Identifying alien bryophytes taking into account uncertainties: A reply to Patiño & Vanderpoorten (2015)

Recently, Patiño & Vanderpoorten (2015, Journal of Biogeography, 42, doi:10.1111/jbi.12492) commented on our manuscripts about patterns and processes of global bryophyte invasions. In particular, they argued that the criteria we have used to identify alien bryophytes (i.e. anomalous geographical distribution, preference for disturbed habitats, indirect associations with some means of human transport) are insufficient in the absence of further evidence. We fully agree with this statement. Consequently, we had used the above-mentioned criteria only for the identification of 'cryptogenic' (i.e. probable alien) species and have stated this explicitly in our manuscripts. Thus, we conclude that Patiño & Vanderpoorten (2015) have drawn misleading conclusions on the way we defined aliens. Nevertheless, we acknowledge that given the excellent long-distance dispersal capacities of bryophytes, diverging opinions between different experts on the native, alien or cryptogenic status of a particular bryophyte species in a given region do sometimes exist.