Plant dispersal by Canada geese in Arctic Greenland

Abstract

Despite the abundance of migratory geese as herbivores in the Arctic, and ongoing changes in their populations and distributions, little is known about their role in seed dispersal. Climate change requires Arctic plants to adjust their distributions, and avian vectors may have an important role to play. We present the first study of endozoochory (internal transport) of Arctic plants by Canada geese. In central west Greenland, we collected 50 faecal samples, from which we extracted 2943 intact seeds from six species and four families, all but one of which (a non-native species) are extremely common and widespread in this part of Greenland. The majority (95%) of seeds were from Empetrum nigrum, but Carex nardina (3%) and Vaccinium uliginosum (2%) were also abundant. One seed of the non-native Persicaria lapathifolia was recorded. These results suggest migratory geese are likely to be vital vectors of Arctic plants. Although the sample size was small, there were indications that non-breeding geese may disperse more seeds than breeding geese, which stay closer to lakes to reduce the risk of predation, rarely accessing dwarf-scrub heath where non-breeders ingested seeds. Future research should address such possible links between reproductive status and seed dispersal in waterbirds.