The Environments and Primary Production of Cushion Species at Mt Field and Mt Wellington, Tasmania

Abstract

Primary production of four species of alpine cushion plants were studied over a 2-year period. The climate of these areas was found to be severe but with a high degree of variability on a seasonal and yearly basis. The growing season at the higher altitude sites generally exceeded 6 months. Net above ground primary production of the four cushion species ranged from 282 to 709 g m-2 year-1. Reproductive effort fluctuated between species and years, ranging from 0 to 30% of net above ground production. Patterns in dry matter accumulation suggest no individual species would show consistently superior growth rates under present climatic conditions. Soil moisture and soil nutrient status was found to be similar between all sites. Altitude of the sites (830-1400 m) was found to be strongly correlated with the timing of flowering and/or seed set but appeared to have little effect on net primary production.