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Polar Biol (2011) 34:16791688 DOI 10.1007/s00300-011-1099-6
ORIGINAL PAPER
Antarctic hairgrass expansion in the South Shetland archipelago and Antarctic Peninsula revisited
G. A. Torres-Mellado R. Jaa
M. A. Casanova-Katny
Received: 7 April 2011 / Revised: 11 August 2011 / Accepted: 16 August 2011 / Published online: 20 September 2011 Springer-Verlag 2011
Abstract Populations of both native higher Antarctic plants, Deschampsia antarctica and Colobanthus quitensis, increased during the last decades. However, for D. antarctica, previous population studies on the South Shetland Islands and the Antarctic Peninsula have been too sporadic, patchy, and methodologically different to allow general conclusions. Our aim was to compare sites with D. antarctica along a northsouth latitudinal transect with an integral census method to assess the possible impact of climatic change on grass population dynamics. During two summer seasons (20092010), plant populations were censed on Fildes and Coppermine Peninsula and several localities on the west coast of the Antarctic Peninsula. Largest plant populations were found on Fildes Peninsula with vegetation cover (VC) of 4446%. Six out of eleven stands of D. antarctica on Coppermine Peninsula were new
records, with increasing plant number and VC (0.122%). In the Antarctic Peninsula, contrarily to our expectation, only at Forbes Point, D. antarctica VC was relatively high (ca. 2%) and a new stand of C. quitensis was found. At three previously reported sites, plants had disappeared. Our monitoring conrms that northern D. antarctica populations are expanding, but that this expansion is not continuous along the Antarctic Peninsula and inconsistent with the gradient of relative temperature increase in northsouth direction. We suggest that other abiotic and biotic factors are inuencing the colonization and expansion of vascular plants in this particular ecosystem.
Keywords King George Island Robert Island
Paradise Harbour Deschampsia antarctica Colobanthus
quitensis Sanionia uncinata Global climatic warming
Plant expansion Population dynamics
Introduction
The Antarctic continent is experimenting one of the fastest trends of increasing temperatures on earth (Hansen et al. 1999; Turner et al. 2009), and regional warming is especially pronounced in the Antarctic Peninsula (Bracegirdle et al. 2008) as has been documented by READER (Reference Antarctic Data for Environmental Research, Turner et al. 2005, 2009). Climatic records during the last 50 years indicate that temperature changes have taken place, with a large increase in the annual...