Conservation of savannas
Conservation of savannas focuses on the preservation and management of tropical and subtropical grassland ecosystems, characterized by distinct wet and dry seasons. These environments are rich in biodiversity, hosting a variety of herbivorous and predatory animals, insects, and birds. Human activities, particularly hunting, poaching, and agricultural expansion, pose significant threats to these ecosystems. Many countries have set up nature preserves to protect valuable savanna resources, but illegal wildlife trade continues to severely impact populations of species like the African bush elephant and various birds.
Savannas are typically found at the edges of tropical rainforests and depend on seasonal fires to maintain their grassland structure. The ecosystems are sensitive and can be easily altered by human-induced changes such as land conversion for agriculture and cattle ranching. Recent studies indicate that a significant portion of Africa's savanna conservation areas are underperforming, prompting calls for enhanced management of existing protected lands. The health of apex predators, such as lions, is often used as a measure of the overall biodiversity and ecological health of savannas. As awareness of these issues grows, conservation efforts are increasingly crucial to ensure the survival of these vital ecosystems.
On this Page
Subject Terms
Conservation of savannas
DEFINITION: Tropical or subtropical grassland environments with wet and dry seasons
Savanna environments host large populations of insects, birds, herbivorous grazing animals, and predatory animals. Many nations have established nature preserves to protect valuable savanna resources, as hunting and poaching have rapidly reduced the populations of some once-numerous savanna inhabitants and agricultural encroachment has shrunk the land area of savannas worldwide.
Savannas form in tropical or subtropical wet-dry climates, with moisture from the intertropical convergence zone dominant in wet months. Savannas have an average temperature of at least 16 degrees Celsius (64.4 degrees Fahrenheit) during the coolest months and receive between 50 and 255 centimeters (20 and 100 inches) of rain yearly. Savannas have poor drainage; the vegetation in savanna regions is dominated by drought-resistant grasses and a few trees. Fires, which occur during the dry season and prevent forests from developing, are essential in maintaining these grasslands.
Savannas form at the borders of tropical rain forests. In Africa, the savanna of the Sahel lies to the north of the rain forest, and northern and southern savannas meet in the East African savanna. The Colombian and Venezuelan llanos of the Orinoquía region are north of the Amazon rain forest, and the Argentine pampas and Brazilian cerrado are south of the rain forest. Almost the entire country of Uruguay is savanna. Savannas occupy roughly 25 percent of the continent of Australia, running across the northern tropics. South of the Himalaya Mountains, the Terai-Duar savanna in northern India, Nepal, and Bhutan is maintained by the yearly monsoon.
Savannas support large numbers of herbivorous and predator animals, birds, reptiles, and insects. Termites play an important role in savanna ecosystems; their mounds dot savannas worldwide. Termites consume cellulose and lignin from living grasses and trees, as well as vegetative litter. Primates (including human beings) exploit savanna termites as a high-protein source of food.
During the wet season (which may arise from monsoonal rains), large animal herds graze over the grasslands; during the dry season, herds move toward lakes and rivers. Predators follow the herbivores. Migratory birds from Asia, Europe, and North America winter in Southern Hemisphere savannas, joining large numbers of ground-living sedentary birds. Historically, sleeping sickness in Africa, spread by the tsetse fly, and malaria, spread by mosquitoes, kept human populations from exploiting many savannas, but modern insecticides and modern medicines have mitigated these disease factors somewhat, and human occupation of savannas has climbed steadily since the mid-twentieth century.
Human activities are the major threat to savannas worldwide. Illegal trade in of savanna birds, such as South American parrots, and African and Asian animals, including tigers, lions, and primates, is a multibillion-dollar industry worldwide. Some endangered birds and animals are prized as pets; others are killed for their pelts or for use of their body parts in foods or medicines. Efforts to stop the trade in endangered species and their products have had limited results. For example, hunting of the endangered African bush elephant (also known as the Savanna elephant) was prohibited in 1989, but poachers continue to kill the elephants for their ivory tusks. The of these elephants stood at only an estimated ten thousand in 2010. Deaths of African elephants from poaching peaked in 2011, allowing the world's population of African elephants to rebound. However, poaching remains a continued threat to their survival.
It has been estimated that if conversion of the Brazilian cerrado savanna to croplands continues at the rates seen in the late twentieth century, the savanna will disappear by 2030. Oil production in the Venezuelan llanos and Brazilian cerrado may also alter the savanna biome. In Australia, pressure from the cattle industry to alter the natural savanna to provide for optimal beef production has changed the savanna ecosystem. Problems have arisen there from the introduction of nonnative plant species, land clearance, and pastoral grazing, which has changed the natural pattern of fires in the savanna.
In 2021, researchers estimated that roughly eighty percent of Africa's savanna conservation land was failing. The study used the conservation status of African lions relative to their environmental carrying capacity. Because lions require a large population of prey species to sustain themselves, the health of lion populations is often used as an indicator of the biodiversity levels within a savanna. With this information, researchers suggested devoting additional efforts to securing and stabilizing existing protected savannas rather than expanding the protected regions.
Bibliography
Bassett, Thomas J., and Donald Crummey, eds. African Savannas: Global Narratives and Local Knowledge of Environmental Change. Portsmouth, N.H.: Heinemann, 2003.
Mistry, Jayalaxshmi, and Andrea Berardi, eds. Savannas and Dry Forests: Linking People with Nature. Burlington, Vt.: Ashgate, 2006.
Pennington, R. Toby, and James A. Ratter. Neotropical Savannas and Seasonally Dry Forests: Plant Diversity, Biogeography, and Conservation. Boca Raton, Fla.: CRC Press, 2006.
Roach, Mary. “Almost Human.” National Geographic, April, 2008, 126-145.
Vasquez, David. "New Research Suggests That Over 80% of Africa's Savanna Conservation Land Is Failing." Lion Recovery Fund, 9 Dec. 2021, lionrecoveryfund.org/new-research-suggests-that-over-80-of-africas-savanna-conservation-land-is-failing/. Accessed 23 July 2024.