This project will conduct comprehensive research to construct and test detailed models of population and community ecology, with a focus on African lion populations. First, the project will investigate lion population dynamics at the level of individual social groups as well as larger-scale sub-populations, constructing statistical models with population-level, group-level, and individual variables to determine the relative impacts of short-term variability in demographic performance and environmental conditions on population growth and stability. Comprehensive data on day-to-day variation in prey availability within the ranges of 24 different lion groups will be measured and used to link the shifting mosaic of migratory herbivores and territorial behavior of the lions in a spatial food-web model across the landscape. Second, the project will investigate the role of spatial heterogeneity in stabilizing the coexistence of competing carnivore species. Cheetahs, leopards, lions and hyenas may show divergent niche strategies that create a reticulated pattern of occupancy within an overall pattern of coexistence. Third, the project will measure cycle-length of four viral diseases in the lions to test predictions of multi-host disease transmission models.
The project will continue to train Tanzanian researchers, collaborate with Tanzanian scientists and provide research opportunities for American graduate students and undergraduates, including individuals from under-represented minorities. Results from the study will help wildlife managers to predict consequences of habitat change and fragmentation, to identify the landscape features necessary for species co-existence, and to measure the effectiveness of disease control programs.
Over the past three years, we have published seven scientific papers (with two more in press) that focused on: factors affecting population size of the Serengeti and Ngorongoro Crater lions, lion feeding success as a function of moon phase, the effects of rainfall on exposure to anthrax, the virology of disease outcomes of FIV-infection, effects of grass fires on ranging patterns, and new methods for estimating the extent of lion predation on giraffe. Several of these papers have implications beyond basic ecology. For example, the moon-phase analysis showed that Serengeti/Ngorongoro lions are least successful in catching prey during the full moon, which helps to explain why most lion attacks on humans occur in the first week after the full moon. The Serengeti lions also provide an important benchmark for estimating the requirements for successfully conserving lion populations across Africa. Though not yet published, we have also completed an in-depth analysis of interspecific competition between lions, cheetahs and African wild dogs. We were able to show that while cheetahs are able to co-exist with lions, African wild dogs can only persist in areas with low lion population densities. The major outcome of the past three years’ support has been to establish a large-scale camera-trap grid to monitor the spatiotemporal distribution of large mammals within the long-term lion study area. This generated such an extraordinary amount of data (over one million photographs per year) that we teamed up with Zooniverse to develop Snapshot Serengeti (www.SnapshotSerengeti.org), an online citizen science interface where volunteers around the world identify animals captured in the camera trap photos. More than 160,000 people have helped to classify >3 million pictures, and SnapshotSerengeti was chosen as one of the "Top Ten" Citizen Science projects, by The Ecologist in 2013. Snapshot Serengeti involves non-scientists directly in research, thereby encouraging understanding of basic scientific principles and processes. Our blog (blog.snapshotserengeti.org) engages users in the rationale behind our scientific questions, the need for long-term research to answer ecological questions, the proposal writing, funding, and paper writing processes, the data reduction process, and more. We also maintain a discussion forum (talk.snapshotserengeti.org), in which users engage directly with scientists and each other. We also maintain a Facebook page (www.Facebook.com/SnapshotSerengeti) and twitter account (@snapserengeti). Zooniverse is currently incorporating Snapshot Serengeti into classroom lesson plans (www.zooteach.org), and the University of Minnesota has integrated the camera data into an "authentic science" laboratory curriculum in introductory biology classes with funding from the Howard Hughes Medical Institute. After learning how to identify species and classifying photographs, the students map distributions of camera-trapped animals over time, space and differing environmental conditions. The "Savanna Ecology" module will soon be available for undergraduate courses throughout the US, creating opportunities for thousands of students to participate in ongoing research and to investigate existing and future databases. Preliminary analysis shows the power of the camera traps for documenting the timing and extent of animal movements in the lion study area. Figure 1 shows the extraordinary year-to-year variation in timing and location of seasonal rainfall and associated distribution of migratory and resident herbivores. The background of each panel is the NDVI (a satellite image that shows the amount of vegetative growth with green being more active growth vs brown showing no growth) of the lion study area. The size of the circle around each camera trap is proportional to the number of animals recorded at each camera trap each month. Data are from two consecutive years: 2010, when the November rains failed, and 2011, which enjoyed normal November rainfall. Serengeti’s migratory wildebeest herds did not return to the lion area in November 2010 whereas they swamped the study area in November 2011. In contrast, the non-migratory hartebeest showed a similar distribution each month each year. After meeting the logistical challenges of handling this enormous database, we are now poised to make numerous important scientific contributions in the coming years.
