Fynbos often seems dull, scraggly and unproductive from a distance. But get closer and you will find a diversity of species, life and bursts of colour, especially among the different protea species standing sentinel in this fine, bushy vegetation.
The Cape Floral Kingdom where fynbos occurs is the smallest of six floral kingdoms in the world, but one of the richest when it comes to plant abundance. It is home to around 8 200 plant species, many found nowhere else on the planet.
Throughlong-term monitoring of certain protea species in the Grootvadersbosch Nature Reserve near Heidelberg, scientists areusing this popular fynbos genus as an indicator of the health levels in fynbos.Fynbos needs fire to persist and recruit, but if it burns too often it can alsobe destroyed. With increasing temperatures and fire frequency, fynbos may be atrisk – one of the reasons monitoring is so vital.
Proteas as indicator species for Fynbos
Specific protea species have been selected as indicatorspecies for monitoring the effects of fire because they are common and abundantand also the slowest to mature in fynbos, says CapeNature regional ecologist DrAnneLise Schutte-Vlok. “If we allow forthe slowest maturing species to flower and set seeds, we would haveaccommodated all other species in the landscape. Then we would not lose speciesfrom the system,” she explains.
In Grootvadersbosch they are keeping an eye on the large, bushy proteas – the oleander-leaf protea (Protea neriifolia), broad-leaf sugarbush (Protea eximia) and the common sugarbush (Protea repens). These are numbered in permanent monitoring plots within the reserve. Every year, teams revisit the same 100 plants to measure the height and the number of flowers. If a plot burned, whether planned or by wildfire, teams also look at new seedling recruitment.
Fire and Fynbos
Different fynbos species need to burn at different intervals to ensure their survival. Too frequent fires can destroy fynbos, but if fynbos burns too little it can hamper new recruitment. Schutte-Vlok says, “We work on a general rule of thumb that 50% of the individuals in a population need to have flowered three times before the veld burns.”
For now, the burn period in Grootvadersbosch is set at 15 years, but monitoring will reveal whether this time period is adequate or not. “If areas on Grootvadersbosch burn at less than 15-year return intervals, we need to take steps to address it as there is a possibility the biodiversity could be negatively affected,” says Schutte-Vlok.
- There are about 360 species in the Proteaceae family in South Africa.
- The genus protea, of the family Proteaceae, was named by Swedish botanist Carl Linnaeus in 1771.
- Species of the genus proteas are known as sugarbushes because of their excessive nectar production.
- The King Protea is South Africa’s national flower.
- Members of the Proteaceae family are also found in Australia, South America and Madagascar. Pollen fossils show that Proteaceae ancestors grew in Gondwanaland 75–80 million years ago before the continents split.
Approximately 70% of Grootvadersbosch is clad in fynbos vegetation. The reserve also boasts 250ha of indigenous afromontane forest, some of the most significant in the southwestern Cape, with large species diversity.
Written by René de Klerk
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