Photos

Native vs. introduced demographic comparisons

Main Goal: To test the assumption that invaders exhibit increased performance in their introduced relative to native ranges
Approach: Gather demographic data from the literature on performance in the native and introduced range of invaders, create a ratio statistic (PI/PN) and evaluate whether in general this ratio is >1, <1 or about 1 through meta-analysis.
Secondary Goals: To evaluate whether there are taxonomic or other variables that are associated with different response ratios. To evaluate whether different mechanisms thought to be associated with invasion (e.g. enemy release, hybridization) are linked to different response ratios. To collate data on congeners of the focal species not considered to be invasive for comparison with those that are invasive.

John Parker, Mark Torchin and Oliver Bossdorf told us about the work they have started on this. John and Mark have been finding data on the GISP list of the 100 worst invaders, while Oliver has focused on comparing data from two plant databases (Netherlands and U.S).

We discussed ways to expand upon this work and to help John, Mark, and Oliver out.  We need volunteers to:
- help Oliver extract data from additional databases
- help John and Mark with the 100 worst invaders

We discussed the latter in a bit more detail. John and Mark have evaluated different search strategies for demographic data for invaders, and now species from GISP’s 100 worst invaders need to be assigned to RCN members with at least some degree of taxonomic expertise to gather the data.

Potential participants that were listed at the meeting, separated along taxonomic lines include:
Plants:
Rieks van Klinken
Harald Auge
Montse Villa
Oliver Bossdorf
Sheryl Atkinson
John Parker
Peter Kotanen
Ruth Hufbauer
Dana Blumenthal
Charles Mitchell

Aquatic invertebrates:
Jeb Byers
Greg Ruiz
Mark Torchin
Whitman Miller
Vadim Panov

Insects:
Vojtěch Jarošík
Ruth Hufbauer
Wolfgang Nentwig
Howard Cornell

Vertebrates:
Wolfgang Nentwig
Margarita Lampo
Marty Lynn

If you want your name in one of those sections, and you either were not there or it somehow didn’t get listed, please let us know!

Other tasks:
• Mark, John, Ruth, and Rob will define the metrics used to asses performance and what covariates are needed, and come up with a workable spreadsheet for people to fill in.  Variables of interest and covariates discussed at the meeting include: size, fecundity, density, time since invasion, date data were collected, lat/long.
• Assign someone or some group to start looking into congeners of the 100 worst invaders that are not culturally considered ‘invasive’ but that have been introduced around the world.  This group of species would provide some phylogenetic perspective on potential differences in performance.

GIN-wide Sampling Effort

Main Goal: To test the assumption that introduced plants are larger and more abundant in their introduced ranges, using garlic mustard as an example species.
Approach: Similar to the above comparison but using a world-wide field survey to gather data on performance in the native and introduced range of garlic mustard, using the geographically widespread membership of GIN.

Oliver Bossdorf and Rob Colautti have put together a beautiful draft of a sampling design for this based on conversations in Prague. The goal is essentially the same as for the broader comparison of performance in the native and introduced range, but with a focus on a collecting field data for a single species. The flier they made has been sent out to several people for review, and will shortly be broadcast for wider input. We hope to get all willing GIN members involved, and perhaps school groups or other citizens groups as well. The people in Prague who spent the most time working on this also included Petr Pysek, Harald Auge, Peter Kotanen, and Ruth Hufbauer.

Joint Experimental Effort

Main Goal: Evaluate interactions between disturbance and competition in the success of invaders and restoration of native plant communities.
Approach: Set up geographically replicated experiments manipulating disturbance and seed additions, and then track community response (introduced focal species and natives) through time.

Urs Schaffner, Dana Blumenthal and others worked on developing this experimental approach to a broad geographic comparison. Urs has started a sabbatical down under hosted by Rieks van Klinken.  He will send more details on this shortly.

Evolutionary Dynamics Workshop

Carol Lee, Kristina Schierenbeck and Bob Holt are organizing a workshop to promote the integration of ecological and evolutionary perspectives and approaches into the study invasive species. Their aim is to create a venue in which discussion among the participants would lead to novel synthetic research and publications in a special issue of Evolutionary Applications .  For example, the integration of population genetics and population dynamics could yield insights into the lag period of invasions, evolutionary responses to novel environments, and range expansions, oscillations, and extinctions. Also, integrating empirical data on ecological factors, such as predation, parasitism or competition, with genetic factors, such as quantitative genetic variance or the genomic architecture of critical traits, could enhance our understanding of factors that limit invasions and improve the efficacy of predictive models. Invasive species provide an ideal testing ground for many basic evolutionary theories, and we hope that this workshop will help expand this potential.

They plan to hold the workshop at North Lake Tahoe, California, USA for three days in March 2009 (prime ski season, tentative dates March 19-22, 2009). The Reno-Tahoe International Airport provides ready access to Lake Tahoe, and from a number of major airports. Papers from this symposium will be submitted to the journal Evolutionary Applications (and peer-reviewed), with the workshop organizers acting as associate editors. Evolutionary Applications has expressed enthusiasm in publishing this special issue.

An open call to participate in this workshop was sent out in September, with reminders in October. The deadline for expressing interest in presenting by submitting a paragraph on the topic was November 1, 2008. People interested in taking part in the workshop without presenting are welcome to join.

Ecological Society of America Workshop

Rob Colautti has submitted a proposal to ESA to run a panel discussion aimed at evaluating whether introduced species represent a truly novel threat, or whether they have essentially the same impacts as ecologically similar natives. The invited panelists include Mark Caotte, Peter Kotanen, John Maron, Dave Richardson, and Dov Sax thus far. Rob is interested in including others with marine and/or animal expertise to balance out the group.