Spatial and temporal diversity of the bryophyte Arctic flora and associated cyanobacterial and fungal biota

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Inhospitable to most higher plants, arctic environments are dominated by cryptogams, including mosses, liverworts (collectively, bryophytes) and lichenized fungi. Initial studies on the Arctic suggest a mixed origin of the present bryophyte flora, with frequent long-distance dispersal events and local, pre-glaciation, diversification. As an initial step to uncover the origin of the Canadian arctic flora, I propose to use genomic resources to study the diversity, timing of origin and dispersal patterns of subarctic and arctic bryophytes. The alarming increase in global warming, due partly to anthropogenic activities, poses a threat to these critical ecosystems, and in particular bryophyte species that lack high dispersal capabilities (via spores or gametophyte fragments). The high dispersal capacity of most bryophytes brings the question whether their associated epiphyte flora (bacteria and fungi) is equally dispersed with bryophyte fragments or spores or it is native to the Arctic. Some arctic cyanobacteria and fungi display broad ranges (even bipolar distributions) whereas other have more localized distributions in subarctic and arctic regions. Despite the dramatic contribution of cyanobacteria, and probably fungi, to boreal and arctic ecosystems, at least regarding nitrogen fixation, we know little about the genetic diversity of the epiphytic and endophytic flora of subarctic and arctic Canadian bryophytes. Here I propose to take a concerted approach to study the bryophyte hosts and the associated epiphytes, to provide