Micro‐site influence on seed longevity and seedling emergence of a bunchgrass (Themeda triandra) in a semi‐arid savanna

Abstract

The influence of micro‐site (shaded, exposed, buried) on the seed longevity and seedling emergence of Themeda triandra was tested using experimental seed banks. Deep shade considerably reduced soil surface temperature. Seeds did not persist in any micro‐site for longer than one year. The fate of most seeds in the first year was to germinate but most buried seeds died before emergence; <20% of seed decayed. Greatest seedling emergence occurred with seed on the surface, particularly if shaded. The temporal pattern of emergence depended on micro‐site, with implications for seedling risk. Limited seed longevity may render T. triandra, an obligate seed‐reproducing species, vulnerable to failure of seedling recruitment.