Bryofloristics of Victoria Island, Nunavut

The Arctic tundra represents a heterogeneous landscape with diverse habitats where bryophytes are a dominant component. Victoria Island, the second largest island (217,291 km²) in the Canadian Arctic Archipelago, lacks a checklist of bryophyte species and collections are few. Floristic habitat (FHS) and non-random quantitative sampling were performed in 2018 and 2019 in the vicinity of Cambridge Bay and Wellington Bay to assess bryophyte diversity. Based on 728 specimens, 89 bryophyte taxa (81 Bryophyta and 12 Marchantiophyta) were enumerated to date, of which 60 are new records for the island. Barcoding techniques utilizing genetic sequence data from 285 specimens, based on nrDNA (internal transcribed spacer region ITS2) and cpDNA (rbcLa and trnL-F) regions were generated in collaboration with BOLD (Barcode of Life Database, University of Guelph).

A detailed non-random quantitative sampling of meso- and microhabitats for bryophytes included a range of hydric to xeric terrestrial sites with different snow cover regimes. Non-metric multidimensional scaling (NMDS) and multi-response permutation procedures (MRPP) indicate significant differences in species composition between sites. Soil moisture and snow cover regime significantly affect species composition (analyses of similarities, ANOSIM). Indicator species analyses (ISA) show that Scorpidium spp., Pseudocalliergon brevifolium, Drepanocladus arcticus, and Cinclidium latifolium are significantly associated with sites with more hydric conditions, Tomentypnum nitens, Hypnum bambergeri, and Orthotrichum speciosum with mesic conditions, and Encalypta spp. with xeric conditions.

The results from Victoria Island, based on complementary morphological and sequence data, establishes a robust checklist and discernment of bryophyte assemblages in the Cambridge Bay vicinity. This study also forms a baseline to explore the genetic and floristic diversity for a comprehensive arctic bryophyte flora program (Bryophyte Flora of the Canadian Arctic Archipelago (BRYCAA), La Farge Lab.)