Saving Stripes

A couple of posts ago I wrote about the problem of land degradation. This is a problem plaguing arid rangelands all over the world (did you know they cover nearly half of the world’s land surface?). Although not very productive, these lands support nearly a quarter of the world’s human population and a lot of the world’s large wild mammals. Here in Kenya this includes our favorite Grevy’s zebra! So figuring out how to manage these lands sustainably – and prevent further land degradation – is really important!

Here’s the question, though: in a place like northern Kenya, where pastoralists have grazed their cattle for centuries, why is land degradation a problem now? What’s changed in the last century?

One major change is that people have become more sedentary. In the past, pastoralists used to migrate over large areas, following the rains. In Kenya, colonial and post-colonial authorities started privatizing the land, constraining pastoralists to “group ranches” (ranches owned and managed by a group of families). This, combined with other social changes, has led many pastoralists to stop migrating.

How might this affect the land? For one thing, when cattle and other livestock graze the same area day in, day out, the area tend to get overgrazed. This is most obvious around settlements and water source. In contrast, where people and their livestock migrate, the land tends to stay in better condition, less degraded.

Now, development organizations – which used to encourage people to settle down and take ownership of private piece of land – are actually encouraging pastoralists to maintain their nomadic or semi-nomadic ways of life!

In many cases it might not be possible for people to return to a truly nomadic lifestyle. So an important question is, can we manage livestock and rangelands in a way that simulates migrations? Can we reap some of the benefits of migration without having to travel huge distances?

Siva and I, along with several other colleagues, are setting up a big experiment to answer this very question. We’re going to graze cattle in two different ways on large experimental plots here on the Mpala Research Centre. In the “simulated migration” areas, cattle will be kept in tightly bunched herds and will only graze a small patch of land each day, after which they’ll be moved to a new grazing area. In the “business as usual” areas, cattle will graze the same large area every day.

For the last couple of months, I’ve mostly been preparing the experiment – picking experimental sites, sorting out logistical details, etc. On one of the days when we were hauling posts to set up plot boundaries, we were joined by a very eminent naturalist, Jonathan Kingdon (THE authority on African mammals) – who didn’t mind chipping in to carry a few posts!

A couple of questions to ponder… what impacts might a “simulated migration” have on the landscape? Will they be positive or negative impacts? Can the effects of “migration” on a small scale (the scale of a single ranch) mimic the effects of migration over a whole ecosystem?

More thoughts on this to come! Meantime, send us your thoughts!

-Corinna