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A SPRINGTAIL SUMMER IN THE ARCTIC

Springtails are key contributors to soil ecosystem functioning and occur in virtually all environments. These small (typically 1 mm or less in length) arthropods are absent only from the most extreme habitats, and elsewhere can reach densities of hundreds of thousands of individuals per square meter. Because many species are relatively easy to rear in the laboratory, and owing to their importance in soil systems, much is known about their life histories. In consequence, they make useful model organisms to examine ecological theory.

A small group of researchers at the C·I·B has been doing just that. Initial work concerned the differences in life histories and physiological tolerances among introduced and indigenous species from sub-Antarctic Marion Island (1-6). The research demonstrated that in many respects invasive springtails will be at an advantage over their indigenous counterparts as the climate continues to warm and dry at the island.

The research into this group of animals has subsequently been broadened in partnership with colleagues from South Africa, Norway, Sweden and France. Much systematic and ecological work is now being done on the group in the Western Cape, examining its contribution to decomposition processes (7) and to biodiversity variation across the Cape Floral Kingdom. Resolving the taxonomic impediment for this group in the Western Cape is a key component of the research. The work also includes a macroecological investigation of phenotypic plasticity in species from the sub-Antarctic, South Africa, Azores, Norway, and the Arctic.

It is for this macroecological study that Steven Chown and Charlene Janion recently joined their Norwegian colleague Hans Petter Leinaas (University of Oslo) on a two week visit to the High Arctic archipelago of Svalbard (c. 78 to 79°N). The research involved the collection of several species for rearing in the laboratory for tests of ideas concerning the nature and scope of phenotypic plasticity in species from polar, temperate and subtropical environments. The group spent much of their time working at Longyearbyen, with the assistance of Steve Coulson and his group at The University Centre in Svalbard (www.unis.no). The project is also registered with the Norwegian Polar Institute (http://npweb.npolar.no) whose staff provided excellent support at Ny Ålesund. At 79°N the research community and its support through Kings Bay AS at Ny Ålesund is the world’s northernmost community.

In addition to the field work focused on springtails, the opportunity was also taken to learn about the general environment and about other animals and the plants of the archipelago. Late June and early July turned out to be a good time for many Arctic flowers and a variety of birds, mammals and insects were also easily seen during field work.

The work was successful with close to 20 species being collected. It also provided much experience for the newcomers to the Arctic environment, indicating the kinds of further collaborative work that might be undertaken to understand how springtails respond to climatic variation. Rapidly changing environments both at Svalbard and at Marion Island also provide an opportunity for further exploring how variation among these environments, which show such dramatic differences in thermal seasonality (8), is likely to influence the way changing climates affect soil ecosystems. The new research station at Marion Island, to be opened in November 2010, and the excellent facilities at Longyearbyen and at Ny Ålesund would certainly lend themselves well to addressing important questions such as these from a bipolar perspective.

The work undertaken here is funded by a science liaison grant from The Research Council of Norway and the South African National Research Foundation, and was supported by The University Centre in Svalbard, the Norwegian Polar Research Institute, the University of Oslo and the Centre for Invasion Biology at Stellenbosch University.

    Scientific reading
  1. Chown, S.L. et al. 2007. Phenotypic plasticity mediates climate change responses among invasive and indigenous arthropods. Proc. R. Soc. Lond. B 274, 2531-2537.
  2. Slabber, S. et al. 2007. Acclimation effects on thermal tolerances of springtails from sub-Antarctic Marion Island: indigenous and invasive species. J. Insect Physiol. 53, 113-125.
  3. Worland, M.R. et al. 2006. Supercooling point frequency distributions in Collembola are affected by moulting. Funct. Ecol. 20, 323-329.
  4. Janion, C. et al. 2009. Assemblage level variation in springtail lower lethal temperature: the role of invasive species on sub-Antarctic Marion Island. Physiol. Entomol. 34, 284-291.
  5. Leinaas, H.P. et al. 2009. Effects of thermal acclimation on water loss rate and tolerance in the collembolan Pogonognathellus flavescens. Physiol. Entomol. 34, 325-332.
  6. Janion, C. et al. 2010. Trait means and reaction norms: the consequences of climate change/invasion interactions at the organism level. Evol. Ecol., in press.
  7. Bengtsson, J. et al. 2010. Variation in decomposition rates in the fynbos biome, South Africa: the role of plant species and plant stoichiometry. Oecologia, in press.
  8. Chown, S.L. et al. 2004. Hemispheric asymmetries in biodiversity – a serious matter for ecology. PLoS Biol. 2, e406, 1701-1707.

Charlene Janion and Hans Petter Leinaas searching for springtails close to the station at Ny Ålesund.