Plant form, tiller dynamics and above-ground standing crops of the range of Cortaderia pilosa communities in the Falkland Islands

Cortaderia pilosa is the dominant pasture species in the Falkland Islands. Extensive sheep ranching for wool production is the primary land use, but present range management grossly under-utilizes the annual production of this grass. (2) Plant form varies from tussocks of several hundred tillers to sparse tillers in less favourable sites where tussocks do not form. Tussock plants had large vegetative tillers and more reproductive tillers than plants from a non-tussocky pasture. Flowering is sporadic and shows great annual variation. (3) At any one time, four green leaves were usually present on a mature C. pilosa tiller. Leaves showed considerable longevity and only about four leaves per tiller were produced annually, during October-April. (4) Variations in plant growth form result in large differences in above-ground standing crop. The decline in standing crop in spring, when conditions were favourable for plant growth, is explained.