Archive | January 2013

A note from the field

### I’m still getting sorted out in Tanzania – here’s a post I wrote from my first full field season when I learned how to drive a Land Rover. Excitement. ####

“Oh Dear God, We are going to DIE.”

I remember that phrase on constant repeat in my head during my unprepared and ill-advised ascent of the Polish Tatras.  I had decided to climb a mountain in late May with little more than a t-shirt and ultralight rain jacket – the kind that costs an arm and a leg because it weighs no more than a paper clip and fits in a tea-cup – a coarse park map and no compass.  Just as I was convinced of my imminent demise then, I am now.  “Oh God, we are going to die.”  I mutter it under my breath to myself as the ancient Land Rover steering wheel ricochets between my hands.   We are on the long road from Arusha to Serengeti, and I am convinced that at any moment the wind will blow us straight off of the fresh tarmac.  Even on the best road in the district, the Landy pulls and sways, as though yearning for the ditch along the road, and I constantly remind myself to breathe as I focus hard on staying straight.  Dala dalas stuffed with passengers pass by effortlessly but I am scared to turn my head lest I lose my tenuous grip on our straight path forward.

It is June 22, 2010.  Today I am 27 years old, crossing that bridge from “mid-20’s” to “late-20’s,” and while I joke about how my bones creak and short-term memory is fading, I am still too young to die.  Meshack laughs quietly beside me – he is our prized fundi, our expert mechanic, and is making the long trek to Serengeti for no other reason than to make sure that I (and the car) make it there in one piece.  “Twende!” he says, motioning forward.  Let’s go.  I gulp loudly and clench the wheel tighter.  There really is no respite from the terror – on the open tarmac I have to go faster; as we slow for villages there are pedestrians and bicyclists, peddlers and Maasai and livestock that weave alongside the road erratically, and I am convinced that at any moment one of them will meander into the path of my Monster Truck.   Winding up the gnarled and pockmarked Crater road are blind turns and oncoming trucks that only further the terror of the already perilous ascent.  I am torn between the urgent need to reach the park gates before they close, and my desire to remain alive and in more or less one piece.  When we stop at the Crater rim (in part for Patriki to take a picture, in part for me to try and restart my heart), Meshack glances at his watch nervously.  Ever so gently, he offers, “Maybe it would be faster if I drive?”

I almost kissed him.  The passenger seat in a Land Rover has never felt quite so luxurious – before or since – though I still question my lifespan on a daily basis from the driver seat.  For example, George, my coworker on the Lion Project, has been teaching me to drive off road.  “It is just fine,” he assures me as we begin to climb the veritable of dusty soil and clumpy vegetation.  Except when it is not fine.  As we circle and spin and weave through aardvark hole-ridden hilltops, I can see him clutch the window frame suddenly in panic, his foot involuntarily slamming down where the break pedal should be.  The Landy falls into the abyss where ground once was.  Ka-thunk.  I hold my breath and resist the visceral urge to slam on the accelerator and clear away from the danger as fast as I can.  The Landy keeps chugging forward, powered by the magic that is low-range.  The rear tire plummets to the depths of hell and haltingly crawls back out.  We are alive.  Barely.  George laughs.  “Avoid that green grass!” he reminds me.  I am lost – it’s all green.  “That’s green!” I point, “and that! And that over there!”  It is all green and it all looks the same, but George sees some magical difference.  I’m told that in time I will see it too.  In the meanwhile, however, I maintain my running commentary.  “OH dear God, we are going to die!…Oh, okay, we’re okay.  Oh that’s a hole! Oh, okay, we are alive.  That’s just grass.”  …Except when it’s not.

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Fire!

Maybe you’ve seen fire in some of the images you’ve classified and thought “oh no!”

fire

Fire is actually an important component of savanna ecosystems. Fire kills young trees and seedlings, reducing the number of big adult trees that grow over time. Since trees compete with grasses for light and soil moisture, fire actually helps the grasses and keeps the savannas open.

Dr. Rico Holdo, a professor at the University of Missouri, and his colleagues modeled and wrote about the interactions of fire, rain, grasses, trees, and the various animals in the Serengeti. The interactions get complicated quickly, but I’ll try to give you a run-down of how they see fire acting in this ecosystem.

First, as I’ve mentioned, fire suppresses trees and encourages grasses. If you have both fire and rain, but no animals, then something interesting happens: the rain encourages the trees, but it encourages the grasses, too. As the grasses get taller, there is more fuel for fire, and the fires become more widespread and more damaging. These fiercer fires really hurt the trees – in fact, the damage from fires (because of more rain) is more important than the extra boost the trees get directly from the rain. So more rain actually means fewer trees.

With me so far? We’re now going to throw animals into the mix – well, at least some of the animals. Let’s talk about the grazers. The grazers eat the grass, and this reduces the fuel available to fire. If you have a lot of grazers, like we do in the Serengeti, the grass height is reduced a lot. That means fewer fires and that rain once again helps the trees. Further, many of the grazers are migratory and move around the landscape a lot. They don’t eat the savanna grasses in a neat, tidy, organized way. Instead, they create a patchy mosaic of grass heights, and with those different grass heights come different susceptibility of patches of grass to burn.

With rain and fire and grazers, we now have a landscape of grasses of different lengths, patchy fires, and some areas dense with trees and some areas with fewer trees. All that variation means more diversity – more diversity of the grasses, plants, and trees, and more diversity of the animals that rely on them.

All that diversity due, in part, to fire.

You can read the scientific paper by Dr. Holdo and his colleagues here:
Holdo, Ricardo M., Robert D. Holt, and John M. Fryxell. “Grazers, browsers, and fire influence the extent and spatial pattern of tree cover in the Serengeti.” Ecological Applications 19.1 (2009): 95-109.

Season 4

Dear devoted Snapshot Serengeti ID-ers: I know the last couple weeks have been tough, especially with the appearance of those two words that strike fear into the heart of every Serengeti addict (I mean ID-er): “We’re done.”

Well, we’ve got good news for you: we’re not really done. Like Margaret wrote the other day, we expected to have several weeks (or more!) to prepare Season 4 for posting. We hadn’t really expected to you guys to process three seasons of images in one week. Clearly. So, it’s been a bit of a scramble…but we’re finally ready to give you Season 4. Even cooler? Yours will be the first eyes to really take a look at these photos.

Prior to launching Snapshot Serengeti, Seasons 1-3 had been looked at by a small group of volunteers on a prototype application called “Serengeti Live.”  We’ve been able to use the preliminary data to start answering research questions, refine our analytical methods, and show funding agencies that this project is really cool and worth continuing. However, each image had only been looked at once, so there were a lot of mistakes, which is why we still needed your help with those Seasons.

But Season 4 has never been seen before. It contains all the photographs collected during my last field season in Serengeti – February through July 2012. The rains were pretty bad that season – I can’t tell you how many times I got stuck in the mud trying to get to those cameras. Oh, yeah, and the neighbor’s outdoor toilet (choo in Swahili) sunk. But with the rains came the wildebeest, who honked/mooed (I don’t think there is a word for the sounds they make) outside our homes at night. And in July I lugged back a huge, dust-covered hard drive full of photos.

ChooDown3

Choo down!

With every SD card I collect, I do some basic error-checking – so I’ve taken a very cursory flip through the photos and tried to trim down the number of “broken camera” shots of the dirt, grass, or sky, as well as some of the “lawn-mowing” images.  But other than that, this is unexplored territory.  These photos are new, unseen, unexplored…you’re the first!

I’m excited to see what you find.

Imagine this layer of mud on *everything.*

Imagine this layer of mud on *everything.*

Earth Wolf

### Today’s post is a guest post from Lora Orme, an undergraduate conducting directed research with us at the University of Minnesota. ###

Often mistaken for a hyena, the aardwolf (whose name means “earth wolf”) of southern and eastern Africa is actually smaller and more docile than its carnivorous cousin (which belongs to a different sub-family). Both the striped and spotted hyenas primarily call large mammals “dinner,” but the aardwolf is more interested in a tasty termite column than meat. Because of its food choice, the aardwolf’s jaw is much less powerful and smaller than a hyena’s jaw, but the aardwolf has a specialized tongue that is longer and sticky. It licks up various insects (with a preference for termites) off of the ground, rocks, and trees with only minor digging with its front claws. For an aardwolf, a fully belly can mean as many as 300,000 termites! The aardwolf will memorize the locations of termite mounds to save the time and effort of finding new snack spots, and will be careful to leave enough of the population alive so that its food source will be “re-stocked.” At the end of a long night of dining on insects, the aardwolf returns home to an under-ground burrow.

At one point, the aardwolf’s burrow most likely was stolen from another small mammal such as a hare, aardvark, or porcupine. Although able to create a new burrow, it takes much less energy for the aardwolf to use a pre-existing one. The burrow provides a safe-haven in the daylight hours when the nocturnal aardwolf normally sleeps or relaxes.

Aardwolves, while primarily solitary, will coexist in groups of six to a dozen neighbor burrows. They congregate for safety in numbers (and more rarely to help rear young), but more often to find a mate. Males will seek females within their own territories and in those of neighbors, sometimes leading to male-male conflicts which are solved with barks, blunt-teeth gnashing, and musky scent-release from glands (the smell of which has been compared to a skunk).

A mating pair will form during the breeding season (spring or fall) and gestation lasts around 100 days, ending in a litter of three to five cubs. Usually birth occurs during the rainiest months of the year when termites are most available, providing plenty of nutrients for the growing young. The males contribute to the partnership by guarding the nest while the females nurse. Both parents supervise the cubs in their first foraging adventures about 3 months after birth.

Because the aardwolf acts as a control on the termite population, it often lives and scavenges near or on farms. Most farmers detest the termites that may destroy crops or infest homes, so they welcome the service of the aardwolves. Unfortunately, aardwolves are preyed upon by some larger carnivorous mammals such as the jackal. Even humans represent a threat to the species because the aardwolf is hunted for its unique fur.

Upon a closer look, aardwolves have distinctive pointed ears for acute hearing; after all, their prey is very small! The aardwolf’s paw is also distinctive from a hyena because it has five toes instead of four. The aspect you might notice first, however, is the bushy pointed tail that looks as if it has been dipped in a can of black or dark brown paint. In a confrontation, an aardwolf’s furry mane will raise from head to tail making it appear larger in size to (hopefully) persuade the opposition to back down.

See if you can spot one of these night-walkers as they prowl for termites!