Islands in the ice: Potential impacts of habitat transformation on Antarctic biodiversity

Abstract

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.

Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system

“…In March 2022 (autumn) extreme temperatures, almost 40 ˚C higher than normal, were reported as an atmospheric river, or plume of warm, moist air, moved onto the Antarctic plateau. Heatwaves such as these accelerate melting of icebanks [ 79 ], potentially exposing vegetation to high springtime UV-B radiation from which they have previously been protected [ 36 ]. The impacts of these heatwaves and the subsequent ice melt have been poorly studied in Antarctica in part due to the lack of environmental monitoring with networks of sensors tracking temperature and climate variables at appropriate scales.…”

Climate change and extreme events are changing the biology of Polar Regions

“…Extreme events are happening more frequently in polar regions (Bokhorst et al, 2022; González‐Herrero et al, 2022; Robinson et al, 2020), These often occur outside of the growing season (Chown et al, 2022; Constable et al, 2022; Treharne et al, 2019), making them more challenging to study. As temperatures rise, ice‐free areas will expand in Antarctica as they have in the Arctic, but there is still considerable uncertainty as to how Antarctic species will be affected as their habitats transform (discussed in Lee et al, 2022).…”

Emerging biological archives can reveal ecological and climatic change in Antarctica

“…At a more regional scale, Antarctica and its surrounding sub‐Antarctic islands have unique ecosystems under increasing pressure from global climate change, including local changes in response to ice sheet variability, glacier retreat and sea ice extent (Constable et al, 2022 ). As the substantial risks currently facing these ecosystems are becoming clear (Chown et al, 2022 ; Lee et al, 2022 ), research questions are increasingly focusing on understanding the ecosystem impacts of climate change in the Antarctic region. Terrestrial and marine biological archives can reveal the paleoecology of a species or ecosystem, which shows their responses to environmental and climate change.…”

“…Biota in the Antarctic terrestrial and lacustrine environments are largely limited to the ice‐free areas comprising 0.18%, or 21,745 km 2 of the Antarctic continent (Burton‐Johnson et al, 2016 ), where ice cores are unavailable (Convey et al, 2008 ) (Figure 1 ). These ice‐free areas provide a substrate for groups such as mosses, lichens, algae, invertebrates, fungi, and microbes (Convey et al, 2008 ; Lee et al, 2022 ), from the tops of nunataks protruding through the ice to the many coastal oases (Wauchope et al, 2019 ). Ice‐free areas are also important breeding grounds for several species of birds, including some penguins, petrels, and seals.…”