Saving Stripes

Category: Uncategorized | Date: Mar 26 2009 | By: savingstripes

These days it’s DRY. It rained once in January, but otherwise it’s been dry since mid-November. The grass is all yellow and gray, the trees have dropped their leaves and, worst of all, the rivers have stopped flowing. The river that passes by us at Mpala is called the Ewaso Ngiro (“brown river”) and this is the first time in living memory that it has stopped flowing.

To get water, cows and other animals have to walk deep into the river bed to drink from remnant pools:

A different river runs by the house where we live; it’s called the Nanyuki River. The Nanyuki stopped flowing weeks ago, and now even the remaining pools are drying out. The river is our main water supply for bathing, washing, toilets, etc. (everything except drinking – we harvest rainwater for drinking). So naturally, we’re starting to worry… anybody know of a good rain dance?

The rains are supposed to start in late March, but here we are, March 26^th, and the skies are clear and blue. We can only hope that the clouds will gather soon…

Meantime, Siva has headed off to the US for six weeks of work there. So it’s just me and the critters. The squirrels are totally free these days, but they still spend most of their time near the house. I put out food for them every day, but now I’m having problems with bigger squirrels stealing the food. I’m not sure how to make sure the babies are getting enough to eat. They are still not fully grown and, like a good surrogate mother, I worry about them! I suppose the big squirrels are also feeling hungry, though, since there isn’t much out there for them to eat.

So we all wait for another dry day to go by – hopefully bringing us one day closer to the start of the rainy season.

-Corinna

4 responses so far

Category: Rangeland management | Date: Mar 23 2009 | By: savingstripes

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

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Category: Uncategorized | Date: Mar 16 2009 | By: savingstripes

Hi everybody,

I want to use the next few posts to respond to comments some people have made on the blog.

First, a number of you noticed some of the differences between plains zebra and Grevy’s zebra and were interested to know more about zebras in general.

Isn’t it interesting how well-known zebras are in so many cultures – what’s the first thing you think of when you think of black and white stripes? Or the letter “z”? – and yet, how many people know that there are three different species of zebra in the world?

First there’s the plains zebra – the most numerous and most familiar species of zebra. Plains, or Burchell’s zebras, are the ones you usually see on TV documentaries about African wildlife. There are more than a million of them and they’re found in the savannahs of eastern and southern Africa all the way from Kenya through Tanzania, Zambia, Zimbabwe, Botswana, Namibia, and down to South Africa. There is some variation in their stripe patterns and the habitats in which they’re found, but it’s the same species throughout this large geographical range. Basically, they are the stocky, bold-striped zebra familiar to most people.

The second species is the mountain zebra. This zebra is endangered and only found in a few reserves in South Africa and Namibia. They look a lot like the plains zebra – with bold, broad stripes – but their bellies are white, they have a grid-iron pattern on their back and rump, and their muzzles are thicker and browner than plans zebras’. In terms of behavior, they are quite similar to plains zebras.

Finally, there is the zebra I care about the most – Grevy’s. It’s the largest and prettiest and most interesting of the zebras (I’m not biased ). Ancestors to this zebra have been found as widely separated as China, Uzbekistan, and South Africa, so they were once quite a cosmopolitan zebra! It’s thought that they may have evolved separately from the other two species of zebras.

Grevy’s are about 33% larger than plains zebras, with fine stripes and a white belly. They have big, round ears (they’re really cute) and a slightly brownish muzzle. Here’s a photo of several Grevy’s and plains zebras together. The tight group of plains zebras on the right is a harem of females nuzzling each other.

Socially, Grevy’s and plains zebras are quite different. Plains zebras form harems – one male (the stallion) guards and defends a group of females (anywhere from 2 to 12) and their foals. This group stays together, moving as a unit. Sometimes many harems may join together to form large herds, but these herds are usually ephemeral. Males that are unable to gather a harem live in “bachelor” herds – waiting until they have a chance to challenge a stallion for his harem. This type of society is better adapted to plains (and mountan) zebra habitats which tend to be less arid than the areas where Grevy’s live.

Grevy’s, by contrast, have a looser social structure. Females live in groups, but these groups do not always stay the same. The members of these groups may change daily or weekly, or occasionally they last even longer. In the dry lands that Grevy’s live in, females must wander in search of grass and water, sometimes parting ways with their friends. Males who want to mate with females cannot defend any one group – because the group is always changing members! Instead, a male chooses to hold onto a piece of real estate that he knows will attract females. Males will patrol and defend their territories from other males. The picture below shows a typical male posture – head held high,  standing guard over his territories (“monarch of all he surveys”?)

Here’s another male standing guard over his territory – battle scarred (see his ears and neck) from fighting off challengers to his land…

By occupying and defending areas with good grass and good access to water, a Grevy’s stallion knows that he has what every girl wants – a safe place to eat and drink and raise her babies!

Finally, an interesting factoid – Equids, the mammal family to which zebras belong, first appeared and thrived in North America millions of years ago. Yet, today all zebra species are found only in Africa! In fact, none of the remaining wild equids are found in North America. Why might that be? And what makes some species – like Grevy’s – more endangered than others?

-Siva

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Category: News | Date: Mar 12 2009 | By: savingstripes

While we work on replying to your comments, here’s a quick update on our various projects.

Collaring: Unfortunately, I’ve had to postpone plans for collaring zebras. The vets from Kenya Wildlife Service who were going to help catch the zebras aren’t available to do the collaring right now. I’m headed to the US in ten days, so I’ve postponed the collaring until June. In some ways it might be for the best, since there will be more zebras around in June, after the rains (right now it is really dry here, but it should rain a lot in April and May). A bit disappointing as I was hoping to get some collars on now – we really don’t know where the zebras disappear to in the dry season and this would have been a great chance to figure that out!

Dung collection: On Monday I was in the field again collecting poop down on Ol Pejeta – a wildlife conservancy about an hour south of here. We had a really successful day (after a slow start). Ol Pejeta mostly has plains zebras, with just a few Grevy’s. We wanted to get dung from plains zebra mothers and their foals, so we can compare their genetics and parasites. We also got dung from a few Grevy’s, and maybe even one Grevy’s-plains hybrid (yes, they exist! I will write more about them sometime soon). Maybe you are wondering – why do I care about plains zebras, which are common and not endangered at all? Well, the answer to “why are Grevy’s so rare” is probably closely linked to the answer to “why are plains zebras so common” – since both species are generally similar.

Here are a couple of pictures from our day at Ol Pejeta:

Rangeland management project: We have been busy in the field the rest of this week setting up experimental plots for our rangeland management experiment. Corinna is going to post more about this – check back soon!

Squirrels: The squirrels are getting big (70 grams now) and we think it’s about time to release them. We moved their cage outside and the last few days we’ve let them out for a bit in the late afternoon. At first the little girl squirrel freaked out, clinging, frozen, to the wall of the house (while the little boy happily climbed into a tree and started eating leaves and ants). But now they are both more relaxed and bounce around on our veranda and in the surrounding trees. We’re planning to let them out for a little while every day before finally leaving the cage open all the time. Some of you have asked how we keep the dog from eating the squirrels – and the answer (for now at least) is by keeping him indoors when they’re loose!

Here’s a picture from back when the squirrels were tiny:

That’s the latest for now… more soon!

-Siva & Corinna

One response so far

Category: News | Date: Mar 10 2009 | By: savingstripes

Over the weekend we were visiting Paula, who runs WildlifeDirect. In talking to Paula we realized something: none of the comments she or anybody else was posting were coming through to us!

The friendly folks over at WildlifeDirect have now fixed this technological glitch and lo and behold, we can see that many people have commented with their thoughts, questions, and observations.

So, first of all, thank you all for your comments! Secondly, we will now start replying. Stay tuned – more soon.

-Corinna & Siva

2 responses so far

Category: Uncategorized | Date: Mar 04 2009 | By: savingstripes

Here’s the problem: we still don’t really know why Grevy’s populations aren’t increasing. Hunting – which almost certainly contributed to their decline – has been banned since the 70s. Yes, the occasional zebra is the casualty of illegal hunting, but that alone can’t explain why the population remains so small.

So why aren’t Grevy’s rebounding? One possibility is disease. Very little is known about this in Grevy’s zebra. What parasites do they carry? How are these parasites affecting the zebras? Are some zebras more likely to suffer the effects of parasites than others?

One new project I’m starting will try to answer some of these questions. But how? Dung! It’s not glamorous, but it works. Here’s what you do: you drive around looking for zebras. When you see a group, you watch them intently until the miracle happens and one decides to defecate. Quickly, you photograph that animal and run out of the car looking for the fresh poop. Scoop it up, and you’ve got your sample. What, I wonder, must the zebras think as they watch us running around and picking up what they’ve just dropped?

This is what I’ve been doing in the field the last few days, along with a colleague, Vanessa. Vanessa is an expert on ungulate parasites and we’ll be working together on this project.

What will the dung tell us? Back at the lab, Vanessa and I are looking at the dung samples under a microscope to count and identify the parasites living inside them. Then we’ll send samples to a lab which can tell us whether the zebra has been eating well or not – how much protein it’s getting, how fat it is, etc. Finally, another colleague of ours will extract DNA from the dung.

With this information, we can start asking some deeper questions – like, do animals living in particular areas suffer from higher parasite loads? Do more inbred animals have higher parasite loads? How do parasite loads affect how fat and healthy the zebra is?

It’s definitely not the most fragrant job I do, but hopefully it’s not just a load of… you know….

-Siva

2 responses so far