Vol.31, No.02. 2020
Table of Contents
ARTICLES | Biology and Ecology
Extreme events as ecosystems drivers: Ecological consequences of anomalous Southern Hemisphere weather patterns during the 2001/2002 austral spring-summer
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The frequency and severity of extreme events associated with global change are both forecast to increase with a concomitant increase expected in perturbations and disruptions of fundamental processes at ecosystem, community and population scales, with potentially catastrophic consequences. Extreme events should thus be viewed as ecosystem drivers, rather than as short term deviations from a perceived ‘norm’. To illustrate this, we examined the impacts associated with the extraordinary weather pattern of the austral spring/summer of 2001/2002, and find that patterns of ocean-atmosphere interactions appear linked to a suite of extreme events in Antarctica and more widely across the Southern Hemisphere. In the Antarctic, the extreme events appear related to particular ecological impacts, including the substantial reduction in breeding success of Adélie penguins at sites in the Antarctic Peninsula as well as for Adélie penguin and snow petrel colonies in East Antarctica, and the creation of new benthic habitats associated with the disintegration of the Larsen B Ice Shelf. Other major impacts occurred in marine and terrestrial ecosystems at temperate and tropical latitudes. The suite of impacts demonstrates that ecological consequences of extreme events are manifested at fundamental levels in ecosystem processes and produce long-term, persistent effects relative to the short-term durations of the events. Changes in the rates of primary productivity, species mortality, community structure and inter-specific interactions, and changes in trophodynamics were observed as a consequence of the conditions during the 2001/2002 summer. Lasting potential consequences include reaching or exceeding tipping points, trophic cascades and regime shifts.
1 Australian Antarctic Division, Department of the Environment and Energy, 203 Channel Highway, Kingston, Tasmania 7050 Australia; 2 School of Zoology, Private Bag 55, University of Tasmania, Hobart, Tasmania 7001 Australia; 3 Antarctic Climate and Ecosystems Cooperative Research Centre, Private Bag 80, University of Tasmania, Hobart, Tasmania 7001 Australia; 4 CSIRO Oceans and Atmosphere, Hobart, Tasmania 7001 Australia