Living on the edge-plants and global change in continental and maritime Antarctica

Antarctic terrestrial ecosystems experience some of the most extreme growth conditions on Earth and are characterised by extreme aridity and sub-zero temperatures. Antarctic vegetation is therefore at the physiological limits of survival and, as a consequence, even slight changes to growth conditions are likely to have a large impact, rendering Antarctic terrestrial communities sensitive to climate change. Climate change is predicted to affect the high latitude regions first and most severely. In recent decades, the Antarctic has undergone significant environmental change, including the largest increases in ultraviolet B (UV-B; 290-320nm) radiation levels in the world and, in the maritime region at least, significant temperature increases. This review describes the current evidence for environmental change in Antarctica, and the impacts of this change on the terrestrial vegetation. This is largely restricted to cryptogams, such as bryophytes, lichens and algae; only two vascular plant species occur in the Antarctic, both restricted to the maritime region. We review the range of ecological and physiological consequences of increasing UV-B radiation levels, and of changes in temperature, water relations and nutrient availability. It is clear that climate change is already affecting Antarctic terrestrial vegetation, and significant impacts are likely to continue in the future. We conclude that, in order to gain a better understanding of the complex dynamics of this important system, there is a need for more manipulative, long-term field experiments designed to address the impacts of changes in multiple abiotic factors on the Antarctic flora.