Associate Professor Queen's University Kingston, Ontario, Canada
Abstract: Negative environmental impacts associated with vegetation decline have triggered an increase in the restoration efforts of critical landscapes. Arctic ecosystems are under extreme ecological pressure from extensive natural resource extraction combined with warming at a rate 2-3 times faster than the mean increase in global temperature. Local adaptation can be an important consideration in plant restoration, but for most native populations inhabiting arctic ecosystems, the question of “how local is local?” remains unexplored. A lack of data on genetic diversity and population structure hinders the ability to successfully establish restoration sites as genetic variation is necessary for evolutionary change to occur. Species in the Calamagrostis Adans. genus are perennial rhizomatous grasses that occur primarily in cool-temperate regions of the world. Within North America, C. canadensis, C. stricta and C. purpurascens are widespread across heterogeneous environments. However, taxonomic identification has been complicated by variation in morphology, ploidy, apomixis, and hybridization. We aimed to investigate genome-wide population structure and genetic diversity among 26 collections of C. canadensis (N= 10), C. stricta (N= 9) and C. purpurascens (N= 7) from the Northwest Territories to aid in seed collection and identification of units for restoration projects in the Canadian Arctic using double digest restriction-site associated DNA sequencing (ddRAD-seq). Our results showed evidence for interspecific hybridization of C. stricta with C. canadensis and C. purpurascens but not between C. purpurascens with C. Canadensis. Our STRUCTURE analysis identified three individuals with over 40% admixed ancestry and five individuals with over 20% admixed ancestry. We found no evidence of isolation by distance within each species despite the large geographical distance between populations within each species. Lastly, we aim to increase our sample size by using the cost-effective PCR based genotyping in thousands by sequencing (GT-seq), we have selected 347 loci and will focus on identifying population structure and genetic diversity differences between cultivars and natural populations. In conclusion, this study suggests that populations of Calamagrostis species in the Northwest Territories might experience moderate rates of hybridization between species, but moderate to low levels of gene flow between populations within each species, possibly due to the large geographic distance separating some populations.
