Variation in Seedling Recruitment of Cape Proteaceae after Fire

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Abstract
Seedling recruitment of closed cone (serotinous) Proteaceae was surveyed in 31 burnt areas in mature mountain fynbos of the Southern Cape, South Africa. The number of seedlings per pre-burn individual (parent) varied greatly from fire to fire. This variability could be partially explained by pre-burn densities since these were frequently negatively correlated with number of seedlings per parent. Seedling recruitment differed significantly with season of fire. The most successful seedling establishment followed autumn burns. Summer burns were often less favorable and had a greater variability from fire to fire. Winter and spring burns lead to very poor seedling establishment, mostly well below replacement levels, so that successive fires in these seasons would rapidly lead to local extinction. Density-dependent regulation of seedling populations is apparently due to the reduction of the reproductive effort, and thus seed reserves, per individual with increased pre-burn crowding. The causes of seasonal variation, which appear to be density independent, have not been satisfactorily explained though they are important for the prediction of fire succession in all Proteaceae which store seed in the canopy.