Abstract

Birds likely act as dispersal vectors for bryophyte diaspores, and the exploration of their role in shaping bryophyte biogeography has only recently begun. Our preliminary studies suggest that birds consume bryophytes either inadvertently or to supplement their diet, and given the totipotency of bryophyte tissues, birds may thus contribute to local or regional endozoochoric bryophyte dispersal. This research sought to determine whether consumption and defecation of bryophytes by two montane bird species, the White-bellied Seedsnipe (Attagis malouinus) and Upland Goose (Chloephaga picta), contributes to bryophyte dispersal in the Chilean Sub-Antarctic region. We collected feces of both species opportunistically in the Dientes de Navarino mountains and placed recovered bryophyte specimens on agar growth plates to determine post-dispersal viability. We extracted total DNA from feces and targeted specific plant chloroplast loci to assess the diversity of bryophytes consumed. We detected bryophyte fragments in 41 of 47 screened fecal samples, including 23 and 18 from seedsnipes and goose, respectively. Sporophyte fragments of Polytrichum and Pohlia mosses composed over 80% of each of 11 Upland Goose feces. We analyzed the nutrient content of Pohlia mosses from fecal sample sites and found that their composition is 9-10% protein. We did not confirm the growth of any mosses beyond extraction from fecal samples of either bird species, although one Polytrichum specimen showed signs of new tissue growth prior to plating. These discoveries suggest that Upland Geese feed intentionally—albeit occasionally—on Pohlia and Polytrichum spp., and that both species may thereby contribute to the dispersal of bryophytes in the Sub-Antarctic.