Fynbos
Rugged mountains frame this valley, the epicenter of the most botanically diverse region in the world. Light and shadow play on the sandstone slopes overhead while the Palmiet River meanders through shrubland below. It’s a dramatic scene. From the high peaks that form the far end of the valley the wind often blows down, picking up speed as it is funneled to the east and out to sea. In this landscape where few plants are taller than a human, there isn’t much to stop the advancing wind. But on this day everything is calm.
We are in South Africa hiking though Kogelberg Nature Reserve, about 50 miles southeast of Cape Town. This mountainous area is part of the Cape Fold Belt, a series of mostly parallel mountain ranges running through the Western Cape. Having risen about 250 million years ago, these mountains are much older than the high ranges of the Asia, Europe, and the Americas but young compared to other mountains in South Africa. The Barberton Greenstone Belt in the northeast of the country is about 3.6 billion years old, the oldest exposed rock in the world. That aside, the mountains of Kogelberg look ancient and this large tract of protected land is beautiful and important.
While these mountains have been here for a long time, the plant community they hold is relatively young. Home to a palm filled subtropical forest until about 30 million years ago, a gradual change to a drier, season driven climate made forests of palm trees impossible in the area. Plants that had eked out a living during the wet and warm times slowly came to dominate under the drier conditions. This was the beginning of fynbos, the plant community now characteristic of this part of the world.
Fynbos, translated to “fine bush”, is the name of a plant community comprised primarily of small to medium sized evergreen shrubs interspersed with various herbaceous plants and bulbs. Trees are almost entirely absent from this landscape. It is similar in appearance to the chaparral of southern California and shrubland of the Mediterranean, areas drenched in sunshine and filled with gnarly leathery leaved shrubs. But if the landscape looks familiar, the plants here are completely unique.
Conebush (Leucodendron) and other fynbos plant species. Saddle below Platberg, Kogelberg Nature Reserve.
Fynbos is the dominant plant community in what has been dubbed the Cape Floristic Region, an area encompassing the Western Cape of South Africa and considered one of six recognized plant kingdoms. These six areas, which together cover the entire landmass of Earth, are defined and demarcated by similarities of the plant communities within and differences from the other five. The other kingdoms cover most or the entirety of whole continents, so it is remarkable that a sliver of land roughly equal to the size of Maine is recognized as one of them. It is by far the smallest. The largest kingdom, the Holarctic, covers an absolutely massive amount of land, the majority of the Northern Hemisphere.
The reason the Cape Floristic Region is designated as a floral kingdom is the high number of unique species found here. To use Maine as a reference again, within that state’s borders you will find approximately 1,500 species of plants. Within the similarly sized Cape Floristic Region there are 9,000 known plant species. Coupled with the sheer number and density of species, the Cape Floristic Region exhibits high endemism. About two-thirds of plants here grow nowhere else on Earth. Walking through fynbos, an outsider will see unknown plants and lots of them.
High peaks over Palmiet River Valley, Kogelberg Nature Reserve
With a basic concept of geography and plant biology in mind, it’s not hard to imagine why so many fynbos plants are endemic to this area. The southern tip of Africa is surrounded by vast ocean on three sides. To the north there is land but it is hot arid desert: Karoo, Namib, and Kalahari. The Cape Floristic Region is a climatic island from which plants have no easy way of getting in or out. What is less clear is why there should be such an unusually high number of plant species here. There are many factors involved and a combination of these is likely the reason for the diversity. First, soils across the Western Cape are mostly infertile but vary greatly from one location to the next. The differing nutrient availability and chemistry promotes differentiation in plants. Secondly, the general weather pattern in this area varies greatly from east to west due to the conflicting influence of converging oceans and their distinct character, the cold Atlantic and the warm Indian. Weather also varies from south to north due to the mountainous terrane. The varied soil and weather combined with a complex topography creates a matrix of microclimates throughout the Western Cape. Distinct and isolated microclimates are great places for life to diversify.
Disturbance also plays a role in creating and sustaining this diverse plant community. Wildfires are common and vital to healthy fynbos. Flames clear out old plants, prone to forming overcrowded thickets, and rejuvenate the nutrient poor soil with the ashes. Fynbos plants are well adapted to fire and these frequent disturbances accelerate generational succession thus speeding evolution. While small scale disturbance likely encourage diversity, major disturbances can inhibit life. Advancing ice sheets and glaciers during past ice ages have mostly impacted the north and so it is no coincidence that there is less plant diversity in the temperate regions of the Northern Hemisphere. Along the equator and in temperate regions of the Southern Hemisphere, such as the Western Cape, evolution has had a long time to work uninterrupted by major disturbance.
Although this landscape is famous for diversity, fynbos is fundamentally characterized by the presence of a small number of plants. The first are the restios (Restionaceae), reed-like plants which are perhaps less charismatic than other fynbos plants but are none the less the ultimate indicators of fynbos. If there are no restios in sight, you are not in true fynbos. Heathers (Erica) are another indicator and have the highest number of species found throughout fynbos. Members of the protea family, conebush (Leucadendron), pincushion (Leucospermum), and of course sugarbush (Protea), are also extremely prevalent in this community and the most distinctive fynbos plants. King protea (Protea cynaroides) flowers are spectacular and a fitting national symbol of South Africa.
An interesting aspect of fynbos is that from a distance, the plant community appears homogenous. There is not great variation in height among the plants and many of them share the characteristic waxy leaves and form. The towering mountains, rocky outcrops, and roiling ocean grab your attention. The landscape itself is dramatic and on this grand scale, the vegetation can just looks green and brown. But at closer range, the true character of fynbos is obvious. The subtle difference in textures is revealed, the nuance of flower and leaf color muted from afar, is shown. You notice the feathery Elegia capensis and Berzelia spp., the spiky restios, the soft down on the silvery leaves of Leucadendron argenteum, the endless color variation of heathers, the magnificent protea flowers. You also notice the diversity. It is a hodgepodge of different plants, all side by side, that look absolutely beautiful together.
Fynbos comes alive just as the sun is setting and so we head out again in the evening to bask in the glow. Low angle light, catching the shades of red, pink, and yellow common to young leaves of many shrubs in the protea family, illuminates this landscape in a way that I have never seen anywhere else. There is a function to this color: tender new leaves are more susceptible to damage and water loss from the intense summer sun than hardened older leaves and light colors reflect sunlight better than green. I am caught up in the sight and in awe of all this life that is so well adapted to its home, this strange and beautiful place that holds so many different plants.
Oudebos River Valley, Kogelberg Nature Reserve