Water and Environmental Change in Africa

This blog has explored the many impacts of deforestation on the water cycle across the African continent. However, I thought it was necessary to explore the possible negative impacts of afforestation notably in South Africa where non-native eucalyptus have become invasive and are discovered to be using up significant amount of freshwater especially when growing on riparian areas and wetlands.  Eucalyptus trees have been found to 'drink South Africa dry'  The negative impacts of afforestation The positive effects that arise from reforesting land are highly dependent on the type of species chosen. The ideal tree species depends on the physical characteristics of the land, which is undergoing reforestation. As Mbow et al, 2014 explain, soil characteristics, land topography, rainfall patterns, agricultural practices and priorities for food security as well as economic development all matter when deciding what tree species to use to reforest deforested land.     ...

With all the bad news we are hearing these days, I thought a piece of happy news about how African forest elephants have been discovered to help in the fight against climate change might bring a smile to our faces.  The International Monetary Fund (IMF) reported that elephants that call the Central African forest home have been discovered to play an important role in carbon sequestration and thus, climate change mitigation. There were once over 1.1 million forest elephants that roamed the continent but with increasing poaching and deforestation, the populations have severely suffered and are now considered "vulnerable" by the IUCN .  However, they play a crucial role within the Congo Basin as "environmental engineers." As they travel through the forest looking for food, they thin out young trees - that are in competition for water, space and light - by either consuming or stepping on them. They have a significant impact on the young tree growth due to their size an...

In the previous post, I discussed how agroforestry in Sub-Saharan Africa can help mitigate the effects of climate change through carbon sequestration and water recycling. In this post, I will explore two agroforestry case studies from the Sahel and South Africa. A typical agroforestry system. Source: Katungulu, 2018 Increasing Productivity in the Sahel  The Sahel is a semi-arid region stretching from Western to Eastern Africa. It is the transition from the Sahara to the North and the humid savannah to the South. Primary production in the region is limited by water availability, especially in the Northern Sahelian zone. Woody trees influence the soil water balance through rainfall interception, evapotranspiration and soil infiltration and runoff. In addition, they provide protection for young crops through windbreak and shading. However, the positive influence of agroforestry on soil fertility and primary production in croplands depends on average annual rainfall and soil type. Woo...

Sub-Saharan Africa has seen drastic population growth in the past decade with nearly 50% of the population living in dense urban centres. Such rapid growth puts pressure on agricultural production and thus, land use. Decline in soil fertility and increasing soil erosion are threatening the survival of small scale farming in Africa Additionally, farm production is under threat from climate change, especially the unstable monsoon patterns and the production of livestock fodder.  What is Agroforestry?  Agroforestry is the intentional addition of plants and trees in croplands and livestock systems. It is a practice credited in reducing the impacts of climate change on land and providing food and resources to both people and livestock. In recent years, more studies have investigated the benefits of agroforestry in Sub-Saharan Africa to improve soil fertility, prevent soil erosion and produce high quality, year round fodder for livestock while generating income for local communiti...

The Green Wall Initiative of Africa. Picture from: National Geographic What is the Green Wall Initiative? In recent years, Northern Africa in particular has seen a decline in the quality of arable land notably due to climate change and poor land management. Desertification, land degradation and drought along with climate change and extreme weather events has a drastic impact on the food security and livelihoods of communities living in the Sahel region of Northern Africa. The Green Wall for the Saharan and the Sahel Initiative (GGWSSI) was proposed in 2005 with the objective of growing 8000 km long line of trees and plants across the entire Sahel from Senegal to Djibouti crossing 12 African nations to try and halt desertification The objectives are: "By 2030 restore 50 million hectares of land, sequest 250 million tons of carbon; support 300 million people in communities along the Sahel and provide access for 10 million smallholder farmers to climate resilient agricultural technol...

The Congo Basin is located in Central Africa spanning across six countries. It is one of the three main rainforests worldwide and plays a key role in regulating monsoon patterns across much of Africa. There are about 10,000 species of tropical plants in the Congo Basin and approximately 30% are endemic to the area. Additionally many endangered animals call the Congo home from mountain gorilla, chimpanzees and forest elephants. The Congo rainforest has been inhabited by humans for over 50,000 years and is key to providing them with shelter, food and freshwater. Increasing rates of deforestation is threatening this fragile ecosystem and not only is the biodiversity within under threat, but the entire hydrological cycle of Africa as well.  Picture courtesy of: Planet.com  representing the  Congo Basin in green The Congo basin is highly dependent on precipitation as there are few low intensity aquifers in the region to sustain farming and human activity. Much of the economic...