deadline, in most cases, is March 5.
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4. Case statements (Nationwide, USA)
From: Betsy Lyman (blyman(at)tnc.org)
I am looking for examples of case statements that folks may have written
for their invasive species programs. An example of one of these is on the
TNC Wildland Invasive Species Team website
(http://tncinvasives.ucdavis.edu/mando.html). Other examples, if they are out
there, would be appreciated.
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5. Invasive frogs (Colorado, USA)
From: Steve Kettler (skettler(at)tnc.org)
We are interested in impacts to native frogs and fish, and potential
control methods. Anything you could send would be great!
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6. Aquatic invasives on canoes (Wisconsin, USA)
From: Nancy Braker (nbraker(at)tnc.org)
I'm looking for information on the threat of introduction of invasive
aquatic species via non-motorized boats. We are developing use policy for
a preserve with a system of small lakes, and while we know we do not want
to provide boat launching facilities or drive in access, we are wondering
if we need to restrict the ability of the public to carry in canoes or
kayaks to these lakes. None of these lakes have access via rivers or
creeks, so all boat would have to come over land at least 1/2 mile.
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7. Native invasives in sensitive wetlands (Maryland, USA)
From: Deborah Landau (dlandau(at)tnc.org)
Does anyone have information/suggestions on controlling (native) woody
species moving into sensitive wetland areas? We have some "Delmarva Bays"
(AKA Carolina Bays) with red maple, sweet gum and persimmon trees rapidly
encroaching and displacing the native herbs & grasses. We have tried
limited cutting & girdling, but resprouts have been a problem. Any success
stories?
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8. Weed meeting 26-27 March (Idaho, USA)
From: Barry Rice (bamrice(at)ucdavis.edu)
Bas Hargrove (The Nature Conservancy, Idaho) sent us information about a
meeting in Idaho being held by the Western Aquatic Plant Management
Society. If you are interested in registering, look at the documents
(including a schedule, preregistration, and call for papers) I have placed
on our web site at:
http://tncinvasives.ucdavis.edu/meetings.html
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9. Cockleburs! (Texas, USA)
From: Barry Rice (bamrice(at)ucdavis.edu)
Glen Gillman (ggillman(at)tnc.org) contacted our office---he has cockleburs
(Xanthium sp.) on a organic cattle farm TNC is involved with in Texas.
Does anyone have experience using non-chemical control methods (either
successfully or not!) on Xanthium, in native short grass?
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10. Proceedings on fire and weeds (Global)
From: Heather Montanye (hmontanye(at)tnc.org)
--The following message was brazenly stolen from the TNC Fire listserve,
and reposted here--Barry
If you are interested in receiving a copy of the Proceedings of the
Invasive Species Workshop: The Role of Fire in the Control and Spread of
Invasive Species (the information contained was compiled from the Fire
Conference 2000: The First National Congress on Fire Ecology, Prevention,
and Management), contact:
Emily Tracy, Diversity Intern, Biological Resources Division, 12201
Sunrise Valley Dr., MS 301, Reston, VA 20192, 703-648-4093,
Emily_Tracy(at)usgs.gov
Be sure to include your address and how many copies you wish to have.
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11. Fungal bio-herbicides (Vermont, USA)
From: Catey Ritchie (critchie(at)tnc.org)
I recently learned of a fungus-based herbicide (Myco-Tech) that has been
used in Canada for controlling deciduous trees in power lines. The
fungus (Chondrostereum purpureum), also known as silver leaf disease, is
naturally occurring in many temperate forest communities and does not
appear to increase the local population of the fungus over the long
term. Does anyone have any experience with this "herbicide" on invasives
such as buckthorn? Would this be considered biological control?
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12. Eastern Invasives Network (Global)
From: Christa Lynn Wilson (clw7(at)cornell.edu)
The Eastern Invasives Management Network was officially launched with a
highly successful first workshop held December 11-13, 2001 on St.
Simon's Island, Georgia near the Altamaha River Bioreserve. The network
is coordinated by the Wildland Invasive Species Team and is designed to
help practitioners develop and implement landscape-scale prevention and
management strategies for invasive plant threats. For more information
about the network go to <http://tnc-ecomanagement.org/Weeds/>, where you
will find an overview of the network, a summary of the first meeting, and
detailed information about the landscapes participating in the network.
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13. Literature reviews (Global)
From: John Randall (jarandall(at)ucdavis.edu)
**Articles on impacts of invaders:
Belnap, J. and S.L. Phillips. Soil biota in an ungrazed grassland:
response to annual grass (Bromus tectorum) invasion. 2001. Ecological
Applications 11(5): 1261-1275.
The authors examined ground litter and soil food web structure in
Bromus tectorum (cheatgrass) invaded and uninvaded areas of two native
grassland associations from two pristine sites (never plowed, never
grazed) in Canyonlands National Park, Utah. The native grasslands were
dominated by spring-active C3 Stipa species and by the predominantly
fall-active Hilaria jamesii, respectively.
Bromus invasion had significant impacts on soil litter and soil biota
in both associations but impacts on soil biota in Stipa were generally
opposite those in Hilaria. Ground litter increased by a factor of 2.2 in
invaded Hilaria and a factor of 2.8 in invaded Stipa. Active bacteria
decreased in invaded Hilaria but increased in invaded Stipa. Most higher
trophic-level soil organisms increased in invaded Hilaria but decreased in
invaded Stipa. On the other hand, soil and live-plant-infecting fungi
increased in invaded Hilaria and invaded Stipa. The authors point out that
uninvaded Hilaria grasslands are relatively continuous and thus experience
less structural change than Stipa grasslands which typically have large
bunches of grass separated by large patches of bare ground before they are
invaded, only to have these patches filled with Bromus following invasion.
They also note that the soil biota in the two types of native grasslands
is strikingly different, the Stipa grasslands having more complex food
webs, possibly as a result of the greater concentration of food-rich
resources in the grass bunches there. Bromus invasion made the soil biota
in Stipa areas remarkably similar to that in uninvaded Hilaria. Bromus
invasion also extended the growing season in both communities since Bromus
is winter active while none of the dominant native grasses are.
The results suggest that both resource control (in this case greatly
altered by Bromus) AND internal community dynamics drive the structure of
soil food webs. The authors also found differences between invaded and
uninvaded locations, the latter having siltier (finer) soils, more
continuous cover of plants and litter, low species richness of soil biota
and greater biomass of bacteria and fungi. This study observed only the
differences between uninvaded and already-invaded sites and so could not
rule out whether the differences between then existed before the invasion
or were caused by the invasion. However, the fact that many of the
apparent impacts of the invader were opposite in the two types of
grasslands and the fact that recently invaded Hilaria grasslands were far
more like those invaded 50 years earlier suggest that the invasion drove
the changes and did so rapidly.
Evans, R.D., R. Rimer, L. Sperry and J. Belnap. 2001. Exotic plant
invasion alters nitrogen dynamics in an arid grassland. Ecological
Applications 11(5): 1301-1310.
The authors quantified the effects of Bromus tectorum (cheatgrass)
invasion on nitrogen cycling (litter biomass, C:N ratio, lignan:N ratio,
potential soil microbial respiration and net N mineralization,
plant-available N and gaseous N loss) in a 97 hectare grassland that has
never been plowed or grazed within Canyonlands National Park, Utah. They
examined uninvaded and invaded grasslands dominated (or formerly
dominated) by Hilaria jamesii.
Bromus invasion significantly increased litter biomass and its litter
had significantly greater C:N and lignan:N ratios than did native litter.
This lead to decreased potential rates of net N mineralization in invaded
sites. In a wet spring inorganic N was 50% lower in invaded sites but in a
dry spring there was no difference in this characteristic between invaded
and uninvaded sites. Bromus may decrease N loss in the short term by
decreasing substrate availability but in the long term Bromus invasion
likely greatly increases N loss because it increases fire frequency and
the resultant N-volatilization.
The authors hypothesize that Bromus invasion and land use change have
established positive feedbacks that will decrease N availability, further
favor Bromus and otherwise change native species composition.
Ehrenfeld, J.G., P. Kourtev and W. Huang. 2001. Changes in soil functions
following invasions of exotic understory plants in deciduous forests.
Ecological Applications 11(5): 1287-1300.
The authors studied soil pH, nitrogen cycling and litter dynamics in New
Jersey deciduous forests whose understories were either uninvaded or
invaded by the exotics Berberis thunbergii (barberry) and/or Microstegium
vimineum (Japanese stiltgrass).
Soils beneath each of the exotics had high pH values and higher
nitrification rates and often higher net N mineralization rates than soils
beneath the most common native understory shrub, Vaccinium pallidum. These
differences were also found after 16 months in greenhouse studies, when
the same three species were grown in separate pots with soils that were
initially the same. Berberis litter had much higher N concentrations than
did that of the native shrub species or Microstegium. It also decomposed
much more rapidly than did the litter of native overstory species (oaks,
etc.) and with little immobilization of N. In contrast, Microstegium
litter decomposed more slowly than that of native species and it
immobilized N. The authors suggest that although pH and nitrification
increase under both species of invaders, it does so due to different
mechanisms. Both species evidently favor uptake of nitrate which may lead
to the increase in soil pH observed, but while Berberis produces a large
biomass of N-rich roots and of N-rich leaf litter, Microstegium
populations produce small masses of N-poor litter with very small masses
of N-rich roots that leave much of the surface layer of soil with few or
no roots. The authors speculate that the ability to change soil functions
in ways such as these two species do may be an important characteristic
that enables a non-native species to invade intact communities. In
addition, they note that sites whose soil functions can be altered may be
more invasible.
Mack, M. C., C.M. D'Antonio and R.E. Ley. 2001. Alteration of nitrogen
dynamics by exotic plants: a case study of C4 grasses in Hawaii.
Ecological Applications 11(5): 1323-1335.
The authors synthesize the results of long-term investigations of the
impacts of exotic grasses in submontane woodlands on the island of Hawaii
where native grasses and grass-like plants were historically rare.
Overall they found that the indirect effect which these grasses
(primarily Schizachyrium condensatum, Melinus minutiflora and Andropogon
virginicus) have on N cycling by promoting fires was far greater than
their direct effects. They compared litterfall, decomposition, N
mineralization from soil organic matter and plant uptake and production in
invaded-but-unburned forest, invaded-forest-where- grasses-were-removed
and invaded-areas-where-fires-had-eliminated-the-trees. They also measured
ecosystem N loss in unburned, naturally burned and experimentally burned
sites.
The grasses had relatively small effects on N cycling in unburned
woodland despite being abundant in these sites for about 30 years.
Increases in grass litter, primary production of biomass and N apparently
were compensated for by decreases in the litterfall and production of the
dominant native tree (Metrosideros polymorpha). On the other hand, N
cycling was greatly altered in burned areas, with sharply reduced
litterfall and biomass production but higher rates of N mineralization
from soil organic matter. As a result, total plant N uptake in burned
areas was only 17% of the annual net N mineralization and aboveground N
pools were significantly reduced as well.
Fires also reduced the non-symbiotic N fixation in burned sites,
apparently by sharply reducing the amount of litter from the dominant
native tree whose litter is an important site for fixation. Fire and the
subsequent loss of native woody species also led to decreased N inputs and
increased N mineralization from litter and soil organic matter which could
result in a more "leaky" N cycle. This might result in decreases in total
ecosystem N in frequently burned, grass-dominated sites over many decades
or centuries but no significant difference was yet detectable in total
ecosystem N between unburned and burned sites because >95% of N in these
systems was contained in the soil while <5% was in the biomass.
**Article on resistance to herbicide:
VanGessel, M.J. 2001. Glyphosate-resistant horseweed from Delaware. Weed
Science 49: 703-705.
Horseweed (Conyza canadensis) is a native species which is commonly
weed in no-till corn and soybean fields in the mid-Atlantic states.
Populations of horseweed that had developed resistance to the herbicide
glyphosate were found in no-till fields of soybean in Delaware after just
3 years in which glyphosate applications were the sole weed control method
used. The soybeans planted in these fields had been genetically engineered
to be resistant to glyphosate but it was expected that other species
growing there would remain susceptible. Horseweed is a native species that
was not highly susceptible to glyphosate in the first place and which has
not been reported to our program as a weed on any natural area. However,
the appearance of populations that are truly resistant to glyphosate after
just 3 years of exclusive use of glyphosate is noteworthy.
**Articles on ecology and control of specific invaders:
Decruyenaere, J.G. and J.S. Holt. 2001. Seasonality of clonal propagation
in giant reed. Weed Science 49(6): 760-767.
Results of this study indicate that giant reed (Arundo donax) in
southern California would be most easily controlled by applications of
phloem mobile herbicide (e.g. glyphosate) during late summer or early
autumn before the onset of winter dormancy or repeated clippings initiated
in early spring. If a single mechanical removal operation is to be used it
will be most effective if carried out in autumn when severed pieces are
least likely to resprout.
Lesica, P. and S. Miles. 2001. Natural history and invasion of Russian
olive along eastern Montana rivers. Western North American Naturalist
61(1): 1-10.
Meekins, J.F. and B.C. McCarthy. 2001. Effect of environmental variation
on the invasive success of a nonindigenous forest herb. Ecological
Applications 11(5): 1336-1348.
Garlic mustard (Alliaria petiolata) establishment, growth and seed
production were greater in lowland and forest edge sites than in upland
and more heavily shaded forest interior sites. Litter disturbance had no
apparent effect on garlic mustard establishment and growth.