Monitoring biological invasion across the broader Antarctic: a baseline and indicator framework

Biological invasion is one of the key threats to the conservation of the broader Antarctic region. We provide an evidence-based assessment of the status of biological invasion in the region as a basis for future monitoring and management. We adapted the indicator framework for global biological invasion monitoring by collating information on (i) numbers of alien species and those invasive species impacting biodiversity (ii) trends in the extinction risks of native species impacted by invasive species and (iii) trends in relevant agreements, management intention and species eradications. Drivers of invasion including risk-associated human activities and trends were also evaluated. The number and trends in activities associated with invasion risk are broadly distributed across the region and increasing. Over 560 alien species from a wide range of taxa occupy the region, concentrated largely on the Southern Ocean Islands, with a high proportion of these considered to be invasive and to have negative biodiversity impacts. There has been a decline in the conservation status of species in the region that are impacted by invasives. Although policy responses to deal with the problem have increased since the 1970s, as have the number of successful eradications, management implementation statistics are patchy and progress in this area less apparent. The Antarctic Biological Invasions Indicator (ABII) provides a system for information exchange across the region and a vehicle for targeted monitoring and surveillance. It also enables inclusion of the region in global efforts to track both IAS and interventions for managing the threat. In a region that appears particularly prone to impacts from alien species, substantial further effort is needed to implement and monitor the effectiveness of management responses.