Sphagnum peatlands of Kosciuszko National Park in relation to altitude, time and disturbance

Sphagnum peatlands or bogs in the Kosciuszko National Park ranging from montane to alpine in elevation were sampled on two occasions spanning a maximum interval of 32 years. Data analysed for individual samples (305 quadrats) clustered into consistent microhabitat (hummock/hollow) groups and subalpine/alpine subgroups. Quadrat data were aggregated for sites (13 bogs) and analysed for floristic trends over time. Cluster and ordination analyses showed a large change in a single montane bog, but relatively little composition (presence/absence) change for the subalpine and alpine bogs. Analyses of dominant species in alpine (three) and subalpine bogs (three) showed some temporal trends in cover. There appears to be an increase in the cover of Sphagnum and a decrease in shrub cover in the subalpine bogs over the 20-32 years. Changes in shrub cover in undisturbed subalpine sites are attributed to shrub senescence and lack of recruitment. Changes at a site with intensive ski field development (Smiggin Holes) were analysed separately and compared with adjacent sites with no such development. Sphagnum cover had not increased at this site and shrub decline was pronounced. Bare ground and ruderal species increased in cover whereas 13 native species that were originally recorded in 1959 were not re-recorded in 1991. The detection of vegetation change in bogs through monitoring is important for adaptive management of vegetation under intensive use.