Spatiotemporal dynamics of urbanization and landscape anthropization in Kinshasa, Democratic Republic of Congo, from 2001 to 2024

Cities are not merely collections of buildings; they are living landscapes that constantly reshape the ground beneath them. When a city grows, it does not simply add more concrete; it transforms the very nature of the land, turning forests into farms and grasslands into neighborhoods. This process, known as urbanization, is happening faster in Africa than anywhere else on Earth. In these rapidly expanding regions, the line between the city and the countryside often blurs, creating a complex zone where nature and human activity compete for space. Understanding how this transformation happens is crucial, because the way a city spreads determines not only where people live, but also how water flows, how wildlife survives, and whether the land can support the population in the future. Scientists study these changes by looking at the Earth from above, using satellite images to track how the ground cover shifts year by year, revealing the hidden patterns of growth that are invisible from street level.

In the Democratic Republic of Congo, the capital city of Kinshasa offers a striking example of this rapid change. A new study has mapped the evolution of Kinshasa's landscape over a twenty-three-year period, from 2001 to 2024, to understand exactly how the city has expanded and what has been lost in the process. The researchers focused on the entire urban area and its surrounding outskirts, using satellite images to classify the land into eight distinct categories: dense forests, forests along rivers, open grasslands, wetlands, farmland, bare soil, built-up areas, and water. By analyzing these images with advanced computer algorithms, the team was able to see not just how much the city grew, but how the different types of land converted into one another over time.

The results paint a clear picture of a landscape under increasing human pressure. At the start of the study in 2001, the dominant feature of the region was open grassland, which covered nearly 58 percent of the area. Forests, including the dense woodlands and the strips of trees along rivers, made up about 20 percent. By 2024, the balance had shifted significantly. The grasslands had shrunk to about 47.5 percent, and the forests had declined dramatically to less than 8 percent. In their place, two human-made classes of land had surged. Farmland expanded from roughly 6 percent to nearly 27 percent, while the area covered by buildings and infrastructure more than doubled, rising from 3 percent to 6.6 percent. This transformation indicates that the city is not just growing outward; it is fundamentally altering the ecosystem, replacing natural vegetation with agriculture and housing.

The study also revealed that this change did not happen all at once or in a uniform way. The researchers broke the timeline into several periods to see how the pace of change varied. The most intense period of growth occurred between 2014 and 2019, when the city expanded at its fastest rate. During these years, the conversion of natural land into farmland and housing accelerated sharply. Before 2014, the growth was more moderate, but the later years showed a surge in development that outpaced the earlier trends. This suggests that recent political and economic shifts in the country may have influenced the speed at which the city expanded, pushing the urban frontier further into the surrounding countryside.

To understand the shape of this growth, the researchers looked at how the city spread from its center. They divided the area into rings, moving outward from the city center in five-kilometer steps. They found that the city did not simply expand in a perfect circle. Instead, the growth was uneven, with the most intense development occurring in the intermediate zones, roughly 15 to 30 kilometers from the center. This area, often called the peri-urban zone, became the primary frontier for new construction. The city core remained dense, but the most dramatic changes happened in these middle rings, where scattered patches of buildings began to merge into larger, continuous urban areas. This pattern, where the city spreads out and then the scattered parts join together, is known as a diffusion-coalescence process. It means that Kinshasa is not just getting bigger; it is becoming more connected, with the gaps between neighborhoods filling in.

The impact of this expansion on the natural world is profound. The study measured the "disturbance" of the landscape, a way of quantifying how much human activity has disrupted the natural environment. In 2001, this disturbance index was low, indicating that natural vegetation still dominated the region. By 2024, the index had more than tripled, signaling that human-modified land uses were becoming the primary feature of the landscape. The forests and grasslands that once formed a continuous cover were being broken up into smaller, isolated fragments. This fragmentation is dangerous for the environment because it cuts off the paths that animals use to move and reduces the ability of the land to manage water and prevent erosion. The wetlands and river forests, which are critical for filtering water and protecting against floods, are particularly vulnerable as they are often the first to be converted into farmland or housing.

One of the most significant findings is the role of agriculture in this transformation. While the growth of buildings is expected in a growing city, the massive expansion of farmland was a major driver of change. The data shows that much of the lost grassland and forest was converted into fields. This suggests that the city's growth is not just about people moving into houses, but also about the need to feed a growing population. The peri-urban areas have become a hybrid space where farming and living coexist, often without clear planning. This creates a complex challenge for city managers, who must balance the need for food production with the need to protect the remaining natural ecosystems.

The study concludes that Kinshasa is following a trajectory of rapid, uncontrolled expansion that threatens its ecological stability. The loss of forests and the fragmentation of grasslands are not just numbers on a chart; they represent a real decline in the city's natural defenses and its capacity to support life. The researchers emphasize that without stronger planning and protection for the remaining natural spaces, the city risks losing the very resources it needs to survive, such as clean water and protection from floods. The findings call for a new approach to urban development that recognizes the value of the peri-urban zone, not just as a place for new construction, but as a critical area where nature and human activity must be managed together. By understanding exactly how and where the city is growing, planners can make better decisions to ensure that Kinshasa's future is sustainable, preserving the natural landscape while accommodating the needs of its people.