The Spirit of Mawson - Australasian Antarctic Expedition 2013 - 2014

Australasian Antarctic Expedition

Botany

From a plant point of view, the three largest islands, Auckland, Campbell and Macquarie, together with Stewart Island, can be regarded as the southernmost point of the New Zealand mainland. While having only limited floras, the subantarctic islands make up for their lack of diversity in their spectacular range of large-leaved herbs (usually called megaherbs) endemic to the islands, while alien species threaten to dominate native vegetation in some areas. On all the islands, winds from the westerly quarter play a dominant role in restricting woody growth and, on the most exposed cliff edges, tussock as well. How different species on the subantarctic islands have responded to human activity and climate change is an important area of research.

The research program

  1. On the AAE 2013-2014 we set out to discover what are the key environmental factors limiting woody vegetation on Auckland and Campbell Island?
  2. On the AAE 2013-2014 we investigated how plant perform at the limits of woody vegetation across Auckland and Campbell Islands?

  3. On the AAE 2013-2014 we wanted to find out how does bark thickness vary among the woody species on the subantarctic islands and whether there is evidence for the hypothesis that fire is the major driver of thick bark globally?

Research Papers

Palaeoecological signatures of vegetation change induced by herbivory regime shifts on subantarctic Enderby Island

Wood, J.R., Wilmshurst, J.M., Turney, C.S.M. and Fogwill, C.

Testing the impact of large herbivore extinction remains a major challenge. Here we use a peat core from subantarctic Enderby Island to investigate how dung fungi alongside pollen can be used to reconstruct the impact of mammals on vegetation.

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Growth response of an invasive alien species to climate variations on subantarctic Campbell Island

Palmer, J.G., Turney, C.S.M., Fogwill, C., Fenwick, P., Thomas, Z., Lipson, M., Jones, R.T., Beavan, B., Richardson, S.J. and Wilmshurst, J.M.

Alien plants are species that have established themselves outside their natural distribution and are now a recognised threat to biodiversity around the world. On Campbell Island is a single Sitka spruce tree - ‘The Loneliest Tree in the World’ – a species more commonly found along the North American Pacific coast. Here we report a study looking at the tree’s past growth rates and likely future response to climate change. Although the tree is growing extremely well, the absence of cones and the likely continuing wet climate suggests the Sitka spruce is a limited threat to the long-term ecology of Campbell Island.

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Integrating pollen and historical records to trace the invasion of a tree daisy (Olearia lyallii) on subantarctic Auckland Islands

Wilmshurst, J.M., McGlone, M.S. and Turney, C.S.M.

Alien plants are a major environmental problem, particularly on islands where they can rapidly transform unique indigenous ecosystems. Nowhere is this more true than on the subantarctic islands. Here we show the alien daisy tree was introduced by sealers in 1807, supported by nutrient delivery from nesting sea birds, seals and sea spray.

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