Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica

Abstract

International audienceInvasive alien species are among the primary causes of biodiversity change globally, with the risks there of 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 [Nakicenovic 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

Biological invasions in terrestrial Antarctica: what is the current status and can we respond?

“…1 in Molina- Montenegro et al 2014). These findings are also closely consistent with areas predicted to be at highest risk of non-native species introductions, based on propagule pressure and climate suitability (Chown et al 2012b). Figure 5 shows the number of non-native plants (upper panel) and invertebrates (lower panel) discovered within Antarctica over time (pre-1990s, 1990s, 2000s, 2010s).…”

“…However, no terrestrial species introduced to the Antarctic continent intentionally (mainly for scientific research reasons) have been formally identified as invasive (Smith 1996), but intentional introductions to most subAntarctic islands, before the adoption of legislation prohibiting or controlling this activity, have resulted in substantial impacts (see Convey and Lebouvier 2009). Under current legislative systems, unintentional introductions present the greatest threats to sub-Antarctic and Antarctic ecosystems (Frenot et al 2005), with non-native species potentially being introduced associated with visitors' clothing and personal effects Chown et al 2012b;Huiskes et al 2014), cargo Tsujimoto and Imura 2012), building material (Lee and Chown 2009) and fresh foods .…”

“…It is well recognised that the implementation of effective biosecurity practices is the most cost-effective method of reducing non-native species establishment and subsequent impacts (Chown et al 2012b) (for examples see the Council of Managers of National Antarctic Programs (COMNAP) and Scientific Committee on Antarctic Research (SCAR) 'Checklists for supply chain managers of National Antarctic Programmes for the reduction in risk of transfer of non-native species', available at: https://www.comnap.aq/SitePages/ checklists.aspx). This is particularly true for Antarctica, where there are relatively few standard access points and routes, and human activities have the potential to be highly regulated by individual national operators and the tourism and fishing industries.…”

“…Bargagli 2005;Frenot et al 2005;Kerry and Riddle 2009;Tin et al 2009;Convey 2010, 2012;Cowan et al 2011;Chown et al 2012a) and human-assisted establishment of nonnative species, both in the context of those introduced from beyond the Antarctic region and in the movement of Antarctic biota between different eco-regions within the continent, has been identified as one of the most pervasive threats to indigenous ecosystems Chown et al 2012b;Terauds et al 2012). …”

Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

“…The underlying mechanisms could include efficient dispersal strategies for microorganisms via aerial (Hughes et al, 2004;Pearce et al, 2010) or vector-based transport including animals. Beyond these natural dispersal mechanisms, anthropogenic mediated dispersal for example via ships and planes (Cowan et al, 2011;Chown et al, 2012) could facilitate the dispersal of microorganisms. The high cosmopolitan fraction of cyanobacteria, in contrast to other bacterial taxa, suggests this phylum employs the above mentioned dispersal strategies, likely profiting from broad tolerances to extreme physical and chemical conditions (Vincent, 2000a;Vincent and Quesada, 2012).…”