Fire!

September has been and gone with the temperatures steadily rising as we wait for the first rains of the year. By the start of September all of the collared zebra were found in the Boteti region of the Makgadikgadi in order to drink the fresh river water as all waterholes in the eastern Makgadikgadi had dried up.

It has been a long and tough month within the Makgadikgadi as massive bush fires gripped the park in early September. On 6th September the fire spread through the whole park from east to west having started outside the national Park in an area around some cattle posts. I think it was started by a farmer burning a field to promote new growth for his cattle and it spiralled horribly out of control due to the strength of the wind.

The morning after the fire started I was heading through the park to do grass sampling but got blocked by the fire which was burning across the road. After travelling off road to get around the fire, I rejoined a road where the fire was burning to the north, east and west of us without knowing how far the fire had spread. Driving through the burnt grassland with nothing but black ash left we saw Steenboks and Gemsboks looking very confused with their new surroundings as they tried to find shade and food.

On the drive into Khumaga and the Boteti we came across two groups of around 500 zebra huddled close together and clearly in a state of shock all standing around not knowing what to do. Other herds of zebra had fled from the fires and remained close to the Boteti in unburnt areas waiting to see what happened next. By this stage the fire was continuing to burn throughout the park and continued to head west towards Meno A Kwena and the tar road.

The fire burnt for a few more days as it back burnt through thick grassland. The fire even burnt through the trunks of some mature Leadwood trees causing the trees to topple. Driving through the burnt areas was horrifying as we saw the true scale of the devastation while trying to avoid areas that still smouldered even up to a week after the fire had passed through. A massive area of the park has been burnt which is visible if you look at the following two satellite images taken just before and just after the fire. Click on the links below and look for the white salt pans towards the centre of the image and then look to the area North and West of the pans before and after.

Pre-fire: http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=SERVIR_Africa_South_Central.2010248.aqua.1km This is at 1km resolution but by clicking on the 250m alternate pixel size link near the top of the page you can get a more detailed image

Post-fire: http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=SERVIR_Africa_South_Central.2010252.aqua.1km The same resolution applies for this image but unfortunately there is a bit of cloud around so is not quite so clear.

Within days of the fire passing through the Makgadikgadi, new green shoots were seen coming from the burnt tufts of grass. Despite there still being some fairly large areas which survived the fire, zebra and other herbivores were seen to be actively choosing to graze in the burnt areas on these lush green shoots. These shoots are high in nutrients and provide good grazing but as they are quite sparse the zebra need to constantly be on the move to find sufficient grazing resources. One collared zebra has been recorded 31km from the nearest point where it could access the water in the Boteti River as it searches for suitable grazing as well as going for up to 5 days between drinking bouts.

I am heading back down to the Boteti region this week in order to continue fieldwork. I will be particularly interested to see exactly where the zebra are grazing as well as assessing any changes in their body condition as a result of the fire. I am also interested to see whether the behaviour of the zebra has changed and whether they have adjusted their activity patterns in order to find sufficient nutrients.

Fires are often an ecological disaster but they have the potential to rejuvenate grass sward by removing the moribund grass and allowing for fresh growth. However, unless the rains are forthcoming and persistent, it may take sometime for the sward to restore itself. I will monitor with interest how the Makgadikgadi changes over the next few months and what effect this has on the zebra.