Heating up the Holocene

With direct meteorological data on the Antarctic Peninsula only dating back to the 1950s, scientists must search elsewhere for climate change records of the distant past. A series of expeditions to analyse ancient moss are poised to provide a longer-term perspective on the region’s warming pattern

Editors' comment

In September 2011, Aberdeen (UK) hosted the World Conference on Marine Biodiversity (WCMB). Within this Conference, the multidisciplinary international Science Research Programme (SRP) of the Scientific Committee on Antarctic Research (SCAR) “Evolution and Biodiversity in the Antarctic — The Response of Life to Change (EBA)” was granted a generous platform, which included a full-day Side Meeting on Advances in Evolution and Biodiversity in Marine Antarctic Environments. To mark the importance of this subject, as an outcome of the WCMB we decided to promote an EBA Special Issue of Marine Genomics, focussing on marine biodiversity in the polar regions. The contributions in this issue address the role of environmental change, variability and extreme events in the biological processes of marine organisms, including subjects such as phylogeography, phylogeny, phenotypic plasticity and molecular/physiological adaptations in the vertebrates and invertebrates of both polar oceans

Habitat moisture availability and the local distribution of the Antarctic Collembola Cryptopygus antarcticus and Friesea grisea

Population densities of the Collembola Cryptopygus antarcticus and Friesea grisea were compared in two maritime Antarctic habitats with different moisture availability. C. antarcticus was absent from the drier rock platform habitat, where F. grisea was the only collembolan collected. In contrast, the sand/pebble habitat on East Beach had greater moisture availability, and C antarcticus dominated the arthropod community, with juveniles (individuals < 1 mm length) representing 58% of the population. The hygropreference characteristics of F. grisea were determined in relative humidity (RH) gradients (12-98% RH) at 10 and 20 degreesC. F. grisea demonstrated a stronger preference for 98% RH conditions than C. antarcticus, suggesting that the former species is less likely to vacate moist refuges when available. The movement of both species was also monitored at 10 and 15 degreesC under conditions of 33, 75 and 100% RH. C. antarcticus was more active than F. grisea at both temperatures, and its movement increased at a greater rate as a consequence of reduced RH. The limited desiccation tolerance of C. antarcticus, combined with the increased water loss that would result from its continued movement under declining RH conditions, suggests this species is not well suited to drought-prone environments. In contrast, the reduced movement and 'risk averse' behavioural strategy of F. grisea, i.e. taking advantage of moist refuges when available, facilitates water conservation between precipitation/habitat rehydration events. This study provides the first evidence that moisture availability and habitat structure are potential habitat segregation mechanisms between these two Antarctic Collembola

Tundra plants protect the soil surface from UV

In the Arctic, seasonal ozone depletion is resulting in periods of enhanced UV-B radiation at ground level while regional climate change is associated with increasing temperatures. These changes are likely to alter plant distribution, biodiversity and morphology, which may have knock-on effects for microbially driven biogeochemical cycling and other soil processes. Our study examined the transmission of solar UV radiation through arctic tundra plants using a portable UV radiometer and the DLR-biofilm biological UV dosimeter. A strong negative correlation was found between vegetation cover and UV transmission to the soil surface. Penetration of UV to the soil beneath tundra plants varied depending upon plant morphology, being greater through low creeping plants than cushion plants, grasses or mosses. UV transmission to the soil surface beyond the foliage edge also varied with plant morphology and the presence of flowers

The effectiveness of Virkon® S disinfectant against the invasive chironomid Eretmoptera murphyi and implications for Antarctic biosecurity practices

The flightless midge Eretmoptera murphyi is thought to be continuing its invasion of Signy Island via the treads of personnel boots. Current boot-wash biosecurity protocols in the Antarctic region rely on microbial biocides, primarily Virkon® S. As pesticides have limited approval for use in the Antarctic Treaty area, we investigated the efficacy of Virkon® S in controlling the spread of E. murphyi using boot-wash simulations and maximum threshold exposures. We found that E. murphyi tolerates over 8 h of submergence in 1% Virkon® S. Higher concentrations increased effectiveness, but larvae still exhibited > 50% survival after 5 h in 10% Virkon® S. Salt and hot water treatments (without Virkon® S) were explored as possible alternatives. Salt water proved ineffective, with mortality only in first-instar larvae across multi-day exposures. Larvae experienced 100% mortality when exposed for 10 s to 50°C water, but they showed complete survival at 45°C. Given that current boot-wash protocols alone are an ineffective control of this invasive insect, we advocate hot water (> 50°C) to remove soil, followed by Virkon® S as a microbial biocide on ‘clean’ boots. Implications for the spread of invasive invertebrates as a result of increased human activity in the Antarctic region are discussed

The protection of Antarctic terrestrial ecosystems from inter and intra-continental transfer of non-indigenous species by human activities: a review of current systems and practices

Invasions by non-indigenous species are amongst the greatest threats to global biodiversity, causing substantial disruption to, and sometimes local extinction of, individual species and community assemblages which, in turn, can affect ecosystem structure and function. The terrestrial environment of Antarctica consists of many isolated ‘islands’ of ice-free ground. Prolonged isolation makes Antarctic biodiversity vulnerable to human-mediated impacts, in particular (1) the introduction of non-indigenous species from outside Antarctica, and (2) the redistribution of indigenous Antarctic species between biologically distinct areas within the continent. The Protocol on Environmental Protection to the Antarctic Treaty, the primary instrument through which environmental management is addressed within the Antarctic Treaty System, says little about unintentional introduction of non-indigenous species to Antarctica, and nothing specifically about human-mediated transfer of native species from one area to another. We review the effectiveness of the Antarctic protected area system, the primary means through which area-specific environmental protection is achieved under the Antarctic Treaty System. This reveals that the measures described in most Antarctic Specially Protected Area (ASPA) and Antarctic Specially Managed Area (ASMA) Management Plans, by themselves, may not be sufficient to (1) minimise the possibility of introduction of plants, animals and microbes not native to the protected area or (2) adequately protect the many unusual assemblages of species, type localities or only known habitats of certain species found in Antarctica. We discuss issues that should be considered in the development of a more effective system, including the implementation of appropriate biosecurity measures across different spatial scales and applied to different biological groups

Biotic interactions in Antarctic terrestrial ecosystems: are they a factor?

Antarctic terrestrial ecosystems are noted for their relative simplicity and limited trophic structure. In this context, knowledge of biotic interactions in structuring terrestrial soil communities would seem beneficial from a theoretical perspective as well as from a conservation perspective. Unfortunately, although biotic interactions are generally seen as being insignificant in these unique ecosystems, this view is based upon few explicit studies and very little is known of the role that biotic interactions may play. Accordingly, we review our current understanding of these interactions, including analogues from other appropriate ecosystems. On the basis of this review, we conclude that: (1) Antarctic terrestrial systems are predominantly abiotically-driven systems; and (2) a network of manipulative field and laboratory experiments are needed for establishing any role for biotic interactions in structuring Antarctic soil environments

Responses of invertebrates to temperature and water stress: A polar perspective

As small bodied poikilothermic ectotherms, invertebrates, more so than any other animal group, are susceptible to extremes of temperature and low water availability. In few places is this more apparent than in the Arctic and Antarctic, where low temperatures predominate and water is unusable during winter and unavailable for parts of summer. Polar terrestrial invertebrates express a suite of physiological, biochemical and genomic features in response to these stressors. However, the situation is not as simple as responding to each stressor in isolation, as they are often faced in combination. We consider how polar terrestrial invertebrates manage this scenario in light of their physiology and ecology. Climate change is also leading to warmer summers in parts of the polar regions, concomitantly increasing the potential for drought. The interaction between high temperature and low water availability, and the invertebrates׳ response to them, are therefore also explored