PLANT COMPETITION OVER WINTER IN ALPINE SHRUBLAND AND GRASSLAND, SNOWY MOUNTAINS, AUSTRALIA

The influence of neighbors during a winter on transplants of three species was investigated near the timberline of the Snowy Mountains of southeastern Australia. The study species included the timberline tree Eucalyptus pauciflora, a grass most abundant above timberline, Poa costiniana, and a rosette composite most abundant at higher altitudes, Celmisia longifolia. Transplants were grown with and without neighbors, in both shrubland and grassland. Shrubland sites were near the timberline, grassland sites were 200 m above the timberline. Plant sizes were measured at the beginning and end of one winter and regression equations used to determine biomass changes. Plant growth and competition occurred during winter. Neighbors significantly reduced growth of P. costiniana in both habitats and C. longifolia in shrubland. The growth of E. pauciflora was not influenced by neighbors, but in the absence of neighbors it grew significantly faster in shrubland than in grassland. These results indicate that neighbors can restrict plant growth even in winter and may contribute to vegetation patterns in alpine habitats.