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Global Invasive Species Team listserve digest #073
Wed Nov 29 2000 - 15:45:42 PST

1. Snow geese, and burning Phalaris arundinacea (Illinois)
2. Impacts of snow geese (New York)
3. Herbicide impacts on damselflies (Hawaii)
4. Aquatic weed control class (Florida)
5. Glyphosate on insects (California)


1. Snow geese, and burning Phalaris arundinacea (Illinois)
From: David Hodge (dhodge(at)tnc.org)

A possible solution concerning snow geese would involve using dogs
normally used for herding. In some areas in Chicago, golf courses use
breeds of dogs such as border collies and Australian sheep dogs to try to
"herd" Canada geese. Needless to say, the geese don't like this and leave.
This may work for some areas that have problems with snow geese.

I work in a high quality fen that is burned with some frequency. It has an
infestation of reed canary grass (Phalaris arundinacea) that is burned
every two to three years. We have not seen a decrease in reed canary
grass. I realize that the burn frequency discussed was much greater than
every two to three years. However, we have seen a decrease when we burned
early in the spring, let it resprout and then hit it with herbicide. In
the high quality area we use 2% Poast (2-[1-(ethoxyimino)butyl-5-
[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexen-1-one]), in the low quality
area we use either 5% Roundup (Glyphosate) in upland areas or 5% Rodeo
(Glyphosate) in wetter areas. In heavy infestations we may come back two
to three times and spray what we have missed.


2. Impacts of snow geese (New York)
From: Cris Winters (cwinters(at)tnc.org)

I don't how to keep snow geese off the marshes, but in the course of
producing a report I did in about 1994 related to the Delaware Bay Estuary
health, I heard from some land managers at Bombay Hook NWR that the goose
grazing has somewhat mixed impacts. It can clear large areas of marsh
vegetation, making invasion by Phragmites more likely. However, it also
results in more - and needed - feeding areas for migrating shorebird on
the mud flats.


3. Herbicide impacts on damselflies (Hawaii)
From: Pat Bily (pbily(at)tnc.org)

Solber and Higgins, 1993, Wildlife Society Bulletin 21:299-307, discusses
Rodeo (glyphosate) impact on invertebrates, as well as cattail and
waterfowl. Invertebrate abundance was greater in untreated cattails within
Rodeo treated wetlands than in control wetlands, and was less abundant in
treated and natural openings. This implies a relationship between
vegetated wetlands and invertebrates. There was also a mention of low
doses of Rodeo not impacting Chorella algae, but high doses causing
negative impact; Algae are an important component for some consumer
invertebrates, and a disruption in the food chain could impact
damselflies. Monsanto likely has more up-to-date information, and probably
on specific species like damselflies.


4. Aquatic weed control class (Florida)
From: Barry Rice (bamrice(at)ucdavis.edu)

A short class on aquatic weed control is being held 13-18 May in Fort
Lauderdale, Florida. It may be a little "urban" in emphasis. (I am not
sure.) There is more information on the program at:


5. Glyphosate on insects (California)
From: Mike Kelly (mkellysd(at)aol.com)

I have no specific info on the impact of glyphosate on damselflies.
However, at our 1999 California Exotic Pest Plant Council's Symposium,
Joel Trumbo of the California Dept. of Fish and Game presented a paper on
glyphosate trials on amphibians in the lab and in the field and found a
safety margin of more than 1000x when used according to the label. You
have to use the aquatic approved version, Rodeo. The terrestrial version,
Roundup Pro, contains a surfactant that does have an impact on some
aquatic organisms. Pure glyphosate acts on an amino acid pathway that
plants, but not animals have. I am familiar with most of the literature on
glyphosate and wildlife, and can't recall anything specific on insects.

Updated December 2000
©The Nature Conservancy, 1999