Below is an excerpt from an email exchange with a weed manager who asked a very pertinent question: As a non-scientist trying to control garlic mustard, what incentive is there to participate in this study, other than making a contribution to basic science?

Our overall question is whether the abundance of garlic mustard is generally different in the introduced range than in the native range. Our project has three main goals, which are still subject to funding review. First, we hope to build a more interactive website to allow management 'teams' (including conservation or weed control groups like yours) to monitor the effectiveness of the control over multiple years. This is important because annual variation in climate (e.g. spring thaw, average spring temperature, etc.) may create annual variability in abundance, even to the point where abundance could increase for a year or two, as well as variability in the regrowth of native species. The real question is whether there is an overall declining trend. Second, we plan to combine data from all the different regional control efforts to evaluate the effectiveness of pulls vs. herbicide, and whether the effectiveness differs by geographic region and level of infestation. Third, we are planning a direct experimental test that involves different levels of manual removal (control, 75%, 95%) and tree sapling addition (control vs. saplings added). So we will get a sense of the effectiveness of control per unit effort, as well as testing a potentially new strategy of sapling addition. Once these projects are complete we will post the results and recommendations on our website.

However, I would also argue more generally that there is a false dichotomy between management and science because ecological questions are quite relevant to management. Understanding the ecology of a species can lead to much more effective management decisions, but it also takes a lot more time and effort to get there. For example, the introduction of biocontrol agents has received a lot of attention, but its effectiveness remains highly variable and unpredictable. It is predicated on the 'enemy release hypothesis', which suggests that invaders 'escape' from natural enemies in the native range and this gives them an advantage over natives. I'm sure you know that biocontrol can be effective but is very risky business since it essentially introduces one nonindigenous species to deal with another, sometimes with really dire consequences (e.g. mosquito fish, or cane toads). As it happens, there is currently a plan in motion to license the import and release of a biocontrol beetle for garlic mustard, so it is quite relevant to our study. Biocontrol today is a lot more cautious than it has been historically, but there will always be a great deal of uncertainty when dealing with entire ecosystems. If garlic mustard is doing the same thing in Europe and North America, it would suggest that garlic mustard is not heavily controlled by biocontrol agents and this would not be an effective strategy, and so the risk of introducing a new beetle would probably not be warranted. Similar arguments could be made for above-ground and below-ground processes (e.g. the effect of soil microbes or allelopathic chemicals).

On the other hand, if there IS a quantifiable increase in the growth and density of garlic mustard in North America, it suggests that there is something fundamentally different from the native range. The next step would be to identify what that is: perhaps herbivores, perhaps allelopathic chemicals, perhaps genetics/evolution, perhaps something else. Having this data will not only tell us if there is a difference, but will show us which populations to focus future studies on. After all, the abundance will not be uniform across the entire native range.

We might also be able to figure out whether age structure differs between ranges. Do the North American ones produce more seeds, or do seedlings have better survival, or do adults have better survival? These could inform better management decisions, such as: should we risk biological control, what time of year should we focus our control efforts, should we focus on adult plants or should we remove juveniles too, would activated carbon be a useful tool (i.e. alleleopathy)?

The truth is that these are just a few ideas, and new ideas could emerge from the data. The reason I enjoy science so much is that I am often surprised about the way things turn out, and new discoveries can lead to unforeseen management options. I hope this addresses your question, and I hope you will consider participating in our study.