Research questions being asked:
Spotted hyenas are top predators in most parts of Africa. This project inquires whether spotted hyenas can function as sentinels to inform us about the health of entire African ecosystems. We know from our prior research in the Masai Mara National Reserve, Kenya, that human disturbance induces changes in the natural behavior and stress physiology of spotted hyenas, and that these trends precede worrisome changes in hyena numbers by roughly five and three years, respectively. Thus we know that specific behavioral and hormonal trends in hyenas predict the health of their own populations with enough advance warning to permit wildlife managers to intervene with revised management policies. Now we want to find out whether these same behavioral and hormonal trends in hyenas can also predict the health of the other animals that live in the same areas as the hyenas. If so, then hyenas can function as sentinels to give us early warning of declining ecosystem health throughout sub-Saharan Africa.
What you need to know:
Sentinel species are used to inform us about environmental processes that are too difficult or too expensive to measure directly. In conservation biology, an ideal sentinel species is a large-bodied, wide-ranging creature occupying top positions in local food webs. Spotted hyenas are large carnivores that range widely throughout most African ecosystems. They are easier to monitor than other predators, they are the most abundant large carnivores in Africa, and they occur in habitats ranging from savannas and swamps to deserts and montane forests.
Historically sentinel species were used on a presence-absence basis, much like a canary in a coalmine. Unfortunately, by the time such a sentinel vanished to indicate that a habitat was deteriorating, it was too late to save what remained. Here we will inquire whether behavior or stress hormones of spotted hyenas can tell us when habitats are becoming degraded long before the sentinel species disappears, when there is still plenty of time to work with local wildlife managers to save these habitats.
In many protected areas in Africa today, tourists have no negative impacts, but human activity associated with livestock grazing is disturbing wildlife. Here we will compare behavior of spotted hyenas living in a heavily disturbed area inside the Reserve with that of hyenas inhabiting an undisturbed are of the Reserve. We will also study their stress physiology non-invasively by measuring excreted stress hormones. We will monitor numbers and distributions of the other carnivores that live side-by-side with the hyenas, as well as the numbers and distributions of all the antelope species preyed upon by the hyenas. If hyenas are effective ecosystem sentinels, their behavior or physiology will predict population trends in these other animal species.
Why this matters:
I have worked in the Masai Mara National Reserve continuously since the 1980s, and during that time I have seen some disturbing changes. The human population along the edge of the Reserve has grown exponentially since I started my work here, and so have numbers of livestock, many of which are grazed daily inside the Reserve. We have seen numbers of lions and antelope decline over the years. Spotted hyenas are the most adaptable carnivores present, so they are still abundant in both disturbed and undisturbed portions of the Reserve, yet various aspects of their behavior have changed dramatically since the 1980s in disturbed regions, and their stress hormone concentrations have increased markedly. This situation is far from unusual these days in Africa, as wildlife populations are declining continent-wide, even within the boundaries of protected areas. We urgently need to develop a method for cheap and effective monitoring of the health of African ecosystems so managers can intervene in a timely fashion. That is precisely what we propose here.
Wildlife represents one of the most important natural resources in Africa’s developing nations; wild animals attract tourists, they serve as “flagships” for the protection of biodiversity, and they also play key roles in critical ecosystem processes. As Africa’s human population grows, many wild animals are becoming threatened or endangered. Our project is therefore important to the future of Kenya and other developing African nations that rely heavily on ecotourism for acquiring jobs and foreign exchange.
What your money can do:
This project will require extensive counting and mapping of the animals living in the same areas as our hyenas within the Masai Mara National Reserve. The hyenas range over large areas of rugged terrain, and because the hyenas have the potential to eat us, we must do all our work from vehicles. Although I already own the vehicles from which this work would be done, your money will allow us to buy fuel, car parts, digital voice recorders, range finders, and GIS software so we can monitor numbers and spatial distributions of animals. In addition your money will allow us to buy the reagents and disposable lab equipment needed to measure excreted stress hormones. Most importantly, your money will allow us to purchase anesthetic and other supplies we need to immobilize specific hyenas in both disturbed and undisturbed areas, and fit them with radio collars so we can closely monitor their use of space in relation to distributions of competing carnivores and prey animals living in the same habitats. To give you an idea of what it costs to do this work, gasoline in Kenya costs $6.00 per gallon, each vial of anesthetic costs over $50.00, and each radio collar costs hundreds of dollars.
This work can help us develop an early warning system for detection of threats to entire ecosystems throughout sub-Saharan Africa. Because students participate in all aspects of this research, it will also permit the training of a new generation of wildlife biologists willing to work very hard to conserve African ecosystems. We routinely collaborate with scientists at the Kenya Wildlife Service, so important changes can potentially be made as necessary in the management of Kenya’s natural areas via the actions of our collaborators. Ultimately I anticipate that this work will have important long-lasting effects on our ability to conserve biodiversity throughout the African continent.
Kay Holekamp is a University Distinguished Professor in the Department of Zoology at Michigan State University. She graduated from Smith College, then received her Ph.D. at the University of California at Berkeley. Since 1988 she has been studying spotted hyenas in the Masai Mara National Reserve in Kenya, and she is now considered one of the world’s leading hyena experts. She has published many articles on the biology of hyenas and other carnivores in both professional journals and lay publications. Holekamp is currently chair of the IUCN’s Hyaena Specialist Group, and she developed and maintains the IUCN’s educational website about hyenas at http://www.hyaenidae.org/. When she is in the field in Kenya, she contributes to the New York Times blog entitled Scientists at Work (http://scientistatwork.blogs.nytimes.com/author/kay-e-holekamp/), and she and her students also maintain a hyena project blog of their own at http://msuhyenas.blogspot.com.