Seed dynamics of Themeda triandra in the montane grasslands of South Africa

Abstract

Seed production, viability, dispersal, predation and seed banks of Themeda triandra were determined to assess the potential of the seeds of this indigenous species in the re-establishment of degraded grassland. Annual seed production of T. triandra increased with length of burning rotation, ranging from 21 seeds m^–2 in the annual winter burn to 757 seeds m^–2 in the five-year burn. High predation of seeds (70–98%) and low viability (37% in 15-month-old seeds) contributed to the poor representation of T. triandra in the seed bank (<1.2%) when compared to the above-ground vegetation (<29.2%). These attributes, together with its poor dispersal (<1.75 m), indicate that seed dynamics of T. triandra will play a limited role in the restoration of grasslands in degraded areas.

Keywords: burning; disturbance; regeneration

African Journal of Range & Forage Science 2009, 26(1): 19–26