BioSynC Hosts Global Climate Change Meeting
Kannan Mahadevan
From October 5-8th, BioSynC hosted a working group meeting whose ultimate goal was to develop objective criteria to assess species’ relative vulnerability to global climate change. The meeting featured 11 participants from the U.S. and Germany and drew together experts from fields that, according to meeting facilitator Dr. Joseph Bernardo, are normally “off in different departments”: ecophysiology, population genetics, quantitative genetics, and phylogenetics.
Traditionally, species’ endangerment has been assessed with reference to ecological factors—large-scale criteria such as population size or geographical range size. But considering that climate change has surpassed habitat loss as the leading threat to global biodiversity, the premise of the ecological model—that populations will recover if their habitat is protected—can no longer be taken for granted. In his proposal, Bernardo noted that species persistence in the face of climate change will follow from three aspects of biology: “tolerance of changing conditions…; migratory capacity to track optimal habitat patches as climate change ensues; and the evolvability of these two factors in response to changing conditions.” To measure these three aspects, Bernardo’s working group is choosing empirical physiological and genetic traits that can be applied to all species, mirroring the way IUCN ecological categories objectively determine species conservation status.
Take the example which Bernardo gave me: the common cuttlefish (Sepia officinalis). This species, according to ecological criteria such as population trends and range size, is not threatened. But according to its physiology, the cuttlefish does not have a very high tolerance for thermal extremes. And though the cuttlefish has high genetic diversity across its entire range, much of the diversity is restricted to local populations, which implies a low migratory capacity. All in all, these new data suggest higher susceptibility to the stress of climate change than do ecological criteria.
In this second in a series of three meetings, traits hashed out in the first meeting. were revisited and made operational by application to case studies. In order to make the new framework analyzable statistically, previously subjective categories such as ‘low, medium, or high’ dispersal potential were defined rigorously, quantified, and given scores. When asked about the importance of the working group setting, Bernardo was unequivocal: the work is greatly accelerated by this kind of synergy and focused effort, and by the opportunity for synthesis of different fields provided by BioSynC. The group hopes that the criteria they have developed would ultimately be used by conservation entities such as IUCN and Conservation International. In addition, their proposed contribution to the EOL covers a variety of content: detailed methods for how to convert empirical data into a parameter estimate, as well as worked case studies linked to their corresponding species pages.
What, then, are the implications of this new framework for conservation? To answer this, Bernardo made an intriguing analogy with genetic counseling. If I am told I have a high genetic propensity for diabetes, I will do all I can to minimize my environmental susceptibility—i.e. exercise frequently, adjust my diet, etc. Similarly, the finding that a species is genetically or physiologically vulnerable to climate change might inform strategies to manage it ecologically. The analogy makes it clear that these physiological and genetic criteria are not meant to replace traditional ecological ones; rather, they would complement each other to create a broader, more complete description of species vulnerability than currently exists.
