Phylogeny and Speciation in Sphagnum Section Subsecunda

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This project applies a variety of laboratory and field techniques to understanding ecological and genetic processes in peatmosses (Sphagnum). The project has three major components. The first part involves a global analysis of peatmoss diversity in order to determine if genetic relationships reflect geographic proximity or structural similarity among plants. The second part of the research investigates ecological, genetic, and morphological variation in a group of closely related species that are widespread in North America, Europe, and Asia. Analyses of DNA sequences to understand genealogical relationships will be complemented with studies of chromosome number, investigations of ecological differences among species, and experimental work designed to clarify the genetic basis of morphological variation. The last part of the project focuses on the genetic processes occurring within populations that give rise to the broader biodiversity patterns documented in the first two parts of the work. DNA fingerprinting methods will be used to determine reproductive patterns in natural populations and the extent to which co-occurring species hybridize. The research has implications beyond this group of plants per se. Sphagnum frequently dominates habitats in which it occurs, forming deep peat deposits in boreal regions of the Northern Hemisphere. Sphagnum-dominated peatlands constitute an important reservoir for global carbon, are critical to the movement of methane (CH4) and other atmospheric gases including CO, N2O, NH3, H2S, COS, and DMS, and play a prominent role in determining patterns of regional hydrology, permafrost, and biodiversity. It has been stated that more biomass is bound up in the genus Sphagnum than in any other living genus of plants. Boreal peatlands provide habitat for diverse organisms including many unique plants, protists, animals, and fungi. In terms of its ecological dominance, the genus Sphagnum is without parallel among plants. This project addresses fundamental issues related to the generation and maintenance of biodiversity. In particular, the research will clarify species delimitation in this critically important group, evaluate the extent to which species are ecologically equivalent and hence mutually replaceable, and clarify the importance of local scale genetic processes such as hybridization in generating biodiversity. The project integrates graduate and undergraduate training into the research program and will make all information publicly available through the worldwide web. Student involvement provides an important contribution to the continuing development of scientific infrastructure in the United States.