Evidence of targeted consumption of mosses by birds in sub‐Antarctic South America

Abstract

Bryophyte consumption is uncommon among bird species globally and is often presumed incidental. We sought to determine whether herbivorous bird species of the high Andes, including the white-bellied seedsnipe (Attagis malouinus) and Chloephaga geese (C. picta and C. poliocephala), consume bryophytes, and if so, how frequently. We collected 26 seedsnipe and 22 goose droppings from alpine and sub-alpine habitats of Navarino Island, Chile and examined their contents for bryophyte diaspores. We detected bryophyte fragments in 84.6% and 90.9% of seedsnipe and Chloephaga goose faecal samples, respectively. We also extracted DNA from three bryophyte fragments isolated from goose droppings and sequenced three chloroplast loci for each sample. We inferred through a barcoding analysis that at least one species of Chloephaga goose consumes Polytrichum strictum and Notoligotrichum trichodon. The composition of 11 collected goose droppings was >50% Polytrichaceae bryophyte fragments, suggesting that at least one Chloephaga goose species foraged deliberately on moss species of this family. These new observations suggest that bryophytes are part of the diet of some high Andean birds and that birds might disperse bryophytes internallyvia endozoochoryin the sub-Antarctic.

Seed dispersal by neotropical waterfowl depends on bird species and seasonality

“…Additionally, Willson, Traveset, and Sabag (1997) observed seeds of four fleshy‐fruit plants in faeces of upland goose and ashy‐headed goose ( Chloephaga poliocephala ) in Tierra del Fuego. Russo, Robertson, MacKenzie, Goffinet, and Jimenez (2020) found evidence that these geese species also disperse mosses by endozoochory. Silva et al.…”

Do birds disperse mosses? Evidence of endozoochory in upland geese Chloephaga picta and white-bellied seedsnipes Attagis malouinus in sub-Antarctic Chile

“…Previous research has attempted to cultivate fragments found in fecesin vitro with some success (Wilkinson et al, 2017;Russo et al, 2020). In this study, we partially followed Russo et al's (2020) fragment-processing methods.…”

“…Previous research suggests that birds, such as mallard ducks (Anas platyrhynchos ) and sub-Antarctic geese and shorebirds, might be capable of dispersing bryophytes through endozoochory (Wilkinson et al, 2017;Russo et al, 2020). Additional evidence of bryophyte dispersal through endozoochory has been reported in spectacled flying foxes (Pteropus conspicillatus ) (Parsons et al, 2007) and freshwater fish (Boedeltje et al, 2019).…”

“…To our knowledge, the first observations of the consumption of bryophytes by C. picta and A. malouinus in sub-Antarctic South America were made by Behling et al (2016). More recently, Russo et al (2020) observed that fecal samples collected on a drying snowmelt bed were comprised of about 50-80% sporophyte fragments from the moss family Polytrichaceae, and those collected on flooded meadows were comprised of about 80-100% bryophyte sporophytes. Of all fecal samples the authors uncovered, 91% ofC.…”

“…Even though viable bryophyte gametophyte fragments have been recovered from avian species that feed on these plants, previous research has attempted to cultivate or regenerate these fragments with little success (Parsons et al, 2007;Wilkinson et al, 2017;Russo et al, 2020). Given that the dispersal and establishment of plants involves sequential and interdependent steps to be successful under field conditions, it is inappropriate to assume that finding bryophyte fragments in bird feces is directly correlated with successful dispersal.…”