A First Look at Invasive Species

I was kind of surprised by the lectures proposed for one of our busy days during the course. Putting together invasive species and bat ecology seemed kind of odd to me at first. But then I was very surprised to discover the extent to which this day would, in fact, make a lot of sense.

In the morning, Brian Leung, professor at McGill University, discussed the importance of being able to make predictions on invasive species dispersal. An invasive species can be defined as a non-indigenous species of which the introduction causes or is likely to cause negative environmental impacts. Considering our limited time, information, and resources, we collectively need to target those species that we want to act on, even if we don’t always have all the data we would like to include in decision-making. He presented to us his work on invasive forest pests (Leung et al. 2014), as well as marine pests in the Great lakes (Leung et al. 2012). Brian also talked about the three phases of invasions – which consist of the arrival at a site, the establishment at that location, and the subsequent spread (Elton 2000) – and the evaluation of risk, which is defined by the probability of invasion and the severity of the impact. With regards to modelling, he didn’t hesitate to point out the fact that models are “wrong”, but that some are better than others, and that it is important to remember that they can still be helpful to engage stakeholders in environmental matters. During his lecture, I kept wondering what reception his research is getting from policy makers, and if some industries are trying to attract him to develop research. With international exchanges and trades, pests now know no frontiers or limits. To get an idea on their dispersal can help save a lot of money on their subsequent management.


Photo of Round Goby (Neogobius melanostomus) found on the Ontario’s invading species awareness program website

Then, at night, we went to STRI’s new building to meet the Bat lab team. Spending time with them was amazing. We discussed a variety of subjects (e.g. echolocation), witnessed the growing interest in their work of the local community, and discovered some of the species present in Panama. But it is truly the encounter of a young intern that struck me. We began to talk of her master’s project which concerned white nose syndrome (WNS) in bats. What she told me was astonishing. WNS is the fungus Geomyces destructans which spreads on bats and disrupts their hydration, and therefore their hibernation cycles (Blehert et al. 2009). It appears that bats in Europe can resist to the disease, whereas in North America, the populations are declining (Leopardi, Blake, et Puechmaille 2015; Wibbelt et al. 2010). She even told me that the communities of researchers and speleologists are trying to work together to limit the expansion of the disease and to try to protect the environment where bats hibernate.


Photo found on bat conservation international website

Species in Panama, or in tropical environments, are not targeted. Such bats normally have all the time they need to clean themselves and get rid of the fungus. Still, some researchers are concerned with climatic variation and the effects that this fungus could eventually have on bat populations living in changing and fragile environments. What I found so disturbing about our conversation is the fact that even as scientists that want to find new ways to protect the environment, we may also be one of the vectors of diseases and pest dispersal. It really does make me look at our dirty hiking boots in a new way. So, even if we see ourselves as actors involved in environmental protection, it is important to keep in mind our potential impact, and to advocate for everyone interested in conservation to care about those aspects. I already knew that we needed to be careful with what we may bring from an environment to the other, but this day and those talks were a nice reminder that we may have an unimagined impact. I will try to keep that understanding with me throughout my studies and expeditions from now on.


Blehert, D. S., A. C. Hicks, M. Behr, C. U. Meteyer, B. M. Berlowski-Zier, E. L. Buckles, J. T. H. Coleman, et al. 2009. « Bat White-Nose Syndrome: An Emerging Fungal Pathogen? » Science 323 (5911): 227‑227. doi:10.1126/science.1163874.

Elton, Charles S. 2000. The Ecology of Invasions by Animals and Plants, 2. University of Chicago Press. Chicago, USA.

Leopardi, Stefania, Damer Blake, et Sébastien J. Puechmaille. 2015. « White-Nose Syndrome Fungus Introduced from Europe to North America ». Current Biology 25 (6): R217‑19. doi:10.1016/j.cub.2015.01.047.

Leung, Brian, Nuria Roura-Pascual, Sven Bacher, Jaakko Heikkilä, Lluis Brotons, Mark A. Burgman, Katharina Dehnen-Schmutz, et al. 2012. « TEASIng Apart Alien Species Risk Assessments: A Framework for Best Practices ». Édité par Marcel Rejmanek. Ecology Letters 15 (12): 1475‑93. doi:10.1111/ele.12003.

Leung, Brian, Michael R Springborn, James A Turner, et Eckehard G Brockerhoff. 2014. « Pathway-Level Risk Analysis: The Net Present Value of an Invasive Species Policy in the US ». Frontiers in Ecology and the Environment 12 (5): 273‑79. doi:10.1890/130311.

Wibbelt, Gudrun, Andreas Kurth, David Hellmann, Manfred Weishaar, Alex Barlow, Michael Veith, Julia Prüger, et al. 2010. « White-Nose Syndrome Fungus ( Geomyces destructans ) in Bats, Europe ». Emerging Infectious Diseases 16 (8): 1237‑43. doi:10.3201/eid1608.100002.



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