Limpopo River ecosystem

• Category: Inland Aquatic Biomes.
• Geographic Location: Africa.
• Summary: This large river flows from the heart of southern Africa through four countries and into the Indian Ocean, watering a mosaic of land rich in biodiversity.

The Limpopo River meanders eastward from highlands in southern Africa through savannas, agricultural and rural homestead areas, finally emptying into the Indian Ocean in Mozambique. Along its course, it waters the borderlands of South Africa, Botswana, and Zimbabwe. The area is characterized by relatively high human population density with the major land use consisting of seasonal subsistence farming. The Limpopo River is world-renowned for its abundance of wildlife.

At more than 154,441 square miles (400,000 square kilometers), an area larger than Germany, the river forms one of the largest watersheds in Africa. It is the second-largest river in Africa to empty into the Indian Ocean, flowing for 1,087 miles (1,750 kilometers) from one of its main source catchments: the Waterberg, or Water Mountain, massif, north of Johannesburg, South Africa. The river basin is characterized mainly by flat or undulating plains with African savanna.

Climate is generally warm and tropical, and rainfall varies from 8 to 47 inches (200 to 1,200 millimeters) per annum across the course of the Limpopo. Through most of the year, the water flows sluggishly, containing much silt and many sandbars. During the dry season, from April to October, much of the upper sections of this annual river run dry. The rainy season from November to February and the large catchment area ensure that most of the river flows with a high water volume during the wetter months. The region is also prone to flooding in wet years, like the catastrophic floods in 2000, in which almost 800 people died, the 2007 floods, which displaced nearly 90,000 people, and the 2013 floods that killed 68 and affected over 180,000 people.

From below the confluence of its major tributary in Mozambique, the Olifants, or Elephant, River, the Limpopo River mainly remains permanently navigable. Climate change has impacted the Limpopo River in several ways, most notably reducing water supplies during the dry months.

Biodiversity

A salient feature of the Limpopo River is the wealth of biodiversity within its waters and also within the surrounding ecosystems. Near the river mouth in Mozambique, two biodiversity hot spots intersect: the East African Coastal Forest biome and the northern tip of the Maputaland-Pondoland-Albany hot spot area.

The river also bisects Great Limpopo Transfrontier Park, a collaborative protected area of nearly 13,514 square miles (35,000 square kilometers), roughly the area of Belgium, covering the international borders of South Africa, Botswana, Zimbabwe, and Mozambique. This region has exceptional diversity and abundance of large mammals and, to a lesser extent, plant species. It is also world-renowned as a birding destination, with roughly 750 species to be seen along the watercourse.

The Limpopo hosts at least 50 species of freshwater fish and at least 18 additional introduced species. Species like bull shark (Carcharhinus leucas) have been sighted in the river almost 93 miles (150 kilometers) inland from the sea.

The Limpopo River region is relatively well conserved via formal protected areas and private reserves. Its natural beauty and wealth of wildlife are stimulating a burgeoning ecotourism industry. Large amounts of water hyacinths (Eichhornia crassipes) grow in the slow-moving waters, creating such a dense cover that it can reduce the oxygen available to fish in the river. Riparian forest cover dots the banks of the Limpopo, creating good shelter and diverse habitats for the creatures that live there.

Human Settlement

In 1932, the remnants of an ancient culture along the Limpopo River in very north South Africa were discovered. Subsequent research has shown that the kingdom of Mapungubwe had extensive building complexes, as well as mastery of stone masonry and gold forging, and far-flung trading partners. In the period around 1000 CE, people were likely attracted to the area for its vast agricultural opportunities, and because it contained many elephants (Loxodonta africana) with the allure of ivory as a major trading commodity. This civilization gave rise to the kingdom of Zimbabwe in the thriteenth century—though it seems that a decrease in annual rainfall, with a concomitant decrease in pastoral activities, led to the eventual downfall of Mapungubwe. The area is now a World Heritage Site, as well as a national park; research continues here.

In modern times, the region is a melting pot of cultures; most people have rural livelihoods, and the area is characterized by relatively low infrastructure. The population density is high around the Limpopo River, however, at 35 people per 0.4 square mile (1 square kilometer). Poverty is severe, with many dependent on the variable flows of the Limpopo River for their subsistence-agriculture practices. Economic inequality across national borders here leads to tides of illegal immigrants, contributing to social instability and difficulties in policing environmental mandates.

The demand for water in the Limpopo River is unevenly spread. The agricultural sector taps about 50 percent, while the urban sector uses 30 percent. Livestock is very important, with an estimated 2.2 million animals in the area, 70 percent of which are cattle. South Africa is responsible for 60 percent of total water extraction, and Zimbabwe for 30 percent; Mozambique and Botswana combined account for only 10 percent of extractive use. Water supplies from August to October are insufficient for human demand; shortcomings are likely to increase with demand and irrigation management is expected to be a critical aspect of planning. Recognizing the need for collaborative efforts to manage this large watercourse, the governments of South Africa, Botswana, Zimbabwe, and Mozambique established the Limpopo Watercourse Commission in 2003. It is mandated to foster equitable sharing of the resource of the Limpopo River, to promote sustainable development initiatives, and to help prevent a repeat of the type of climate-change-driven downfall that occurred here some 800 years ago.

Climate change in the region is likely to further stress water resources in the region. Climate trajectories for the region project significant warming, which will increase droughts in the region. Cyclones near the coastal areas are predicted to be more intense as the effects of climate change are felt. These variations in water could further exacerbate the stress on water resources.

Bibliography

Huffman, Thomas, N. Mapungubwe: Ancient African Civilisation on the Limpopo. Johannesburg, South Africa: Wits University Press, 2005.

Nhassengo, Osvaldo Silva Zefanias, Hiroaki Somura, and June Wolfe III. "Environmental Flow Sustainability in the Lower Limpopo River Basin, Mozambique." Journal of Hydrology: Regional Studies, vol. 36, 2021. DOI: 10.1016/j.ejrh.2021.100843. Accessed 1 Dec. 2024.

“What Does Climate Change Mean in the Limpopo Basin.” One World Group, 15 Nov. 2013, www.globalwaters.org/sites/default/files/SouthernAfrica‗RESILIM‗Nov‗2013.pdf. Accessed 1 Dec. 2024.