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www.thevillagenews.co.za
3 March 2021
MY ENVIRONMENT
The Beauty and the Disa By Dr Anina Lee
L
ate summer is a magical time for those who venture into the shady kloofs along streams and waterfalls in the Cape mountains because that is when one of the most famous of all Cape plants blooms: the red disa (Disa uniflora). Next to the king protea (Protea cynoroides), the disa is probably the most recognised of the fynbos flowers and is carried proudly as an emblem by many sports teams and organisations. The red disa was first associated with Table Mountain, where it grows on the upper slopes. This may seem strange for a flower that favours moist conditions, but it's all because of the 'table cloth' on Table Mountain. Moist air rises from the ocean up the mountain, reaches the cold air on top and condenses into a water-bearing cloud covering the mountain. This cloud cover is said to produce twice as much water annually on the mountain as rainfall does, and it provides the ideal habitat for the disa. This iconic beauty is found in protected areas from Hermanus to Cape Town and north into the Cederberg. Locally, the Klein River Mountains and the Kogelberg are favourites for Disa uniflora sightings. But, the story of the disa has another dimension. Those who
are fortunate enough to hike our Cape mountains in summer may have noticed a large butterfly of rare beauty. Wear anything red, and this butterfly will seek you out, hoping that you will provide a sip of nectar. This is the Table Mountain Beauty, also known as the 'Mountain Pride' butterfly (Aeropetes tulbaghia). It is awe-inspiring – the largest and most beautiful of southern Africa's ‘brown’ butterflies. This butterfly sees red – literally. It is so specialised that it is only attracted to red flowers – or anything else that's red. So it has a unique niche in nature, pollinating only red flowers that bloom in summer. Butterfly and flower have evolved in parallel, doing their thing in the season when there is less competition from others. So connected are the flower and insect that this butterfly is the only pollinator of Disa uniflora. If the Mountain Pride should go extinct, so will the Disa. Unfortunately, this outcome is entirely on the cards. Insect apocalypse Do you remember the days when a road trip meant washing a myriad of splattered insects off your windscreen at each refilling stop? When last did you have to do that? The change happened so slowly that we hardly noticed. Is it too late for insects – and for us? 1
According to a 2019 global scientific review, the world's insects are hurtling down the path to extinction, threatening a "catastrophic collapse of nature's ecosystems". According to the best data available, the total mass of insects is falling so precipitously that they could vanish within a century. The planet is at the start of a sixth mass extinction in its history, with huge losses already reported in larger animals that are easier to study. But insects are by far the most varied and abundant ani-
mals. They are essential for the proper functioning of all ecosystems, as food for other creatures, as pollinators and recyclers of nutrients.
and fish that eat insects. But it could also see the extinction of the Mountain Pride butterfly, which would mean the disappearance of one of our most precious and iconic flowers.
We all know about the critical role that pollinating insects play in food production, but food production is the crux of the problem. Or rather, the problem is the exponential growth of the human population and the need to feed the ever-rising numbers. The authors of the review concluded: "Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades. The repercussions this will have for the planet's ecosystems are catastrophic, to say the least." Intensive agriculture is the primary driver of the decline in insect populations through land transformation and the heavy use of pesticides. Urbanisation and climate change are also significant factors. Insect loss spells disaster for the many birds, reptiles, amphibians
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1 & 2. The red disa (Disa uniflora) flowers in late summer in the shady kloofs along streams and waterfalls in the Cape mountains, including Vogelgat. PHOTOS: La Canopée & Ronnie Hazell 3. The Mountain Pride butterfly (Aeropetes tulbaghia) is the only pollinator of Disa uniflora. If the Mountain Pride should go extinct, so will the Disa. PHOTOS: Pinterest
