Gwen K. Noda
University or California, Los Angeles
gwennoda@ucla.edu
Potamopyrgus antipodarum now occupies most of the remaining habitat
of the threatened Bliss Rapids snail, Taylorconcha serpenticola,in
the Snake River, Idaho. The Bliss Rapid snail was federally listed,
in part, due to concerns for potential competition with P. antipodarum.
I have studied competition between both species since 1999 and will
report on controlled competition studies conducted in the laboratory
and at two sites in Banbury Springs, Snake River, Idaho at four seasons.
Both species were subjected to eight treatment densities to evaluate
intra and interspecific competition effects on growth rates. Results
show that growth rates of both species were negatively effected by
intraspecific competition at all seasons and sites reported. Growth
rates of the Bliss Rapids snail were also more affected by P. antipodarum
(interspecific competition) than by itself (intraspecific competition).
Based on this study and additional research conducted by myself and
others, I suggest that headwater springs in the Thousand Springs
complex, Idaho, including Banbury Springs, are not ideal habitats
for the Bliss Rapids snail but provide refugia from P. antipodarum.
Not enough time has elapsed to determine if the Bliss Rapids snail
will be excluded from habitats where both species now coexist and
factors other than competition for limited food resources allow the
Bliss Rapids snail to persist in some shared habitats.
Studies of a Trematode Parasite
for
Biological Control of an Invasive Freshwater Snail
Alison Emblidge and Mark Dybdahl
Washington State University
aemblidge@wsu.edu
Biological control can provide an alternative when chemical and
mechanical control methods are impractical or unacceptable. Because
New Zealand mud snail (NZMS) (Potamopyrgus antipodarum) populations
in the western United States
are widespread and comprised of a single geneticclone, the species
is an ideal candidate for biological control. A trematode parasite,Microphallus
sp., may be an appropriate biocontrol agent because it is strongly
adapted to its local host. However, testing must be conducted in order
to find a matched, host-specific control agent. Previous
attempts to infect this clone and another invasive clone in Europe
using New Zealand parasites have failed. To find a matched control
agent, the western U.S. P.
antipodarum clone was exposed in the laboratory to parasites from the
North and South Islands of New Zealand and from Victoria, Australia.
Australian parasites were collected from a P. antipodarum population
harboring the same snail clone found in the
western U.S. These parasites successfully infected snails collected
from Thousand Springs, Idaho, and therefore represent a match. North
Island New Zealand
parasites infected only a small percentage of the western U.S. NZMS
clone. These results suggest that biocontrol is feasible using Microphallus
sp.
Effects of Potamopyrgus antipodarum on macroinvertebrates
and fish diets
Chelsea Cada
Montana State University, Bozeman, MT
ccada@montana.edu
Abstract unavailable
Potamopyrgus antipodarum interspecific
competition modeling exercise
Billie Kerans
Montana State University, Bozeman, MT
bkerans@montana.edu
Abstract unavailable
Potential factors affecting the spread of Potamopyrgus
antipodarum in south-eastern Australia.
Sarina Loo
Department of Biological Sciences
Monash University, Melbourne, Australia
Email: Sarina.Loo@sci.monash.edu.au
An understanding of the rate of spread and potential distribution
of aquatic invaders would aid the evaluation of the environmental,
economic and social costs of dealing with invasive species. A critical
objective is to develop a capacity to predict locations that have
a high likelihood of future invasion. Although the mudsnail Potamopyrgus
antipodarum has widely spread in south-eastern Australia since its
initial introduction from New Zealand in the mid-nineteenth century,
its range may still be expanding. I am exploring a subset of sites
from within the Victorian distribution of P. antipodarum to compare
the change in its distribution from 1994 to the current time with
these objectives: to assess (i) the snail’s rate of spread,
(ii) its persistence at previously invaded sites, (iii) changes in
land-use variables that may have affected spread, and (iv) the interactions
between the distributions of P. antipodarum and the native snails
from the family Hydrobiidae. In addition, the current known Australian
P. antipodarum distribution will be compared to its distribution
documented in 1988. The potential Australian distribution of P. antipodarum
will then be estimated based upon its environmental tolerances and
habitat preferences using a predictive model. An estimate of the
costs of control and invasion prevention for P. antipodarum will
be made. If adequate data are available, intercontinental comparisons
between the rates of spread may be undertaken.
***Cancelled****
Competitive Interactions and Grazing Effects of Three, Common
New Zealand Macroinvertebrates
Joseph R. Holomuzki, The Ohio State University, 1680
University Dr., Mansfield, OH 44906 holomuzki.3@osu.edu
Barry B.F. Biggs, National Institute of Water and Atmospheric Research,
P.O. Box 8602, Christchurch, NZ
We experimentally studied competitive interactions and grazing effects
of the hydrobiid snail Potamopyrgus antipodarum, the leptophlebiid
mayfly Deleatidium spp., and the conoesucid caddisfly Pycnocentrodes
aeris, common, co-occurring grazers in many New Zealand streams.
Snails, mayflies, and caddisflies reared alone and combined at ambient
densities in plastic containers (400 mL) revealed that costs of coexisting
differed between species. Snail growth was unaffected by the presence
of other taxa. Snails spent relatively little time on periphyton-covered
tiles and frequently burrowed into the surrounding sand substrate,
where they presumably consumed epipsammic algae. Caddisfly growth
was also unaffected by competitors, but pupation rates were significantly
higher in caddisfly-alone treatments than in combined-species treatments.
Similarly, mayfly emergence rates differed among treatments, being
highest in the mayfly-alone treatment. These negative effects were
likely a result of food limitation, given that herbivory in all treatments,
except snails-alone, significantly reduced algal abundance relative
to ungrazed controls. Herbivory by all three taxa had only a slight
effect on benthic algal assemblage. Diatoms, particularly Staurosirella
leptostauron, Achnanthidium spp., and Gomphonema parvulum, were the
predominant algae in all treatments, but the green alga Mougeotia
sp. was more abundant in ungrazed controls than in grazer-containing
treatments. Linkages between flood regime, predation, and streambed
features are likely important in mediating competition between these
taxa in real streams.
The New Zealand Mudsnail Invasion in Idaho:
A Cooperative Effort to Increase
Public Awareness
Dave Hopper & Megan Laxalt
U.S. Fish & Wildlife Service
Snake River Office
Boise, Idaho
dave_hopper@fws.gov
Discovery of the New Zealand mudsnail in federal and state fish
hatcheries along the Snake River in south Idaho prompted the need
of these agencies to prevent the spread of this invasive species.
Hatcheries developed fish stocking protocols to better contain the
snails and the agencies and cooperating agencies began a program
to educate the public and solicit their help in controlling the spread
of the snail. As an initial outreach effort, the cooperators developed
a poster to that was distributed to recreational vendors and outfitters,
and to be posted at boat ramps, campgrounds, and other strategic
locations throughout Idaho. Cooperators in this project included:
Idaho Department of Fish & Game, U.S. Bureau of Reclamation,
Idaho Power Company, Idaho Department of Parks and Recreation, and
the U.S. Fish & Wildlife Service. To date, posters have been
provided to over 200 private outfitters and vendors and have been
posted at numerous locations throughout the state. Continuing public
education is being pursued in the form of public service announcements
and articles in local newspapers and newsletters, and will be developed
to address other invasive species.
Assessment of New Zealand Mudsnail Potamopyrgus
antipodarum
As Potential Fish Parasite Vector
L. Staton1, B. MacConnell1, B. Kearns2 and C. Hudson1
1 Bozeman Fish Health Center, USFWS, 920 Technology Blvd.
Suite G, Bozeman, MT 59718 Email: linda_staton@fws.gov
2 Department Ecology, Montana State University, Bozeman,
MT 59717
The New Zealand mudsnail (NZMS), Potamopyrgus antipodarum, has become
established in Yellowstone National Park and the Madison River, Montana.
The impacts of this aquatic nuisance species on resident fish populations
are not fully understood. Digenetic trematode parasites have complicated
life cycles involving bird, snail, and fish hosts. Trematode infection
in fish may contribute to poor growth and cause significant tissue
damage. In its native habitat, the NZMS is host to 14 trematodes.
To date, no parasites have been found in P. antipodarum in American
waters. A study to investigate the potential of NZMS to transmit
parasites to salmonids in the Madison River drainage was initiated
in June 2003. Duplicate samples of NZMS from each of 6 sites were
collected monthly and examined for parasites. Fish collected near
each site were inspected for parasitism. In addition, success of
parasite transmission will be determined by histological analysis
of laboratory exposed westslope cutthroat trout, Oncorhynchus clarki
lewisi, to NZMS collected from each site. Preliminary study results
will be presented.
An Integrated Research Model
for Aquatic Invasives
Gretchen Rupp, Director
Montana Water Center
Montana State University
Bozeman, Montana State University
grupp@montana.edu
For seven years, the Montana Water Center has operated the Whirling
Disease Initiative, a national research program concerned with the
whirling disease pathogen that affects salmonid fish. A national
panel of stakeholder representatives provides overall direction.
A scientific steering committee drives the initiative from year to
year, selecting projects for funding by a competitive process. The
US Fish & Wildlife funds the initiative, with match provided
by state agencies. This initiative may be a good model for an integrated,
multi-year research program on aquatic invasive species.
Update on USFWS Aquatic Nuisance
Species Program
Tina Proctor
U.S. Fish and Wildlife Service
Denver, Colorado
The U.S. Fish and Wildlife Service has been asked by the ANS Task Force
to take the lead in developing a New Zealand Mudsnail Management
and Control Plan. The NZMS Management and Control Plan Team will
meet in conjunction with the 3rd Annual NZMS Conference on August
27, from 1-5 pm at Montana State University. The Plan will include
sections on distribution of the snails around the world, the history
of the invasion in the U.S., NZMS biology, strategies for future
detection, reducing negative
impacts and population control and management. The Team will be working
together to determine the best way to present current information,
and
suggest research that still needs to be done.
Where NZMS are NOT found
in the GYE
Mark F. Dybdahl
School of Biological Sciences
Washington State University, Pullman, WA 99164 (dybdahl@wsu.edu)
The ultimate impact and introduced range of exotic populations of
the New Zealand mud snails depend on its ability to tolerate abiotic
conditions. Most separate worldwide populations consist of a single
clonal lineage, and each is expected to have narrow abiotic tolerances.
Here, I present data from distributional and growth/reproduction
studies in the Greater Yellowstone Ecosystem that indicate conditions
that might limit the ultimate range of NZMS. A systematic survey
of 9 shoreline transects to 20 m depth in Hebgen Lake suggests that
the local NZMS clone does not occur there despite the influx of snails
from the Madison River. A survey of benthic habitats in Yellowstone
Lake near West Thumb thermal features also failed to detect NZMS.
Small streams in the Madison River watershed also consistently lack
NZMS (Canyon, Sentinel, Upper Polecat, West Fork of Iron Springs).
An invasion front in one stream (Iron Springs) appears stable, but
has advanced upstream in another (Little Firehole) since 1998. Growth,
reproduction and survival measured in cage enclosures occurs in all
of these small streams in both winter and summer, with one exception
(West Fork of Iron Springs). Variation in the rates of growth and
reproduction are related to temperature and weakly to several water
chemistry parameters. Unifying features of small streams that lack
snails include low temperatures and low alkalinity. Taken together,
these results suggest that some lakes and small streams may not support
the spread of the clone of NZMS inhabiting the GYE.
Experimental Studies of Competition,
Predation, and Habitat Use with Potamopyrgus antipodarum from
the Middle Snake River, Idaho
Steven Lysne
Department of Biology
Boise State University
It has been suggested the exotic New Zealand mudsnail (Potamopyrgus
antipodarum: Hydrobiidae, Gray) may compete with native species of
freshwater snails for food or space. As an ancillary project to my
Masters’ thesis research, I investigated selected interactions
between P. antipodarum and the abiotic and biotic environment in
laboratory experiments. P. antipodarum was tested for substrate use,
detachment tolerance, predation by crayfish, and competition between
it and the endangered Utah valvata snail (Valvata utahensis: Valvatidae,
Call). I found P. antipodarum utilized gravel substrates significantly
more than others tested in the study, displayed mean detachment velocities
of approximately 0.25 m s-1 , was preyed on by native crayfish of
the genus Pacifastacus, and potentially competes with the native
V. utahensis. Results suggest that although there may be some level
of competitive interaction between the mudsnail and native species,
mudsnails will likely not displace the endangered V. utahensis. P
antipodarum is preyed on by native crayfish so this may represent
one mechanism of mudsnail population regulation (i.e. top-down control)
and the mudsnail may utilize different habitats when they occur sympatricly
with V. utahensis in the Snake River. Experimental results should
be tested with filed investigations and in congruence with monitoring
programs to follow population trends of both V. utahensis and P.
antipodarum in the middle Snake River.
