Compton, Rebecca , Pringle, Anne .
Contrasting correlations between species and genetic diversity in pollution-sensitive and pollution-tolerant species of lichen across an urban to rural gradient.
The forces that shape species diversity may simultaneously influence genetic diversity within species. A vast literature on lichens, pollution and climate change makes clear that many lichen species are either disappearing or shifting ranges in response to anthropogenic stresses. In this study, three cemeteries positioned along an urban to rural gradient in eastern Massachusetts were used to explore both the species and the genetic diversity of lichens in response to air pollution. Although the literature suggests species and genetic diversity will covary in predictable patterns, few studies have explored whether environmental stresses that cause the loss of species diversity will negatively impact the genetic diversity of remaining species. As expected, we documented a trend towards greater species diversity away from the urban center of Boston. Genetic diversity was measured using sequence data from the internal transcribed spacer (ITS) region in both a pollution-sensitive species of lichen, Xanthoparmelia plittii, and a pollution-tolerant species, Physcia subtilis. Results suggest that only a single unique genotype of X. plittii has managed to survive in the urban habitat. In this case, species and genetic diversity are positively correlated. In contrast, species and genetic diversity are negatively correlated within the pollution-tolerant P. subtilis: the greatest species diversity was found at the rural extreme of the gradient, but the greatest genetic diversity was found at the urban extreme of the gradient.
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1 - Harvard, Organismic and Evolutionary Biology, BioLabs 3103, 16 Divinity Ave, Cambridge, MA, 02138, USA
2 - Harvard University, Department of Organismic and Evolutionary Biology, 16 Divinity Ave, Cambridge, MA, 02138, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood D/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 11:30 AM