Central to Fynbos ecology is the role played by the periodic fires and its smoke, and apart from the interval between them, the intensity of the flames. The shorter the interval, the cooler the fire, as there has not been enough time for a build-up of combustible material though this is not always the case as abnormal dryness and wind conditions can vary. The plants have evolved survival strategies spread over many thousands of fire intervals. Fynbos is in balance with fire intervals of around 12 years or more, but unfortunately in recent times the interval is reducing.
As more frequent human induced fires have been occurring for a very short time, the natural evolution of seed storage and germination strategies lie in the deep past and one must assume that the majority of fires that started over previous millions of years were caused by lightning or earthquakes (leading to falling rocks). In the mountainous fynbos region of the Cape, the lightning season is around the equinoxes, just prior to the onset of the winter rains when the fynbos is summer dried. The lightning is more often “sheet” as opposed to ground strikes that actually start the fires. Stronger earthquakes also start fires but they are not seasonal nor in any way frequent.
The intensity of the flames during a veld fire plays a part in germination. The deeper the ants bury the seeds, the less a cooler fire can penetrate and there is no effective heat pulse except to the shallowest buried seeds which may or may not help break dormancy (more about this later). In fact cooler fires allow the deeper seeds to maintain their dormancy and are preserved for the next hotter fire. A neat way of not putting all the eggs into one basket as there may be a poor survival rate of the shallow seeds due to other conditions.
Another way that the risk is spread lies within the seed itself as the freshest seeds need a few years of maturing before they germinate. Leucospermum conocarpodendron seeds have a lower percentage germination rate in their first year from seed drop while 1-year-old seeds are better, both under laboratory-type conditions. This allows some of the most recent seed to be carried over to the next fire, thereby ensuring that there is a lessened chance of local extinction.
Mimetes stokoei was considered extinct as there had been no new plants seen for 50 years and after three cool fires had passed over the seeds in the ground, it is believed a hot enough fire contributed to their subsequent germinating.