Studying Gorilla Habitat and Biodiversity
In recent years our work has expanded to include biodiversity research focusing on other species, many endangered, that live in gorilla habitat.
Both mountain gorillas and Grauer’s gorillas share their habitats with an enormous number of species, many of which are found nowhere else in the world. In Rwanda, we have worked closely with the National University of Rwanda to develop a series of research areas that enable us to better understand the biodiversity of the Virungas and also to provide research opportunities for university students. In Congo, we have conducted censuses and contributed important data on the distribution and density of a number of species, including chimpanzees, elephants and okapi.
Biodiversity research at Karisoke™
Founded in 2002, Karisoke's Biodiversity Program works to preserve the diverse plants and animals in Rwanda's Volcanoes National Park. Species endemic to the park have a high probability of survival owing to international and governmental protection efforts directed at the famous mountain gorilla. As the gorillas and other species in the park depend on the same habitats, ensuring conservation of the former includes conservation of the latter.
Although study of the mountain gorillas has always been the main focus of our scientific work at the Karisoke™ Research Center, our work now includes studies of many more of the species that occupy gorilla habitat.The program's main objective is the long-term monitoring of biodiversity changes in the park and neighboring habitats. Understanding species distribution, habitat requirements and population trends is helpful for implementing effective conservation. Specifically, we set up standardized scientific methods to study the various species and we initiate research projects to provide baseline and updated data to be monitored in the future. At the present time, the Karisoke Biodiversity Program has established baseline information regarding key study species that need to be monitored long-term.
Many plants and animals unique to the Virungas are endangered, yet little research that could help save them was done until recently. Karisoke™ is making major contributions to this effort, including a biodiversity manual that describes 1,000 key species. Karisoke™, in collaboration with the Rwanda Development Board, also holds weekly seminars where scientists from around the world come to share their research findings with our staff. Today, the Biodiversity Research Program has two permanent field teams of three people each, in addition to the program coordinator.
Some of our current biodiversity research projects include:
Research on mammals in gorilla habitat
Golden monkey studies
Golden monkeys are a unique species of endangered primate found only in two areas of the Albertine Rift: the Virunga Massif (volcanic mountains) and the Gishwati Forest Reserve. Two groups of golden monkeys in Volcanoes National Park were habituated in 2002 for research and tourism purposes. Biodiversity Research Program Coordinator Deogratias Tuyisingize began scientific research on these monkeys in 2005. During a preliminary survey in 2007 he estimated a total population of 4,850 golden monkeys in the park. After four years the population was estimated at 3,498.
Based on Tuyisingize's findings, more research projects were designed by university students to understand the golden monkey's behavior and inform park managers about the monkeys' conservation needs. These studies included "Positional Behavior of Golden Monkeys" (2007, by Biodiversity Program Research Assistant Bernadette Arakwiye); "Impact of Tourism on Golden Monkey Behavior" (2008); and "Female Relationships in Golden Monkeys" (2009). Current long-term studies focus on the monkeys' behavioral ecology. Further research should shed light on the population trends and breeding requirements of the golden monkeys, as well as threats to the golden monkey habitat.
Large mammal ecology studies
Given the ecological importance of large mammals and their vulnerability to extinction, in 2008 Karisoke launched a survey of large mammals in Volcanoes National Park, focusing on duikers, bushbuck and buffalo, to detect changes in their density and distribution over the past 20 years. The survey found that all the species surveyed had experienced a minimum 26 percent decrease in density, mainly due to poaching. Also, undergraduate projects have evaluated the conflicts between large mammals and local people surrounding the park at four-year intervals since 2003. An undergraduate project conducted in 2011 revealed that buffalos are conflicting with local people, primarily due to crop raiding. Also, illegal activities (such as snares) are still being carried out higher up in the park. A large decline in population size can sometimes serve as sufficient indication that a species merits conservation interest. Long-term monitoring of the four large mammals’ densities every four years is recommended to investigate changes in their population.
Small mammal ecology studies
Many small tropical animals, such as forest-dwelling shrews and rodents, are endangered by habitat degradation, especially climate variation that affects plant diversity. More long-term monitoring is needed to inform conservation planning. Deogratius Tuyisingize began a small mammal study as part of his Master of Science studies at the University of Cape Town, South Africa. He found 15 of the 19 species previously reported in the park. His focus was to study a number of small mammals in the gorillas' habitat and extrapolate the research to other areas such as Buhanga Ecopark (where a student from the National University of Rwanda is studying small mammal diversity) and Gishwati Forest. In May 2011, Tuyisingize was awarded a grant from the Chicago Field Museum to support capacity building and scientific interchange with the scientists at the Field Museum.
Bird ecology research
Birds are one of the most reliable indicators of biodiversity in Volcanoes National Park, partly because they have dispersed into and diversified in various altitudes and gorilla habitats. One of the central goals of the bird ecology research is to understand and predict the abundance of species in the park. Population trends are often used to help identify species of conservation interest. Karisoke is conducting a series of long-term bird monitoring projects, especially on the status of and trends in bird populations in the park. The data collected on bird abundance, density and species richness have proven to be extremely valuable in detecting long-term regional or national declines and in defining conservation actions.
The park houses more than 145 species of birds, including 15 endemic to the Albertine Rift and two threatened species. Our work in this area has focused on the Grauer's rush warbler (which lives only in the wetlands of this region) and other endemic species which seem to be switching their habitats toward higher altitudes, and migratory species that are being affected by weather changes. Student interns at Karisoke have carried out many other studies on the distribution and feeding ecology of endemic birds. Bird monitoring provides long-term data on the status and trends in avian abundance, density and species richness but also on climate change; these data have proven to be extremely valuable in detecting long-term regional or national declines and in defining conservation actions. A priority is to extend the bird studies to other nearby ecosystems such as the Rugezi Wetlands and Gishwati Forest, and provide further information on environmental impacts on birds, including impacts on their breeding behavior.
Study of the many varieties of plants that make up the habitat for gorillas and other endemic animals is of critical importance to conservation, especially monitoring changes in food plant availability. Gorillas and golden monkeys rely on a few key species. We predict that plant food scarcity would influence the animal species distribution at Volcanoes National Park. In order to have a better understanding of what drives population dynamics and distributional patterns of animals in the park, we need to document resource availability on a larger scale and continue monitoring longitudinal changes in food abundance. Changes in food plant availability may be one of the earliest observed responses to rapid global climate change and could potentially have serious consequences for animals, such as the primates of Volcanoes National Park, that depend on these resources. It is important to evaluate animal food plant abundances and compare the density and biomass of different animals to understand why these animals are restricted to some areas or habitats.
Volcanoes National Park houses more than 950 plant species. The various other botany projects underway include collection of plant species information, creation of a photo database, and identification of plants used as food by gorillas and golden monkeys. Karisoke maintains an herbarium of more than 600 plant species and contributes specimens to Rwanda's national herbarium.
Karisoke's botany team has catalogued more than 1,300 plants found in the park; discovererd several new species; surveyed plants in nearby Buhanga park; and studied the impact of ecotourism on plant diversity in Volcanoes National Park.
Many students from the national university have completed their senior theses on botany-related questions, including crop raiding by animals in the park, aquatic ecosystems, the cause of water loss, gorilla food distribution, habitat changes at different altitudes, and the consumption of medicinal plants by gorillas. An innovative project has found that many medicinal plants are used both by gorillas and by the traditional healers who live near the park, and is exploring whether the gorillas seek these plants and are protected by them.
The high elevations found in Volcanoes National Park may have a profound effect on herpetofaunal diversity. At the present time, very little is known about the amphibians and reptiles of the Virunga region. A current study in collaboration with the University of Texas has found 12 of the 17 species formerly recorded, of which eight are endemic to the Albertine Rift. Extensive amphibian monitoring has begun, aiming at finding additional species. This may be a challenge, as warming temperatures have allowed for the emergence of a fungus disease that has been wiping out amphibian species around the world. Further studies will look for this disease in the gorilla habitats. Although amphibians have been recently studied in the park, long-term amphibian studies are still needed in order to monitor changes over time.
Because carnivores are at the top of the food chain, previous field observation of carnivores indicates that a wide assessment is critical in order to prioritize conservation actions and understand habitat requirements and adaptation to and tolerance of human encroachment. Observations from scats and footprints found along trails in the park indicate that it may host many carnivores, including side-striped, civet, genet, serval, and golden cats. No previous studies have specifically targeted assessing carnivore abundance, which requires a diverse set of approaches because they are elusive species. Earlier surveys were inappropriate for carnivore studies, so in order to have a good picture of the secretive animals of the park we are preparing to monitor the carnivores there using a more suitable method, such as camera traps.
Scientists are increasingly recognizing the importance of smaller species for ecological and conservation monitoring, because some are particularly sensitive to environmental pollution and changes in habitat. Butterflies are important as pollinators for some species of plants and they are more widely dispersed than other invertebrate groups, so they are key indicators of climate change. If the climate warms, temperature-adapted species will move higher until they reach the top of the mountains, and then they have to adapt. A study carried out in Volcanoes National Park in August of 2010 found 18 species. Due to the role of butterflies as indicators of biological processes, monitoring butterflies will help us to monitor global change and recommend a policy for biodiversity. Long-term butterfly monitoring is expected to provide early warnings of change in gorilla habitats.
Studies of environmental change
Environmental factors such as temperature and rainfall influence the nutritional quality of plants in each habitat. Karisoke™ is studying long-term changes in species diversity and distribution in light of climate change, among amphibians, butterflies, and small mammals. It is predicted that both climate change and human impact will put significantly increased pressure upon habitats, and biodiversity conservation initiatives are imperative. At the moment, although there is growing concern that some species have declined, much of the evidence is either anecdotal or derived from short-term studies. Karisoke™ is also measuring rainfall and its effects on gorilla habitat, and studying how the forest is recovering from a fire (caused by humans) that spread over a large area in 2009, in order to develop a fire management strategy. A future project will be to install a weather station in the park which will provide reliable information on the environmental impacts on gorilla habitat.