Article

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

Article

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

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Abstract

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.

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... Indeed, in the case of Aichi Target 9, concerning the identification and control of priority invasive alien species and the pathways through which they are introduced, the Antarctic region is also in a much better position than the rest of the globe. Although concerns remain about transfer of species among the ACBRs (55), overall, few species have been introduced and pathways of introduction are well understood (57). The substantial impacts that can be caused by invasive species-as demonstrated repeatedly elsewhere on the planet, including on the sub-Antarctic islands, such as predation of indigenous species and changes to nutrient cycles-have prompted much action. ...
... While much progress has been made in the Southern Ocean to reduce seabird bycatch of threatened procellariiform seabirds (mostly albatrosses), several species have continued to decline (66). Many have very wide foraging ranges with distributions that extend outside the Southern Ocean, thus threats are also being posed by more northerly fisheries (67), though land-based predation by invasive alien species is also significant (56,57). ...
... On land, for the Antarctic continent, habitat alteration in the broadest sense is of most significance, including alteration of the extent to which the continent's areas can be considered wilderness largely free from human impact (11,53,123). Biological invasions are a growing threat to the Antarctic Peninsula and its associated islands (55,57), and some evidence is emerging of anthropogenic, climate change-related impacts. In the sub-Antarctic, the impacts of past and limited current exploitation of marine species and climate change in the Southern Ocean, and on land biological invasions, climate change, and their interactions, are by far the most significant drivers of system change (54,57). ...
Article
Antarctica and the Southern Ocean comprise a critical part of the Earth System. Their environments are better understood than ever before, yet the region remains poorly considered among international agreements to improve the state of the global environment. In part the situation owes to isolated regional regulation within the Antarctic Treaty System, and in part to the dated notion that Antarctica and the Southern Ocean are well conserved and relatively free from human impact. Here we review growth in knowledge of Antarctic environments and anthropogenic pressures on them. We show that the region's unusual diversity is facing substantial local and globally mediated anthropogenic pressure, on a par with environments globally. Antarctic environmental management and regulation is being challenged to keep pace with the change. Much benefit can be derived from consideration of Antarctic environmental and resource management in the context of global agreements.
... Although the absolute number of recorded biological invasions to the Antarctic remains relatively low compared to trends globally (Hughes & Convey, 2010;McGeoch, Shaw, Terauds, Lee, & Chown, 2015), the region has proven susceptible to the ecological impacts of biological invasions when they have occurred (Courchamp, Chapuis, & Pascal, 2003;Frenot et al., 2005;Lebouvier et al., 2011). In consequence, biological invasions have been identified as one of the primary conservation risks of the broader Antarctic Tin, Liggett, Maher, & Lamers, 2014). ...
... Thirty-two plants, 12 invertebrates, 22 vertebrates, two fungi and one protist were used. These included widely known invaders, such as black wattle (Acacia mearnsii), have already been introduced to at least one sub-Antarctic island, and two (Mustela erminea, Rubus ellipticus) are congeners of species that have been introduced or were the subject of introduction attempts (Headland, 2012;McGeoch et al., 2015). ...
... Current climatic barriers may prevent invasion to the Antarctic continent by all of the worst globally invasive species and all but four of the modelled cold-tolerant species, but the milder climates of the Southern Ocean islands are less effective barriers to non-native species establishment (Tables 1 and 2; Figure 2). In part this may account for the higher number of alien species that are presently observed on the Southern Ocean islands compared to the Antarctic continent McGeoch et al., 2015). The susceptibility of these islands is perhaps unsurprising when one considers their climate relative to other invaded regions globally. ...
Article
Biological invasions are a substantial threat to Antarctic biodiversity and a priority conservation policy focus for Antarctic Treaty Parties and the sovereign states of surrounding islands. Key to their strategies is prevention, including assessment of establishment risk for alien species. Despite establishment of some of the worst globally invasive species across the Antarctic region, assessments of establishment potential of these species are non-existent. Here, we address this deficit and determine whether these invasive species constitute a significant conservation threat to the broader Antarctic region both now and in response to future regional climate change.
... Terrestrial invasions have led to population declines of several species and even local extinctions, and have impacted ecosystem processes and functioning (Frenot et al. 2005;McGeoch et al. 2015). Invasions have also led to greater taxonomic homogeneity amongst the islands, as many of the same species have become invasive across several of the islands (Greve et al. 2005;Shaw et al. 2010). ...
... Indeed, given the fact that introduction pathways to the PEIs are few and generally well-understood, and because the islands are highly isolated, the management of these pathways is much simpler than those associated with the South African mainland (Faulkner et al. 2016). Not only the nature of human activities, but also the amount of human traffic to the islands affects the dynamics of invasions (McGeoch et al. 2015). The number of voyages to the PEIs has not increased recently. ...
... The new base, and the new research and supply vessel, the S.A. Agulhas II (completed in 2012), house more people than did the old base and research vessel. Therefore, the numbers of people that arrive at, and overwinter on, the island annually has increased, which is likely to increase the opportunities for the introduction of new species (McGeoch et al. 2015). ...
Chapter
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The sub-Antarctic Prince Edward Islands (PEIs) constitute South Africa’s most remote territory. Despite this, they have not been spared from biological invasions. Here, we review what is known about invasions to the PEIs for terrestrial taxa (vertebrates, invertebrates, plants and microbes), freshwater taxa and marine taxa. Currently, Marion Island is home to 46 alien species, of which 29 are known to be invasive (i.e. they are alien species that have established and spread on the island). Prince Edward Island, which has no permanent human settlement and is visited only infrequently, has significantly fewer alien species: only eight alien species are known from Prince Edward Island, of which seven are known to be invasive. The House Mouse (Mus musculus), which occurs on Marion Island, can be considered the most detrimental invader to the islands; it impacts on plants, insects and seabirds, which result in changes to ecosystem functioning. The impacts of other terrestrial invaders are less well understood. At present, no invasive freshwater or marine taxa are known from the PEIs. We conclude by discussing how invasion threats to the PEIs are changing and how the amelioration of the climate of the islands may increase invasion threats to both terrestrial and marine habitats.
... These factors lead to low propagule pressure from invasive plants, whereas the climatic conditions are inhospitable to many potential alien species. However, low native species richness combined with the nature of islands increases susceptibility to invasion (Frenot et al. 2005) and the associated negative impacts of alien species (McGeoch et al. 2015). Most invasive species are of European origin, and relatively long lived with a large ecological range (Frenot et al. 2005). ...
... Management plans are now in place to control or eradicate several non-native plants in the sub-Antarctic and Antarctica (de Villiers et al. 2006; Committee for Environmental Protection 2011; Hughes et al. 2015;McGeoch et al. 2015;Greve et al. 2017). In many instances, however, the impacts of invasive plants remain unknown with few studies available quantifying such impacts (Shaw 2013), which restricts the development of effective management. ...
... Poa annua is of greatest concern due to its widespread distribution and environmental impact (McGeoch et al. 2015). Originally from Europe, P. annua is a cosmopolitan weed (Heide 2001), common in temperate turf grass where it is well adapted and a persistent problem (Downing et al. 1970;Wu et al. 1987;Lush 1988;Christians 2006). ...
Article
The Antarctic region is one of the most inhospitable frontiers on earth for weed invasion. On Australia's world heritage sub-Antarctic Macquarie Island only three species of invasive weeds are well established (Poa annua L., Stellaria media (L.) Vill. and Cerastium fontanum Baumg.), although isolated occurrences of other species have been found and removed. These weed species are believed to have initially been introduced through human activity, a threat which is likely to increase, although strict biosecurity is in place. All three weeds are palatable and may have been suppressed to some extent by pest herbivore (rabbit) grazing. Given the high conservation value of Macquarie Island and threats to ecosystem structure and function from weed proliferation following rabbit eradication, well targeted invasive plant control management strategies are vital. We propose that a successful restoration program for Australia's most southerly rangeland ecosystem should integrate both control of non-native plants as well as non-native herbivores. Of the non-native plants, S. media may most easily be managed, if not eradicated, because of its more limited distribution. Little, however, is known about the soil seed bank or population dynamics after rabbit eradication, nor the effect of herbicides and non-chemical control methods in cold conditions. A current research project on this non-grass species is helping to fill these knowledge gaps, complementing and building on data collected in an earlier project on the ecology and control of the more widespread invasive grass, P. annua. With an interest in off-target herbicide impacts, our work also includes a study of the movement and fate of herbicides in the cold climate Macquarie Island soils. Research in such a remote, cold, wet and windy place presents a range of logistical challenges. Nevertheless, outcomes are informing the development of effective, low-impact control or eradication options for sub-Antarctic weeds.
... This inherently involves, amongst other actions, understanding the risk factors associated with human-assisted colonization and biological invasion processes . In the very different culture of the early decades of Antarctic exploration and marine mammal exploitation in the nineteenth and first half of the twentieth centuries, no biosecurity measures were applied and a number of domestic species (livestock, companion animals, sled dogs and ponies) were deliberately introduced to the broader Antarctic region, along with a range of accidental introductions of plants, rodents and invertebrates, particularly associated with fodder (Frenot et al. 2005, McGeoch et al. 2015. While the greatest impacts of these introductions were felt in the sub-Antarctic islands, marine exploitation industries were active in this period in the Maritime Antarctic South Orkney and South Shetland islands and in at least the northern Antarctic Peninsula (e.g. ...
... Here, we explore this body of research by means of an evidence-based literature review and narrative synthesis. As elsewhere, biological invasions in Antarctica are shaped by the integration of causal factors related to the intrinsic traits of each non-native species, the unique conditions of their arrival and the characteristics of the recipient abiotic and biotic environment (McGeoch et al. 2015, Pyšek et al. 2020. Several hypotheses and concepts have been formulated to help elucidate the key drivers of the outcomes of invasions (Catford et al. 2009, Jeschke 2014, Enders et al. 2020. ...
... The management of non-native species in Antarctica requires decisive actions that assist in the decisionmaking process (McGeoch et al. 2015). In this study, we identify substantial knowledge gaps around Antarctica's non-native species that remain to be addressed, particularly in disentangling the relative influence of reproductive (e.g. ...
Article
Understanding the success factors underlying each step in the process of biological invasion provides a robust foundation upon which to develop appropriate biosecurity measures. Insights into the processes occurring can be gained through clarifying the circumstances applying to non-native species that have arrived, established and, in some cases, successfully spread in terrestrial Antarctica. To date, examples include a small number of vascular plants and a greater diversity of invertebrates (including Diptera, Collembola, Acari and Oligochaeta), which share features of pre-adaptation to the environmental stresses experienced in Antarctica. In this synthesis, we examine multiple classic invasion science hypotheses that are widely considered to have relevance in invasion ecology and assess their utility in understanding the different invasion histories so far documented in the continent. All of these existing hypotheses appear relevant to some degree in explaining invasion processes in Antarctica. They are also relevant in understanding failed invasions and identifying barriers to invasion. However, the limited number of cases currently available constrains the possibility of establishing patterns and processes. To conclude, we discuss several new and emerging confirmatory methods as relevant tools to test and compare these hypotheses given the availability of appropriate sample sizes in the future.
... Currently there are no known populations of non-native marine species in the waters surrounding Antarctica, see Chapter Two. Plants and insects, however, have become established in small numbers on land, primarily around research stations and facilities (Hughes & Pertierra, 2016;McGeoch et al., 2015). The introduction of a flightless midge on Signy Island has changed nutrient cycling in the soil, demonstrating that small, easily missed species can still have considerable impact if they establish and spread (Bartlett, 2019). ...
... Relatively few non-native species, terrestrial or marine, live in Antarctica compared to other regions of the world (Hughes & Pertierra, 2016;McCarthy et al., 2019;McGeoch et al., 2015). The combination of physical and physiological barriers likely block most arrivals, and human activity began crossing the physical barriers only relatively recently. ...
... Climate change in Antarctic environments and human activity in the region are recognised as major factors increasing the risk of invasion by terrestrial species and likely for marine species, too (Frenot et al., 2005;Galera et al., 2018;Hughes & Convey, 2010;McGeoch et al., 2015). Thus far, terrestrial non-native species have faced substantial natural barriers (Chown et al., 2012) that are now weakening through changing climate and increasing human activity (Duffy et al., 2017). ...
Thesis
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Invasive non-native species are a major threat to global biodiversity. For at least 15 million years coastal Antarctica has been poorly connected to nearby temperate ecosystems due to physical and physiological barriers. Yet, Antarctica is experiencing significant environmental change and becoming increasingly exposed to ship-borne human activity that crosses the physical barriers. These factors may facilitate the establishment of non-native marine species. This doctoral research adds insight into the risk of non-native marine species being transported to Antarctica via ships’ hulls and internal seawater systems, with particular focus on pathways of introduction and species found within those pathways. To begin my research, I assessed the current knowledge of non-native marine species in the Antarctic region: the physical and physiological factors that resist establishment of non-native marine species; changes to resistance under climate change; the role of legislation in limiting marine introductions; and the effect of increasing human activity on vectors and pathways of introduction. Evidence of non-native marine species was limited: up to 2019 just four marine non-native and one cryptogenic species that were likely introduced anthropogenically had been reported free-living in Antarctica or in the sub-Antarctica islands, but no established populations have been reported. An additional six species had been observed in pathways to Antarctica that are potentially at risk of becoming invasive. I estimated there may be approximately 180 vessels and 500+ voyages in Antarctic waters annually. However, these estimates are necessarily speculative because relevant data are not recorded comprehensively. In response to the scarcity of data on ship movements into the Southern Ocean, I obtained data on ship activity in the Southern Ocean from 2014-2018 inclusive and developed a ship traffic network for Antarctic-going vessels. I analysed the ship movements and conducted a spatially-explicit assessment of introduction risk for non-native marine species in all Antarctic waters. I found that vessels connect Antarctica via an extensive network of ship activity to all global regions, and especially South Atlantic and European ports. Ship visits were more than seven times higher to the Antarctic Peninsula and the South Shetland Islands than elsewhere around Antarctica. I found that, while the five recognised ‘Antarctic Gateway cities’ are important last ports of call, an additional 53 ports had vessels directly departing to Antarctica from 2014-2018. I identified ports outside Antarctica where biosecurity interventions could be most effective and the most vulnerable Antarctic locations where monitoring programmes for high-risk invaders should be established. Biofouling communities within the major pathway to Antarctica from Europe via the South Atlantic, identified in the network analysis, became my next focus. I obtained biofouling samples from the polar research vessel RRS James Clark Ross and found that niche (protected) areas of the hull represent significantly greater colonisation (species richness) and propagule pressure (individual abundance) than exposed areas of the hull. The composition of the biological communities did not differ among exposed and niche areas, but did change significantly among the three surveys conducted. Only six species were found on the ship’s hull in Antarctica, but they included a known invasive bryozoan, Tricellaria inopinata, and barnacles that have no counterparts in Antarctica. While the role of hull fouling is recognised as a globally important vector for introductions of non-native marine species, the role of a vessel’s internal pipework has been overlooked. I conducted the first comprehensive study of biofouling macrofauna living inside an Antarctic vessel’s internal seawater systems, finding breeding communities of Jassa marmorata (Amphipoda) and mytilid mussels throughout the internal pipework system. I found fouling communities that occluded ~9-17% of a pipe’s cross-sectional area, increasing running costs for ships. Since ships are constantly pumping their water through their pipework, they are likely to be releasing propagules at all stages of their voyages, including in polar regions. Before I started my research, Antarctic operators and policy-makers were unaware of the total number of vessels that visit Antarctica. Now, I have provided comprehensive insight into the most traversed routes to Antarctica and identified Antarctic locations that are the most likely recipient locations for non-native marine species. I found that non-native species from temperate regions can survive passages through polar areas and that sheltered sections of the hull and internal systems are especially important sites for both propagule and colonisation pressure. Together, these results demonstrate that Antarctica is well connected to worldwide marine ecosystems and that biofouling on ships poses an important and growing introduction risk to Antarctica.
... Among other things, they discuss the traits of the invasive species likely to successfully expand in a new ecosystem (e.g., Kleunen et al. 2010;Moles et al. 2008), predict the effects of climate change (Gilman et al. 2010), or search for links between ecological and evolutional changes (Facon et al. 2006). These theoretic and conceptual works are also intended to be applicable for developing management (research and conservation) programs, and their theoretical frameworks are "tools to organize research and evaluate the state of a subject area" (Foxcroft et al. 2011;McGeoch et al. 2015; Thomsen et al. 2011). Many models and frameworks, either of a broad nature (e.g., Blackburn et al. 2011;Gilman et al. 2010;Moles et al. 2008; Thomsen et al. 2011), or describing specific species and/or regions (e.g., Facon et al. 2006;Foxcroft et al. 2011;McGeoch et al. 2015) have been proposed by their authors as appropriate for the analysis of other invasions. ...
... These theoretic and conceptual works are also intended to be applicable for developing management (research and conservation) programs, and their theoretical frameworks are "tools to organize research and evaluate the state of a subject area" (Foxcroft et al. 2011;McGeoch et al. 2015; Thomsen et al. 2011). Many models and frameworks, either of a broad nature (e.g., Blackburn et al. 2011;Gilman et al. 2010;Moles et al. 2008; Thomsen et al. 2011), or describing specific species and/or regions (e.g., Facon et al. 2006;Foxcroft et al. 2011;McGeoch et al. 2015) have been proposed by their authors as appropriate for the analysis of other invasions. However, to our knowledge such use has seldom been reported in the literature (Vardien et al. 2012). ...
... This further diminishes the probability of invasion. The lack of any Arctic or alpine species in a list of 15 worst invasive alien plants in broader Antarctic (McGeoch et al. 2015) seems to confirm this hypothesis. ...
Article
Full-text available
Successful alien species invasion depends on many factors studied mostly in post invasion habitats, and subsequently summarized in frameworks tailored to describe the studied invasion. We used an existing expanded framework with three groups of contributing factors: habitat invisibility, system context and species invasiveness, to analyze the probability of alien species invasions in terrestrial communities of Maritime Antarctic in the future. We focused on the first two factor groups. We tested if the expanded framework could be used under a different scenario. We chose Point Thomas Oasis on King George Island to perform our analysis. Strong geographical barrier, low potential bioclimatic suitability and resource availability associated with habitat invasibility significantly reduce the likelihood of biological invasion in Antarctica. An almost full enemy release (low pressure of consumers), the high patchiness of the habitat, and the prevalence of open gaps also associated with habitat invasibility increase the possibility of invasion. The dynamics of functional connectivity, propagule pressure and spatio-temporal patterns of propagule arrival associated with human activity and climate change belonging to the system context contribute to an increase in the threat of invasions. Due to the still low land transport activity migration pathways are limited and will reduce the spread of alien terrestrial organisms by land. An effective way of preventing invasions in Antarctica seems to lie in reducing propagule pressure and eliminating alien populations as early as possible. The expanded conceptual framework opens up wider possibilities in analyzing invasions taking place in different systems and with multiple taxa.
... Sub-Antarctic and cool-temperate islands of the Southern Ocean are some of the most remote environments in the world, yet their ecosystems are susceptible to invasion by non-native species (Frenot et al. 2005;Convey et al. 2006b;Shaw 2013;McGeoch et al. 2015). Low temperature, remoteness and associated low human visitation to these Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s1084 ...
... Convey et al. 2010;Laparie et al. 2010;Williams et al. 2016), their broader ecosystem impacts remain largely unknown. Vertebrates such as house mice (Mus musculus), black rats (Rattus rattus) and brown rats (Rattus norvegicus) were introduced unintentionally, but others such as rabbits (Oryctolagus cuniculus), cats (Felis catus), sheep (Ovis aries), mouflon (Ovis ammon musiman), cattle (Bos Taurus), goats (Capra hircus), pigs (Sus Scrofa), reindeer (Rangifer tarandus), weka (Gallirallus australis), and trout (Salmo trutta) were purposefully released as companions, food or game (Headland 2012;McGeoch et al. 2015). As has occurred globally, non-native mammals have transformed SOI ecosystems through habitat destruction, causing extinctions and altering ecosystem processes (e.g. ...
... As has occurred globally, non-native mammals have transformed SOI ecosystems through habitat destruction, causing extinctions and altering ecosystem processes (e.g. Courchamp et al.2003;Campbell and Donlan 2005;Frenot et al. 2005;Wanless et al. 2007;Jones et al. 2008;Nogales et al. 2013;McGeoch et al. 2015;McCreless et al. 2016). ...
Article
Full-text available
Isolation and climate have protected Southern Ocean Islands from non-native species. Relatively recent introductions have had wide-ranging, sometimes devastating, impacts across a range of species and ecosystems, including invertebrates, which are the main terrestrial fauna. In our comprehensive review, we found that despite the high abundance of non-native plants across the region, their impacts on native invertebrates are not well-studied and remain largely unknown. We highlight that non-native invertebrates are numerous and continue to arrive. Their impacts are multi-directional, including changing nutrient cycling regimes, establishing new functional guilds, out-competing native species, and mutually assisting spread of other non-native species. Non-native herbivorous and omnivorous vertebrates have caused declines in invertebrate habitat, but data that quantifies implications for invertebrates are rare. Predatory mammals not only indirectly effect invertebrates through predation of ecosystem engineers such as seabirds, but also directly shape community assemblages through invertebrate diet preferences and size-selective feeding. We found that research bias is not only skewed towards investigating impacts of mice, but is also focused more intensely on some islands, such as Marion Island, and towards some taxa, such as beetles and moths. The results of our review support and build on previous assessments of non-native species in the Antarctic region—that the responses of invertebrate fauna on these islands are under-reported and often poorly understood. Given the importance of invertebrates as indicators of environmental change, and their potential utility in quantifying change associated with island restoration projects (such as eradications), these knowledge gaps need to be urgently addressed.
... Invasive species are, and will be, one of the most prevalent threats facing native biodiversity of the Antarctic (Hughes et al., 2015;McGeoch et al., 2015). This threat is compounded by increasing human visitation and climate warming across the region. ...
... Convey et al., 2002) or through its facilitation of non-native species establishment. Thus far, biological invasions to the largely ice-covered Antarctic remain low relative to global trends (Hughes and Convey, 2010;McGeoch et al., 2015) with the few documented invasions of plants and invertebrates limited to research stations and to the northern Antarctic Peninsula and associated islands (see Hughes et al., 2015 for a comprehensive review of the current state of continental invasions and discussion of management shortfalls under the Antarctic Treaty). However, when they have occurred, the ecological impacts of biological invasions to the broader region, which extends to the sub-Antarctic, have been severe (Frenot et al., 2005) and biological invasions are identified as one of the primary conservation risks to the Antarctic (Chown et al., 2012;Hughes et al., 2015). ...
Article
Warming across ice-covered regions will result in changes to both the physical and climatic environment, revealing new ice-free habitat and new climatically suitable habitats for non-native species establishment. Recent studies have independently quantified each of these aspects in Antarctica, where ice-free areas form crucial habitat for the majority of terrestrial biodiversity. Here we synthesise projections of Antarctic ice-free area expansion, recent spatial predictions of non-native species risk, and the frequency of human activities to quantify how these facets of anthropogenic change may interact now and in the future. Under a high-emissions future climate scenario, over a quarter of ice-free area and over 80% of the ~14 thousand km² of newly uncovered ice-free area could be vulnerable to invasion by one or more of the modelled non-native species by the end of the century. Ice-free areas identified as vulnerable to non-native species establishment were significantly closer to human activity than unsuitable areas were. Furthermore, almost half of the new vulnerable ice-free area is within 20 km of a site of current human activity. The Antarctic Peninsula, where human activity is heavily concentrated, will be at particular risk. The implications of this for conservation values of Antarctica and the management efforts required to mitigate against it are in need of urgent consideration.
... Biological invasions (along with climate change and interactions among these two change drivers) are the most significant terrestrial conservation challenges facing the region (Frenot et al. 2005;Chown et al. 2015a;Hughes et al. 2015). In consequence, an increasing amount is known about the correlates of invasion, the pathways for and vectors of non-native species, and the management strategies required to limit inadvertent introductions, especially given deliberate introductions are, for the most part, not permitted to the continent and its surrounding islands (Hughes and Convey 2012;Molina-Montenegro et al. 2014;McGeoch et al. 2015;Hughes and Pertierra 2016). Nonetheless, as is more broadly the case, the extent of information on impacts is surprisingly limited, particularly for plants (Gremmen et al. 1998;Frenot et al. 2001;Le Roux et al. 2013, Molina-Montenegro et al. 2012a, which is remarkable given that plants together with invertebrates are the most speciose groups of non-native species across the region (Frenot et al. 2005;Hughes et al. 2015), and are showing propensity for establishment on the continent itself (Molina-Montenegro et al. 2014). ...
... Overall, this study indicates that the substantial concerns already expressed about invasive plant species for the Antarctic continent (Shaw et al. 2014;Hughes et al. 2015) are warranted, and particularly so for P. annua which is already spreading in the region (Olech and Chwedorzewska 2011;Molina-Montenegro et al. 2012aHughes et al. 2015;Atala et al. 2019). Moreover, it provides additional evidence supporting general concerns about the impacts of grasses , and for a region where few investigations have been made of the impacts of invasive alien species on local populations (McGeoch et al. 2015). ...
Article
Full-text available
Biological invasions represent significant economic and conservation challenges, though it is widely acknowledged that their impacts are often poorly documented and difficult to predict. In the Antarctic, one non-native vascular plant species is widespread and studies have shown negative impacts on native flora. Using field “common garden” experiments, we evaluate the competitive impact of the increasingly widespread invasive grass Poa annua on the only two native vascular species of Antarctica, the forb Colobanthus quitensis and the grass Deschampsia antarctica. We focus on interactions between these three plant species under current and a future, wetter, climate scenario, in terms of density of individuals. Our analysis demonstrates Poa annua has the potential to have negative impacts on the survival and growth of the native Antarctic vascular species. Under predicted future wetter conditions, C. quitensis communities will become more resistant to invasion, while those dominated by D. antarctica will become less resistant. Under a recently developed unified scheme for non-native species impacts, P. annua can be considered a species that can cause potentially moderate to major impacts in Antarctica. If current patterns of increased human pressure and regional climate change persist and mitigation action is not taken (i.e. reduction of propagule pressure and eradication or control measures), P. annua is likely to spread in Antarctica, especially in the Antarctic Peninsula region, with significant negative consequences for some of the most remote and pristine ecosystems worldwide. Tighter biosecurity across all operators in the region, improved surveillance for the species, and prompt, effective control actions will reduce these risks.
... Antarctica has been described as the "final frontier for marine biological invasions" (McCarthy et al., 2019, p. 2221), with formerly ice-bound shores now available for colonization by poleward-moving species. Invasions in Antarctica are being accelerated by new facilities and new forms of tourism accompanied by increased ship traffic, such that more alien species have already been observed (Huiskes et al., 2014;McGeoch et al., 2015;Cardenas et al., 2020) and even more are predicted (Duffy et al., 2017;Hughes et al., 2020). ...
... Better coordination of actions targeting IAS across sectors would be valuable (Keller et al., 2011). Protocols are needed to assess the feasibility of eradicating newly established IAS and to design cost-effective management of widespread IAS that cause the most severe impacts (McGeoch et al., 2015). The UN CBD introduced a commitment to endorse these principles in the 2011-2020 Global Biodiversity Strategy by adopting Aichi Target 9. Several reviews have highlighted the need for more action and the global inadequacy of current measures (Butchart et al., 2010;Tittensor et al., 2014), and the last decade has seen significant progress in this direction. ...
Article
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Biological invasions are a global consequence of an increasingly connected world and the rise in human population size. The numbers of invasive alien species – the subset of alien species that spread widely in areas where they are not native, affecting the environment or human livelihoods – are increasing. Synergies with other global changes are exacerbating current invasions and facilitating new ones, thereby escalating the extent and impacts of invaders. Invasions have complex and often immense long‐term direct and indirect impacts. In many cases, such impacts become apparent or problematic only when invaders are well established and have large ranges. Invasive alien species break down biogeographic realms, affect native species richness and abundance, increase the risk of native species extinction, affect the genetic composition of native populations, change native animal behaviour, alter phylogenetic diversity across communities, and modify trophic networks. Many invasive alien species also change ecosystem functioning and the delivery of ecosystem services by altering nutrient and contaminant cycling, hydrology, habitat structure, and disturbance regimes. These biodiversity and ecosystem impacts are accelerating and will increase further in the future. Scientific evidence has identified policy strategies to reduce future invasions, but these strategies are often insufficiently implemented. For some nations, notably Australia and New Zealand, biosecurity has become a national priority. There have been long‐term successes, such as eradication of rats and cats on increasingly large islands and biological control of weeds across continental areas. However, in many countries, invasions receive little attention. Improved international cooperation is crucial to reduce the impacts of invasive alien species on biodiversity, ecosystem services, and human livelihoods. Countries can strengthen their biosecurity regulations to implement and enforce more effective management strategies that should also address other global changes that interact with invasions.
... Biological invasions (along with climate change and interactions among these two change drivers) are the most significant terrestrial conservation challenges facing the region (Frenot et al. 2005;Chown et al. 2015a;Hughes et al. 2015). In consequence, an increasing amount is known about the correlates of invasion, the pathways for and vectors of non-native species, and the management strategies required to limit inadvertent introductions, especially given deliberate introductions are, for the most part, not permitted to the continent and its surrounding islands (Hughes and Convey 2012;Molina-Montenegro et al. 2014;McGeoch et al. 2015;Hughes and Pertierra 2016). Nonetheless, as is more broadly the case, the extent of information on impacts is surprisingly limited, particularly for plants (Gremmen et al. 1998;Frenot et al. 2001;Le Roux et al. 2013, Molina-Montenegro et al. 2012a, which is remarkable given that plants together with invertebrates are the most speciose groups of non-native species across the region (Frenot et al. 2005;Hughes et al. 2015), and are showing propensity for establishment on the continent itself (Molina-Montenegro et al. 2014). ...
... Overall, this study indicates that the substantial concerns already expressed about invasive plant species for the Antarctic continent (Shaw et al. 2014;Hughes et al. 2015) are warranted, and particularly so for P. annua which is already spreading in the region (Olech and Chwedorzewska 2011;Molina-Montenegro et al. 2012aHughes et al. 2015;Atala et al. 2019). Moreover, it provides additional evidence supporting general concerns about the impacts of grasses , and for a region where few investigations have been made of the impacts of invasive alien species on local populations (McGeoch et al. 2015). ...
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Biological invasions represent significant economic and conservation challenges, though it is widely acknowledged that their impacts are often poorly documented and difficult to predict. In the Antarctic, one non-native vascular plant species is widespread and studies have shown negative impacts on native flora. Using field "common garden" experiments, we evaluate the competitive impact of the increasingly widespread invasive grass Poa annua on the only two native vascular species of Antarctica, the forb Colobanthus quitensis and the grass Deschampsia antarctica. We focus on interactions between these three plant species under current and a future, wetter, climate scenario, in terms of density of individuals. Our analysis demonstrates Poa annua has the potential to cause negative impact on the survival and growth of the native Antarctic vascular species. Under predicted future wetter conditions C. quitensis communities will become more resistant to invasion, while those dominated by D. antarctica will become less resistant. Under a recently developed unified scheme for non-native species impacts, P. annua can be considered a species that can cause potentially moderate to major impacts in Antarctica. If current patterns of increased human pressure and regional climate change persist and mitigation action is not taken (i.e. reduction of propagule
... Climate change in Antarctic environments and human activity in the region are recognized as major factors increasing the risk of invasion by terrestrial species and likely for marine species, too (Frenot et al., 2005;Galera, Chwedorzewska, Korczak-abshire, & Wódkiewicz, 2018;Hughes & Convey, 2010;McGeoch, Shaw, Terauds, Lee, & Chown, 2015). Thus far, terrestrial non-native species have faced substantial natural barriers (Chown et al., 2012) that are now weakening through changing climate and increasing human activity (Duffy et al., 2017). ...
... Since the early 2000s concern has grown over biosecurity measures in place for Antarctica, particularly for terrestrial environments (Chown et al., 2012;Hughes & Convey, 2010Hughes & Frenot, 2015;Hughes et al., 2011;Lewis et al., 2003;McGeoch et al., 2015), and a decision-making process for dealing with suspected introduced species has been formulated (Hughes & Convey, 2012). ...
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Antarctica is experiencing significant ecological and environmental change, which may facilitate the establishment of non‐native marine species. Non‐native marine species will interact with other anthropogenic stressors affecting Antarctic ecosystems, such as climate change (warming, ocean acidification) and pollution, with irreversible ramifications for biodiversity and ecosystem services. We review current knowledge of non‐native marine species in the Antarctic region, the physical and physiological factors that resist establishment of non‐native marine species, changes to resistance under climate change, the role of legislation in limiting marine introductions, and the effect of increasing human activity on vectors and pathways of introduction. Evidence of non‐native marine species is limited: just four marine non‐native and one cryptogenic species that were likely introduced anthropogenically have been reported freely living in Antarctic or sub‐Antarctic waters, but no established populations have been reported; an additional six species have been observed in pathways to Antarctica that are potentially at risk of becoming invasive. We present estimates of the intensity of ship activity across fishing, tourism and research sectors: there may be approximately 180 vessels and 500+ voyages in Antarctic waters annually. However, these estimates are necessarily speculative because relevant data are scarce. To facilitate well‐informed policy and management, we make recommendations for future research into the likelihood of marine biological invasions in the Antarctic region.
... Considering that many of the tested species germinated and grew under the contemporary scenario it is likely that they will be able to do so under current field temperature conditions. The tested species represent only a small fraction of the potential species pool that could reach Antarctica through human transport 12,13,44 , and the success or failure of some plant types/ species does not necessarily, therefore, represent the future success of other species within certain plant functional types. Diurnal temperature fluctuations can be an additional important factor behind seed germination 43,45 indicating that various temperature modulations may need to be tested before specific species can be ruled out. ...
... These findings also highlight the potential danger from the large number of non-native plant species that are already established on sub-Antarctic islands 23,44,63 , in particular South Georgia which lies on the Scotia Arc, that may act as stepping stones for species to reach the Antarctic Peninsula. Our data also indicate that typical Antarctic Peninsula soil 64,65 , as used in this study, provides a suitable substrate to support non-native plant growth if seeds can reach these locations. ...
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The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming. Establishment and subsequent range expansion of non-native plants depend in part on germination ability under Antarctic conditions, but quantifying these processes has yet to receive detailed study. Viability testing and plant growth responses under simulated Antarctic soil surface conditions over an annual cycle show that 16 non-native species, including grasses, herbs, rushes and a succulent, germinated and continued development under a warming scenario. Thermal germination requirement (degree day sum) was calculated for each species and field soil-temperature recordings indicate that this is satisfied as far south as 72° S. Here, we show that the establishment potential of non-native species, in number and geographical range, is considerably greater than currently suggested by species distribution modelling approaches, with important implications for risk assessments of non-native species along the Antarctic Peninsula.
... Despite their high conservation value, the Southern Ocean Islands (SOI) (which include the sub-Antarctic islands) have been invaded by non-native species. Thirteen invasive animal species have been successfully eradicated from a number of islands (McGeoch et al. 2015). Over time, control programs are tackling more complex situations, more widespread organisms and multiple species simultaneously (see Department of Conservation 2017; Royal Society for the Protection of Birds 2017; South Georgia Heritage Trust 2017). ...
... Whilst good progress is being made controlling invasive mammals, controlling non-native plants is less successful. Over 280 alien plant species have established on the SOI (McGeoch et al. 2015;Shaw 2013), however by 2013 only 21 recorded management actions had been undertaken to control or eradicate alien plants (Shaw 2013). To date, the only recorded successful eradications have been the grasses Anthoxanthum odoratum L., Agrostis stolonifera L. and A. capillaris L. and dock Rumex crispus L. from Macquarie Island (Copson and Whinam 2001;Department of Primary Industries, Parks, Water and Environment, unpublished data), a species of Rumex on Enderby Island in the Auckland Islands group (Shaw 2013) and Plantago lanceolata L., Hypochaeris radicata L. (Gremmen and Smith 1999), Alopecurus geniculatus L. and Holcus lanatus L. from the Prince Edward Islands (Greve et al. 2017). ...
Article
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Eradication of alien plants is notoriously challenging, however eradication projects reap great biodiversity benefits, particularly on islands. To date only individual plants or small restricted populations have been successfully eradicated from the Southern Ocean Islands (SOI). The next phase in conservation for the region is tackling more widespread, abundant alien plant species. Several on-going and proposed control programs for such weeds exist in the SOI and Antarctic regions. If eradication of a widespread species is to be successful, a number of factors need to be considered. ‘Organisational’ factors such as management agency capacity, resources and the availability of effective control methods are critical to the success of an eradication. ‘Site and species’ factors such as infestation extent, number of discrete populations, dispersal processes and detectability typically show a cumulative effect on success. We assessed the site and species factors for Stellaria media, an alien species on sub-Antarctic Macquarie Island, to determine the feasibility of its eradication from the island. Organisational factors can successfully be met with adequate funding. Site and species factors which reduce the likelihood of eradication included large gross infestation areas, large plants with high reproductive output (precocity or fecundity), dense seed banks, short pre-reproductive period, extended seed longevity and vegetative reproductive capacity. We recommend a small-scale eradication trial for restricted, easily accessible populations of S. media on Macquarie Island to further evaluate the likelihood of broader eradication.
... Biological invasions (along with climate change and interactions among these two change drivers) are the most significant terrestrial conservation challenges facing the region (Frenot et al. 2005;Chown et al. 2015a;Hughes et al. 2015). In consequence, an increasing amount is known about the correlates of invasion, the pathways for and vectors of non-native species, and the management strategies required to limit inadvertent introductions, especially given deliberate introductions are, for the most part, not permitted to the continent and its surrounding islands (Hughes and Convey 2012;Molina-Montenegro et al. 2014;McGeoch et al. 2015;Hughes and Pertierra 2016). Nonetheless, as is more broadly the case, the extent of information on impacts is surprisingly limited, particularly for plants (Gremmen et al. 1998;Frenot et al. 2001;Le Roux et al. 2013, Molina-Montenegro et al. 2012a, which is remarkable given that plants together with invertebrates are the most speciose groups of non-native species across the region (Frenot et al. 2005;Hughes et al. 2015), and are showing propensity for establishment on the continent itself (Molina-Montenegro et al. 2014). ...
... Overall, this study indicates that the substantial concerns already expressed about invasive plant species for the Antarctic continent (Shaw et al. 2014;Hughes et al. 2015) are warranted, and particularly so for P. annua which is already spreading in the region (Olech and Chwedorzewska 2011;Molina-Montenegro et al. 2012aHughes et al. 2015;Atala et al. 2019). Moreover, it provides additional evidence supporting general concerns about the impacts of grasses , and for a region where few investigations have been made of the impacts of invasive alien species on local populations (McGeoch et al. 2015). ...
Article
Full-text available
Biological invasions represent significant economic and conservation challenges, though it is widely acknowledged that their impacts are often poorly documented and difficult to predict. In the Antarctic, one non-native vascular plant species is widespread and studies have shown negative impacts on native flora. Using field "common garden" experiments, we evaluate the competitive impact of the increasingly widespread invasive grass Poa annua on the only two native vascular species of Antarctica, the forb Colobanthus quitensis and the grass Deschampsia antarctica. We focus on interactions between these three plant species under current and a future, wetter, climate scenario, in terms of density of individuals. Our analysis demonstrates Poa annua has the potential to have negative impacts on the survival and growth of the native Antarctic vascular species. Under predicted future wetter conditions, C. quitensis communities will become more resistant to invasion, while those dominated by D. antarctica will become less resistant. Under a recently developed unified scheme for non-native species impacts, P. annua can be considered a species that can cause potentially moderate to major impacts in Antarctica. If current patterns of increased human pressure and regional climate change persist and mitigation action is not taken (i.e. reduction of propagule
... Hughes and Convey 2012;Vicente et al. 2016), can, however, be much improved with more accurate information on the species actually being transported, the pathways involved for particular species, and the environments likely to receive them (McGeoch et al. 2016). Indeed, such information is essential not only for reducing the risks and costs of biological invasions (Simberloff et al. 2013), but also for monitoring the way in which pressure from this environmental driver is changing through time (McGeoch et al. 2015). ...
... It might thus be expected that in more simple situations, such as that represented by operations to the Antarctic continent, surveillance in the form of interception might prove more useful, especially since propagules of plants already recorded as alien to or invasive in the broader region are routinely recorded (Huiskes et al. 2014). In consequence, routine interception and recording, while not generally reported for the Antarctic continent, could prove to be valuable for improving the success of attempts to understand and reduce the threats posed by biological invasions in the region: by indicating colonization pressure, highlighting introduction pathways, and identifying high risk invertebrate species that are being transported to the region (McGeoch et al. 2015;Houghton et al. 2016). ...
Article
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Despite the significance of invertebrate species in the alien and invasive faunas of both sub-Antarctic and, increasingly, some Antarctic locations, little information exists on the numbers and identity of species being transported to the Antarctic region. Here we provide information on a decade (2006/2007–2016/2017) of detections in the surveillance program established at Scott Base in the Ross Sea region of continental Antarctica. The program found 233 individuals in 134 detection events, belonging to at least 14 Orders and 51 Families. Among these were alien, pest and synanthropic species recorded elsewhere on the globe or in the broader Antarctic region. These included sciarid flies known to have established in station sewage-treatment plants elsewhere on the continent. Flies, spiders and moths were most commonly detected, and typically in food (60% of interceptions), and then in clothing and equipment (11%), aircraft and cargo (11%) and packaging material (11%). Detected groups were similar to those found in the two other extensive surveillance efforts (King George Island and East Antarctica), highlighting the need to continue and improve surveillance across the region. For invertebrates, further control of the supply chain prior to embarkation of cargo and personnel may be the most effective management option to prevent further transport of non-indigenous species to the Antarctic.
... glacier melting, phytoplankton community shifts, changes in sea ice duration and extent) (Bers et al., 2013;Convey et al., 2009;Convey & Peck, 2019;Schofield et al., 2017;Schram et al., 2015). This makes the Western Antarctic Peninsula one of the most sensitive regions to potential invasions by introduced species in Antarctica (Hellmann et al., 2008;Hughes et al., 2020;McGeoch et al., 2015;Meredith & King, 2005). Increased temperatures and related environmental shifts indeed may favour the acclimation of non-native species introduced from warmer climates over cold-adapted native taxa (Galera et al., 2018;Hellmann et al., 2008). ...
... The Antarctic Treaty (ATCM, 2006) propagule pressure within stored water (Lee & Chown, 2009a). Our results strongly highlight the importance of the upcoming 2024 regulation to further protect Antarctic marine life from non-native species introduction, in complement to conservation measures applied for visitors and ships approaching Antarctic coasts (Hughes et al., 2020;Lennox et al., 2015;McGeoch et al., 2015). ...
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Aim The Western Antarctic Peninsula is challenged by climate change and increasing maritime traffic that together facilitate the introduction of marine non‐native species from warmer regions neighbouring the Southern Ocean. Ballast water exchange has been frequently reported as an introduction vector. This study uses a Lagrangian approach to model the passive drift of virtual propagules departing from Ballast water hypothetic exchange zones, at contrasting distances from the coasts. Location Western Antarctic Peninsula. Methods Virtual propagules were released over the 2008–2016 period and at three distances from the nearest coasts: 200 (convention for the management of Ballast Water, 2004), 50 or 11 nautical miles (NM). Results Results show that exchanging Ballast water at 200 NM considerably reduces the arrival of propagules in proposed marine protected areas of the western side of the Antarctic Peninsula. On the eastern side, propagules can reach north‐eastern marine protected areas within a few days due to strong currents for all tested scenarios. Seasonal and yearly variations indicate that exceptional climate events could influence the trajectory of particles in the region. Ballast water should be exchanged at least 200 NM offshore on the western side of the Antarctic Peninsula and avoided on the eastern side to limit particle arrival in proposed marine protected areas. Focusing on Deception Island, our results suggested that the Patagonian crab (Halicarcinus planatus) observed in 2010 could have been introduced in case of Ballast water exchange at 50 NM or less from the coast. Main conclusions This study highlights the importance of respecting Ballast water exchange convention to limit the risk of non‐native species introduction. Ballast water exchange should be operated at least at 200 NM from the coasts, which further limits particle arrival in shallow water areas. This is especially important in the context of a more visited and warmer Southern Ocean.
... The extremely harsh abiotic conditions in the Antarctic put particular pressure on alien organisms. Many alien plant propagules reach the region due to human-mediated transport (e.g., Hughes, Convey, Maslen, & Smith, 2010;Lityńska-Zając, Chwedorzewska, Olech, Korczak-Abshire, & Augustyniuk-Kram, 2012;Cuba-Díaz, Troncoso, Cordero, Finot, & Rondanelli-Reyes, 2013; for data on the broader Antarctic, see McGeoch, Shaw, Terauds, Lee, & Chown, 2015). ...
... Understanding of these processes is crucial for implementing successful management policies. In a situation where much of the international scientific community's concern is devoted to minimizing the anthropogenic impact on Antarctic ecosystems (e.g., Hughes, Pertierra, Molina-Montenegro, & Convey, 2015;McGeoch et al., 2015;Znój et al., 2017), the monitoring and eradication of even such a spatially limited invasion as in the case of P. annua on King George Island become an important conservation issue. Station. ...
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We studied an invasion of Poa annua on King George Island (Maritime Antarctic). The remoteness of this location, its geographic isolation and its limited human traffic provided an opportunity to trace the history of an invasion of the species. P. annua was recorded for the first time at H. Arctowski Polish Antarctic Station in the austral summer of 1985/6. In 2008/9 the species was observed in a new locality at the Ecology Glacier forefield (1.5 km from „Arctowski”). We used AFLP to analyze the genetic differences among three populations of P. annua: the two mentioned above (Station and Forefield) and the putative origin of the introduction, Warsaw (Poland). There was 38% genetic variance among the populations. Pairwise ФPT was 0.498 between the Forefield and Warsaw populations and 0.283 between Warsaw and Station. There were 15 unique bands in the Warsaw population (frequency frorm 6 to 100%) and one in the Station/Forefield populations (which appears in all analyzed individuals from both populations). The Δ(K) parameter indicated two groups of samples: Warsaw/ Station and Forefield. As indicated by Fu’s Fs statistics and an analysis of mismatch distribution, the Forefield population underwent a bottleneck and/or founder effect. The Forefield population was likely introduced by secondary dispersal from the Station population.
... Considering this, statistics plays an important role in production, analysis, integration and dissemination of environmental data (El-Shaarawi & Teugels 2005), becoming a tool for understanding natural environments (Dowd et al. 2014;Marcionilio et al. 2016). It is also important in monitoring air pollution (Bellini et al. 2007), in preventing pollution in aquatic environments (Paroissin et al. 2016), in analyzing the effects of pollution on heath , in evaluating and monitoring environmental impacts (McGeoch et al. 2015) and in environmental-related politics (Scott 2007). ...
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Environmental issues emerge in complex dimensions, which require an interdisciplinary framework in Environmental Sciences. Due to the diversity in statistical methods, graduate programs need to upgrade in order to form environmental scientists. Here, we test the hypothesis that QUALIS A1 Journals in the Environmental Science area use more complex statistical analyses. We describe the tests offered by graduate programs with PhD degree in Environmental Sciences. A total of 33.5% of 1560 papers evaluated had no statistical analysis. A1 journals used more T-Test, Chi-Square and Mann-Whitney tests than B1 journals. We found no difference between the use of univariate, multivariate and Bayesian analyses. In Brazil, there are 37 graduate programs in Environmental Sciences, of which 10 do not offer statistics course. Among the 38 courses offered, 73.7% provide only univariate statistics and 34.2% provide multivariate statistics. We conclude that quality in papers is not dependable on the complexity of statistical analyses, but on their theoretical framework.
... Their existence provides a unique opportunity to address two relevant issues: species introductions and biogeographical distribution of Antarctic microfauna. The threat of exotic species introductions to Antarctica has never had a higher profile (McGeoch et al. 2015, Houghton et al. 2016), but while introduced species are known for the Maritime Antarctic and also inside some stations in Antarctica, no exotics have been established at the more climatically extreme continental regions (see Chown et al. 2012, Hughes et al. 2015. ...
Article
Over a century ago microfaunal diversity was first recorded by James Murray in lakes at Cape Royds, Ross Island, Antarctica. The report stands as the seminal study for today’s biodiversity investigations, and as a baseline to evaluate changes in faunal communities and introductions. In the present study, Cape Royds lakes were revisited and the mitochondrial c oxidase subunit I (COI) gene and morphology were used to compare diversity of Rotifera, Tardigrada and Nematoda with the records Murray published in the early 1900s. Cyanobacterial mats and the water column were sampled for microfauna from the five largest lakes using methods described by Murray. Across all five lakes similar patterns were observed for species distribution of all three phyla reported by Murray over 100 years ago. Some changes in species assemblages were identified within and between lakes, but there were no new introductions of named species for the Cape Royds region. Some of the species included by Murray in his monograph have been recently redescribed as Antarctic endemics, but others still retain their original name from the Northern Hemisphere holotypes and are also in need of revision to adequately determine the true endemism for these faunal groups.
... Poa annua L. is a cosmopolitan weed (Heide, 2001). Its introduced range extends to the Arctic (Warwick, 1979), Antarctic Peninsula and subantarctic (Frenot et al., 2005;McGeoch, Shaw, Terauds, Lee, & Chown, 2015; 2015). On subantarctic Macquarie Island, P. annua was accidentally introduced by seal hunters nearly 150 years ago. ...
Article
Poa annua is a cosmopolitan weed in turf grass. It is a widespread non-native species in the subantarctic and also occurs in the Antarctic Peninsula. It has highly variable morphology, longevity and reproductive capacity across both its invaded and native range. Little is known about the ecology of P. annua in the subantarctic, particularly its longevity, morphological variation across small spatial scales and competitive ability. We monitored individual P. annua plants on subantarctic Macquarie Island to assess their longevity; quantified morphology and biomass allocation across environmental gradients; and assessed community diversity indices in areas of varying P. annua density. We show that P. annua plants on Macquarie Island are perennial, and their morphology varies with elevation, animal disturbance and soil properties. At low altitude, coastal sites with high animal disturbance and deep, sandy soils, P. annua plants are larger and native plant diversity is low. Conversely, at high altitude sites P. annua plants are smaller and the diversity of native species is not reduced. This new information informs why P. annua is the most successful plant invader in the subantarctic and quantifies some key characteristics enabling an invasive species to function well beyond its natural range. Community ecology theory can also explain patterns in the ecology of P. annua on Macquarie Island.
... Recent advances have been made in understanding global and regional patterns in the naturalization of alien taxa, and in biodiversity informatics for global environmental problems, including biological invasions (e.g. Capinha et al., 2015;McGeoch et al., 2015b;van Kleunen et al., 2015). Digital infrastructure for big data on Essential Variables is under development (Canhos et al., 2015;Jetz et al., 2012;Nativi et al., 2015). ...
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Managing biological invasions relies on good global coverage of species distributions. Accurate information on alien species distributions, obtained from international policy and cross-border cooperation , is required to evaluate trans-boundary and trading partnership risks. However, a standardized approach for systematically monitoring alien species and tracking biological invasions is still lacking. This Perspective presents a vision for global observation and monitoring of biological invasions. We show how the architecture for tracking biological invasions is provided by a minimum information set of Essential Variables, global collaboration on data sharing and infrastructure, and strategic contributions by countries. We show how this novel, synthetic approach to an observation system for alien species provides a tangible and attainable solution to delivering the information needed to slow the rate of new incursions and reduce the impacts of invaders. We identify three Essential Variables for Invasion Monitoring; alien species occurrence, species alien status and alien species impact. We outline how delivery of this minimum information set by joint, complementary contributions from countries and global community initiatives is possible. Country contributions are made feasible using a modular approach where all countries are able to participate and strategically build their contributions to a global information set over time. The vision we outline will deliver wide-ranging benefits to countries and international efforts to slow the rate of biological invasions and minimize their environmental impacts. These benefits will accrue over time as global coverage and information on alien species increases.
... case of vascular plants and insects, introductions do indeed seem to weaken isolation-richness relationships(Figure 3d-i). These differences between the taxa can, in part, be ascribed to differences in the diversity and origin of introduced species among the groups, with plants and insects including species that are very widely distributed across the region (McGeoch,Shaw, Terauds, Lee, & Chown, 2015;Shaw et al., 2010). ...
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We investigated turnover and richness in Antarctic springtails to understand large‐scale patterns in soil faunal diversity and how these are altered by biological invasions. Antarctica and the Southern Ocean Islands. Collembola (springtails). We developed a database of all springtail species recorded from the Antarctic region. The relationship of species richness and turnover to high‐resolution environmental data was explored using generalized linear models and generalized dissimilarity models, and compared among indigenous and introduced species. Endemicity and species turnover were assessed using beta‐diversity and multi‐site zeta diversity metrics to explore whether introduced species have homogenized assemblages across the region. Indigenous, endemic and introduced species richness covaried positively with temperature. Endemic richness was further related to thermal heterogeneity, and introduced species richness to human occupancy. Indigenous and introduced species richness covaried positively. Species turnover across the region was high, and the introduction of non‐indigenous species further differentiated assemblages. Species similarity between sites was not related to distance, nor was geographic isolation correlated with species richness. Assemblage turnover was influenced by the area and temperature range of islands. Energy availability appears to be the primary covariate of species richness, with human presence additionally influencing introduced species richness, in agreement with other soil‐dwelling taxa. Dispersal limitation surprisingly does not seem to be important in structuring these assemblages, nor does island age appear to affect richness; this may in part reflect the severe glacial history of the region. The differentiating effect of introduced species on assemblages suggests that anthropogenic introductions originate from distinct source pools, challenging common assumptions for the Antarctic. Positive covariance between indigenous and introduced species richness accords with the “rich get richer” hypothesis. Thus, the most biotically diverse terrestrial areas of Antarctica may be the most prone to future biological invasion.
... Invasive alien species (IAS) are defined as 'a species that is established outside of its natural past or present distribution, whose introduction and/or spread threaten biological diversity' (IUCN 2016) and are increasingly recognised as a threat to global biodiversity, ecosystem services and human health (Walther et al. 2009;McGeoch et al. 2010;Early et al. 2016). The threat is likely to increase on subantarctic islands that are projected to experience substantial climate changes over the next century (Whittaker & Fernández-Palacios 2007;Kueffer et al. 2010;Lebouvier et al. 2011) and may act as 'stepping stones' across the Southern Ocean to the Antarctic continent (Frenot et al. 2005;Gregory 2009; Lee & Chown 2009;Nikula et al. 2010;Chown et al. 2012;Hughes & Convey 2012;McGeoch et al. 2015). While palaeoecological studies provide important insights into the timing and ecological impact(s) of IAS (Wilmshurst et al. 2015), there are few baseline measurements of growth response to climate in these remote islands. ...
Article
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Invasive alien species (IAS) are a recognised threat to biodiversity and ecosystem services. With increasing tourism and projected 21st century climate changes across the mid-to high-latitudes of the southern hemisphere, subantarctic islands are potentially highly vulnerable to IAS, but suffer from a dearth of baseline monitoring. Here we report tree-ring measurements from a lone exotic Sitka spruce (Picea sitchensis (Bong.) Carr) on subantarctic Campbell Island to determine past growth rates and likely future response to climate changes. Though the samples were unable to resolve exactly when the tree was planted, the fast growth rate indicates it is likely to have been later than the reported date of 1901. Since at least 1941, the tree appears to have responded favourably to the relatively warm summers experienced on Campbell Island, resulting in growth more rapid than that observed in natural stands (North American Pacific Coast). Although trees of similar age are normally mature and produce cones, none have so far been observed on Campbell Island-possibly the result of the fast growth causing an extended 'juvenile' or pre-reproductive phase-preventing seeding across the island. Importantly, relatively dry periods are needed for cones to open and disperse seeds, conditions not recorded in the instrumental record. Examination of the Coupled Model Intercomparison Project 5 (CMIP5) outputs show increasing rainfall across the region during the 21st century under a range of emission scenarios, suggesting that even when mature, the Sitka spruce poses a limited threat to the long-term ecology of Campbell Island.
... Invasive species research has identified the sources and types of propagules as well as their pathways to Antarctica (Q.54). 8,129,130 Distinguishing range shifts from introductions remains underinvestigated, as do studies of potential impacts (Q.55). 131,132 Climate-change impacts on establishment likelihood have been evaluated, although species distribution modeling is underutilized. ...
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The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popular beliefs that Antarctica is pristine, stable, isolated, and reliably frozen. An aspirational roadmap for Antarctic science has facilitated research since 2014. A renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond. Progress is already evident, such as addressing uncertainties in the causes and pace of ice loss and global sea-level rise. However, much remains to be learned. As an iconic global “commons,” the rapidity of Antarctic change will provoke further political action. Antarctic research is more vital than ever to a sustainable future for this One Earth.
... The Post-2020 Biodiversity Framework proposes the use of the Driver-Pressure-State-Response (DPSR) and Theory of Change (ToC) frameworks in the design of informative indicators (OECD, 2019). In the context of IAS, the DPSR framework distinguishes individual invasion indicators based on the underlying pathways for IAS (Drivers; e.g., trade or transport), indicators of IAS change (Pressure; e.g., number or abundance of IAS), biophysical conditions or state as a consequence of IAS impacts (State; e.g., number of impacted native species), and societal responses to IAS (Response; e.g., actions to control IAS) (McGeoch et al., 2010(McGeoch et al., , 2015. Response indicators can be further compartmentalized, according to the Theory of Change (ToC) framework, into indicators of inputs (i.e., resources needed for a response, e.g., budget or staff), processes (i.e., progress of the response that uses inputs; e.g., committees or actions), outputs (i.e., measure of the amount and quality of the response results; e.g., research, reports or policy instruments), outcomes (i.e., IAS changes resulting from the response action; e.g., number or abundance of IAS taxa), and impacts (i.e., measures of the improved condition of the invaded site). ...
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Monitoring the progress parties have made toward meeting global biodiversity targets requires appropriate indicators. The recognition of invasive alien species (IAS) as a biodiversity threat has led to the development of specific targets aiming at reducing their prevalence and impact. However, indicators for adequately monitoring and reporting on the status of biological invasions have been slow to emerge, with those that exist being arguably insufficient. We performed a systematic review of the peer-reviewed literature to assess the adequacy of existing IAS indicators against a range of policy-relevant and scientifically valid properties. We found that very few indicators have most of the desirable properties and that existing indicators are unevenly spread across the components of the Driver-Pressure-State-Response and Theory of Change frameworks. We provide three possible reasons for this: (i) inadequate attention paid to the requirements of an effective IAS indicator, (ii) insufficient data required to populate and inform policy-relevant, scientifically robust indicators, or (iii) deficient investment in the development and maintenance of IAS indicators. This review includes an analysis of where current inadequacies in IAS indicators exist and provides a roadmap for the future development of indicators capable of measuring progress made toward mitigating and halting biological invasions. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
... However, there are increasing reports of non-native plants and invertebrates in the APR, almost exclusively in the vicinity of research stations and visitor sites (Hughes, Pertierra, et al., 2015;Molina-Montenegro et al., 2012;Volonterio, Leon, Convey, & Krzeminska, 2013). There is poor understanding of the rate of non-native species arrival and establishment across marine, freshwater and terrestrial environments due to a general lack of monitoring (Enríquez et al., 2019;Hughes & Pertierra, 2016;McGeoch, Shaw, Terauds, Lee, & Chown, 2015). Nevertheless, non-native invertebrates have been found in several locations where soil samples have been taken, suggesting that actual levels of introductions may be greater than currently documented (e.g. ...
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The Antarctic is considered to be a pristine environment relative to other regions of the Earth, but it is increasingly vulnerable to invasions by marine, freshwater and terrestrial non-native species. The Antarctic Peninsula region (APR), which encompasses the Antarctic Peninsula, South Shetland Islands and South Orkney Islands, is by far the most invaded part of the Antarctica continent. The risk of introduction of invasive non-native species to the APR is likely to increase with predicted increases in the intensity, diversity and distribution of human activities. Parties that are signatories to the Antarctic Treaty have called for regional assessments of non-native species risk. In response, taxonomic and Antarctic experts undertook a horizon scanning exercise using expert opinion and consensus approaches to identify the species that are likely to present the highest risk to biodiversity and ecosystems within the APR over the next 10 years. One hundred and three species, currently absent in the APR, were identified as relevant for review, with 13 species identified as presenting a high risk of invading the APR. Marine invertebrates dominated the list of highest risk species, with flowering plants and terrestrial invertebrates also represented; however, vertebrate species were thought unlikely to establish in the APR within the 10 year timeframe. We recommend (a) the further development and application of biosecurity measures by all stakeholders active in the APR, including surveillance for species such as those identified during this horizon scanning exercise, and (b) use of this methodology across the other regions of Antarctica. Without the application of appropriate biosecurity measures, rates of introductions and invasions within the APR are likely to increase, resulting in negative consequences for the biodiversity of the whole continent, as introduced species establish and spread further due to climate change and increasing human activity.
... Invasive species research has identified the sources and types of propagules as well as their pathways to Antarctica (Q.54). 8,129,130 Distinguishing range shifts from introductions remains underinvestigated, as do studies of potential impacts (Q.55). 131,132 Climate-change impacts on establishment likelihood have been evaluated, although species distribution modeling is underutilized. ...
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The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popular beliefs that Antarctica is pristine, stable, isolated, and reliably frozen. An aspirational roadmap for Antarctic science has facilitated research since 2014. A renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond. Progress is already evident, such as addressing uncertainties in the causes and pace of ice loss and global sea-level rise. However, much remains to be learned. As an iconic global “commons,” the rapidity of Antarctic change will provoke further political action. Antarctic research is more vital than ever to a sustainable future for this One Earth.
... As a result, the often-endemic terrestrial biota of the Southern Ocean islands as well as of the Antarctic continent are exposed to new biotic interactions arising from the arrival of alien species (e.g. Hughes, Pertierra, Molina-Montenegro, & Convey, 2015;McGeoch, Shaw, Terauds, Lee, & Chown, 2015;Volonterio, Ponce de Leon, Convey, & Krzeminska, 2013). The combined impact from changing environmental conditions along with biological invasion processes, has led to reports of collapsing ecosystems in the wider Antarctic region (e.g. ...
Article
Correlative species distribution models (SDMs) are subject to substantial spatio‐temporal limitations when historical occurrence records of data‐poor species provide incomplete and outdated information for niche modelling. Complementary mechanistic modelling techniques can, therefore, offer a valuable contribution to underpin more physiologically informed predictions of biological invasions, the risk of which is often exacerbated by climate change. In this study we integrate physiological and human pressure data to address the uncertainties and limitations of correlative SDMs and to better understand, predict and manage biological invasions. Western archipelagos of the Southern Ocean and martime Antarctica. Eretmoptera murphyi (Chironomidae), invertebrates. Mahalanobis Distances were used for correlative SDM construction for a species with few records. A mechanistic SDM was built around different fitness components (larval survival and life stage progression) as a function of temperature. SDM predictions were combined with human activity levels in Antarctica to generate a site vulnerability index to the assess colonization risk of E. murphyi. Future scenarios of ecophysiological suitability were built around the warming trends in the region. Both SDMs converge to predict high environmental suitability in the species' native and introduced ranges. However, the mechanistic model indicates a slightly larger invasive potential based on larval performance at different temperatures. Human activity levels across the Antarctic Peninsula play a key role in discerning site vulnerabilities. Niche suitability in Antarctica grows considerably under long‐term climate scenarios, leading to a substantially higher invasive threat to the Antarctic ecosystems. In turn changing conditions result in growing physiological mismatches with the environment in the native range in South Georgia. Long‐term studies of invasion potential under climate benefit from integrating correlative predictions with physiological experiments, as the invasion potential varies depending on the area and the timescale examined. This study also highlights a conservation paradox whereby the accidental introduction of an insect represents a threat to the Antarctic ecoystems that contrasts with its endangered status at the native range.
... The biodiversity of the terrestrial faunas of these regions is often dominated by invertebrate groups to a greater extent than is typical elsewhere. Many of these cold ecosystems are also, in effect, isolated island ecosystems, with recognized particular vulnerability to invasions by non-native species (McGeoch et al., 2015). ...
Article
Polar and alpine regions are changing rapidly with global climate change. Yet the impacts on biodiversity, especially on the invertebrate ectotherms which are dominant in these areas, remain poorly understood. Short‐term extreme temperature events, which are growing in frequency, are expected to have profound impacts on high‐latitude ectotherms, with native species being less resilient than their alien counterparts. Here, we examined in the laboratory the effects of short periodic exposures to thermal extremes on survival responses of seven native and two non‐native invertebrates from the sub‐Antarctic Islands. We found that survival of dipterans was significantly reduced under warming exposures, on average having median lethal times (LT50) of about 30 d in control conditions, which declined to about 20 d when exposed to daily short‐term maxima of 24°C. Conversely, coleopterans were either not, or were less, affected by the climatic scenarios applied, with predicted LT50 as high as 65 d under the warmest condition (daily exposures at 28 °C for 2 h). The native spider Myro kerguelensis was characterized by an intermediate sensitivity when subjected to short‐term daily heat maxima. Our results unexpectedly revealed a taxonomic influence, with physiological sensitivity to heat differing between higher level taxa, but not between native and non‐native species representing the same higher taxon. The survival of a non‐native carabid beetle under the experimentally imposed conditions was very high, but similar to that of native beetles, while native and non‐native flies also exhibited very similar sensitivity to warming. As dipterans are a major element of diversity of sub‐Antarctic, Arctic and other cold ecosystems, such observations suggest that the increased occurrence of extreme, short‐term, thermal events could lead to large scale restructuring of key terrestrial ecosystem components both in ecosystems protected from and those exposed to the additional impacts of biological invasions.
... It is theorized that through investment in flexible life histories and stress tolerance adaptations that Antarctic species are generally poor competitors (Convey, 1996;Hughes et al., 2019). Examples from the sub-Antarctic islands indicate that non-native species in the region can be extremely competitive and have devastating, broadscale impacts on an entire ecosystem (Angel et al., 2009;Lebouvier et al., 2020;McGeoch et al., 2015). Does this mean that some native Antarctic species will start to be encroached on by more competitive species, or that communities will become more homogeneous? ...
Article
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Antarctic biodiversity faces an unknown future with a changing climate. Most terrestrial biota is restricted to limited patches of ice‐free land in a sea of ice, where they are adapted to the continent’s extreme cold and wind and exploit microhabitats of suitable conditions. As temperatures rise, ice‐free areas are predicted to expand, more rapidly in some areas than others. There is high uncertainty as to how species’ distributions, physiology, abundance and survivorship will be affected as their habitats transform. Here we use current knowledge to propose hypotheses that ice‐free area expansion i) will increase habitat availability, though the quality of habitat will vary; ii) will increase structural connectivity, although not necessarily increase opportunities for species establishment; iii) combined with milder climates will increase likelihood of non‐native species establishment, but may also lengthen activity windows for all species; and iv) will benefit some species and not others, possibly resulting in increased homogeneity of biodiversity. We anticipate considerable spatial, temporal, and taxonomic variation in species responses, and a heightened need for interdisciplinary research to understand the factors associated with ecosystem resilience under future scenarios. Such research will help identify at‐risk species or vulnerable localities and is crucial for informing environmental management and policymaking into the future.
... Each of these islands includes one or more invasive Collembola species (5, 1 and 13 species, respectively), defined as alien species which have spread to multiple sites and/or vegetation communities. The invasions are thought to have occurred since human occupation of the islands commenced in the 1800s (Deharveng, 1981;Gabriel et al., 2001;Greenslade, 2006;Hugo et al., 2006;Terauds et al., 2011), along with invasions by vascular plants, and in the case of Marion and Macquarie, mammals (Frenot et al., 2005;McGeoch et al., 2015). The islands include different invasive Collembola and plant species, thus resulting in quite different invasive alien species assemblages. ...
Article
The Antarctic climate-diversity-invasion hypothesis (ACDI) predicts that in Antarctic soil systems, climate change should lead to increases in the abundance and diversity of indigenous assemblages. Where biological invasions have occurred, however, invasive alien species should have negative effects on indigenous faunal assemblages. To assess these predictions, we provide the first systematic ecological survey of the Collembola assemblages of pristine, sub-Antarctic Heard Island (53.1°S, 73.5°E) and compare the results to similarly conducted surveys of three other sub-Antarctic islands (Marion, Prince Edward, and Macquarie), characterised by assemblages including invasive Collembola. In particular, we examine differences in densities of three indigenous species (Cryptopygus antarcticus, Mucrosomia caeca, Tullbergia bisetosa) shared between the invaded islands and Heard Island. On average, density of these species was four or more-fold significantly lower on the invaded islands than on uninvaded Heard Island. Yet mean assemblage densities of springtails, accounting for variation among vegetation communities, did not differ substantially or significantly among the islands, suggesting that compensatory dynamics may be a feature of these systems. The invasion impact prediction of the ACDI is therefore supported. On Heard Island, indigenous assemblage variation is strongly related to vegetation community and less so to elevation, in keeping with investigations of Collembola assemblage variation elsewhere across the Antarctic. These findings, in the context of field experimental and physiological data on Collembola from the region, suggest that the climate-diversity predictions of the ACDI will play out in different ways across the Antarctic, depending on whether precipitation increases or decreases as climates change.
... Biological invasions are widely recognized as being one of the most significant threats to biodiversity and are expected to increase with global warming (Shaw et al. 2010;McGeoch et al. 2015). Sub-Antarctic islands are deeply affected by climate change (Lebouvier et al. 2011) which makes their ecosystems more suitable to less stress-adapted non-native species (Pertierra et al. 2017). ...
Article
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Biological invasions are a major threat to the terrestrial ecosystems of the sub-Antarctic islands. While non-native plants generally have negative impacts on native arthropods, few studies have investigated how both native and non-native arthropods and plants interact in the sub-Antarctic islands. This was the aim of our study, which was conducted on three islands of the Kerguelen archipelago. The design was based on the spatial proximity of areas dominated by non-native or native plant species. Trait-based indices were calculated to characterize the functional structure of plant communities, considering plant stature and leaf traits. Native and non-native vegetation had contrasting functional composition but their functional diversity was similar. The effects of the type of vegetation, native or non-native, and plant functional diversity on arthropods were tested. Native macro-arthropod richness and abundance were similar or higher in non-native vegetation, and benefited from greater plant functional diversity. Abundances of macro-herbivores, macro-decomposers and macro-predators were also similar or higher in non-native vegetation. Conversely, the abundances of micro-arthropods, Symphypleona springtails and Oribatida mites, were higher in native vegetation but we also found that plant functional diversity had a negative effect on Symphypleona. Our results suggest that non-native plants can affect micro-arthropods directly or indirectly, likely through their effects on abiotic factors. By affecting macro-arthropod abundances across different trophic groups and by depleting micro-arthropods, non-native plants can alter trophic interactions, functional balances and the functioning of whole ecosystem.
... Preventing arrivals, or ensuring the early detection of introduced species to facilitate a rapid response, is particularly important given the subsequent difficulty of eradication, especially of invertebrates Shaw 2014;Hughes et al. 2015). Key to doing so is appropriate risk assessment for species likely to arrive, surveillance both of vectors and pathways, and surveillance for arrivals and species that may be extending their ranges (Chown et al. 2012;Hughes and Convey 2012;Volonterio et al. 2013;McGeoch et al. 2015;Houghton et al. 2016;Lee and Chown 2016). Where such surveillance is not routinely undertaken, other studies can inform conservation actions based on information on new arrivals or on range expansions documented during routine ecological studies (Crafford and Chown 1987). ...
Article
Collembola are an important group of indigenous terrestrial invertebrates in the sub-Antarctic region and, compared to the most continental regions, their limited diversity is well known. Several invasive species, introduced by humans, have also established in the region, with some of these widespread while others are more restricted to disturbed areas. In this study, we report the spread of two non-indigenous Collembola species on Macquarie Island. Protaphorura fimata (Gisin, 1952) (Collembola:Poduromorpha:Onychiuridae) and Proisotoma minuta (Tullberg, 1871) (Entomobryomorpha:Isotomidae) are both cosmopolitan species that have been present on the island for several decades, but restricted to the area around the research station. Here, we report their spread up to 3 and 11 km, respectively, from the research station. We discuss the implications of this finding for biosecurity across the Antarctic region. We also document the presence of a new non-indigenous species, Parisotoma notabilis (Schäffer, 1896) (Entomobryomorpha:Isotomidae).
... SDGs) as part of the discourse concerning both conservation and the general biodiversity status (Lacher and Hilton-Taylor, 2018). The Red List Index provides a measure for the change in aggregate extinction risks across groups of species (IUCN, 2019), and was used as a measure of the state of biodiversity by McGeoch et al. (2015) in monitoring biological invasions across the broader Antarctica. Biocapacity "On the supply side, a city, state or nation's biocapacity represents the productivity of its ecological assets (including cropland, grazing land, forest land, fishing grounds, and built-up land)" (Global Footprint Network, 2019). ...
Article
Small Island Developing States are under significant threat from global change and unsustainable local practices. These issues are generally exacerbated by an inherent vulnerability to social, economic and ecological changes consequential to their unique island characteristics (e.g. limited resources), which is often described as “islandness”. These unique island characteristics or “islandness” have shaped, and continue to shape, their socio-ecological systems which, from a real-world geographic perspective, the island and its communities form an integrated socio-ecological landscape. It can be argued that “islandness” contributes immensely to understanding the socio-ecological systems of an island, and in considering “islandness” as a fundamental element that significantly influences socio-ecological systems on islands, socio-ecological systems then materialise as socio-ecological islandscapes. This study ultimately sets out to initiate the development of the socio-ecological islandscape concept through (1) providing the preliminary framework, and (2) gaining insights into what impact each of the unique characteristics of “islandness” has on a system, both as individual components and as a collective, through the use of Bayesian Belief Networks. The results of the study provide evidence of the influence that “islandness” has on both the social and ecological components of a socio-ecological system. Differences in degree of influence between the unique island characteristics (e.g. size vs. isolation) also showed how some characteristics have greater impacts. The socio-ecological islandscape framework proposed in this study propagates a research agenda focused on the SES-landscape-SIDS-islandness nexus, due to its apparent effect on the economic disadvantages and ecological fragility faced by SIDS that threatens their sustainability.
... Among the grasses, Poa annua L. (vernacular name: annual bluegrass or annual meadow grass) is an exemplar invasive species, being the most widespread invasive plant in the broader Antarctic region (McGeoch et al., 2015;Shaw et al., 2010). As a ruderal species, P. ...
Article
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The link between the successful establishment of alien species and propagule pressure is well‐documented. Less known is how humans influence the post‐introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differently impacted by humans. We analysed microsatellite and genome size variation, and then compared the genetic diversity and structure of invasive Poa annua L. on two sub‐Antarctic islands: human‐occupied Marion Island and unoccupied Prince Edward Island. We also carried out niche modelling to map the potential distribution of the species on both islands. We found high levels of genetic diversity and evidence for extensive admixture between genetically distinct lineages of P. annua on Marion Island. By contrast, the Prince Edward Island populations showed low genetic diversity, no apparent admixture, and had smaller genomes. On both islands, high genetic diversity was apparent at human landing sites, and on Marion Island, also around human settlements, suggesting that these areas received multiple introductions and/or acted as initial introduction sites and secondary sources (bridgeheads) for invasive populations. More than 70 years of continuous human activity associated with a meteorological station on Marion Island led to a distribution of this species around human settlements and along footpaths, which facilitates ongoing gene flow among geographically separated populations. By contrast, this was not the case for Prince Edward Island, where P. annua populations showed high genetic structure. The high levels of genetic variation and admixture in P. annua facilitated by human activity, coupled with high habitat suitability on both islands, suggest that P. annua is likely to increase its distribution and abundance in the future.
... The most immediate conservation threats to species, ecosystems, and resources in Antarctica and the Southern Ocean, include climate change, marine exploitation (fisheries), pollution events, competition for scarce ice-free ground, and biological introductions and invasions (Blight et al. 2010;Brooks et al. 2018;Chown et al. 2012b;Frenot et al. 2005;Hughes et al. 2018;Hughes and Grant 2017;McGeoch et al. 2015;Tin et al. 2009), along with challenges in governance ). ...
Chapter
The continent of Antarctica has an area of c.1.4 million km2 , and the surrounding Southern Ocean (waters south of the Antarctic Polar Front) comprises 9.6% of the world’s oceans, both possessing significant environmental, scientific, historic, educational, and intrinsic values (Burton-Johnson et al. 2016; Hughes et al. 2018; Xavier et al. 2016b). Antarctica is the coldest, windiest, and driest continent on Earth, with temperatures in parts of its central icy plateau descending below 90 °C (Cassano 2013; Scambos et al. 2018). Antarctica includes about 10% of the planet’s land surface and its ice contains about 70% of its freshwater (Kennicutt II et al. 2014; Walton 2013). It became isolated from other continents around 25–35 My ago, in the final stages of the breakup of Gondwana (Convey et al. 2018; Storey 2013), and this has led to high levels of endemism, particularly of certain marine groups such as fish and crustaceans (Xavier and Peck 2015), and many terrestrial groups (Pugh and Convey 2008). Antarctica hosts a wide diversity and abundance of species, particularly but not only in the marine environment (Convey 2017; De Broyer and Jażdżewska 2014). The Antarctic Treaty governs the region south of the 60° parallel of latitude, with its main objectives being to ensure peaceful use of Antarctica, promote international scientific cooperation and deliver environmental protection (Bennett et al. 2015; Berkman 2009; Hughes et al. 2018).This book chapter reviews climate change, fisheries and governance of the Antarctic region.
... Although prevention measures are the most cost-effective and successful actions to stop the spread of NIS (Leung et al. 2002;Hulme 2006;Joyce et al. 2019), artificial structures still harbor more NIS than the neighboring natural substrates (Rivero et al. 2013). Consequently, long-term NIS monitoring is mandatory to coordinate and subsidize decision making and political stances toward their control (Blossey 1999;McGeoch et al. 2015). Studies using mathematical models and projects aiming to keep track of invasive species have increased our knowledge on their invasive potential and on the changes of the invaded community (Cockrell and Sorte 2013;Seebens et al. 2013;Maistrello et al. 2016;Creed et al. 2017a). ...
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Marinas create physical and biotic conditions distinct from those in natural habitats which can facilitate the establishment of non-indigenous species (NIS) in coastal ecosystems. Using a series of images spanning nine years, we detected the introduction and followed the expansion of the NIS Tubastraea coccinea and T. tagusensis populations at a recreational marina in a region of Southeastern Brazil where sun-corals are rarely found on natural substrates. Because sun corals are known to reduce diversity in natural invaded environments, we evaluated how different densities of sun-corals affected the benthic community. Overall, the NIS populations have grown exponentially from 2010 to 2019 inside the marina, occupying up to 60% of the available space. However, the population growth in the breakwater stopped in 2016. Local variation in the population growth across the marina might be associated with the high phytoplankton biomass and larval retention inside the marina, which are results of the lower hydrodynamics. The expansion of sun-coral coverage did not significantly affect the richness of benthic communities but was associated with a reduction of the native bryozoan Amathia brasiliensis, the overall abundance of mobile crustaceans, and an increase in the area covered by the exotic bryozoan S. errata. The fast substitution of a native ecosystem engineer for a NIS suggests signs of invasion meltdown associated with the expansion of Tubastraea spp.
... Invasion across the sub-Antarctic region is relatively recent with most of the islands discovered only 200 or so years ago (see Frenot et al. 2005). Invasion studies from the sub-Antarctic and Antarctica (Hughes and Worland 2010;Frenot et al. 2005;McGeoch et al. 2015), and more broadly (Williamson and Fitter 1996;Kolar and Lodge 2001;Sol et al. 2012;Walther et al. 2009), show only a minority of non-native species introduced become invasive, while many other non-native species establish and are 'persistent' neither expanding or contracting their range over decades. Our survey found Arthurdendyus vergrandis had very low or localised populations, and we found no evidence that Styloniscus otakensis and Puhuruhuru patersoni have expanded their ranges, remaining restricted to the north of the island. ...
Article
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Spanning the Southern Ocean high latitudes, Sub-Antarctic islands are protected areas with high conservation values. Despite the remoteness of these islands, non-native species threaten native species and ecosystem function. The most ubiquitous and speciose group of non-native species in the region are invertebrates. Due to their cryptic habits and ambiguous establishment history, the impacts of non-native invertebrates on native species and ecosystems in the region remains largely unknown. Understanding how non-native invertebrate species are transported, disperse, establish and colonise new habitats is key to understanding their existing and future impacts. This research is fundamental to improving biosecurity practise and informing future management of Southern Ocean islands. We undertook invertebrate surveys on Macquarie Island to determine the current status of four non-native macro-invertebrates—Kontikia andersoni and Arthurdendyus vegrandis (Platyhelminthes: Geoplanidae), Styloniscus otakensis (Isopoda: Styloniscidae) and Puhuruhuru patersoni (Amphipoda: Talitridae). Arthurdendyus vergrandis was not intercepted in our surveys, while we found S. otakensis and P. patersoni had not expanded their range. In contrast, K. andersoni has more than doubled its previously mapped area and expanded at a rate of ~ 500 m-yr since 2004. We discuss the possible underlying mechanisms for the dramatic range expansion of K. andersoni and consider the implications for the future management of Macquarie Island.
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Monitoring the progress parties have made toward meeting global biodiversity targets requires appropriate indicators. The recognition of Invasive alien species (IAS) as a biodiversity threat has led to the development of specific targets aiming at reducing their prevalence and impact. However, indicators for adequately monitoring and reporting on the status of biological invasions have been slow to emerge, with those that exist being arguably insufficient. We performed a systematic review of the peer-reviewed literature to assess the adequacy of existing IAS indicators against a range of policy-relevant and scientifically valid properties. We found that very few indicators have most of the desirable properties, and that existing indicators are unevenly spread across the components of the Driver-Pressure-State-Response and Theory of Change frameworks. We provide three possible reasons for this: i) inadequate attention paid to the requirements of an effective IAS indicator, (ii) insufficient data required to populate and inform policy-relevant, scientifically robust indicators, or (iii) deficient investment in the development and maintenance of IAS indicators. This review includes a gap analysis of where current inadequacies in IAS indicators exist, and provides a roadmap for the future development of indicators capable of measuring progress made toward mitigating and halting biological invasions.
Article
Plant eradication is difficult, particularly in remote, protected areas. The Southern Ocean Islands are very isolated and highly protected, but the flora contains many alien plants. Small restricted populations have been eradicated, but eradication of established species has proven difficult. A better understanding of the efficacy of control methods at sub‐Antarctic temperatures and their off‐target impacts may increase eradication success. With interest in controlling non‐native Poa annua in the region, we aimed to determine if physical and chemical methods can control P. annua (the sub‐Antarctic biotype) in sub‐Antarctic conditions and examined their impact on native plants. We quantified the effectiveness of physical control methods on P. annua in situ on sub‐Antarctic Macquarie Island through field‐based experiments and assessed their selectivity on P. annua compared with native grasses. We also quantified the effectiveness of several herbicides on P. annua at sub‐Antarctic temperatures and assessed their selectivity on native grasses. Of the four physical disturbance methods tested, none effectively reduced P. annua cover as one‐off treatments. Of the herbicide treatments, glyphosate and trifloxysulfuron sodium were effective and were less damaging to native grass species, indicating potential selectivity. Physical control was of limited effectiveness, but did not affect native species richness. An integrated weed management programme utilising the strategic use of selective herbicides with follow‐up chemical and physical intervention may balance control and biodiversity outcomes. This research highlights the importance of site‐specific testing of control methods and understanding off‐target impacts of control when managing alien plant species in protected areas.
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From 2014 to 2018, we performed three on-site eradication actions of Poa annua occurring on King George Island. We aimed at (1) assessing the population response to eradication efforts, (2) evaluating the campaign success, and (3) identifying the most important factors likely to influence eradication success. The first partial eradication action reduced the initial population of around 1500 tussocks to around 1100 tussocks with less than 4 m ² canopy area. In treated locations, we observed high re-establishment where no soil removal was performed, while only a marginal recruitment where plants were removed with associated soil. In the 2017/2018 season, we recorded over 1800 tussocks, which all were subsequently removed. Performing eradication according to the prescribed scheme (plant and soil removal) should result in eradication success. We evaluate that the probability of successful eradication of the population is high because of small size and number of separate infestation sites, complete spatial and ecological isolation of infestation, high accessibility of target population, and well-known current location of infestation sites. The factors which reduce the likelihood of eradication success are long reaction time, high adaptation of the species to new environmental conditions, and high propagule longevity. Reinvasion possibility and frequent personnel changes in the eradication team resulting in varying levels of personnel awareness and experience may also negatively influence eradication success. An invasion, not managed for many years, may still be targeted, but its successful eradication depends on the “human factor”, which may drive the success of the action in opposing directions.
Article
Mitochondrial and nuclear sequence data from two Antarctic ameronothroid mites, Halozetes belgicae and Alaskozetes antarcticus , were used to address three key questions important for understanding both the evolution of biodiversity and its future conservation in the Antarctic Peninsula Region: i) Do populations of mites across the Antarctic Peninsula and Scotia Arc constitute distinct genetic lineages? ii) What implications does the spatial genetic structure in these species have for current understanding of the region’s glacial history? iii) What are the conservation implications of these findings? Our results indicate that both mite species have been present in the Antarctic since at least the Pliocene. At the regional scale, both species are comprised of a number of divergent, but sympatric, lineages that are genetically as distinct as some species within the genera Halozetes and Alaskozetes . At the local scale, complex structure suggests limited and stochastic post-Holocene dispersal. For both species, considerable spatial genetic structure exists across the region, similar to that found in other terrestrial invertebrates. These results support the implementation of stringent biosecurity measures for moving between the Scotia Arc islands and the Antarctic Peninsula, and throughout the latter, to conserve both evolutionary history and future evolutionary trajectories.
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While media usage has helped biodiversity gain a central spot in the contemporary conservation landscape, it is acknowledged that high biodiversity in itself is not always the best indication of conservation value. There are multiple reasons why low-biodiversity systems have to be valued. Such systems are easier to appreciate by the general public in their entirety, and also easier to study, with most model systems referring to low numbers of species. In remote and environmentally harsh settings, biodiversity can increase via biological invasion, which is usually perceived as a negative anthropogenic impact. Island systems, typically lower in biodiversity compared to continental settings, are, specifically thanks to the available niche space, laboratories of speciation and potentially macroevolutionary innovation. Although biodiversity hotspots are at the centre of global conservation efforts, coldspots have their own dynamics and conservation needs, generally poorly understood at this stage due to the high-biodiversity focus. Here, I discuss the media relevance and, where applicable, distortion, of these aspects. I conclude by recommending a local rather than global focus in the marketing of conservation, which could encourage an appreciation of naturally low biodiversity.
Article
Antarctic terrestrial biodiversity occurs almost exclusively in ice-free areas that cover less than 1% of the continent. Climate change will alter the extent and configuration of ice-free areas, yet the distribution and severity of these effects remain unclear. Here we quantify the impact of twenty-first century climate change on ice-free areas under two Intergovernmental Panel on Climate Change (IPCC) climate forcing scenarios using temperature-index melt modelling. Under the strongest forcing scenario, ice-free areas could expand by over 17,000 km(2) by the end of the century, close to a 25% increase. Most of this expansion will occur in the Antarctic Peninsula, where a threefold increase in ice-free area could drastically change the availability and connectivity of biodiversity habitat. Isolated ice-free areas will coalesce, and while the effects on biodiversity are uncertain, we hypothesize that they could eventually lead to increasing regional-scale biotic homogenization, the extinction of less-competitive species and the spread of invasive species.
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Sub-Antarctic islands share many similarities in their history of human interaction and impacts before the mid-twentieth century. Large impacts on land were associated with the marine exploitation industries of sealing and whaling. Their onshore activities involved consider - able construction and pollution in many accessible landing bays, inevitably destroying large areas of coastal terrestrial habitat. Consider- able transfer of nutrients to terrestrial environments will have been associated with scavengers utilising large carrion supplies. Attempted establishment of agricultural industries, particularly the introduction of grazing mammals, took place on several islands and, although rarely proving economically viable, often resulted in the long-term creation of feral populations. These were accompanied by introductions of other alien vertebrates, plants and invertebrates to most sub-Antarctic islands, although precise records of introduction events, or subsequent biological studies in this period, largely do not exist. Thus, exploitation industries in this region inevitably led to considerable alterations and impacts to terrestrial ecosystems almost from the outset of human contact with the islands. In the absence of baseline ecological and biodiversity studies, the true magnitude of many of these impacts is difficult to assess, although their legacy continues to the present day. Indeed, the almost complete removal of fur seals may have allowed coastal vegetation to become more extensive and lush than hitherto, paradoxically now regarded as "typical" and threatened by recovery of seal populations.