| Previous digest | Subsequent digest |
Global Invasive Species Team listserve digest #053
Tue, 25 Jan 2000 13:36:03 -0800 (PST)
--CONTENTS--
1. Round-up Pro donated by Monsanto (Florida)
2. Unique and successful weed control strategies sought (Nationwide)
3. Recent weed articles (Nationwide)
---------------------------------------
1. Round-up Pro donated by Monsanto (Florida)
From: Chris Bergh (chrisbergh(at)earthlink.net)
Chris Bergh of the Florida Keys program says that Monsanto has offered to
give TNC's Keys Program 100 gallons of Round-up Pro (glyphosate) in 2.5
gallon jugs or 120 gallons in 30 gallon drums. The Keys program does not
need it, but Monsanto will ship it anywhere. Chris says that Monsanto
would prefer to donate the Round-up Pro as a single shipment, but he
thinks that Monsanto would be able to split it up as much as 4 ways. I'd
encourage folks to use the 30 gallon drums if possible. More bang for the
gift.
---------------------------------------
2. Unique and successful weed control strategies sought (Nationwide)
From: Callie Hurd (kalaphia(at)aol.com)
I am writing a technical manual for weed control on Nature Conservancy
preserves and I am interested in hearing from people about unique and
successful weed control strategies they have developed. If anyone has some
techniques they would like to share (e.g., killing burdock and wild
parsnip by "stabbing" the root corm), please contact me, Callie Hurd, at
kalaphia(at)aol.com or at TNC's Invasive Species Team, 530-754-8891.
Thank you!
---------------------------------------
3. Recent weed articles (Nationwide)
From: John Randall (jarandall(at)ucdavis.edu)
IMPACTS OF INVASIVE PLANTS:
Anttila, C.K., CC. Daehler, N.E. Rank and D.R. Strong. 1998. Greater
male fitness of a rare invader (Spartina alterniflora, Poaceae) threatens
a common native (Spartina foliosa) with hybridization. American Journal
of Botany 85(11):1597-1601.
Eastern saltmarsh cordgrass is a non-native invader on the Pacific coast
where it interbreeds with the native California cordgrass. The invader
produces far more pollen than the native and its pollen is more likely to
germinate, fertilize and cause seed to be produced by the native. It
appears that very large native populations are likely to be genetically
assimilated and the native genetic type eliminated. The non-native grows
in lower intertidal habitats than the native and eliminates open mudflats
used by foraging shorebirds. If the hybrids behave more like the
non-native they too will eliminate important habitat for shorebirds and
marine life.
Benoit, L.K. and R.A. Askins. 1999. Impact of the spread of Phragmites in
the distribution of birds in Connecticut tidal marshes. Wetlands
19(1):194-208.
Phragmites australis is native to the northeastern US but highly invasive
in many fresh and brackish marshes there. The authors assessed
differences between bird populations in salt and brackish marshes
dominated by Phragmites and other native plants. They found significantly
fewer species and fewer state-listed species in Phragmites marsh than in
short-grass (at least 50% Juncus gerardii, Distichlis spicata, Spartina
patens and S. alterniflora) marsh. Bird communities were similar, however,
in Phragmites and cattail dominated marshes although Virginia rails were
positively correlated to cattail cover but not to Phragmites cover. The
authors concluded that although Phragmites invasion may benefit some bird
species it negatively impacts other marsh bird species that have already
declined.
Brooks, M.L. 1999. Alien annual grasses and fire in the Mojave Desert.
Madrono 46(1):13-19.
Provides evidence that red brome (Bromus madritensis ssp. rubens), and
Mediterranean grass (Schismus spp.), facilitate and are probably necessary
for the spread of wildfires in the western Mojave. Native communities
rarely if ever experienced fires and are degraded by them. Fires fueled by
red brome were hot enough to consume small shrubs but usually did not
ignite large shrubs like creosote bush. Fires fueled by Schismus spp.
were patchier and were rarely hot enough to ignite even small shrubs.
Christian, J.M. and S.D. Wilson. 1999. Long-term ecosystem impacts of an
introduced grass in the northern Great Plains. Ecology 80(7):2397-2407.
This is an excellent paper. The authors examined stands of undisturbed
prairie, successional prairie (fields abandoned ~50 years ago, ~50 year
old fields planted with crested wheatgrass (Agropyron cristatum).
Crested wheatgrass lowered species richness and diversity and was more
likely to exclude physiologically similar native C3 grasses. Soils under
crested wheatgrass had significantly less available N, total N and total C
than successional prairie and undisturbed prairie. Cover values were
similar in the fields but crested wheatgrass fields had higher shoot
biomass and lower root biomass. The authors note that since soils under
crested wheatgrass have ~25% less C than successional prairie the planting
of millions of hectares of prairie to crested wheatgrass may have left
2.2-4.8 x 10^14 g of C in the atmosphere that otherwise would have been
stored in the soil! Almost no significant differences were found between
undisturbed and successional prairie, thus the authors note that this
demonstrates that the introduced species had a larger long-term role in
altering ecosystem function than the disturbance itself.
Vanier, C.H., L.R. Walker. 1999. Impact of a non-native plant on
dispersal of a native. Madrono 46(1):46-48.
Here is a previously undescribed impact of non-native plants - altering
seed dispersal of a native. Tumbleweed (Salsola tragus) physically
blocked dispersal of native flat-topped buckwheat (Eriogonum deflexum).
LACK OF IMPACTS OF INVASIVE PLANTS:
Otto, S., P.M. Groffman, S.E.G. Findlay and A.E. Arreola. 1999.
Invasive plant species and microbial processes in a tidal freshwater
marsh. Journal of Environmental Quality 28:1252-1257.
The authors measured sediment microbial biomass and activity in portions
of freshwater marsh along the Hudson with 1. cattails (Typha spp.),
2. Phragmites, or 3. purple loosestrife (Lythrum salicaria). They were
unable to find significant differences in microbial biomass and activity
in May, June and July although cattail has markedly lower N content than
Phragmites or loosestrife. This suggests changes in marsh vegetation do
not cause dramatic changes in microbial biomass and activity, including
de-nitrification, but on the other hand, it may indicate that Phragmites
and loosestrife may sequester more N which may help lead to changes in N
processing and retention in these marshes over the long term. These
measurements were made at the height of the growing season and so may have
missed differences that occur at other times of year.
Treberg, M.A. and B.C. Husband. 1999. Relationship between the abundance
of Lythrum salicaria (purple loosestrife) and plant species richness along
the Bar River, Canada. Wetlands 19(1):118-125.
The authors found no significant difference in species richness between
plots that contained purple loosestrife and those that did not. They also
failed to detect any difference in species richness with increases in
abundance of purple loosestrife. There were no significant differences in
numbers of species of annual plants, herbaceous perennials and woody
perennial between plots with and without purple loosestrife. There were,
however, significantly higher numbers of floating aquatic species in plots
without loosestrife but not a single species was statistically more likely
to be found in plots without purple loosestrife. These results do not
support for the hypothesis that purple loosestrife reduces native plant
abundances in the marshes that it invades. The authors measured only the
numbers of other species in each plot, however, and did not assess density
or cover. Purple loosestrife apparently moved into the study area at
least 12 years ago.