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Molecular Science Meets Muddy Boots Ecology in Kenya

Dik diks eating © Tyler Kartzinel

Meet the NatureNet Science Fellows: Tyler Kartzinel

Forensic analysis of animal dung. It might not be everyone’s idea of glamorous field research, but, when it comes to eliminating competition — both real and perceived — between domestic livestock and some of Africa’s most iconic grassland animals, a little dung can go a long way.

Especially when it’s in the hands (so to speak) of Conservancy NatureNet Science Fellow Tyler Kartzinel.

“Increasingly, endangered wildlife need to share resources with growing populations of humans and livestock,” says Kartzinel, who is working on his fellowship at Princeton University.

“To ensure their coexistence, we need to know how each type of animal uses resources. It was a surprise to me that the diets of all these charismatic animals we’ve been studying and watching for so long — elephants, giraffes, zebras, buffalo — are largely a mystery.”

And that is a problem because the belief that wildlife and domestic livestock compete for grazing resources is at the heart of much of the human and wildlife conflict in Africa’s rangelands.

It’s a conflict Kartzinel’s NatureNet research aims to resolve using novel, cost-effective DNA-based analysis to definitively identify which plants different species — both wild and domestic — are eating, as well as where and when they are grazing. It’s information that will also be important for shedding light on how grazing may affect soil’s ability to store carbon.

For Kartzinel, his work is the perfect combination of high tech molecular science and muddy boots ecology, and has application far beyond African grasslands.

A Forensic Approach You’d See in an FBI Lab

“My goal is to do research that has real-world conservation impacts,” says Kartzinel, who is using DNA to re-create and visualize detailed food webs that show what animals in and around Kenya’s Mpala Research Station are eating. “It’s a forensic approach you’d see in an FBI Lab.”

The process involves sequencing plant DNA that comes out of the dung of herbivores and the animal DNA that comes out of the scat of the big African predators. Kartzinel then uses that information to construct food webs because with DNA scientists can identify the exact species animals are eating.

It’s a method that overcomes one of the key challenges for wildlife and livestock competition studies — the fact that it can be really difficult to actually determine what animals are eating by observation alone.

 Zebras and wildebeests grazing © Emily Whitted / TNC
Zebras and wildebeests grazing © Emily Whitted / TNC

In the past, most savanna grazing studies relied on one of two methods for determining animal diets: direct observation of foraging species (watching and recording what animals are eating in real time), and microhistology (collecting dung and then visually identifying any visible plant parts).

The problems with these methods are that, at best, they give an incomplete picture.

Microhistology requires intensive effort, highly skilled botanical expertise and is still liable to be imprecise. Observing grazers from a distance or at night can make it difficult or impossible to accurately identify the individual species of plants the animals might be eating.

Just because zebras and buffalo might be near each other on the savanna, for instance, doesn’t mean they’re eating the same thing at the same time. And distance makes everything that much more prone to error.

Imagine sitting across a restaurant from someone eating a salad and trying to determine what kind of greens are on their plate — is that romaine or radicchio? Or a mixture? With Kartzinel’s DNA method, those problems are largely resolved and scientists can get a much clearer picture of how the diets of all the animals in a certain geography relate.

Plains zebra and cattle co-exist in Kenya © Anand Mishra/TNC
Plains zebra and cattle co-exist in Kenya © Anand Mishra/TNC

“We know,” he says, “that zebras and cows, for example, might compete under some conditions. We also know that by eating different suites of plant species, multiple types of wildlife and livestock can make rangelands more productive for each other.

“But we don’t have a good way of perceiving and mitigating that competition. We don’t have a good way of predicting and utilizing those benefits. It’s just a lack of ability to measure animal diets at scale and with precision. So if we can build these DNA-based data sets, even just over one season, we’ll learn a whole lot, and if we can come up with a strategy for doing routine monitoring then we can really begin to solve these conflicts.”

Mitigating Human-Wildlife Conflict: Good for People, Good for Animals

When Kartzinel and his colleagues tested the methodology at Mpala, they discovered that cattle diets only partially overlap with wildlife, and that the overlap varies significantly by species.The results of that work, published in Proceedings of the National Academy of Sciences, revealed that cattle have the most overlap with buffalo. The study also highlighted under-appreciated agricultural resources, like the forb Indigofera hochstetteri, that could be, he says, “conserved or propagated in addition to the grasses to maximize rangeland productivity for both wild and domestic herbivores.”

The ultimate goal of his research is to create tools that enable the conservation of the full biodiversity of Africa’s rangelands by helping land managers avoid human-wildlife conflict.

That, he says, “means bringing this kind of science to land managers. We’re working to miniaturize the technology and run analyses using the cloud. These technologies are advancing incredibly fast — quite conceivably in the next few years a game warden or a park ranger or a pastoralist in the field will plug a small device into a smart phone to figure out what a cow or zebra or elephant has been eating. That would really be a game changer.”

Science for Land Managers

Since Kartzinel first began this work in Kenya a few years ago, he has had to store and ship his specimens back to a lab in the United States. Now he’s testing a DNA sequencer that he can use in the field. It’s the size of a harmonica and plugs into the USB port on his computer.

And while the work for his NatureNet Science Fellowship focuses on human-wildlife conflicts in Kenya, he is using methodology and tools that apply to understanding what animals are eating around the world.

NatureNet Science Fellow Tyler Kartzinel

“I am using similar approaches to figure out what Caribbean lizards eat when they invade new areas. People are moving invasive populations of these lizards around the United States and the tropics more generally. So, the tool is pretty universal and I’m applying it wherever I think we have the most to gain.”

That broader perspective is one of the reasons Kartzinel wanted a NatureNet Science Fellowship. It’s emphasis on trans-disciplinary, action-oriented science to solve real problems in the field is well-aligned with Kartzinel’s personal and professional goals.

“We need,” he says, “people to pull the best tools from every tool kit they can reach. We need to integrate information in ways that help us solve problems related to conservation.”

A pursuit of The Nature Conservancy and leading research universities, the NatureNet Science Fellows program is a trans-disciplinary postdoctoral fellowship aimed at bridging academic excellence and conservation practice to confront climate change and create a new generation of conservation leaders who marry the rigor of academic science and analysis to real-world application in the field.

Cara Cannon Byington

Cara Cannon Byington is a science writer for The Nature Conservancy covering the work of Conservancy scientists and partners, including the NatureNet Fellows for Cool Green Science. A misplaced Floridian living in Maryland, she is especially fond of any story assignment involving boats and islands, and when not working, can be found hiking, kayaking or traveling with her family and friends. More from Cara

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