Alien lichens unintentionally transported to the “Arctowski” station (South Shetlands, Antarctica)

Introduced and invasive alien species of Antarctica and the Southern Ocean Islands

Open data on biological invasions are particularly critical in regions that are co-governed and/or where multiple independent parties have responsibility for preventing and controlling invasive alien species. The Antarctic is one such region where, in spite of multiple examples of invasion policy and management success, open, centralised data are not yet available. This dataset provides current and comprehensive information available on the identity, localities, establishment, eradication status, dates of introduction, habitat, and evidence of impact of known introduced and invasive alien species for the terrestrial and freshwater Antarctic and Southern Ocean region. It includes 3066 records for 1204 taxa and 36 individual localities. The evidence indicates that close to half of these species are not having an invasive impact, and that ~ 13% of records are of species considered locally invasive. The data are provided using current biodiversity and invasive alien species data and terminology standards. They provide a baseline for updating and maintaining the foundational knowledge needed to halt the rapidly growing risk of biological invasion in the region.

Warming impacts potential germination of non-native plants on the Antarctic Peninsula

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.

Cladonia lichens as the most effective and essential pioneers in strongly contaminated slag dumps

The epigeic lichen biota of ten post-smelting slag dumps were studied to identify the ecological importance of Cladonia species in spontaneous succession within artificial areas. Species diversity, abundance, constancy and cover indices were determined at the initial stages of vegetation establishment. Substrates under lichen vegetation were characterised in terms of the pH, organic C and total N content, C/N ratio and Zn, Pb, Cd and As concentration. Species occurrence and abundance indices were related to habitat type, enabling the ability to identify species-specific responses to environmental factors. Despite the unfavourable and artificial habitat conditions at dump sites, some Cladonia appear abundant and form swards, with Cladonia rei as a dominant species. They appear to be well-adapted for slag substrate and their special arrangement illustrative of site contamination. Certain sward-forming Cladonia lichens play a fundamental role as effective pioneers in the initial stage of succession and provide stable plant cover development.

Determining the native/non-native status of newly discovered terrestrial and freshwater species in Antarctica - current knowledge, methodology and management action

Continental Antarctic terrestrial and freshwater environments currently have few established non-native species compared to the sub-Antarctic islands and other terrestrial ecosystems on Earth. This is due to a unique combination of factors including Antarctica's remoteness, harsh climate, physical geography and brief history of human activity. However, recent increases in national operator and tourism activities increase the risk of non-native propagules reaching Antarctica, while climate change may make successful establishment more likely. The frequency and probability of human-assisted transfer mechanisms appear to far outweigh those of natural propagule introductions by wind, water, birds and marine mammals. A dilemma for scientists and environmental managers, which is exacerbated by a poor baseline knowledge of Antarctic biodiversity, is how to determine the native/non-native status of a newly discovered species which could be (a) a previously undiscovered long-term native species, (b) a recent natural colonist or (c) a human-mediated introduction. A correct diagnosis is crucial as the Protocol on Environmental Protection to the Antarctic Treaty dictates dramatically different management responses depending on native/non-native status: native species and recent natural colonists should be protected and conserved, while non-native introductions should be eradicated or controlled. We review current knowledge on how available evidence should be used to differentiate between native and non-native species, and discuss and recommend issues that should be considered by scientists and managers upon discovery of a species apparently new to the Antarctic region.