Lake Chad flooded savanna
Lake Chad flooded savanna is a unique ecological region located in west-central Africa, primarily around Lake Chad, which is Africa's fourth-largest lake. This savanna is characterized by a complex landscape of small islands, reed beds, mud banks, and marshy shorelines, providing critical habitat for a variety of wildlife, including many migrating bird species and threatened mammals like hippopotamuses and crocodiles. However, the region faces significant environmental challenges, including severe drought, underground water seepage, and anthropogenic pressures, leading to a drastic reduction in the lake's size and depth over the past decades.
Historically, Lake Chad has supported rich biodiversity and agricultural activities, but its shrinking waters have adversely impacted food security and local livelihoods. The declining water levels complicate fishing practices and disrupt ecological balances, particularly affecting bird nesting sites and fish populations. Governance challenges among the four bordering countries—Cameroon, Chad, Niger, and Nigeria—further exacerbate the issues, as weak legislative frameworks limit effective conservation efforts. Nevertheless, initiatives such as the Lake Chad Basin Commission aim to address these challenges through proposals for interbasin water transfer and restoration projects, seeking to revitalize the lake and support the communities dependent on its resources.
Lake Chad flooded savanna
- Category: Inland Aquatic Biomes.
- Geographic Location: Africa.
- Summary: This savanna is a strategically located home of migrating birds, currently threatened by drought, underground seepage, and anthropogenic influences.
Africa's fourth-largest lake and the pride of west-central African hydrology is now a shadow of what it used to be. Lake Chad is located in the west of Chad, bordering on northeastern Nigeria. The main source of Lake Chad's water is the Chari River, fed by its tributary the Logone, with a small amount coming from the Yobe River in Nigeria and Niger. The lake is freshwater in spite of its high level of evaporation.
Lake Chad's landscape is characterized by many small islands, including the Bogomerom Archipelago; reed beds; mud banks; and a belt of swampland. The shorelines are largely composed of marshes. Lake Chad is very shallow, with a depth of only 34 feet (10.5 meters) in its deepest area, which makes it highly vulnerable to small changes in average rainfall, leading to seasonal fluctuations in average depth of about three feet (one meter) every year.
The lake's current water surface of 965 square miles (2,500 square kilometers) is miniscule compared to its 9,653 square miles (25,000 square kilometers) in the 1960s. Severe droughts in the 1970s as well as underground seepage have adversely affected the volume and depth of this lake. These factors, in addition to climate change and the increased pressure from the approximately 30 million humans nearby and persistent desertification, have led to large-scale destabilization of the ecosystem. They have also made the lake extremely shallow—from an average depth of 12 feet (39 meters) in the 1960s to 1.5 to 5 feet (0.5 to 1.5 meters) today—and have in recent years led to its division into northern and southern pools.
Biodiversity
The lake's rich flora include more than 44 species of algae and yaéré grassland of Echinochloa pyramidalis, Vetiveria nigritana, Oryza longistaminata, and Hyparrhenia rufa. The grassland savanna area is a habitat for numerous species of wildlife, including a fast-diminishing number of hippopotamuses and crocodiles; large species of migrating birds, such as wintering ducks; wading birds such as the ruff (Philomachus pugnax); and other waterfowl and shore birds. The decreasing water levels in Lake Chad have affected bird life across the savanna, particularly reducing the availability of nesting sites for the endangered West African subspecies of black-crowned crane and decreasing the supply of adequate wintering grounds for birds such as the ruff. The savanna surrounds, a semiarid Sahel formation, have not been favorable for the habitation of mammal species.
The decrease in crocodile and hippopotamus has adversely affected fish populations. Crocodiles prey heavily on catfish, which consume the eggs and fry of tilapia and other cichlid fish. Without crocodiles to control catfish populations, the catfish have dramatically reduced tilapia stocks here.
Environmental Threats
The severe droughts that have plagued the Lake Chad savanna area have contributed to the shrinking of the lake and have affected food security and the livelihoods of the people who have made the basin their home. The shrinking lake has also greatly influenced fishing in the area. Low rainfall and underground seepage of water out of the lake have also affected the agricultural productivity of the savanna and greatly undermined people's ability to provide for their basic needs. Water-resource harnessing, in the form of damming the rivers that flow into Lake Chad, has adversely affected the timing and extent of seasonal flooding—undercutting the extent of nutrient-rich sediment deposition around the savanna—as well as disrupting fish migration patterns. Furthermore, each of these factors as well as evaporation from climate change have led to increasing salinization of the lake, which negatively impacts agricultural activities and habitat sustainability around the basin.
Because the lake and savanna are vital to four countries—Cameroon, Chad, Niger, and Nigeria—there have been governance difficulties. These include the challenge of formulation of water-use and land-use policies that would benefit all of the nations as well as take into consideration the peculiarities of each one. The basin's location within some of the poorest countries of the world has not helped resolve these issues, as some of these governments have very weak legislatures and have not manifested concerted efforts to protect the area.
Conservation Efforts
Considering the savanna's ecological and agricultural importance, the Lake Chad Basin Commission (LCBC) has proffered some means for ameliorating the challenges. Suggestions have been made concerning augmenting Lake Chad with water from the Zaire River basin, for example. One such plan proposes moving 3.5 trillion cubic feet (100 billion cubic meters) of water annually from the Zaire River in a navigable canal 1,491 miles (2,400 kilometers) in length. Dams would be built in the receiver and donor areas for electricity generation.
There was an earlier proposal to divert the Ubanghi River into Lake Chad, which would revitalize the dying lake and provide livelihoods in fishing and enhanced agriculture to tens of millions of central Africans and Sahelians. Interbasin water-transfer schemes were proposed in the 1980s and 1990s. In 1994, the LCBC proposed a similar project, and at a March 2008 summit, the heads of state of the LCBC member countries committed to the diversion project. In 2020, the World Bank allotted $346 million to help restore the region.
Bibliography
Bene, C., et al. “Inland Fisheries, Poverty, and Rural Livelihoods in the Lake Chad Basin.” Journal of Asian and African Studies, vol. 38, no. 1, 2003.
Coe, Michael T., and Jonathan A. Foley. “Human and Natural Impacts on the Water Resources of the Lake Chad Basin.” Journal of Geophysical Research, vol. 106, no. 4, 2001.
Kolawole, A. “Environmental Change and the South Chad Irrigation Project, Nigeria.” Journal of Arid Environments, vol. 13, no. 2, 1987.
Sarch, M. T., and C. Birkett. “Fishing and Farming at Lake Chad: Responses to Lake-Level Fluctuations.” Geographic Journal, vol. 166, no. 2, 2000.
"World Bank Provides $346 Million to Strengthen Resilience and Livelihoods in the Lake Chad Region." The World Bank, 26 May 2020, www.worldbank.org/en/news/press-release/2020/05/26/world-bank-provides-346-million-to-strengthen-resilience-and-livelihoods-in-the-lake-chad-region. Accessed 22 Oct. 2024.