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Life out of the ashes – why fynbos must burn in order to survive

Thousands of hectares of Mountain fynbos destroyed in huge veld fire

This is a common newspaper headline at the end of each summer in the Cape Province of South Africa. While recent fires on Table Mountain and the Cape Peninsula have been particularly severe, fires are regular events in the Cape mountains and essential for maintaining the unique floral diversity of the region. The mountains of the South Western Cape are covered by the fynbos (directly translated this means fine bush) of the Cape Floral Kingdom, the smallest, yet for its area, richest plant Kingdom in the World. The majority of these fynbos plants are reliant on fire for their reproduction. For example, the many beautiful Protea that cover the Cape Mountains hold onto their seeds between fires in dried cones. The fires kill the adult bushes, but the seeds are protected inside these cones. Within a few days of a fire the dead bushes release their seeds, which are then blown by the wind until they become trapped by rocks or dead plant material and germinate after the first good rains. Within a couple of years the plants are once again in full bloom. In the prolonged absence of fires, Proteas will flower less and eventually die without their seeds having a chance to germinate. Many other beautiful plants only flower in the first few years after the fire. These include many annuals (eg. Cape daisies) and bulbs (eg. Fire lillies). As time progresses these plants are out competed by others in a fascinating succession that is only reset with the next fire.

Each fire is a unique event, with its own subtle characteristics which influence the group of plants that return after the fire. Thanks to the farsighted research planning of the late Hugh Taylor, a renowned fynbos ecologist, and long-time Simonstown resident, we are a little closer to understanding the long term effects of fire on fynbos vegetation. During 1965 Hugh embarked on a project to establish a plant species list and classify the vegetation communities of the newly proclaimed Cape of Good Hope Nature Reserve. Projects such as this have been undertaken at many sites both prior and since his Cape Point survey, yet his was the first to permanently mark the location of each of his 100 vegetation sites. The names of all species and their abundance within the 50m2 sites was meticulously recorded. He described exactly how to relocate, and clearly photographed, each site. For thirty years the sites were exposed to different external influences, which were recorded in the reserves management records. Some thirty years later it was possible to start to piece together the ecological jigsaw puzzle, which linked the changes in species composition of each site with their fire history over time. Each of the 100 sites were carefully relocated, the exact 50m2 site was again demarcated and the same survey as carried out thirty years earlier repeated. The results in many cases were unbelievable. Far from being constant over time the study showed that our fynbos landscapes change dramatically. On average there was a 40% change in species composition, with many plants migrating across the landscape becoming locally extinct in some areas and colonizing others.

Visitors to areas burnt by fires this summer on the Cape Peninsula are in for a real flowering treat over the next few years. By the end of this winter a covering of green will have returned to our mountains and the spring will be greeted with splashes of flowering colour. Fires maintain the intriguing tapestry that makes the Cape’s fynbos landscapes the richest in the world. So next time you read about the “Devastating Cape fires”, think rather of colour and new life, than scorched earth and destruction.

Written by Sean Privett
Fynbos ecologist
privett@hermanus.co.za

 

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