Fires are a natural part of every forest ecosystem. Wildfires usually ignite with the arrival of summer and its dramatic thunderstorms; there’s plenty of timber lying around with the activity of elephants in the area and, if a lucky lightning strike finds just the right target, ta-da! Fire is born. Over the millennia, however, their patterns seem to have become more intimately tied with the spread of mankind than just good old lightning strikes. Fires can start when a happy camper forgets to keep his eye on that burning toilet roll or can be intentionally lit to flush out game. These unseasonal fires can begin at any time of year and can catch you off guard.
A controlled fire burning on the edge of the fire break.
Our filming operations are facilitated by an existing tourism enterprise where crews restock on essentials such as water, food, and Wi-Fi. Last month, however, our job descriptions grew to include fire-fighters as a frenzied unseasonal fire approached this base camp, fuelled by years of dead grass undergrowth and equally-unseasonal winds. It was all hands on deck to halt the fire in its tracks with filming duties on hold and every individual in the vicinity called out to help. The first line of defence was an enormous fire-break mowed by Brad in his beloved tractor. With enormous flames on the horizon, the crew and employees of the camp positioned themselves along this long line as a fire was lit on its northern edge (see the image above). The team then split into two. Half were responsible for spreading this fire along the fire break, holding bundles of dry grass over the flames and fanning it in a southerly direction along the defensive line. The other half were responsible for beating out any cheeky fires that spread out of control or tried to cross into the fire-break.
Top left: Aron & Sam, fire-fighting extraordinaires. Top left and bottom: beating down the flames on the fire break.
Another, just as critical, role was predator prevention. Big cats are curious creatures and are inevitably attracted to the flames and sounds of a large group of humans on its periphery. Two particularly brazen lion cubs were reluctant to leave, and a young male leopard tried to watch the action. As always with our work, it is critical that these predators are not normalised to the sight of humans on foot. Both for our safety, and for the animals. It did keep us on our toes though! While it was touch and go at some stages, all eventually went as planned. Our controlled fire moved slowly further out from the fire break, where it met the larger fire that caused all the trouble in the first place. All of a sudden, this fire had nowhere to go. It had burnt everything behind it, and the controlled fire had burnt everything in front of it. Eventually, the fire skirted around the firebreak and the camp. It will keep going until it will eventually and naturally be put out by permanent waters or green vegetation.
Left to right: Greg Hartman, Hannah Gormley, and Keabetswe Monageng, fighting fire with fire.
Othusitswe Shomana and Brad Bestelink, fighting fire with fire.
One month later, it is hard to believe there was a fire there at all. Today, a thick carpet of new, lush grass covers what was a barren burnt area and countless herbivores are attracted to this sweet snack. Natural fires are an incredibly important part of any forest ecosystem, to the extent that many species of trees actually require fires in order to grow (it’s nice to have a start to life without any competition after all!). These wildfires clear the underbrush and weakened and pest-riddled trees, opening up the forest floors, letting more light through the canopy, stamping out pest populations, and removing competition so the trees that survive can then grow taller and stronger. An ash-rich nutrient smoothie helps matters even further and as plant diversity increases, so too does animal diversity.
It was all hands on deck to control the fire.
But it’s not all good news. Natural fires are much less frequent than the combined threat of wild and human fires. In the dryland forests of Botswana, it is estimated that 55% of first-year-old shoots are killed by fires (Ben-Shahar, 1996, 1998; Rietbergen-McCracken and Abaza, 2000). These problems are accentuated by a large elephant population. Without the compounding effects of one another, the impacts of elephants or fire activity in isolation are actually pretty limited. However, studies show that even if the elephants do not kill seedlings through browsing, they keep the seedlings at a smaller, more vulnerable stage where they are less resistant to the impacts of fire (Barnes, 2001), and damage in the Chobe region has been found to be most significant where both wildfires and elephants occur (Mmolotsi et al., 2012). When you add climate change to the equation, it’s the perfect storm. Warming temperatures dry out the forests and increase the frequency and intensity of these fires. They grow larger, spread faster, and reach higher. Pollution chokes the surrounding water, animals cannot outrun the flames, and soils are scorched black beyond repair.
Greg Hartman. Before and after the flames.
The Okavango without its trees would be an unrecognisable habitat. The constant evapotranspiration through their leaves is the only reason that it remains a fresh-water system, which is able to support the abundance of life that it does. Wildfires are a natural part of any forest’s life cycle, but they must be left to do that without interference from man. It sounds scary and overwhelming to fight climate change at home, but it doesn’t have to be – have a vegetarian meal or ride public transport to work just one extra time this week. Switch to a renewable energy supplier or take a local holiday instead of travelling abroad. If we all started making these small and tangible changes in our lives, then the outcome won’t be so bad. If not for the Okavango, do it for the elephants. Otherwise, they're the ones that take all the blame.
Sources:
Barnes, M.E. 2001 Effects of large herbivores and fire on the regeneration of Acacia erioloba woodlands in Chobe National Park, Botswana. Afr. J. Ecol. 39, 340–350.
Ben-Shahar, R. 1996 Woodland dynamics under the influence of elephants and fire in northern Botswana. Vegetatio 123, 153–163.
Ben-Shahar, R. 1998 Changes in structure of savanna woodlands in northern Botswana following the impacts of elephants and fire. Plant Ecol. 136, 189–189.
Mmolotsi, R.M., Obopile, M., Kwerepe, B.C., Sebolai, B., Rampart, M.P., Segwagwe, A.T. et al. 2012 Studies on Mukwa (Pterocarpus angolensis, DC) Dieback in Chobe Forest Reserves in Botswana. J. Plant Stud. 1, p154.
Nichols, C.E., Vandewalle, M.E. and Alexander, K.A. 2017 Emerging threats to dryland forest resources: elephants and fire are only part of the story. Forestry.
Rietbergen-McCracken, J. and Abaza, H. 2000 Economic Instruments for Environmental Management: A Worldwide Compendium of Case Studies. Earthscan.
Blog by Hannah Gormley and images by Celvin Bruton.