Antarctica's vegetation in a changing climate

Abstract

Antarctica plays a central role in regulating global climatic and oceanographic patterns and is an integral part of global climate change discussions. The functioning of Antarctica's terrestrial ecosystems is dominated by poikilohydric cryptogams such as lichens, bryophytes, eukaryotic algae, and cyanobacteria and there are only two native species of vascular plants. Antarctica's vegetation is highly adapted to the region's extreme conditions but, at the same time, it is potentially highly susceptible to climatic fluctuations. Biological responses to shifts in temperature, water availability, wind patterns, snow, and ice cover are complex, taxa-specific and act on different temporal and spatial scales. In maritime Antarctica, where warming and mass loss of outlet glaciers have been mainly observed, the vegetation is expected to show increases in productivity, abundance, and cover. In continental Antarctica, observational and experimental evidence is still sparse, but it is pointing toward even drier and harsher conditions for survival. We need more information on what the observed and predicted changes in Antarctic vegetation are for different regions and ecosystems. This will inform us how environmental change and human impact will shape the future of these ecosystems, and whether the speed and magnitude of change have habitat-specific effects and implications. Antarctica's unique ecosystems are changing and in this review, we describe the current situation, tools to measure, and evaluate change and how change is likely to look in the future.

Extreme warm events in the South Orkney Islands, Southern Ocean: Compounding influence of atmospheric rivers and föhn conditions

“…Small, isolated, mountainous islands within the Antarctic polar front of the Southern Ocean, such as the South Orkney Islands (SOIs), South Georgia and the South Sandwich Islands, South Shetland Islands, and the Kerguelen Islands are important Antarctic terrestrial ecosystems and areas of biodiversity (Convey, 2017; Colesie et al ., 2023). Extreme warm air temperatures over these islands can result in ecosystem change either by exceeding upper tolerance thresholds or causing melting of snow and ice fields, for example, leading to the altered patterns of water availability and exposure of the underlying soil and vegetation (Smith, 1990; Calosi et al ., 2008; Convey, 2017; Colesie et al ., 2023). However, although a comprehensive investigation of extreme warm‐temperature occurrences in these maritime islands is of fundamental concern, studies of this kind remain very scarce.…”

Basking in the sun: how mosses photosynthesise and survive in Antarctica

“…Climate change is happening in Antarctica, driven by both increasing greenhouse gases and ozone depletion (Robinson and Erickson 2015 ; Chown et al 2022 ; WMO 2018 , 2022 ; Ranasinghe et al 2021 ; Fox-Kemper et al 2021 ; Constable et al 2022 ). The peninsula and western Antarctica have experienced rapid warming including reductions in ice cover which opens up new land for colonisation (Lee et al 2017 ; Cannone et al 2022 ; Colesie et al 2023 ). The eastern side of the continent has remained cooler, in part due to ozone depletion (Robinson and Erickson 2015 ; WMO 2018 ) but future warming of continental Antarctica is predicted (Chown et al 2022 ; Ranasinghe et al 2021 ; Constable et al 2022 ).…”

“…Whilst water availability is probably the dominant driver of terrestrial biodiversity patterns in Antarctica (Convey et al 2014 ) it is relatively poorly resolved in future models for ice-free areas of Antarctica as well as for the Arctic (Constable et al 2022 ). A key area for research into the future of Antarctic terrestrial ecosystems is what happens to water availability as ice-free areas expand (Lee et al 2017 , 2022b ; Guglielmin et al 2014 ; Cannone et al 2016 , 2022 ; Loisel et al 2017 ; Torres-Mellado et al 2011 ; Favero-Longo et al 2012 ; Yu et al 2016 ; Colesie et al 2023 ).…”

What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.

“…Lichens are symbiotic organisms having great number of species in polar regions. In many maritime Antarctic habitats, lichen diversity and growth rates are high (Colesie et al 2023). Their success in polar vegetation oases is associated with their physiological vigor which is derived from high freezing tolerance (Barták et al 2007, Hájek et al 2016, Haranczyk et al 2003, and fast activation of their photosynthetic processes upon rehydration, both by liquid water or water vapor uptake (Colesie et al 2016, Schroeter et al 2021.…”