Methodology:

The warming experiment was set up on 16 February 2007 at Rothera Point on Adelaide Island in a vegetated gully to the west of the Miracle Span. The experiment consisted of five control plots and five treated plots covered with open top chambers, constructed from 3 mm-thick UV-transparent PMMA Plexiglas (GS2458, Rohm GmbH & Co., Darmstadt, Germany) with upper and lower apertures of 0.10 m2 and 0.37 m2, respectively. On 16 February 2007, 17 March 2007, 10 April 2007, 12 January 2008, 18 March 2008, 16 January 2010, 15 February 2010 and 17 March 2010, four samples each of C. varians and S. uncinata (each measuring c. 10 mm × 10 mm in area, cut down to the bedrock c. 10-20 mm below colonies) were collected from each plot into clean plastic bags. Permanent ice cover precluded sampling in austral summer 2008/09. Directly after collection, the four samples of liverwort or moss from each plot were taken to the Bonner Laboratory on Rothera Point, where they were combined, wrapped in a single ply of preweighed clean tissue paper, and were placed onto stainless steel mesh in a funnel with a tube attached to its neck to which a clip had been added. Water was added to the funnel so that it just covered the bryophyte sample. The funnels were mounted in a retort stand and were left in the dark at c. 13 oC. After 65 h, the clip was released and water was run off from the funnel into a 50 ml capacity tube, which was left, undisturbed, at 4 oC for 24 h. The supernatant was then pipetted off, leaving soil animals in c. 1 ml of water, to which 10 ml of hot (65 oC) fixative, consisting of 4% formaldehyde and 2% glycerol in water, was added. The bryophyte sample and tissue paper were then dried at 80 oC for 48 h, cooled over desiccant and weighed, with dry plant biomass subsequently being calculated, accounting for the weight of the paper.

The fixed nematodes, which had been returned to the UK at room temperature, were examined at × 400 magnification using an inverted microscope, with × 1000 magnification under a compound microscope being used when greater detail was required. Nematodes were identified to genus or species levels based on morphological and morphometric features from the original formal descriptions of the taxa (see Maslen & Convey 2006, Soil Biology & Biochemistry 38, 3141-3151). The total number of nematodes in each sample, along with the numbers of males, females and juveniles of each species, were recorded. In addition, the numbers of gravid females of Plectus belgicae, along with the number of eggs in gravid females of this species, were counted in the extractions from the samplings in 2008 and 2010.

Data quality:

All data has been checked.