Workshop Organizing Committee:
Bruce Maxwell, Montana State University
Bill Dyer, Montana Sate University
Mike Gilpin, Montana, State University
Dan Goodman, Montana, State University
Dave Mortensen, Penn. State University
CIPM Workshop, July 9-12, 2003, Bozeman, MT
Sponsored by The Center for Invasive Plant Management and
the Department of Natural Resources and Environmental Science, Montana State
University
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Workshop Organizing Committee: Bruce Maxwell, Montana State University Bill Dyer, Montana Sate University Mike Gilpin, Montana, State University Dan Goodman, Montana, State University Dave Mortensen, Penn. State University
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Other Participants
| Steve Radosevich, Oregon State Univ. |
Sarah Ward, Colorado State University |
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Matt Lavin, Montana Sate University |
Steve Sutherland, USFS Fire Lab, Missoula |
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Lisa Rew, Montana State University |
Monica Pokorny, CIPM |
| Tad Weaver, Montana State Univ. |
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Problem: Public and private land managers are under directive to aggressively manage non-indigenous plant species (NIS). These land managers are generally under budget and time constraints that force them to prioritize management of NIS. It is plausible that even the species with the greatest reputation for invasion may not have populations that are equally invasive or have significant impacts in all environments where they have become established. It is also plausible that the management of NIS could be more risky with regard to ecosystem impact than the impacts of the NIS on the ecosystem. Thus, land managers need methods to quickly assess the relative potential for invasiveness and impact of the NIS as well as the impact of NIS management on ecosystems.
We are convening a small group of scientists representing conservation biologists and invasive species biologists to discuss the theoretical basis for detecting invasiveness and impact of non-indigenous plant populations. We want to draw on the expertise of conservation biologists who have a rich history of developing methods to estimate population dynamics of rare species. There are a number of excellent papers that describe the ecological principles associated with NIS invasion, but few refer to specific metrics that will allow differentiation of invasive from non-invasive populations or definition of “significant” impacts of a NIS or NIS management on an ecosystem. A range of detailed methods for monitoring plant populations for specific research objectives have been described, but few studies have offered an assessment of methods particularly as they may be influenced by the constraints of managers.
The goal of this workshop is to discuss a theoretical basis for quantifying population dynamics based on the disciplinary perspectives of Conservation Biology and Plant Invasion Biology. The workshop will use introductory presentations with structured or facilitated discussions. The discussion will be focused on identifying metrics of population dynamics and community function that can best be employed to quantify invasiveness and significant impacts to help land managers prioritize management of NIS populations in their management areas. We believe that the discipline of Conservation Biology has a useful history of identifying metrics of population viability and similarly the Invasion and Weed Biologists have a history in quantifying the impacts of weeds on crops and other managed plant communities. Thus, it is our hope that a synthesis of disciplinary principles and field experience will produce a widely acceptable approach for measuring invasiveness and impacts of NIS.
In order to have a well organized and productive workshop we (Bill Dyer and Bruce Maxwell) have gained a commitment of funding from the Center of Invasive Plant Management to have a meeting in July of 2003. Thus, the focus of the workshop will be on discussion with the desired outcome of consensus on a set of metrics or at a minimum a research agenda for identifying metrics that managers could use to determine when populations are invasive or having significant impacts. In addition, we intend for the outcome to be a multi-authored publication of our findings.
Byers, J.E. and L. Goldwasser. 2001. Exposing the mechanism and timing of impacts of nonindigenous species on native species. Ecology 82:1330-1343.
Levine, J.M. 2000. Species diversity and biological invasions: relating local process to community pattern. Science 288:852-854.
Lonsdale, E.M. 1999. Global patterns of plant invasions and
the concept of invisibility. Ecology 80:1522-1536.
Mack, R.N. 1996. Predicting the identity and fate of plant invaders:emergent and emerging approaches. Biological Conservation 78:107-121.
Morin, P.J. 1999. Descriptive models of competition. In, Community Ecology. Blackwell Pub. pp. 34-49. PDF
National Research Council, 2002. Predicting Invasion of Nonindigenous Plants and Plant Pests. National Academy Press. Available at: http://www.nap.edu/books/0309082641/html/
Neubert, M.G., H. Caswell. 2000. Demography and dispersal: calculation and sensitivity analysis of invasion speed for structured populations. Ecology 81:1613-1628.
Parker, I.M. D. Simberloff, W.M. Lonsdale, K. Goodell and M. Wonham. 1999. Impact: toward a framework for understanding the ecological effects of invaders. Biol. Invasions 1:3-19.
Rejmanek, M. 1996. A theory of seed plant invasiveness: the first sketch. Biol. Conservation 78: 171-181.
Sakai, A.K., F.W. Allendorf, J.S. Holt, D.M. Lodge, J. Molofsky, K.A. With, S. Baughman, R.J. Cabin, J.E. Cohen, N.C. Ellstrand, D.E. McCauley, P. O’Neil, I.M. Parker, J.N. Thompson and S.G. Weller. 2001. The population biology of invasive species. Annu. Rev. Ecol. Syst. 32:305-332.
Shea, K. and P. Chesson. 2002. Community ecology theory as a framework for biological invasions. Trends in Ecology & Evolution 17:170-176.
The Workshop funding is prepared to help with travel costs. Let us know what your flight cost will be with the Saturday night stay in Bozeman and we will be able to cover that cost as well as your room cost $55/night. We will also provide a BBQ on Thurs. night and lunch on the whitewater invasive plant survey on Saturday.
Lodging at City Center Motel in Bozeman (406) 587-3158
A block of rooms have been reserved. Make reservations under the name CIPM Workshop by June 27, 2003.
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Wednesday, July 9
Travel to Bozeman
Thursday, July 10
7:45 Van pick-up at motel
8:00 Coffee and begals
8:30 Introduction to Workshop, Bill and Bruce
9:00 Presentation: The state of knowledge on estimating population viability of threatened and endangered species. Mike Gilpin
9:45 Questions
10:00 Presentation: The state of knowledge on estimating population invasiveness. Bruce Maxwell
10:30 Questions
10:45 Break
11:00 Discussion
12:00 Lunch
1:00 What are the common measures of population growth and how are they measured? Appropriate sampling? List advantages and disadvantages.
2:00 What kind of data and how much data is required to be confident about population trends? What are possible misleading signals, i.e. response to disturbance?
3:00 Break
3:30 How useful are demographic models for gaining an understanding of population trends? How should variation in demographic processes such as fecundity be handled?
4:30 Adjourn
6:00 Evening BBQ
Friday, July 11
7:45 Van pick-up at motel
8:00 Coffee and begals
8:30 Presentation: The state of knowledge on plant genetic variation and population source, migration, age and growth behavior? Bill or Alison or Sara Ward
9:00 Questions and discussion
10:00 Break
10:15 Presentation: The state of knowledge on estimating impacts of weeds on ecosystems. Dave Mortensen
10:45 Questions
11:00 Discussion on best methods/metrics for estimating impacts of invasive plants on ecosystems. Advantages and Disadvantages
12:00 Lunch
1:30 Presentation: Can we get managers to collect meaningful data for estimating population trends? Can an adaptive management model be employed? Dan Goodman
2:30 Questions
2:45 Break
3:00 Discussion about what measures can you expect a land manager to make to determine invasiveness and/or impact.
4:30 Plan for summarizing information
5:00 Adjourn
From the notes of Bruce Maxwell and Monica Pokorny. To see notes of Monica Pkorny...
Janet Clark, CIPM Director, gave a short introduction about the CIPM and how this meeting supports the scientific underpinnings of what the Center offers. In addition, she indicated that this could become an annual or biennial event with different themes chosen for each meeting.
Bruce Maxwell gave an introduction to clarify the theme and standardize terminology: Slide presentation
Important Points that came up during discussion:
In response to Maxwell's apparent assumption that new potentially invasive plant species will continue to be introduced and will be detectably invasive when we begin to monitor them, raised some questions about the "lag phase" concept. That is, if one begins to monitor a population and it is in the lag phase, then one may not detect that it is invasive and choose to not manage under Maxwell's proposed sequence of inquiry prior to beginning management. It has been argued (especially by Simberloff) that catching NIS in the lag phase may be the best time to manage with a goal of eradication. Thus, the questions that we considered were: Is the lag phase real? What evidence is there and at what scale? What are the potential causes of the lag phase (e.g. pop. demographics, genetic bottleneck, need for sequential introductions, dispersal, etc)? Can we depend on low frequency of occurrence recently introduced species to be in a lag phase and if so, can we predict when populations will go exponential in growth? Should we just shoot to eradicate NIS before they have a chance to make it out of the lag phase? Is eradication possible?
No workshop participants strongly supported the idea that there is consistent enough evidence, particularly at the population or patch scale, to confidently predict that all newly introduced species will have a lag phase. I think that all would agree that the lag phase is plausible under several of the suggested mechanisms, but those mechanisms particularly the genetic ones, may not act at the scale (population or patch) that is the focus of this workshop.
Mike Gilpin provided an excellent and thought provoking overview of the development and use of population viability analysis in conservation of rare and endangered species. With a few scratchings on the blackboard Gilpin told his history with the punch line that estimating population invasiveness of species may be much more difficult than population viability of rare species. The spatial element is of far less importance with rare species than with NIS. Reliance on models to forecast the fate of species or their populations has many potential pitfalls. The success of using PVA models is highly dependent on the data used to parameterize the models. If trying to use data from managers or even work with managers to make management relevant decisions, a relationship must be forged between the managers, modelers and others that may interact with the decision generated from model results. Individual based models (IBM's) may be more useful than the demographic models used in PVA for developing an understanding of processes important to determining invasiveness of populations. An IBM approach may even be best for forecasting population dynamics, particularly to simultaneously capture the spatial and demographic elements of population dynamics.
Stay tuned for the sound track of Gilpin's talk.
Bruce Maxwell talked about the state of knowledge on estimating plant population invasiveness. Slide presentation
Discussion Topics:
What are the best statistics (measures of central tendency, variance, etc.) to use in estimating invasiveness of populations?
Methods of data collection:
Is there a way to get coarse scale estimates on invasive plant densities and spatial extent?
Differences in patch advancing front and satellite populations.
Presentation by Bill Dyer: The state of knowledge on plant population genetic characterization of invasiveness. Slide presentation
Presentation by Matt Lavin: Clarification of Naturalization Hypothesis and application of Unified Neutral Theory to invasiveness and interpreting impact of invasive plants.
Presentation by Sarah Ward: Reconstructing invasions with genetic characterization of populations.
Presentation by Dave Mortensen: The state of the knowledge on estimating impacts of NIS on ecosystems.
Presentation by Dan Goodman: A modeler's view of invasive species. see chapter in Morin's book.
Steve Sutherland put more thought into the outcomes of two species systems presented in Goodman's presentation and described by Morin. Contact him if you want to see his graphical presentation.
Possible Outcomes of This Meeting:
1. The idea of proposing a Gordon Conference on the same or similar subject matter was generally rejected even though we have an inside track with Big Sky becoming a GC site.
2. Continue to create similar atmosphere workshops with small group discussions to stimulate thought and interaction. Non-tangible outcomes that move science forward and force use to be more thoughtful about the use of our science is important and should continue to be emphasized. Meet again with core group and a few other selected invitees. Make topics more specific, but remained somewhat structured with just a few short presentations. Reading list was a great idea, just don't make it too long.
3. Apply for a grant with NRI to fund a larger workshop with 20-30 people. May lose the character of the workshop that we found to be so valuable.
4. Make the workshop and annual CIPM event, but allow proposals from other groups and States. Probably would need to be more outcome focused...i.e. collaborative grant proposals.
5. Consider publishing an article on our discussions in Frontiers in Ecology and the Environment Forum Section.