Abstract

Dispersal is a fundamental requirement for all organisms, indeed theoretical arguments show that dispersal is still required even in a uniform and predictable environment, and it is obviously a key mechanism by which plants respond to climate change (Hamilton & May, 1977; Huntley & Webb, 1989). In bryophytes, spores provide an especially important means of dispersal (Glime, 2014; Porley & Hodgetts, 2005), and are often small enough to potentially be moved between continents in the atmosphere (Wilkinson et al, 2012). However, waterbirds are also major vectors for a broad range of plant types (Green et al., 2016), and it is likely that bryophyte spores are dispersed by migratory waterbirds, both by epizoochory (external dispersal on plumage or feet) and endozoochory (internal dispersal after ingestion and survival of transit through the gut). Indeed, Proctor (1961) showed experimentally that spores of the liverwort Riella americana survive gut passage through Mallards (Anas platyrhynchos).