Climate, Grazing and Disturbance, and the Population Dynamics of Leucochrysum albicans at Ross, Tasmania

Abstract

A population of an endangered daisy, Leucochrysum albicans (syn. Helipterum albicans), was monitored monthly in grazed and ungrazed plots for several years in a paddock near Ross, Tasmania. The population declined dramatically during the extremely dry summer of 1987, and also experienced high mortality in the dry summer of 1988. Adult plants and germinates were more abundant in grazed than in ungrazed plots for most of the period after this decline. The development of axillary branches on adult plants was much more prominent outside than inside the exclosures. Seedling establishment preferentially occurred on ground dominated by herbs, with establishment being low and extremely brief on grass-covered ground. The frequently disturbed margins of the exclosures were the most favourable sites for establishment of new individuals. The future of this unpalatable rare species seems to be dependent upon management that maintains open and, preferably, disturbed ground.