Abstract: Polyploidy is a very important evolutionary mechanism. However, the advantages and disadvantages of polyploidy are far from being resolved. Saxifraga oppositifolia L. is a circumpolar arctic-alpine species, and one of these species where the effect of autopolyploidy has been overlooked. Three ploidy levels of autopolyploid origin are recorded (diploid, triploid and tetraploid). Saxifraga oppositifolia show considerable variation in both ecology and morphology; it thrives in a wide range of habitats, from early snow free, extremely dry ridges with long growing season, to moist snow beds with short growing season.
We establishment four transects through habitat gradients summer 2018, and added one extra transect summer 2019 in order to study the distribution of ploidy levels of Saxifraga oppositifolia different habitats. Plots were established in three main habitat types (Habitat 1: glacial or fluvial deposits in the valley bottom, Habitat 2: north-east facing slopes in mesic to dry heath vegetation. Habitat 3: dry, open ridges) following and altitudinal gradient from the valley bottom of the main Advent Valley and up the mountain following slopes facing North East in the entrance of Bjørndalen, Endalen, Todalen, Bolterdalen and Foxdalen. In total 15 habitat plots (20 m x 40 m) were established, and we randomly marked out and georeferenced 48 plants within each plot. Within each plot, we placed out data loggers, which measure temperature and for some plots also moisture. A range of different measurmnets, including vegetation analyses, genetic analyses, ploidy analyses and edaphic analyses have been performed, and additional data is still being collected (2021).
We aim to understand the origins of triploids and tetraploids, and identify genetic differences, and physiological and morphological traits related to ploidy levels, and relate these to niche differentiation and ecology.