title: Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica.
abstract: Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007-2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes.
authors.affiliation: Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa. slchown@sun.ac.za
authors.forename: Steven L
authors.initials: SL
authors.lastname: Chown
authors.forename: Ad H L
authors.initials: AH
authors.lastname: Huiskes
authors.forename: Niek J M
authors.initials: NJ
authors.lastname: Gremmen
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Lee
authors.forename: Aleks
authors.initials: A
authors.lastname: Terauds
authors.forename: Kim
authors.initials: K
authors.lastname: Crosbie
authors.forename: Yves
authors.initials: Y
authors.lastname: Frenot
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Hughes
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imura
authors.forename: Kate
authors.initials: K
authors.lastname: Kiefer
authors.forename: Marc
authors.initials: M
authors.lastname: Lebouvier
authors.forename: Ben
authors.initials: B
authors.lastname: Raymond
authors.forename: Megumu
authors.initials: M
authors.lastname: Tsujimoto
authors.forename: Chris
authors.initials: C
authors.lastname: Ware
authors.forename: Bart
authors.initials: B
authors.lastname: Van de Vijver
authors.forename: Dana Michelle
authors.initials: DM
authors.lastname: Bergstrom
mesh_terms: D000864:Antarctic Regions; D006801:Humans; D058865:Introduced Species; D058526:Plant Vascular Bundle / Q000502:physiology; D018570:Risk Assessment; D012639:Seeds / Q000502:physiology; D013045:Species Specificity; D013696:Temperature