Cal EPPC News
Protecting California’s Natural Areas
from Wildland Weeds
Vol. 10, No. 1/2, Summer 2002
Quarterly newsletter of the California Exotic Pest Plant Council
Spring wildflowers on the serpentine habitat of Coyote Ridge, south of San Jose. Tidy tips, goldfields and
Lomatium on the ridgetop provide a nectar source for the endangered Bay checkerspot butterfly (below).
The Santa Clara County WMA funds mapping and control of Yellow starthistle and Wild mustard on the
ridge. [Photos by Cait Hutnik, http://lightofmorn.com]
Inside:
Predicting Plant Invasion
with Modeling
Lassen County WMA
Wins Award
Legislative Updates
Weeds in the News
P r e s i d e n t ’ s
M e s s a g e
Joe DiTomaso, President, CalEPPC Board of Directors
California
Exotic Pest Plant
Council
1442-A Walnut Street, #462
Berkeley, CA 94709
(510) 525-1502
www.caleppc.org
A California 501(c)3 nonprofit organization
Our Mission
CalEPPC works to protect
California’s natural areas
from wildland weeds through
research, restoration, and education.
Executive Dir
ector
Director
Doug Johnson
dwjohnson@caleppc.org
B o a rrd
d of Dir
ectors
Directors
Joe DiTomaso (President)
UC Davis Weed Science Program
Steve Schoenig (Vice President)
California Dept. of Food & Agriculture
Mona Robison (Secretary)
UC Davis Weed Science Program
Becky Waegell (Treasurer)
The Nature Conservancy
Mike Kelly (Past President)
Friends of Penasquitos
Alison Stanton
BMP Ecosciences
Carl Bell
UC Cooperative Extension
Carla Bossard
St. Mary’s College
Matt Brooks
USGS Western Ecological Resource Center
Paul Caron
Caltrans
Tom Dudley
UC Berkeley Dept. of Integrative Biology
Dawn Lawson
US Navy Facilities
Peter Warner
California State Parks
Scott Steinmaus
Cal Poly San Luis Obispo
Bill Winans
San Diego County Watershed Management
CalEPPC News
Summer 2002 – Volume 10, Number 1/2
Editor: Doug Johnson, dwjohnson@caleppc.org
CalEPPC News is published quarterly by the California
Exotic Pest Plant Council. Articles may be reprinted
with permission from the editor. Submissions are
welcome. We reserve the right to edit all work.
2
CalEPPC News
Summer 2002
2002 has brought exciting CalEPPC news and activities. We continue to support the
Cape ivy biological control research program, which is progressing toward finding
potentially effective agents. Meanwhile, the International Broom Initiative is pursuing
biocontrol agents for French broom. The Landscaping Alternatives program has a
grant to support collaboration with nurseries to keep wildland invasives off the shelves.
Our list of rated invasive plants is being revised. And
last, but not least, CalEPPC has hired its first Executive
Director.
Planning for CalEPPC Symposium 2002 is well
underway. This year’s symposium will be held at the
Sacramento Inn on October 11-13. The theme of the
symposium is “Cost & Consequences of Invasive
Species.” Presentations will focus on risk assessments,
direct and indirect economic costs, and threats to
sensitive plant and animal species. This year’s “Working
Group” sessions will include invasive species that have
not traditionally been discussed. As usual, there will be
sessions for members to submit oral or poster presentations—these are designed to allow students and land
managers to discuss new research results or successful weed management programs. (To
submit an abstract see info on page 4.) More information about the program in the
next newsletter.
One of the most significant new developments for CalEPPC this year is the hiring
of Doug Johnson as our first Executive Director. Doug brings a wealth of skills and
experience, and will play an important role part in future accomplishments of the
organization. Along with taking over administrative tasks, he will be involved in
fundraising, publications and project coordination. We’ve already received the first
grant from his fundraising efforts, $8,000 from the Center for Invasive Plant Management for the revision of our invasive plant list.
Through the efforts of board member Alison Stanton, CalEPPC also received a
$15,000 grant this spring to produce a list of landscaping alternatives to invasive
ornamental species. Alison will lead this effort, which will provide a valuable resource
to nurseries, landscape professionals and homeowners. You will be hearing more about
this project at the 2002 Symposium.
A major goal for 2002 is the development of a “risk assessment protocol” for
evaluating and ranking invasive species in California. This will form the foundation for
revising the list of Invasive Non-Native Plants of Greatest Ecological Concern in California. When the committee developing the protocol (chaired by board member Peter
Warner) completes this task, it will spearhead a process for evaluating as many species
as possible in California in order to produce the new list. The protocol will provide
clear criteria for ranking species, making the resulting list more scientifically defensible.
The list is being used ever more often by resource planners, and its authority will be
strengthened by the development of a systematic protocol.
I look forward to serving as your president this year. I’m excited about the
direction CalEPPC is going. Here’s to a successful 2002!
Wildland Weed NewsNewsNewsNewsNews
“Let’s face it, you know all too
well when a plant’s too good to
be true. If it flowers fast and
makes tons of seeds… tolerates
drought, flood, sun and shade…
sends out runners the minute
you turn your back and shows
up all over the yard… Give It
Up.”
Ketzel Levine, “Talking Garden” host
National Public Radio
(Ailanthus altissima). Inclusion on the
Noxious Weed List would add regulatory
weight to the control of these weeds. You
can voice your support for the proposal by
placing a request to have a packet mailed
to you (they will be sent sometime this
summer), then commenting on the
proposal during the comment period. To
request a packet, email your mailing
address to noxtimes@cdfa.ca.gov.
The third National Invasive Weed
Awareness Week (NIWAW), held in
Washington, DC February 25 to March
1, brought a contingent of more than 80
individuals from across the nation to the
capitol to discuss weed issues with their
representatives. CalEPPC helped to fund
travel expenses for Bob Pickard of the
Regional Council of Rural Counties (and
chair of CalIWAC) to attend from
California.
Ketzel Levine, radio host on National
Public Radio’s gardening show, has been
publicizing the issue of invasive plants.
See “Oh No! Not My Wisteria!” at
The National Association of Exotic Pest
Plant Councils is formalizing a new
Memorandum of Understanding among
weed groups across the country. Their
most recent meeting drew representatives
from EPPCs in Florida, Tennessee, the
Mid-Atlantic region, Michigan, Kentucky,
and Maui, as well as California.
The Invasive Spartina Project has
completed mapping invasive and native
cordgrass populations in San Francisco
Bay. The GIS database will direct a
region-wide control project. New
infestations have been found in estuaries
around Point Reyes National Seashore.
Dr. Nelroy E. Jackson, one of the founding Directors of Cal-EPPC, has been
reappointed by Secretary of the Interior
Gale Norton to the Invasive Species
Advisory Committee for another term.
(ISAC advises the National Invasive
Species Council pursuant to Executive
Order No. 13112.) Nelroy will continue
to be an advocate on behalf of California
interests. The first meeting of the new
ISAC is scheduled for May in Washington, DC.
A group of weed mapping specialists
organized by the California Department
of Food & Agriculture is assembling a
Weed Mapping Handbook for local weed
management groups. The handbook will
set flexible standards to facilitate data
sharing. A draft is due out this summer.
For info, contact Steve Shoenig at
sschoenig@cdfa.ca.gov.
State agencies, nonprofit organizations
(including CalEPPC), and industry
representatives have joined together to
form CalIWAC, the California Invasive
Weed Awareness Coalition. This working
group will facilitate collaboration on
public education about invasives issues.
The group has designated July 14-20,
2002 as “California Invasive Weed
Awareness Week,” with tours planned for
elected officials and the public. Plans are
also underway for a statewide weed
summit to coordinate planning efforts.
For info contact Lynette Wilhelm at
lynettew@rcrcnet.org.
The Golden Gate Biosphere Reserve, a
project of the UN’s “People and the
Environment” program, has chosen
invasive species as their outreach theme
for the next year. For info, contact
Natasha Benjamin, nb_ggbr@pacbell.net.
Anderson, Robert L. USDA Forest Service. Image 0364060. www.invasive.org. April, 2002.
The California Department of Food &
Agriculture has issued a “Notice of
Proposed Rulemaking” which proposes
adding eight species to the state’s Noxious
Weed List. The species included are
Spanish broom (Spartium junceum),
Jubata grass (Cortaderia jubata), Giant
reed (Arundo donax), Saltcedar (Tamarix
chinesis, T. gallica, T. parviflora, and T.
ramosissima), Tocalote (Centaurea
melitensis), Cape ivy (Delairea odorata,
syn. Senecio mikanioides), Bull thistle
(Cirsium vulgare), and Tree of Heaven
Don’
Don’tt let this happen to you—
rrenew
enew your membership today!
If ther
e is a rred
ed dot on your addr
ess label, it means that your
there
address
membership is not curr
ent for 2002. Please use the form on
current
the back of this newsletter to rrenew
enew today!
CalEPPC News
Summer 2002
3
Greetings from Doug Johnson
In 1997 I was writing a local park stewardship guide, and somebody
told me, “You’ve got to check with Cal EPPC!” They were right. The
organization was a great source of information for that project, and
ever since then, I turn to Cal EPPC’s publications, symposia and
members whenever I need assistance with wildland weed issues.
My experience with wildland weeds comes from field work in
Mendocino and the San Francisco Bay Area. In the last two years I
have been particularly inspired by the Weed Management Areas I’ve
participated in. Where else can you sit around a table with such a
wide range of people and productively discuss a mutual environmencontinued next page
Cal EPPC
Announcements
Call for Nominations
CalEPPC
Board of Directors
The vision and strategy of Cal EPPC is
set by its 15-member Board of
Directors. Terms for half of the seats
on the board expire December 31,
2002. Elections for new board
members are held each fall, and
election results are declared at the
Symposium in October.
Nominations are now being accepted
for candidates for these seats on the
board. The board needs committed
individuals with:
• willingness and ability to work
collaboratively towards our goals
• knowledge of weed management
• understanding of nonprofit
management and fundraising
• familiarity with California agencies,
organizations and stakeholders
• vision for promoting public
awareness of invasive species issues
Nomination deadline: August 1
Please send nominations to
Executive Director Doug Johnson at
dwjohnson@caleppc.org
4
CalEPPC News
Summer 2002
Doug developing tool-less gorse removal techniques for State Parks.
Announcing:
CalEPPC
Symposium
2002
“Costs and
Consequences of
Invasive Plants”
October 11-13
Sacramento, California
Friday, October 11
Session 1: Laws & Regulations
Session 2: Risk Assessment
Session 3: Economic Impact
Working Groups I
Saturday, October 12
Session 4: Impacts on Native Species
Working Groups II
Session 5: Volunteer Programs
Sessions 6 & 7: Member Papers
Sunday, October 13:
Field Trips:
American River Parkway
Sacramento Wastewater Wetland
Hedgerow Farms
Cache Creek
REGISTRATION INFORMATION
COMING IN AUGUST ISSUE
Call for
Abstracts and Posters
We invite members of CalEPPC,
colleagues and students to submit
abstracts for oral or poster presentations at the CalEPPC Symposium
2002. Oral presentations are 12
minutes with 3 minutes for questions.
Students are especially encouraged to
present their research findings (student
presenters receive a 50% discount on
their registration fee). Topics may
include, but are not restricted to:
• biology and biogeography of
exotic plants
• ecological or economic impacts
• management of noxious weeds
• volunteer and education programs
• development of control methods
• restoration of weed-infested
landscapes
Authors have the option of submitting
a full-length paper at the time of the
meetings, to be published in the
Symposium 2002 Proceedings. The
abstract deadline is July 15, 2002.
Directions for abstract submission, and
information on this year’s meeting, are
provided at
We hope to see you there!
Tom Dudley, session organizer
phone: 510-527-7042 or 204-9138
e-mail: tdudley@socrates.berkeley.edu
P rredicting
edicting Plant Invasion with Modeling
By Scott Steinmaus
How do we know whether a non-native
plant is likely to invade a particular area?
Can we tell when an invasive has stopped
spreading—or where it will someday stop —
based on geographic factors? Such questions
intrigue researcher Scott Steinmaus of Cal
Poly San Luis Obispo. Here he describes
tools he is developing tools to find answers.
As a graduate student, I learned to
question assumptions. Michael Barbour
taught us to challenge the assumption
that we could ever really know the
“native” condition of California. Marcel
Rejmánek taught me to ask, “Is your
invasives problem truly growing over
time, or does it just look that way because
you are doing a better job of measuring
it?” These questions underlie my develop-
ment of models for evaluating the
potential for plant invasions.
P rrediction
ediction is key
Few would disagree with the philosophy that “prevention is the best cure.”
Predicting where a plant species might
become invasive is a key component of
prevention programs.
One technique for making predictions
uses empirical models that are based on
observations without necessarily understanding the mechanism. These predictions are usually accurate only under a
narrow range of conditions within which
the observations were made.
A more robust technique for making
predictions uses a mechanistic understanding of how and why invasion is
successful for a given species. Biological
characteristics alone are often not enough
to predict invasion in a particular location
because they do not consider the other
two components to a successful invasion:
site characteristics and the form of
disturbance. This is where models
become useful.
We look at three components of
invasion:
(1) species characteristics—biological
factors make a species invasive, consider
native weaknesses as well;
(2) site characteristics—ecotones,
complexity, isolation, and environmental
factors; and
(3) disturbance—any diversion from the
native condition that facilitates invasion.
continued next page
Doug Johnson…
continued from previous page
Y ellow starthistle distribution in the W
est
We
tal problem? Working on wildland weeds
presents a special opportunity to work
together with partners brought together
by concern for the health of the land.
With that kind of cooperation, we can
make things happen!
In my first two months on the job we’ve
sent out five grant proposals, and just
gotten word that the first was funded.
Next up is getting this newsletter back on
a dependable schedule. We apologize for
the inconsistency of publication—the last
year has been a challenging transition
time for the organization.
A geographer by training, I am especially
interested in the role of mapping and GIS
analysis in planning for wildland weed
control. Scott Steinmaus’ feature article
in this issue of Cal EPPC News illustrates
one way these tools can be put to work in
the service of useful models that aid our
ability to set control strategies.
Please feel free to contact me at
dwjohnson@caleppc.org.
County-wide data obtained in 2001 from a survey of western state weed
coordinators and compiled by Eric Lane, State Weed Coordinator for Colorado
and chairman of the Western Weed Coordinating Committee (WWCC). Data
has also been assembled at the quarter-quad level through a survey funded by the
Invasive Species Council These maps are intended for use in developing a
regional noxious weed management plan and coordinating regional efforts to
eradicate and contain yellow starthistle as well as leafy spurge. More info at
CalEPPC News
Summer 2002
5
Predicting invasions…
(4) hydrologic disturbance such as
irrigation and groundwater pumping.
continued from preivous page
Species characteristics
Biological characteristics of an exotic
species have been used to predict invasiveness. Two systems of criteria appear least
prone to error: Reichard’s risk assessment
system for woody plants in North
America, and the Australian weed risk
assessment system for all plants (White
and Schwartz 1998). The two systems
use essentially the same criteria:
(1) a history of invasive behavior elsewhere;
(2) closeness of biological relationship to
another species that is invasive;
(3) climatic/ecological similarityof
introduction area to original home range;
(4) aggressive traits such as allelopathic
chemical release or extremely competitive;
(5) biological attributes such as vegetative
reproduction, vine-like growth habit,
short juvenile period, habitat generalist,
easy germination/establishment patterns.
Site characteristics
Cronk and Fuller (1995) provide
general hypotheses that explain common
plant invasions. These may be used to
develop characteristics of sites that lend
themselves to invasion. Susceptibility can
be based on:
(1) an absence of predators;
(2) poorly adapted natives with low
reproductive vigor;
(3) low biodiversity on site; and
(4) empty ecological niches.
Disturbance
Some invasives are aggressive enough
to establish an infestation in an intact
native habitat. Most, however, are
opportunistic and favor the opening
afforded by some type of anthropogenic
disturbance. These can be:
(1) chemical changes such as fertilizer,
sewage, and nitrogen deposition;
(2) physical disturbance such as erosion,
bare ground, roads and construction;
(3) biological disturbance such as removal
of niche plants; and
6
CalEPPC News
Summer 2002
The modeler’s job
Explaining and predicting invasion is
a multidimensional process involving
many variables. In developing a model it
is important to identify, quantify, and
incorporate the most significant mechanistic variables. Including too many
variables can lead to unreliable predictions
because of problems associated with error
propagation and dependencies among the
variables. Thus, the modeler’s job is to
find the optimal set of variables that give
the most useful predictions.
Discriminant analysis is one statistical
method that we can use to classify a
species as invasive or noninvasive based
on its characteristics. For example,
working with Pinus species, Rejmánek
(1995) determined which biological
characteristics contributed most significantly to a discriminant function and thus
were the best
predictors for
invasive behavior in
pines:
invasive species, a climatic matching
model, and ordination methods to
incorporate environmental characteristics
of currently infested sites.
Our overall goal is to design a system
with sufficient flexibility that one can
assess the risk of invasion for any weed in
any location in California. To start,
though, we needed one good question to
test such a system. We decided to analyze
the likelihood that gorse (Ulex europaea
L.) would be an aggressive invader in San
Luis Obispo County. The county’s
WMA was trying to decide whether to
plan for an imminent invasion from
Monterey County to the north, and we
thought maybe we could help.
Climate modeling
Many factors can potentially explain a
successful plant invasion, but if the
climate at a given location is not conducive for growth then it is highly unlikely
that a successful invasion will ever occur.
(1) small mean seed
size with a short
chilling requirement;
(2) minium juvenile
period;
(3) short interval
between production
of large seed crops;
and
(4) maximum
opportunity
for dispersal by
vertebrates.
Similar lists of most
significant characteristics can be
developed for other
species.
Figure 1. Ecoclimatic Index for gorse suitability in California. Higher
values of EI indicate higher suitability. Dots represent sites tested in
the model (sites are determined by presence of a local weather station).
B u c k a rroo
oo Bonzai tackles gorse
My graduate students have taken to
calling our approach to model development the “Buckaroo Bonzai” method
because we incorporate combinations of
eclectic elements, depending on what is
most useful. We use biology of the
So climate is the primary characteristic we
use in assessing a site’s vulnerability to
invasion by a particular plant.
Our literature searches provided us
with the native and current invasive
distribution range for gorse. Gorse is
native to Europe, centering on Ireland,
and has been invasive in cool, moist areas
including tropical latitudes at high
elevations (New Zealand, southeast
Australia, Hawaii, Yucatan highlands, as
well as the Pacific coast of the US).
For the initial stage of our model
development, we focused on the distribution of the species in its native region.
We assume that the species has had every
opportunity to establish throughout the
entire native region, so sites where the
species does not grow provide as much
information as those sites where it does.
From distribution maps of gorse and close
relatives in its native Ireland, we deduced
gorse’s constraints and preferences for
temperature and moisture.
In order to assess the suitability of the
San Luis Obispo climate for gorse we
utilized CLIMEX, software that uses
weather station data (Sutherst et al 1999).
Only 14 of the CLIMEX database’s 2,400
weather stations worldwide were in
California, so we acquired additional data
from a NOAA database that has 321
stations in the state.
CLIMEX computes an Ecoclimatic
Index (EI) for the modeled species with
values between zero (no survival) and 100
(highly suitable climate). The EI is the
combination of a Growth Index (GI) and
a Stress Index (SI). The GI incorporates
climatic preferences for a species and
determines the abundance of a species for
a particular location. The SI incorporates
climatic constraints that describe the
conditions a species cannot tolerate and
determines a species’ distribution. The
predictive model includes parameters such
as the temperature above which development occurs for gorse (i.e. its “base
temperature”). Similarly, thresholds and
rates were estimated for moisture levels
based on gorse’s native distribution.
(Nonlinear responses to temperature and
moisture can be incorporated with
interactions amongst the variables. Values
for these parameters can be determined
experimentally in controlled atmosphere
chambers, extracted from the literature,
or inferred from native distribution.)
With climate and other factors all
figured together, our model gives a clear
prediction that gorse should have only
marginal success south of Monterey
County (Figure 1). With this evidence
we recommended that a relatively low
priority be given to gorse management in
San Luis Obispo except for cooler, wetter
microclimates in the coastal valleys. This
guidance will help the WMA plan its
approach to gorse.
typically grows. We did this by artificially
increasing moisture levels in the NOAA
and CLIMEX databases, which uses only
precipitation for moisture. Once we
parameterized a model that predicted
growth in the locations where it grows in
its native South African habitat we
applied the model to California.
With this model, we found suitable
Other envir
onmental variables
environmental
Canonical correspondence analysis
(CCA) is a dimensionreducing ordination method
used to determine the
environmental variables that
best explain a species’
distribution (Ter Braak
1987). This method is
insensitive to many of the
violations required by
general linear models (such
as ANOVA and multiple
regression), and is not
hampered by high correlations among species or
environmental variables. If
CCA finds that moisture
and temperature are the
most significant factors in
explaining species distribuFigure 2. Ecoclimatic Index for Cape ivy suitability.
tion, then CLIMEX may be
the only model you need for
predictions.
climates all along the California coast just
We gathered information for several
as Mona Robison has found with her field
gorse-infested sites along the coast, using
surveys and distribution mapping (Figure
GPS coordinates to take information such 2). We also predicted that a few cape ivy
as soil type, elevation and aspect from
populations could succeed in the Central
existing GIS layers. Running a CCA on
Valley. Infestions in these locations have
these sites, we deduced that gorse prefers,
just recently been found and reported on
in order of significance: highly disturbed
Mona’s distribution map. These findings
sites (burn or grazed); north facing slopes; speak well for the accuracy of our work.
moderate cover (using leaf area index in
Assessing biocontr
ols
m2 leaf/ m2 ground); moderate riparian
biocontro
charater; low pH soils; and high sand
We can also use CLIMEX to assess
content soils. The CCA tells us that gorse the suitability of an infested location for a
is associated with broom, and avoids pine
biocontrol agent. Insect biological control
species. (We did not include climate in
agents are at a higher trophic level (i.e.
this particular CCA because we were
primary consumer) than the pest (i.e.
attempting to decide which additional
primary producer). Therefore, they are
environmental variables to measure for an typically more sensitive to the climatic
extensive sampling session in the future.)
nuances of a new habitat than the plant
pest is. Predicting the suitability of a
Cape ivy pr
ediction
prediction
climate for a biocontrol agent could make
We also used CLIMEX to predict cape lab and field efforts to assess suitability
ivy invasivity throughout California. Our more efficient.
original model required that we account
continued on page 9
for the higher water availability that exists
in riparian environments where Cape ivy
CalEPPC News
Summer 2002
7
In Print
Readings & Resour
ces
Resources
WHA
T’S “WEED” IN SP
ANISH?
AT’S
SPA
Thomson’s English/Spanish Spanish/
English Illustrated Agricultural
Dictionary
by Robert P. Rice, Jr.
$27.95 Paperback 150pp
1993 Thomson Publications
(559) 266-2964 in Fresno
The book is set up in three distinct
sections. The first is an illustrated section
coupling drawings with the
corresponding phrase. It covers everything from domestic farm animals to
garden tools to plant anatomy (cambium,
meristem, vascular system, etc.). It also
discusses pesticides and spray equipment.
Section Two is an English-to-Spanish
dictionary of words and short phrases.
Nothing on language structure, syntax, or
any language lessons, just a dictionary.
Section Three is the opposite of section
two—Spanish to English.
I am a fairly fluent Spanish speaker
and have been working in agronomy for
most of my life. This book is invaluable if
you are going to be working with people
who are primarily Spanish speakers.
the problem of harmful invasive alien
species. She takes the reader on a worldwide tour of grasslands, gardens, waterways, and forests, describing the troubles
caused by exotic organisms that run amok
in new settings and examining how
commerce and travel on an increasingly
connected planet are exacerbating this
oldest of human-created problems. She
offers examples of potential solutions and
profiles dedicated individuals worldwide
who are working tirelessly to protect the
places and creatures they love.
While our attention is quick to focus
on purposeful attempts to disrupt our
lives and economies by releasing harmful
biological agents, we often ignore equally
serious but much more insidious threats,
those that we inadvertently cause by our
own seemingly harmless actions. A Plague
of Rats and Rubbervines takes a compelling
look at this underappreciated problem
and sets forth positive suggestions for
what we as consumers, gardeners,
travelers, nurserymen, fishermen, pet
owners, business people—indeed all of us
who by our very local choices drive global
commerce—can do to help.
– Island Press
THE BIG PICTURE
A Plague of Rats and Rubbervines: The
Growing Threat of Species Invasions
$25.00 Hardcover, 330pp
2002 Island Press: A Shearwater Book
THE BIGGEST WEED
from “America’s Largest Weed”
Ted Williams, Audubon, Jan 2002
From songbird-eating snakes in Guam to
cheatgrass in the Great Plains, “invasives”
are wreaking havoc around the world. In
A Plague of Rats and Rubbervines, widely
published science writer Yvonne Baskin
draws on extensive research to provide an
engaging and authoritative overview of
“I stuck my hand in euc leaf and bark
litter and couldn’t find the bottom; in
California it can be four feet thick
because the microbes and insects that eat
it are in Australia. Native plants that
manage to push through the litter often
8 CalEPPC News
Summer 2002
State
AB 1811 (Richman) Agriculture: Invasive
Species
This bill states findings and declarations
of the Legislature concerning the nature
of invasive species and the threat they
pose to California. It would require the
Department of Food and Agriculture to
keep all inspection stations open 24 hours
per day, and to develop rapid response
teams with the U.S. Department of Food
and Agriculture and the county agricultural commissioner to address arrivals of
invasive species in a timely manner. This
bill was heard in Assembly Agriculture in
late March, it was held over in order for
the author to explore potential amendments.
– Susan LaGrande
Federal
S 198 (Craig, ID and Daschle, SD) and
HR 1462 (Hefley, CO) The Harmful
Nonnative Weed Control Act
The federal invasive weed bills are still
alive, with various groups working to
increase sponsorship and support.
Unfortunately, the concern over antiterrorism and biosecurity issues has
pushed action on weed items lower down
the priority list. If passed, these bills
would provide additional federal funding
($100 million has been proposed)
through the states to local weed management programs.
– Nelroy Jackson
– Rick Austin, Santa Clara
Valley Water District
by Yvonne Baskin
Legislative Update…
get poisoned; as a natural defense against
competition, eucs exude their own
herbicide, creating what botanists call
“eucalyptus desolation”… Eucs give
nesting birds a false sense of security,
creating population sinks. For example,
the Point Reyes Bird Observatory has
found that in eucs, 50 percent of the
Anna’s hummingbird nests are shaken out
by the wind. In native vegetation the
figure is 10 percent.”
WMA Report
Lassen County
Wins Award
Lassen County’s Special Weed Action
Team (SWAT), a consortium of more
than two dozen agencies, organizations
and businesses, received a “Public-Private
Partnership Award” by the National Fish
& Wildlife Foundation. The award was
presented in Washington, D.C., as part of
National Invasive Weed Awareness Week
in February.
Congressman Joel Hefley of Colorado
presented the award to Carolyn Gibbs,
the Bureau of Land Management’s
representative on Lassen SWAT. “The
award recognized our group for having a
strong educational component, and
commended us for treating more than
10,000 weed-infested acres last year,” says
Gibbs. “We are trying to address the weed
problem on a landscape level, and for the
long term.”
SWAT’s largest undertaking is the
Susan River Tall Whitetop Project, which
involves private landowners, students and
organizations. The project aims to
control the 644,000-acre infestation of
How many partners does it take to control Lepidium latifolium?
The perennial pepperweed project sponsored by hunting group Pheasants Forever and local radio
station KSUE uses a volunteer and his tractor who work with a Lassen County Agriculture
employee driving a BLM truck equipped with a CDFA herbicide spray tank! Says SWAT
coordinator Carolyn Gibbs, “Coordination and cooperation work.”
Lepidium latifolium, also called perennial
pepperweed, along the Susan River.
Herbicide (TelarTM), goat grazing, and
revegetation are methods in use.
The group works with Lassen High
School, Lassen College, and local scout
troops to engage youth in weed projects
and to incorporate weed information into
the classroom. An annual community
weed pull is publicized with newspaper
articles and library displays. The Lassen
County Cattlemen cap off the event with
a barbecue and awards presentation.
to date they are based solely on annual
averages, and we all know there is no such
thing as an “average year” in California’s
climate. As we learn how to better apply
such sophisticated computer tools, we can
begin to develop a better sense for the
larger patterns of non-native species
invasions.
Rejmanek, M. 1995. What makes a species invasive?
In Plant Invasions—General Aspects and Special
Problems. P. Pyšek, K. Prach, M. Rejmánek, and M.
Wade (eds.). SPB Academic Publishing. Amsterdam,
The Netherlands. pp 3-13.
For more info, contact Carolyn Gibbs at
Carolyn_Gibbs@ca.blm.gov.
Predicting invasions…
continued from page 7
A tool in development
The models described here are
intended to aid human intuition, not to
replace it. They should be used as tools,
and considered as a project in process—
always open to improvement. A model is
only as good as its assumptions and input
data, and is only an approximation to
reality.
We are currently compiling a larger
weather database with data from vineyard
and farm weather stations, and incorporating other variables into CLIMEX and
CCA. We are also introducing stochastic
elements into these climatic models, since
References
Cronk, Q.C.B., and J.L. Fuller. 1995. Plant Invaders:
the Threat to Natural Ecosystems. Chapman and Hall.
NY.
Sutherst, R.W., G.F. Maywald, T. Yonow, and P.M.
Stevens. 1999. CLIMEX. Predicting the Effects of
Climate on Plants and Animals. Version 1.1 CSIRO
Publishing. Victoria, Australia.
Ter Braak, C.J.F. 1987. The analysis of vegetationenvironment relationships by canonical correspondence analysis. Advances in Vegetation Science 8:69-77.
White, P.S., and A.E. Schwarz. 1998. Where do we
go from here? The challenges of risk assessment for
invasive plants. Weed Technol. 12(4):744-751.
Dr. Scott Steinmaus is Assistant Professor of
Horticulture & Crop Sciences at Cal Poly
San Luis Obispo. He can be reached at
ssteinma@calpoly.edu.
CalEPPC News
Summer 2002
9
P rro
o g rress
ess with the Nurser
y Industr
y
Nursery
Industry
St. Louis collaborative
seeks to nip invasives in
the bud
This project provides a great example of
wildland protection interests working
together with the nursery industry to reduce
“escapes.” CalEPPC is currently undertaking a landscaping alternatives program with
the California nursery industry. California
Department of Food & Agriculture has also
proposed listing eight additional species on
their Noxious Weed List—see page 3.
A group of botanical garden representatives, nursery professionals, landscape
architects, garden clubbers and government experts recently gathered at the
Missouri Botanical Garden in St. Louis to
explore new ways of fighting unwanted
species.
As a follow-up to the December
conference, the group has released the St.
Louis Declaration on Invasive Plant
Species along with a set of guidelines for
all types of growers referred to as Draft
Voluntary Codes of Conduct.
To get the word out, the group has
created a website (at www.mobot.org/iss)
where gardeners, botanists, landscape
architects and nursery operators – anyone
who grows plants – can learn more about
how to stop the spread of invasives.
The Missouri Botanical Garden and
the Royal Botanic Garden at Kew,
England, convened the St. Louis workshop. Other participants include the
American Association of Botanical
Gardens and Arboreta, the American
Nursery and Landscape Association, the
American Society of Landscape Architects, The Nature Conservancy, the
Garden Club of America and others.
The workshop’s findings set forth a
list of principles—”The St. Louis Six”—
which seeks to provide professional and
amateur growers with a blueprint for
preventing the spread of harmful exotics.
These guidelines call for:
1. Plant introduction protocols that
reduce the chances of bringing in
nuisance plants;
2. Adherence to national goals and
standards while taking regional differences
into account;
3. Promoting prevention and early
detection as the most cost-effective
methods of fighting invasives;
4. Added emphasis on research, public
education and professional training;
5. Organizing a cooperative campaign
that includes leaders from horticulture,
the nursery industry, weed science,
ecology, conservation, botanical gardens,
garden clubs, the media, schools, landscape architecture, foundations and
government agencies; and
6. Formulation of an overall strategy
based on voluntary action, sound management practices and appropriate legislation.
Invasives have serious economic
implications, and there is growing
awareness of the problem among nursery
operators. Craig Regelbrugge of the
American Nursery Landscape Association
said his industry is committed to implementing voluntary guidelines and
educating nurseries and consumers.
The Florida Nurserymen and
Growers Association has already taken
steps to thwart the spread of exotics, said
FNGA representative Hugh Gramling.
Three years ago, the group asked Florida
producers to stop growing and distributing 13 plant species—today, that list has
grown to include 45 species considered
invasive in the state.
Quotable:
got a pest problem. But, it is more “When you throw extremists into the mix,
“thanWe’ve
that. It is an environmental problem and an ecothings get rocky…this will help explain why a heretofor littlenomic problem that, according to a 1999 Cornell
University Report, is costing Americans as much as $137
billion each year.
“Today, it is estimated that there are over 30,000 of
these exotic species in the U.S. They can be devastating to
the environment and they are major factors that lead to
the decline of many sensitive native species. This is a
serious problem, not only for Idaho, but for all of the
United States.
known city group that toils under the name of the Natural Areas
Program has a bulls-eye on its back…[The group] has veered off
into all sorts of misadventures… including, in some cases, the
destruction of groves of tress that it took to be interfering with
the precious native plants the program has vowed to protect…
the program’s most active staffers and volunteers are zealous
native plant enthusiasts who see eucalyptus, Monterey pines and
cypress trees as evil invaders that should be uprooted to make
way for sand dunes, grasslands and other habitats they prefer.
From Idaho Governor Dirk Kempthorne’s
remarks to the inaugural meeting of the Idaho Invasive
Species Council on March 5, 2002.
Columnist Ken Garcia in “S.F. residents battling plant lovers”
San Francisco Chronicle, April 23, 2002, page A13
”
1 0 CalEPPC News
Summer 2002
”
T h e
W I L D L A N D
“Restoring and Managing Central Valley
Native Grasslands”, joint meeting of the
California Native Grass Association and
the CALPAC section of the Society for
Range Mangement
June 6-8, 2002
Santa Nella, CA (Hwy 5 near Los Banos)
History and management of the Central
Valley grasslands. Speakers from BLM,
State Parks, USFWS, UC Berkeley, The
Nature Conservancy, Hedgerow Farms.
Invasive Plant School
June 18-19, 2002
San Diego, CA
Responsible use of herbicides for wildland
weed control. Includes weed biology and
ecology, herbicide basics such as labeling,
classification, application timing, mode of
action, degradation, and adjuvants, and
environmental compliance.
Email Carl Bell at
Invasive Species Symposium
June 18-19, 2002
Davis, CA
Marking the dedication of the University
of California Contained Research Facility,
which has been designed to provide a
secure environment for research on new
or re-emerging pest and disease organisms
affecting agriculture and our natural
evnironment.
“The Power of Nature”, the 29th Annual
Conference of the Natural Areas Association (NAA)
October 2-5, 2002
Asheville, NC
Focusing on conservation of biodiversity
in natural areas, adaptive ecosystem
management, and designing cohesive
nature reserve systems. One session deals
with setting priorities for management of
invasives.
W E E D
C A L E N D A R . . .
“Costs & Consequences of Invasive
Plants”, CalEPPC Symposium 2002
and wetland restoration, invasive species
management, and native grasslands.
October 11-13
Sacramento, CA
Invasive Plants in Natural and Managed
Systems
[see page 4 for details]
“Restoration with a View: Sustaining
Fragile Habitats”, the 9th Annual
Conference of the California Society for
Ecological Restoration (SERCal)
October 24-27, 2002
North Lake Tahoe, CA
Sessions on soil and water quality in the
Tahow basin, public use of restoration
areas, forest dynamics, montane riparian
November 2003
Early notice on a conference that will be a
joint effort of the Weed Science Society of
America, The Ecological Society of
America, EPPCs from around the country,
the Natural Areas Association, Society for
Range Management, and the Society for
Ecological Restoration. Nelroy Jackson
and Carla D’Antonio are Co-Chairs for
the conference.
Letters
Weeds—Cancers of the plant
world?
As a surgeon, I have spent much of
my career dealing with cancer. During
that career, I found that using the
behavior of weeds, especially crabgrass,
very useful in explaining how cancers act,
and in discussing the various available
treatments. (Cancer is the common Latin
name for crabs and the scientific name for
their genus.) Now that I have retired from
active practice, I find myself using the
reverse analogy: cancer is very effective in
discussing the destructive behavior of
invasive exotic plants and animals in
ecosystems.
Just as cancers drain a patients’
resources, the rapid growth of weeds
depletes soil of nutrients necessary for the
health of native plant communities. Both
can interfere with vital functions through
their sheer bulk. The early growth of
cancer is often slower, as is the initial
establishment of a weed infestation. If
conditions are suitable, then there is a
rapid growth phase, which may level off
towards maturity. But where limiting
factors are missing or weak, the invading
species or tumor overwhelms the host
location or individual, resulting in
degradation or death.
Control strategies for weeds and
cancer also have parallels. Maintaining
healthy, intact ecosystems, discouraging
the introduction of invasive exotics, and
pursuing early removal can all help
prevent major infestations. In much the
same way, maintaining good health,
avoiding known carcinogens such as
tobacco, and early detection and removal
of cancer can often result in recovery. In
cases of major infestations with invasive
plants, manual removal often needs to be
supplemented by chemical control, just as
in cancer where chemotherapy and
radiation are often needed.
The comparison of invasive plants
with cancers is not meant to trivialize the
impact of cancer, but to emphasize the
real threat these aliens pose to agricultural, horticultural, and native plant
communities.
Charles Blair, MD, FACS
Santa Barbara County
Views expressed are those of the authors, not
necessarily those of CalEPPC. Send letters
to CalEPPC News, 1442-A Walnut St.
#462, Berkeley CA 94709 or email to
dwjohnson@caleppc.org. Letters may be
edited for brevity.
CalEPPC News
Summer 2002
11
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