|
Organizing
Committee TOP
Barbara Baxter,
The Garden Club of America
Jennifer
Dowdell, American Society of Landscape Architects
Kayri Havens, Chicago Botanic Garden
John M. Randall, The Nature Conservancy & University of California,
Davis
Peter H. Raven, Missouri Botanical Garden
Craig Regelbrugge, American Nursery & Landscape Association
Sarah Reichard, University of Washington
(Chair) Peter S. White, North Carolina Botanical Garden
Editor: Kate Fay, Kate C Fay & Associates, Inc., Boulder,
Colorado
Sponsors,
Convenors, and Financial Supporters TOP
American
Nursery & Landscape Association
American
Society of Landscape Architects
Center
for Plant Conservation
The
Chicago Botanic Garden
Missouri
Botanical Garden
Foreword TOP
Plants are essential to our existence, yet thousands face extinction.
One of the largest threats to native plants and their communities
is invasive species; in fact their toll on the environment is
second only to habitat destruction. Most experts agree that the
keys to managing invasive species are prevention, early detection,
and control or eradication. In October 2002, the Chicago Botanic
Garden was honored to host the second in a series of workshops
addressing the first part of this management triad, the critical
issue of preventing invasive plant introductions.
The Chicago Botanic Garden and the Missouri Botanical Garden
convened this workshop which was entitled Linking Ecology and
Horticulture to Prevent Plant Invasions. Exciting progress was
made in several areas. A list of organizations which have endorsed
the voluntary Codes of Conduct developed at the first workshop
was produced. Two topics critical to the successful implementation
of the Codes were discussed in concurrent sessions. The first
focused on defining “regions of concern”. It is commonly
agreed that plants can be invasive in some regions and relatively
benign in others, and this needs to be considered when developing
invasive plant lists. The second session discussed non-invasive
alternative lists. When horticultural plants are recognized as
invasive, it can be very useful to offer producers and users alternative
plants that satisfy similar requirements in the landscape but
are not invasive. Finally, the workshop identified education as
one of the most important motivating factors for the public, businesses,
and institutions. The development of educational materials targeted
to different audiences, including the media, was set as a goal
for the future.
The Chicago Botanic Garden is committed to the conservation of
plants and plant communities. We are pleased to have assisted
the efforts of scientists and green industry professionals addressing
the crucial and timely issue of invasive plants and believe that
through this collaboration significant progress can be made in
preventing future plant invasions.
Barbara Whitney Carr
President and C.E.O., Chicago Botanic Garden
Executive
Summary TOP
A meeting was held in Chicago on October 31, 2002 to follow-up
on the first Linking Ecology and Horticulture to Prevent Plant
Invasions meeting (St Louis; December 2001) where codes of conduct
designed to minimize the horticultural spread of invasive plants
were first proposed. The second meeting provided an opportunity
to formally assess achievements in publicizing and promoting voluntary
adoption and implementation of the codes by various institutions
and businesses and to discuss some important next steps. It was
convened by the Chicago Botanic Garden and once again brought
together some of the most respected leaders from botanical gardens,
the nursery industry, landscape architecture, garden clubs and
conservation organizations (See Appendix A, List
of Participants).
The December 2001 meeting had already garnered significant interest
and tangible results . The purpose of the Chicago Meeting was
to build upon this success. In particular, participants at this
meeting: 1) Reviewed the status of endorsements of the Codes of
Conduct by institutions and other organizations; 2) Discussed
experiences implementing the Codes of Conduct; 3) Explored the
role “regionality” plays in addressing the invasive
plant species problem; and, 4) Developed rough guidelines for
selecting alternative plant species that could be used in place
of horticultural species recognized as invasive. Appendix B presents
the Codes of Conduct developed at the St. Louis meeting.
The key Findings and Recommendations evolving from the Chicago
Meeting are:
- The initiative taken by The Missouri Botanical Garden, The
Chicago Botanic Garden and all the participants of the two meetings
entitled “Linking Ecology and Horticulture to Prevent
Plant Invasions” is making a difference. The major national
societies and professional associations for botanic gardens
and arboreta, the nursery industry, garden clubs and landscape
architecture have endorsed the appropriate “Codes of Conduct”
and are now taking steps to encourage their members to adopt
and implement them. Three prominent botanical gardens (North
Carolina, Chicago, Missouri) have already implemented protocols
based on the codes and specifically designed to minimize the
spread of invasive plants through their own activities. Other
institutions, organizations and businesses will be encouraged
to implement the codes.
- Education is among the most important factors in motivating
people, businesses and institutions to address the invasive
species problem. High quality materials targeted to different
audiences by appropriate leaders are necessary. The media needs
be encouraged to play a more active role.
- Alternative and invasive plant species lists are useful and
worth developing provided: 1) all stakeholders participate in
their development; 2) there are clear and accepted criteria
for listing invasive plants and alternatives for them; 3) the
specific horticultural needs of different audiences are considered
and addressed; and, 4) regional considerations are given a priority.
There are already some good examples to build from.
- Scientific research and risk assessment (economic and environmental)
models need to be further developed to provide a stronger foundation
for identifying (and listing) plant species as invasive or as
non-invasive alternatives. Less anecdotal information should
be used in making these determinations.
- Lists of invasive species and of alternative should be developed
for states or regions (e.g. based on The Nature Conservancy’s
“ecoregions” or the USDA’s hardiness zones).
Some very useful examples of collaborative efforts to develop
such lists are underway in Florida and Massachusetts and these
may serve as models for similar efforts elsewhere.
- It may be appropriate to formalize the existence of this group
and acknowledge the need for continued communications and efforts
among the groups represented. Steps to formalize the group could
include giving it a name, defining a mandate and plan of action
for the next 1-5 years, and evaluating funding opportunities
to support future meetings.
Historical
Perspecitve: TOP
Progress Towards “Linking Ecology and Horticulture
to Prevent Plant Invasions”
The initial
meeting designed to address the global problem of invasive plants
was entitled: “The Workshop on Linking Ecology and Horticulture
to Prevent Plant Invasions” and hosted by the Missouri Botanical
Garden and the Royal Botanical Garden, Kew (England). Participants
from around the world met in St. Louis in December 2001 and collaborated
to create the Saint Louis Declaration, which consists of two major
components:
- Findings
and Principles that frame the invasive species problem and
present the underlying basis for successful efforts to address
it; and,
- A set of
five Voluntary Codes of Conduct for government agencies,
nursery professionals, the gardening public, landscape architects
and botanic gardens and arboreta. These codes were drafted by
representatives of each respective groups and were designed
to minimize the spread of invasive plants by these groups and
their activities.
These products
were an important first step in responding to the global invasive
plants species problem. The Findings and Principles were developed
by the entire group to provide a consensus statement on the severity
of the problem and outline a general approach to address it. The
Findings include: 1) recognition of key sources of the
problem; 2) its regional nature; 3) consensus that
invasive plants are a real threat to natural systems and biological
diversity; and, 4) that the problem’s magnitude is
large. The Principles inform responses by key stakeholders, including
landscape architects, botanic gardens and arboreta, garden clubs,
garden writers, regional planning groups and trade groups. Specifically,
the Principles:
·
Address how future plant introductions should be pursued;
·
Emphasize the importance of a national problem response framework
that leaves room for regional solutions;
·
Encourage the use of available assessment tools, resources and
voluntary codes of conduct;
·
Establish the importance of public education and professional
training;
·
Stress the fundamental value of broad-based collaboration.
Representatives
of each group at the St. Louis meeting created voluntary professional
Codes of Conduct designed to curb the use and distribution of
invasive plant species through self-governance and self-regulation
for nursery professionals, government agencies, the gardening
public (specifically Garden Clubs), landscape architects, and
botanic gardens and arboreta. Reprints of the Findings
and Principles can be reviewed and downloaded from www.mobot.org/invasives.
As mentioned, The Codes of Conduct are
presented in Appendix B.
By October
31, 2002, the Codes of Conduct were endorsed by the most prominent
national professional associations and societies for each of the
groups mentioned above. Many other conservation and horticultural
organizations also endorsed the codes. Appendix C contains lists
of all endorsement
and articles on this
topic to date. Updates are made to this list periodically and
placed on the website.
Using
the Codes of Conduct: TOP
Status of Endorsements, Code Development, Education and Outreach
Although developing the Findings and Principles and Codes
of Conduct are certainly major steps toward addressing the threats
posed by invasive plant species, endorsing, communicating and
applying them is just as important. A principal reason for holding
the meeting in Chicago was to discuss experiences of those who
have initiated efforts to adopt, explain and use the Codes of
Conduct. The following groups were represented at the Chicago
Meeting and offered summaries of their recent experiences :
·
The Nursery Industry
· The Gardening Public
· Landscape Architects
· Botanical Gardens/Arboreta
These groups
face varying challenges and opportunities as they explore how
best to build awareness and acceptance of the Codes of Conduct.
In all cases they have made a commitment to explore how best to
advance the Codes of Conduct equitably and effectively. This takes
time and patience. Following are summaries of what these groups
have experienced to date:
The Nursery
Industry
The Nursery Industry has been educating its constituency on the
Codes of Conduct so that endorsements and subsequent implementation
can occur. This industry’s emphasis during the past year
has been on the following Codes of Conduct:
Code 2:
Work with regional experts and stakeholders to determine which
species in your region are either currently invasive or will become
invasive. Identify plants that could be suitable alternatives
in your region.
Code 4:
Where agreement has been reached among nursery associations, government,
academia and ecology and conservation organizations, phase-out
existing stocks of those specific invasive species in regions
where they are considered to be a threat.
There is little
opposition within this industry to endorsing and using the Codes
of Conduct, as long as three key considerations are fully explored:
1) Regional groups must be allowed to develop their own
responses to regional invasive plant problems, including guidance
on or lists of invasive plant species, since plants may exhibit
invasive characteristics in one region and not in another; 2)
Efforts to place invasive plant species on official lists must
include research, where needed, to ensure “listed”
plants do, in fact, have invasive characteristics. Lists that
use anecdotal information to determine the “invasive”
potential of a species are not preferred by the nursery industry,
since this highly important approach could cause some plants to
be deemed “invasive” without sufficient basis; and,
3) Well understood criteria for listing a plant as “invasive”
must be developed prior to completing invasive plant species lists.
Industry representatives emphasized the distinction between processes
for identifying and ranking invasive plants, and processes for
selecting and applying non-regulatory or regulatory management
measures.
The Florida
Nurserymen and Growers Association is working particularly diligently
on this issue. Since last year, this organization has identified
a number of research goals they would like to pursue before implementing
the Codes of Conduct. Florida recently adopted and published its
research goals which are a major entrance to directing research
to meet the industry’s needs. The process involves identifying
needs and promoting those within the research community. They
currently are working with the University of Florida to “advertise”
these goals. There are several goals that deal specifically with
invasive plant issues. The industry will encourage research to
determine:
· How to manage the development
of species and cultivars that will not cause pest plant invasions.
·
How to develop science-based best management practices for landscape
maintenance and contractor
professionals.
·
How to develop and improve plant material to protect and fit Florida’s
changing environment, specifically.
·
How to develop genetically altered plant material that will prevent
invasion of economically important plants.
·
What plants will aid quality of life while minimizing impacts
on the environment.
Also, the
Massachusetts Nursery and Landscape Association is participating
in efforts with the state’s Department of Fisheries and
Wildlife to establish criteria for identifying invasive plant
species in Massachusetts.
In short,
the diverse nursery industry is working hard both at the national
level and in key regions to lay the foundation for their active
and effective role in a broad effort to reduce the harmful effects
of plant species with invasive characteristics. Their leadership
role in initiatives such as the establishment of a $5.5 million
nursery and floriculture research partnership with the USDA’s
Agricultural Research Service, and those mentioned above, are
essential collaborative steps.
The Gardening Public
The Garden Club of America (GCA) established its leadership position
in the fight against invasive plants when it became one of the
first national organizations to endorse the Codes of Conduct.
Since endorsing them, the GCA has been communicating with their
197 member clubs located across the Country, including Hawaii.
Each club is being strongly encouraged to endorse the Codes of
Conduct for the Gardening Public and then to implement them with
positive actions in the form of education and community outreach.
The Findings and Principles and Codes of Conduct have been carefully
explained along with other pertinent information in order to communicate
a strong message regarding the nature and severity of the invasive
plant problem. The GCA website (www.gcamerica.org)
will offer excellent tools for further education and club projects
such as informed speakers listed by region, recommended websites
and publications, characteristics to consider for plants to replace
invasive species and examples of organizations for collaborative
projects. The GCA publication will feature some of the most creative
projects developed by individual clubs.
Other groups
representing regional gardening public organizations have also
endorsed the Codes of Conduct. They include the Federated Garden
Clubs of Missouri and Connecticut; and have published their progress
in newsletters to their membership. During its next national board
meeting, the Federated Garden Clubs of America will consider adopting
ways to encourage other regional groups to take active steps toward
addressing the invasive species problem.
Landscape Architects
The American Society of Landscape Architects (ASLA) was also among
the first national organizations to endorse the Codes of Conduct.
It has placed a high priority on communicating efforts underway
to address the invasive plant species problem. The ASLA determined
that more education on the topic was needed since many landscape
architects lacked an in depth awareness of the nature of and solutions
to the invasive plant species problem. The ASLA has increased
efforts to bring about awareness through publishing a series of
articles in Landscape Architecture magazine, advocating for federal
legislation proposed to help curb the threats, and hosting a successful
education session at the ASLA annual meeting held last fall in
San Jose, CA. (The article detailing the Missouri Workshop is
Listed in Appendix C and included in materials posted on the invasive
plant species website (www.mobot.org/invasives).
Recognizing
education and leadership both play a key role in successfully
addressing the invasive plant species problem, the ASLA has asked
their policy committee to consider developing a policy that will
encourage landscape architects to consider the issue of invasive
species when designing and specifying plants in the landscape.
The ASLA’s code of ethics encourages its members to seriously
consider all policies it develops.
A landscape
architect based in Kentucky described ways that the Codes of Conduct
are being considered or implemented in specific regions.
Examples include:
·
Local planning commission regulations that actually disallow using
existing invasive species;
·
Incentives in the planning and zoning regulations to use alternative
species instead of those with invasive
characteristics;
·
Suggested continuing education credits for landscape architects
who attend seminars on invasive plants
and the problems they can cause;
·
Pursuit by public sector employees of contracts with local nurserymen
to produce and market local native
plants;
·
A joint outreach campaign by the Southeast Exotic Pest Plant Council
and a local arboretum which identifies
invasive plants and offers alternatives;
·
And, the formulation of possible research initiatives to further
develop scientific bases for identification
of a plant’s invasive potential in a given region (based
on the plant’s behavior, rather than
its origin).
In summary,
landscape architects and their regional and national representatives
are committed to advancing thoughtful and effective measures to
better understand and curb the threat of harmful invasive plant
species.
Botanical Gardens and Arboreta
The American Association of Botanic Gardens and Arboreta (AABGA)
endorsed the Codes of Conduct in early 2002 and several botanic
gardens have already taken steps to implement them. The North
Carolina Botanic Garden had anticipated development of codes,
and for several years has been implementing protocols designed
to minimize the institution’s use and distribution of invasive
species. Following the 2001 meeting two other prominent botanic
gardens, The Chicago Botanic Garden and The Missouri Botanical
Garden, followed suit, developing and implementing protocols based
on the Codes of Conduct. Summaries of what The Chicago Botanic
and Missouri Botanical Gardens have accomplished to date and what
they have learned so far from their accomplishments can be found
in the entire proceedings document.
Using Codes of Conduct: Further Considerations & Challenges
The Chicago
Meeting included two concurrent, facilitated break-out group sessions
on topics that had been identified as key to promoting implementation
of the Codes of Conduct and effectively addressing the invasive
plant species problem. They are:
1. “Non-Invasive
Alternative Plants”
2. “Regionality Considerations”
Appendix
A identifies what Break-out Group Session each participant
attended.
During the
day, other implementation considerations and challenges were also
raised, although they were not explored in as much depth. Future
meetings may explore them in greater detail. They included additional
work on “invasive species listing criteria”
(which is discussed to some degree in these proceedings) and “standards
for measuring the effectiveness of Codes of Conduct”.
BREAKOUT
GROUP 1: Non-Invasive Alternative Plants:
When horticultural plants are recognized as invasive one positive
way to address the situation is to offer producers and users alternative
(or “replacement”) plants that meet their requirements
but which are not invasive. One breakout group discussed how lists
of and information about non-invasive alternatives could most
profitably be constructed and distributed to appropriate audiences.
“Alternatives lists” are most effective when they
are tailored to individual audiences. Specifically, home gardeners
will benefit most from a list that meets their particular interests
and needs. This will also be the case for a variety of other audiences,
including landscape installation firms, municipalities, nurseries
and business park owners.
There are
a number of good reasons why “alternatives lists”
are appropriate and desirable. First, they offer positive solutions
to a problem, rather than simply urging that certain species should
be avoided and eliminated where already planted (i.e., telling
people NOT to plant certain species). Also, once it has been pointed
out that certain species are invasive or that they have negative
impacts on conservation, there is an obligation to offer people
alternatives that meet their needs but which are not invasive.
Finally, promoting the use alternatives in the first place prevents
or slows the spread of a problem in the long run.
This breakout
group drew a number of general conclusions about the importance
of developing “alternatives lists” and about how they
should be created:
1. Lists of
non-invasive alternatives are useful and worth developing.
2. Gardeners
have already begun asking for lists of non-invasive plants to
use – the demand is already there.
3. The proliferation
of invasive species lists is a problem because it can lead to
confusion about which species are troublesome or not.
4. Standard
criteria for building alternatives lists should be developed.
5. Lists of
alternative species must be regional. As a practical matter due
to the organization of trade groups and state regulations, “alternatives
lists” should be built for each state (or possibly for regions
within states or groups of states where states are smaller, such
as in the Northeast).
6. All stakeholders
(e.g. nursery industry, landscape architects and designers, conservation/biodiversity
groups) must be involved in developing the lists.
7. Lists should
be built to address different audiences, including: homeowners/gardeners,
retail nurseries/growers, landscape design and installation community,
government agencies (e.g., Departments of Transportation), and
researchers who could study and produce better behaved cultivars.
8. “Alternatives
lists” are NOT intended to be “white lists”
(i.e. lists of the only plants permitted). Beware of and prepare
for the potential that people will use these lists for purposes
other than those for which they were developed. The best way to
prevent misuse is to make the intended use of your list clear.
9. Multiple
alternative species for each species to be replaced should be
suggested.
The group also discussed plant characteristics that should be
considered in determining whether a plant is invasive and therefore
worthy of seeking alternatives for and what plant characteristics
should be considered when selecting suitable alternatives (replacements)
for an invasive plant.
This breakout
group concluded its discussion by identifying several guiding
principles for the further development of ways to use alternative
plant species in place of harmful invasive plant species.
Among the foremost principle is that a general set of criteria
for developing such lists should be created – this is of
great importance for ensuring the equitability and reliability
of alternatives lists. On the other hand the lists themselves
should be for single states, groups of small states or regions.
These lists must reflect behavior of the plants in that region.
ALL stakeholders should be involved from the outset in their creation
and should first agree upon criteria for listing plants (both
alternative and invasive species). Furthermore, the listing criteria
should identify which plant a particular alternative species is
replacing. If there are several alternative species available
to replace an invasive plant, then they should all be identified.
This entire effort should be aimed at an audience that includes
consumers, growers, landscape contractors, researchers (to help
them find “better behaved” cultivars) and government
agencies. Finally, tangible next steps need to be taken:
1. Fully define
and fund this project by gathering and officially constituting
a group of all interested parties to collaboratively develop an
overall project description and basis for it;
2. Use this
approach to create national guidelines that can be adopted and
tailored for use in particular states and regions;
3. Develop
case studies on how the process of selecting alternatives works
and the lists that result to help guide others who desire to take
similar steps in other states and regions.
BREAKOUT
GROUP 2: Regionality Considerations
It is commonly
agreed that the potential for a particular plant to behave “invasively”
depends on the region in which it exists. For instance, English
Ivy has high invasive potential in the Pacific Northwest and Middle
Atlantic States, but cold winters appear to limit invasions in
the Midwest and New England. This situation occurs with many plants
species. This means that any effort to address the invasive species
problem must include consideration of what is called “regionality”.
This breakout
group deliberated about several key areas that drive the “regionality”
factor:
1. How best to define a “Region”;
2. A process and appropriate participants for developing invasive
plant species lists that reflect regional considerations;
3. Criteria
for creating regional invasive species lists;
4. Other influencing factors; and,
5. Next steps for addressing “regionality” considerations.
The deliberation
results are presented below:
Defining
“Region”
· Use pre-existing approaches
for defining a region, such as The Nature Conservancy’s
“eco-regions” or
USDA’s hardiness zones;
·
Consider soil and temperature when defining the eco-regions;
·
Evaluate and possibly modify (as needed) the goals of previous
definitions of regions, as they may diverge
too much from those adopted for developing invasive species lists;
·
In some cases it may be appropriate to use distance from a central
point - such as a 100-mile radius
around a botanical garden or nursery- when defining a region.
Process
for Developing Invasive Plant Species List
· Establish a clear purpose
and scope for the list;
·
Identify and convene all key stakeholders in the region and consider
what their motivation and desired
outcome/use for the list will likely be. Key stakeholders should
include all those who could be
affected by the list ;
·
Create an on-going review process for the list to add or drop
species;
·
Develop clear and objective criteria for listing a species;
·
Provide for public review and comment on the list before it becomes
final.
Suggested
Listing Criteria
· Historical documentation
such as herbarium specimens, field note documentation (consider
asking participants
sign an affidavit that says that they were sure they saw the species
in a particular place);
·
Whether the species is actually reproducing out of cultivation,
or is just persistent;
·
The suspected impact of the species and basis for this reasoning
(acknowledging that detailed studies
may not be feasible if there is reason to suspect it does have
a strong negative effect);
·
How many individual plants and plant populations are in the region;
·
Availability and consideration of peer-reviewed papers or other
public data;
·
Plant dispersal ability;
·
Affected habitats of a particular invasive plant and their value;
·
General knowledge about our ability to control the plant;
·
Economic burdens are a separate issue - this is just concerning
possible ecological harm that would
land a species on a list of invasive species. Economic Impact
may be considered in the selection
of response measures.
Other Influencing
Factors (i.e. economic or political)
· The cost and viability
of control/quarantine;
·
The cost of not controlling/quarantining;
·
The ramifications of crossing political boundaries, assuming regional
boundaries are drawn using political
ones;
·
Who the stakeholders and other relevant issues associated with
a particular region.
Next Steps
For Regional Considerations
· Determine how to perform
and conduct simple economic risk/benefits analyses for a few representative
species;
·
Establish what research has been conducted to support whether
a plant should be listed as invasive;
·
Create and adapt a uniform criteria model adaptable to multiple
regions;
·
Actively encourage and facilitate communication among all stakeholders
(e.g. follow the Florida and Massachusetts
examples to develop listing criteria and report progress to others,
such as industry, Exotic
Pest Plant Councils, and state Heritage Programs;
·
Continue to facilitate communication about the Codes of Conduct,
particularly to garden writers and other
media by releasing timely press releases. Also, strategically
consider who should endorse the codes
and make such endorsement requests be adapted to regions.
These ideas
and suggestions regarding “regionality” should be
considered by anyone responding to the invasive plant species
problem, including those implementing the Codes of Conduct. Future
efforts to formulate “next steps”, as well as explore
other suggestions will be considered shortly by the Organizing
Committee of “Linking Ecology and Horticulture to Prevent
Plant Invasions”. In the meantime, these considerations
and challenges offer a useful perspective to anyone working to
address this important problem.
Future Directions TOP
A
number of ideas have emerged to ensure that the initiative taken
by The Missouri Botanical Garden, The Chicago Botanic Garden and
all the participants of the two workshops entitled “Linking
Ecology and Horticulture to Prevent Plant Invasions” remains
influential. These ideas reflect the general consensus that this
effort IS making a difference.
A first step
involved is to continue encouraging major national societies and
professional associations for botanic gardens and arboreta, the
nursery industry, garden clubs and landscape architecture, as
well as government agencies, to endorse and implement the “Codes
of Conduct. They should also take steps to encourage their members
to adopt and implement them. This can be accomplished by following,
evaluating, and then communicating, the progress underway by leading
institutions and businesses. As part of this, high quality materials
targeted to different audiences by appropriate leaders are necessary.
Also, the media needs be encouraged to play a more active role.
A second necessary
step is to convene a group of leaders representing all stakeholder
groups to develop alternative and invasive plant species lists,
building from current good examples of collaborative efforts.
These lists need to reflect clear and accepted criteria for listing
invasive plants and alternatives for them; the specific horticultural
needs of different audiences and appropriate regional approaches.
Lists need to be developed for states or regions.
A third step
is to enhance the tools required for accomplishing the second
step. Scientific research and risk assessment (economic and environmental)
models need to be further developed (also by a group of qualified
representatives of all stakeholder groups) to provide a stronger
foundation for identifying (and listing) plant species as invasive
or as non-invasive alternatives.
In the coming
weeks, the Organizing Committee (see cover for list of committee
members) will discuss the merits, emphasis and financial feasibility
of taking these future steps. They will be considering whether
to formalize the existence of this project and acknowledge the
need for continued communications and efforts among the groups
represented. Steps to formalize the group could include giving
it a name, defining a mandate and plan of action for the next
1-5 years and evaluating funding opportunities to support future
meetings.
Appendix
A. List of Participants TOP
Note: + Regionality
Considerations Break-Out
* Alternative Invasive Plants List Break-out
Ms. Betty Alloway+
Federated Garden Clubs of Missouri
10000 Wornall Road, Apt. 1412
Kansas City, Missouri 64114
Dr. Jim Ault*
Director, Ornamental Plant Research
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Ms. Barbara
Baldwin*
Vice-Chairman, Endangered and Invasive Species
Conservation Committee
The Garden Club of America
3481 S. Race St.
Englewood, CO 80110
Mr. Pierre Bennerup*
Sunny Border Nurseries, Inc.
3637 State Route 167
Jefferson, Ohio 44047
Dr. Richard
E. Bir*
North Carolina State University
MHCREC
2016 Fanning Bridge Rd
Fletcher, NC 28732-9216
Mr. Roy Diblik+
Northwind Perennial Farm
P.O. box 95
Springfield, WI 53176
Ms. Jennifer
Dowdell+
American Society of Landscape Architects
636 Eye Street, NW
Washington, D.C. 20001-3736
Ms. Kate Fay
Kate C Fay & Associates, Inc.
Facilitator
2336 Pearl Street, Suite 102
Boulder, CO 80302
Mr. Galen
Gates+
Director, Plant Collections
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Mr. Hugh Gramling+
Executive Director
Tampa Bay Wholesale Growers Association
1311 South Parsons Avenue
Seffner, Florida 33584
Dr. Derald
Harp+
Asst. Professor – Horticulture
Dept. of Agriculture
Southeast Missouri State Univ.
One University Plaza, MS6100
Cape Girardeau, MO 63701
Dr. Kayri
Havens+
Director, Conservation Science
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Mr. Richard
Hawke*
Manager, Plant Evaluation Program
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Mr. C. Dale
Hendricks*
President
North Creek Nurseries
388 North Creek Road
Landenberg, Pennsylvania 19350
Dr. Lara Jefferson+
Conservation Scientist
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Mr. Gary Knosher+
Midwest Groundcovers
P.O. Box 748
St. Charles, Il 60174
Dr. David
Lentz
Vice President Science
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Dr. Kimberlie
McCue+
Conservation Coordinator
Missouri Botanical Garden
P. O. Box 299
St. Louis, Missouri 63166-0299
Mr. R. Wayne
Mezitt+
President
Weston Nursery, Inc.
P. O. Box 186
Hopkinton, Massachusetts 01748
Ms. Mary Patterson*
Horticulture Committee
The Garden Club of America
291 Stanwich Rd.
Greenwich, CT 06830
alexmaryp@aol.com
Dr. John M.
Randall*
Director, The Nature Conservancy Invasive Species Program
Department of Vegetable Crops and Weed Science
University of California
124 Robbins Hall
Davis, California 95616
Mr. Craig
J. Regelbrugge+
Senior Director of Government Relations
American Nursery and Landscape Association
1250 I Street, Suite 500
Washington, D. C. 20005
Dr. Sarah
Reichard+
Research Assistant Professor
Conservation Biology
University of Washington
Center for Urban Horticulture
Box 354115
Seattle, Washington 98195-4115
Ms. Alison
Stanton*
Perennial Plant Association
Ms. Rena Sumner+
Massachusetts Nursery and Landscape Association
P.O. Box 387
Conway, MA 01341
Mr. John Swintowsky*
Landscape Architect
Jefferson County Parks and Recreation
P.O. Box 37280
Louisville, Kentucky 40233-7280
Dr. Pati Vitt+
Conservation Scientist – Demography
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, Illinois 60022
Dr. Peter
S. White+
Director
North Carolina Botanical Garden
The University of North Carolina at Chapel Hill
CB 3375, Totten Center
Chapel Hill, North Carolina 27599-3375
"The
Chicago Botanic Garden Invasive Plant Policy" TOP
Introduction:
Invasive plants and animals are threatening our nation’s
environment and economy. Invasive species pose an enormous threat
to our native plants, animals and ecosystems. In fact, their toll
on the environment is second only to habitat destruction. Nearly
half of the species listed as threatened or endangered under the
Endangered Species Act are at risk due to competition with or
predation by non-native species. Invasive species can also alter
communities by changing the hydrology or soil chemistry. Invasive
species are costing the United States nearly $125 billion per
year (www.invasivespecies.gov).
Some of the worst weeds in natural areas in Illinois include purple
loosestrife (Lythrum salicaria), Japanese and bush honeysuckles
(Lonicera japonica, L. maackii, L. tatarica, L. morrowii), garlic
mustard (Alliaria petiolata) and buckthorns (Rhamnus cathartica
and R. frangula).
Although invasive
plants are almost always not native to a region, it is important
to note that most non-native species are not invasive. In addition,
some native species can become invasive. For the purposes of this
document, the following definitions will be used:
· Native (indigenous)
– a species that was present in North America prior to European
settlement or has arrived
since through natural means of dispersal.
· Non-native (exotic,
alien, introduced) – a species that was brought to North
America by humans, either
deliberately or accidentally.
· Naturalized –
a non-native species, or native species from another region of
the country, that has become
established in disturbed areas and/or native communities.
· Weedy – a
species that readily spreads, especially in disturbed areas, but
generally does not pose a
threat to the integrity of native plant communities.
· Invasive –
a species, usually non-native, that is able to establish itself
within existing native plant communities
and is posing a threat to the integrity of the community.
When plants
are introduced to a new location, either intentionally or accidentally,
they can spreadprolifically, out-compete native species for resources,
and eventually even dominate the landscape. Biologists are studying
the mechanisms underlying a taxon’s ability to become invasive,
but for now it is still difficult to predict whether or not a
species will become invasive in a new habitat. Some factors common
to many invasive plants include:
· Escape from natural enemies
· Rapid growth and early
maturity
· Production of many seeds
· Ability to reproduce vegetatively
· Seeds that are dispersed
widely (such as by birds or wind) and seeds that germinate quickly
(do not have long dormancies)
· Apomictic seed production
(production of seed asexually)
People have
introduced the vast majority of invasive species, either accidentally
or deliberately. For example, kudzu was introduced to control
soil erosion. Many non-native species came to the United States
with the colonists who wanted familiar food and garden plants.
Some invasive species were, or still are, popular ornamental plants
used in landscaping. The rapid expansion of global trade and human
mobility has led to many species arriving accidentally. Seeds
can hitch rides to new locations in cargo or even stuck to the
bottom of hiking boots.
The federal
government has responded to the invasive species crisis in several
ways. President Clinton issued an Executive Order (13112) on invasive
species in February 1999. The order established the National Invasive
Species Council to provide national leadership on invasive species;
see that Federal efforts are coordinated and effective; promote
action at local, state, tribal and ecosystem levels; identify
recommendations for international cooperation; facilitate a coordinated
network to document and monitor invasive species; develop a Web-based
information network; provide guidance on invasive species for
Federal agencies to use in implementing the National Environmental
Policy Act; and prepare a management plan. The plan, “Meeting
the Invasive Species Challenge Management Plan” was completed
by the Council and signed by President Clinton on January 18,
2001. Of relevance to botanic gardens, the plan calls for the
development of a screening and evaluation process by 2006 for
the introduction of non-native plants to the United States. The
USDA and Department of the Interior will have oversight for plant
importation processes.
Chicago
Botanic Garden – History:
The Chicago Botanic Garden is well known for its diverse and beautiful
horticultural displays. One of its goals has been to develop the
most diverse horticultural plant collection in the Midwest. To
build its collection, the Garden has been an active participant
in exploration trips to countries in Asia and Europe, as well
as other parts of the United States, to bring back new plants
with horticultural merit. The Ornamental Plant Development department
has programs in plant breeding, plant evaluation, and plant introduction
with goals of developing, selecting, recommending, and introducing
the best horticultural plants for the Chicago region to the nursery
industry.
In recent years the Garden has become more concerned about invasive
plants. Nearly one-third of the Chicago Botanic Garden’s
385 acres is devoted to Native Habitat areas. There, Garden staff
are actively implementing and conducting research on management
protocols that remove invasive plants and help prevent their recolonization.
The Chicago Botanic Garden is now evaluating many of the plants
collected abroad through the Plant Exploration program before
they enter the collection. Species that show signs of weediness
in the evaluation period (four years for herbaceous plants, seven
to ten years for woody plants) are destroyed. The Garden’s
Collection Policy states that any plant “which has the potential
to threaten the genetic diversity of local native populations,
has overly aggressive behavior (weedy), or the ability to introduce
pests or diseases will be screened and evaluated before being
accepted into the Collection.”
Today, with an increased awareness about the environmental and
economic threats posed by invasive species, the Chicago Botanic
Garden is expanding and strengthening its invasive plant policy.
The Garden aims to strengthen its role as a conservation leader
without compromising its horticultural mission or the beauty of
its landscapes.
Chicago Botanic Garden Invasive Plant Policy
1. Species
known to be invasive in the Chicago region* will not be added
to the collection. When species are determined to present a risk
of becoming invasive, they will be removed from the collection
and destroyed. Whenever possible, interpretation about invasive
species removal will be provided. The Garden will also develop,
utilize, and promote a list of acceptable noninvasive plants with
similar landscape utilizations as the plants being removed as
part of its interpretive efforts.
2. Attached
(Appendix 1) is a current list of known invasive species. All
species on the list have been assigned one of four courses of
action: (1) Remove – for known invasive species/cultivars
- remove as soon as possible, including all cultivars, and/or
do not add to collection in future; (2) Phase out – for
species that pose a lesser invasive risk, form significant structural
features in landscape, and will be costly and time-consuming to
replace - phase out over a five to ten-year period; (3) Evaluate
– for taxa where invasiveness is suspected but the risk
posed by each cultivar is not known – evaluate wild type
species and all cultivars, then remove invasive taxa, or (4) Watch
List – taxa that are potential or suspected invasive species.
The Watch List includes taxa that are weedy in the Chicago region
but not yet invasive, as well as taxa that are invasive in similar
climates but have not become problematic in this area. If taxa
on the Watch List are found in the collection, they will be monitored
for invasiveness. Addition of Watch List taxa to the collection
should be avoided, especially when suitable landscape/display
alternatives are available.
3. Interpretation
about many of the species under evaluation will be provided. The
list will be reviewed annually by the Garden’s Invasive
Species Working Group and will be revised as needed. Invasive
species removal in Garden areas will be the responsibility of
the Horticulture Department in consultation with the Collections
Department. A reasonable timeframe will be established for the
removal of plants that are key components of designed displays
such that those landscapes are not unduly impacted.
* Chicago
region as defined by Swink and Wilhelm (1994) in Plants of the
Chicago Region, the following 22 counties: Walworth, Racine, and
Kenosha counties in Wisconsin; Boone, McHenry, Lake, DeKalb, Kane,
DuPage, Cook, Kendall, Will Grundy and Kankakee counties in Illinois;
Lake, Newton, Porter, Jasper, LaPorte, Starke, and St. Joseph
counties in Indiana; and Berrien County, Michigan.
4. The Chicago Botanic Garden will follow all laws on importation
and quarantine of plant materials across political boundaries.
The Garden will perform risk assessment for all plants introduced
to the Garden via the Plant Exploration program, to help ensure
that new harmful species do not escape cultivation (as outlined
in Appendix 2). Species new to the United States, whether herbaceous
or woody, will also be evaluated for at least four years after
reaching reproductive maturity. The evaluation will follow the
protocols developed by the Plant Evaluation Program and must be
completed prior to the species’ inclusion in the permanent
collections.
5. The Chicago
Botanic Garden will not distribute plants, seeds, or cuttings
or other propagules of any germplasm within its collections (research
or permanent) that is on the Invasive Species List (R or P) or
under evaluation for invasiveness (E on list or taxa from plant
collection trips). Plants that are, or would likely become, invasive
in the Chicago region, or the upper Midwest, will not be distributed
via the Garden plant sales or the Chicagoland Grows plant introduction
program. The Garden will no longer continue the Index Seminum
(seed exchange) program, but will consider individual requests
for propagules on a case-by-case basis.
6. The Garden
will work to control invasive species in the Native Habitat Areas
and lakes and on Garden grounds generally. Staff training in recognition
and removal techniques of invasive species will be implemented.
The Garden will disseminate information about invasive species
control based on our experiences.
7. The Conservation
Science Department will conduct research on the biology of invasiveness
and assist with the design and implementation of evaluation studies
on the invasive potential of untested plant species.
8. The Ornamental
Plant Development Department will evaluate the invasive potential
of untested plants, and when appropriate, strive to develop noninvasive
forms of known-to-be invasive landscape plants.
9. The Chicago
Botanic Garden will educate the public and the nursery industry
about preventing the introduction and spread of invasive species.
Instructors for the School of the Chicago Botanic Garden will
be provided with a list of regionally-invasive species and will
be asked to provide information about invasiveness to course takers,
and to not recommend plants that the Garden is removing or has
removed from the collections based on the issue of invasiveness.
10. The Garden
will assess the threat that popular or common horticultural plants
may present to related native plants in the wild (conspecifics
and congeners). The possibility of hybridization threatening wild
plant populations and their genetic integrity will be assessed.
If a significant risk is present, alternatives to those horticultural
plants will be sought.
* Many of
the policy statements are adapted from S. Reichard and P. White,
2000. Guidelines for Botanic Gardens with a Conservation Ethic.
World Botanic Gardens Conservation Congress.
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