Human-vectored seed dispersal as a threat to protected areas: Prevention, mitigation and policy

Abstract The growing global population size and the increasing mobility of people can make humans as a potentially super-effective dispersal vector of plant propagules. Therefore, human-vectored dispersal (HVD) on clothing and footwear can be an effective way of the dispersal of invasive alien species (IAS). This can be especially problematic in protected areas, which are not exposed to the mass invasions caused by vehicles, construction works, trade or agriculture, but still exposed to HVD by tourists. In this study, we collected those biosecurity measures which currently apply to the control of IAS dispersed on human clothing. We also extracted relevant findings from studies on HVD for giving recommendations in order to improve policy measures aiming the prevention and mitigation of the spread of propagules of IAS on clothing. Even though many peculiarities of HVD are already known, e.g., retention potential of different fabric and cloth types, traits of the species of the most successful IAS dispersed by HVD and potential dispersal efficiency of HVD, we found that current IAS control measures usually do not consider and do not address sufficiently the threats represented by HVD on cloths. We suggest a number of voluntary and institutional measures that could be easily applied to decrease the chance of dispersing IAS by HVD, including information, self-regulation, legislation, quarantine measures, monitoring, interception and visitor management.