Three Decades of Land Cover Change in East Africa

Eric L Bullock,Sean P Healey,Steve Omondi,Noel Gorelick,Phoebe Oduor,Edward Ouko,Zhiqiang Yang,Warren B Cohen

doi:10.3390/land10020150

Abstract

Population growth rates in Sub-Saharan East Africa are among the highest in the world, creating increasing pressure for land cover conversion. To date, however, there has been no comprehensive assessment of regional land cover change, and most long-term trends have not yet been quantified. Using a designed sample of satellite-based observations of historical land cover change, we estimate the areas and trends in nine land cover classes from 1998 to 2017 in Ethiopia, Kenya, Uganda, Malawi, Rwanda, Tanzania, and Zambia. Our analysis found an 18,154,000 (±1,580,000) ha, or 34.8%, increase in the area of cropland in East Africa. Conversion occurred primarily from Open Grasslands, Wooded Grasslands, and Open Forests, causing a large-scale reduction in woody vegetation classes. We observed far more conversion (by approximately 20 million hectares) of woody classes to less-woody classes than succession in the direction of increasing trees and shrubs. Spatial patterns within our sample highlight regional land cover conversion hotspots, such as the Central Zambezian Miombo Woodlands, as potential areas of concern related to the conservation of natural ecosystems. Our findings reflect a rapidly growing population that is moving into new areas, with a 43.5% increase in the area of Settlements over the three-decade period. Our results show the areas and ecoregions most impacted by three decades of human development, both spatially and statistically.

Highlights

East Africa has undergone rapid economic growth and environmental change over the past 30 years, resulting in considerable gains in livelihood, sometimes at the expense of natural ecosystems
Our analysis revealed 29,040,000 (±1,950,000) ha of land cover change from 1988 to 2017, representing 7.7% of the study region (Figure 2)
The areas of Cropland and Settlement increased by 35% and 43%, respectively, while all other land use classes Land 2021, 10, x FOR PEER REVIEW decreased (Figure 3)

Summary

Introduction

East Africa has undergone rapid economic growth and environmental change over the past 30 years, resulting in considerable gains in livelihood, sometimes at the expense of natural ecosystems. Land cover change in Sub-Saharan and interior East Africa (referred to here as “East Africa” for brevity and consisting of the nations of Kenya, Malawi, Rwanda, Tanzania, Ethiopia, Burundi, Zambia, and Uganda) often involves the conversion of woody natural habitats to less-woody cultivated or developed land cover types. The region contains 60% of the global uncultivated arable land and a population expected to double by 2050 [7,8]. Land use intensification will continue to support the growing population, affecting some of the most environmentally important and threatened ecosystems in the world. 73% of the region is contained in the World Wildlife Fund’s (WWF) list of 200 ecoregions prioritized for conservation, compared to 31% of the continent as a whole [9]

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Results

Conclusion