From Serengeti to Yellowstone

Dr. Anthony (Tony) Sinclair, born in 1944 and raised in Tanzania, has been a pioneering figure in ecology and wildlife conservation, particularly in the Serengeti-Mara ecosystem, where he has worked for over 55 years studying large mammal populations and ecosystem dynamics. His research revolutionized understanding of predator-prey relationships and ecosystem restoration, particularly through his documentation of the Serengeti’s recovery from the 1890 rinderpest epidemic. Currently Professor Emeritus at the University of British Columbia, Sinclair’s work spans multiple continents and has influenced conservation efforts worldwide, including the Greater Yellowstone Ecosystem.  

 

 

Dr. Arthur Middleton, G.R. and W.M. Goertz Professor of Wildlife Management at the University of California Berkeley, leads interdisciplinary research on wide-ranging wildlife and large-landscape conservation. His research group conducts field programs in the Greater Yellowstone Ecosystem, Northern California, and the Andean and Patagonian Steppe of Argentina. Currently serving as senior advisor for wildlife conservation at the US Department of Agriculture, Middleton balances his academic work with practical conservation outcomes for communities.  

 

WC: What first drew you into the field of migration ecology? 

Tony Sinclair:  When I first started research as a student in the mid-1960s, I was given the task of looking at a population of African buffalo that nobody knew anything about. I realized that understanding the buffalo required understanding the wildebeest, whose massive population had a big impact on the entire Serengeti ecosystem. Both populations were growing rapidly, but one was migrating and the other wasn’t. That got me asking, “What is the difference?” and “Is there a link between the very large numbers of wildebeest and the fact that they migrate?” That got me thinking about the underlying cause of migration. At the same time, my early experiences growing up in East Africa had shown me there was something extraordinary about the Serengeti and I was asking, “Why was that the case? Why aren’t there other Serengetis in Africa, or indeed around the world?”  

Arthur Middleton: I think for me it was sort of deep in my bones to be fascinated by the story of ecology, of animals and their movements. I grew up in the creeks and marshes and the forest in the southeastern US, where I witnessed seasonal changes in fish, bird, and marine mammal arrivals and that was my entry into ecology. After graduating from the University of Wyoming, which has a world class wildlife ecology and zoology program, I was working on wolves and their impacts on elk in the Yellowstone ecosystem. But during the years I was out in the field collecting data, what became more interesting to me was the hidden and less appreciated life of the elk. I began to wonder if the patterns I was seeing—the seasonal movements of elk herds back and forth across the landscape—were more widespread. Why was it occurring? How did it play into this predator-prey dynamic that was the dominant ecological paradigm at that moment? That’s what drew me in. 

WC: What are the most important breakthroughs you have witnessed and contributed to in the conservation of large landscapes? 

Anthony Sinclair: As I worked on the question, “Why migration?” I was realizing that wildebeest were moving to areas that have very high-quality food, the best in the ecosystem. They didn’t stay there, because there were times of the year when those areas became unsuitable because of a lack of water, forcing them to move to where the food was less suitable. But that extra food in temporary areas was what allowed them to reproduce and survive so well. It became clear that through migration, wildebeest had access to food resources that non-migrants didn’t have and that allowed them greater numbers in their populations. After looking at other migration systems, this principle became even more clear to us—that migration was all about temporary high-quality food, and access to ephemeral resources is what drove migrations in the world.  

A corollary of that is that migrant herbivore populations are not likely to be regulated by predators, since predators can’t migrate like their prey. They’re stuck raising their young in a den or equivalent for a length of time, by which time the migrants have moved on.  

Arthur Middleton: Genuinely, the breakthroughs that Tony just described are some of the most important frameworks and hypotheses that we tried to pick up and further advance in the Greater Yellowstone Ecosystem.  

WC: Say more, how has Tony’s work changed the approach to studying ecosystems and animal migration in North America?  

Arthur Middleton: Well, I wouldn’t be doing what I am doing if it hadn’t been for Tony’s work in Serengeti. Back when I was a graduate student in 2007, it seemed like every conversation about the Yellowstone ecosystem revolved around predator-prey theory. Wolves were king, and the paradigm of top-down ecosystem control by predators dominated everything. But Tony had this body of work from the other side of the world that presented a different way of looking at that ecosystem. One day I was listening to Tony speak, and he said something that hit me: “Ungulates can be keystones too.” And I finally had my “Aha” moment, realizing that Yellowstone is actually a bottom-up system, and if we don’t start seeing it that way, we’ll never truly understand its full extent or how best to manage it. 

The other thing is that, even though I didn’t know him personally, I watched him from a distance and saw someone who made a long-term commitment to doggedly unpack the ecology and needs for a particular area. Tony showed us how to deeply understand and advocate for an ecosystem—in his case, the Serengeti. That commitment was and still is incredibly inspiring to me. 

WC: What other breakthroughs have you seen and been a part of Arthur? 

Arthur Middleton: One of the biggest breakthroughs in my time has been the set of technological advances that allowed us to see further and deeper into the hidden lives of these wildlife while they’re on the move, foraging across the landscape, and evading predators. Satellite tracking and remote sensing, along with the computational and analytical tools developed to work with this data, has allowed us to prove the migration phenomena that Tony talked about and given us new insights into why animals move across the landscape in their particular patterns and at their specific pace. On the application side, being able to see the detailed movement of these animals across a landscape gives land managers the kind of information they need to make better conservation decisions.  

We have also learned that even some of our biggest protected areas in the world—places like the Serengeti-Mara ecosystem, the National Wildlife Refuge in Alaska, or Yellowstone—are not big enough to contain and fully protect these species. Migrating animals are moving beyond the boundaries of the protected areas and are moving across landscapes that have a mix of land uses. So I think a really important breakthrough that is not progressing fast enough is how we can improve conservation across jurisdictional boundaries. It’s this focus on larger landscape coordination, paired with the development of community-based conservation.  

WC: What are some of the biggest threats to migratory species today?   

Arthur Middleton: I’ve been working in the Yellowstone ecosystem for 17 years. I feel pretty confident now in my assessment that the biggest threat in the coming years is land use change. It’s the conversion of land for building houses, for food, fiber, and fuel production, and for recreation use. People love being near these big western parks and protected areas so there’s a boom of people wanting a piece of it. It’s not just houses, it’s also all the fences and roads that come along with development. Energy development is another threat when not planned and sited well. When roads and other infrastructure are developed in higher densities, it can impede migrating animals on their way to seasonal forage. In other areas of the world, shifts from range or grazing land to crop production can be a big threat.  

We’ve also chopped these systems and these landscapes up into so many pieces, on the ground and in concept, that there’s no one responsible for seeing the bigger picture. We need policies tools that force us to cut through the fragmentation and work across big landscapes, focusing, in this case, on the entire corridor.  

Tony Sinclair: Excellent points. We have to understand that conservation of migration systems is a lot more difficult and complex than conservation of other non-migratory species. People tend to see them as just another species among many, so we need to develop a deeper appreciation that migration systems are fundamentally different—they require additional resources and attention. This is because with non-migratory species you can just draw a line around an area, and for the most part that will encapsulate everything they need in their lives year-round. That’s not the case for migrants. They require, as I mentioned earlier, areas of high-quality temporary food. They also require a refuge area, where they retreat to in the worst time of year. Then require a third area, which is the corridor between the two. As Arthur mentioned, we’ve come to realize how critical it is to protect these corridors and minimize our interference. And one of the biggest threats, in my experience, has been setting up fence lines that restrict wildlife movement. When that happens, migration systems collapse. They collapse down to a resident population.  

There are two other threats that I see. One is overtourism. In Serengeti, there is an all-out policy of bringing in as many people as possible. Thanks to the technology Arthur mentioned, we can now see that wildebeest are avoiding their preferred refuge areas during critical periods due to high tourist concentrations, forcing them to feed in suboptimal habitats. 

And then, if you’re aware of the Atlas of Ungulate Migrations that has just been published, you know there are huge gaps in our knowledge about migrating animals. For example, we only know of one migration system in South America. I simply don’t believe that’s the case. It’s amazing, because you’d think that such migration systems would be obvious and well known, but in fact, they’re not. We can’t apply conservation if we don’t know that these systems exist.  

WC: As leaders in your field, what emerging trends or possibilities in migration ecology and large landscape conservation excite you most about the future?  

Tony Sinclair: For the future, I think the trend toward what I call rewilding is a hopeful sign. Arthur talked about dealing with human-dominated areas and community conservation. I agree. We need to make human-dominated landscapes biodiversity-friendly, especially for migrants that can’t fly; they have to walk through these areas. A nice example is the buffalo migration that Robin Naidoo discovered in Botswana. It goes right through agricultural land, and they’re taking great pains to ensure the corridors and right habitats are there. I think this principle of community conservation and rewilding is the way of the future. 

Arthur Middleton:  For most of my life, the conservation and restoration of nature hasn’t been a societal priority, but I think that’s starting to change. On the international stage, despite whatever opinions we might have about initiatives like 30 by 30, it’s encouraging to see countries signing on to more ambitious nature protection goals. Here in the United States, we’re seeing unprecedented resources for land and water conservation through recent legislation—the Great American Outdoors Act, the Bipartisan Infrastructure Law, and the Inflation Reduction Act. To me, it feels like conservation is finally moving up the priority list. I hope this momentum continues and flows into the kind of initiatives Tony’s talking about with rewilding, especially prioritizing large-scale conservation, corridor protection, and connectivity.  

WC: Why should people care that animals migrate? What’s their value in the ecosystem?  

Tony Sinclair: I think that question can apply to any species on earth. Why do we want to conserve any animal? I think one answer is a philosophical one, which is that we have a moral responsibility to hand down to future generations what we ourselves have been able to enjoy. There is a scientific answer also, which is that we have no idea whether a species we have allowed to go extinct is actually necessary for the wellbeing of our own ecosystems. That includes the migration systems that affect us all the time—not just the ones we’re talking about,  Serengeti and Yellowstone, but bird migrations systems that encompass the whole of North America. We can’t play God and say, “We’ll let this one live and let that one die.”  

Arthur Middleton: I agree with Tony, and also, we have growing indications that the ability of these animals to migrate across large landscapes is fundamental to their productivity and abundance. When you move around the landscape to get temporary food and shelter, you may be able to get more nutrition, get fatter, and grow your offspring better. This, in turn, is important to the productivity of the entire ecosystem. So, if we want to be able to enjoy a wolf or a lion in one of these systems, it may be that we need to pay a lot more attention the ability of the prey to be productive. For communities that depend on wildlife for subsistence, their wellbeing may hinge on the added productivity that these migratory populations provide. 

In the United States, we are no good at this idea of preserving abundance, rather than simply existence. Our wildlife laws and policies are built around rarity and preventing species from going extinct. We really need to figure this out: how to preserve these massive, remarkable phenomena of abundance, from large bird and fish migrations to the vast ungulate movements Tony and I have studied. 

Temple Stoellinger is associate professor of environment and natural resources and law at the University of Wyoming. 

Featured image: Elk rut in Grand Teton National Park (NPS/Adams)

Background image: Wildebeest (Shutterstock)