Wednesday, April 1, 2015

Burn, baby, burn

Savanna ecosystems, including the Masai Mara/Serengeti plains, evolved around the presence of fire.  People have been burning savannas for a long, long time, and before that lighting sparked fires that people weren’t around to set themselves.  This means that the trees, grasses, and animals here in the Mara are all adapted to survive or to regrow after a fire, and that fire is actually an important ecological process for this environment.

Traditionally, pastoralist communities in Kenya and Tanzania would set fires towards the end of the dry season in an attempt to improve the quality of pasture for their herds.  Today, however, how often to burn – and whether to set fires as a wilderness management tool – is a topic that is hotly debated by scientists and conservationists alike.

In Kenya, the management policy is to suppress all manmade fires, but to allow natural fires (usually caused by lightening storms) to burn freely.  In Tanzania, however, rangers deliberately set fires each year throughout the Serengeti plains.  There are two main purposes for the intentional setting of fires: to encourage the new growth of grass for grazers, and to prevent the encroachment of the forest into the savanna plains (interestingly, high densities of elephants also inhibit this encroachment).  Some managers argue that the burns, by stimulating new green grass, also encourage the wildebeest migration to spend more time in burned areas, thus bringing more tourists and more money to those areas.  Whether or not this is the case is still unclear, although a recent paper from our very own David Green suggests that the wildlife response, if any, is short-term.

We in Serena Camp recently had a close encounter with a fire that spread over the border from Tanzania and into Happy Zebra territory.  It came over the border slowly – we first saw the flames in the distance on March 9, but the fire didn’t actually spread into the territory until March 11.  The ungulates were moving slowly away from the flames, but the birds were having a feast on all the fleeing insects at the fire’s border.

Fire in the distance
Photo by Eli Strauss
The birds are feasting on the insects fleeing from the fire.
You can see how hot the fire gets in the heat waves
blurring the birds' forms in this photo.
The birds got so close to the flames!
On March 12, the fire burned the area around the Happy Zebra communal den, and we were momentarily worried about the cubs.  The hyenas, however, were totally unfazed by the fire, and the cubs all made it through just fine.  Two days later, the clan moved their communal den across the road to where it hadn’t burned, but Silkwood and her cubs, Nightshade and Amanita, are still using the burned den as a natal den.  
Silkwood sacked out by the den
 in the middle of the freshly-burned area. 
The fire was still smoking behind Silkwood
when we awakened her from her nap. 
The game trail the hyenas used to get to the communal den
was so packed down that it didn't burn.
Now that the rains have finally come to our area of the Mara, we are excited to see the new green grass plains that will emerge in Happy Zebra territory!

Fresh green grass emerging from the burned area
Zebras munching on the new, nutritious growth
To learn more about fire in the savanna, read the blog Safari Ecology, by Dr. Colin Beale of the University of York. 

1 comment:

dee said...

Really enjoyed the post Tracy, and as always, your photographs are wonderful.

Michigan State University | College of Natural Science