Thousands of trees were planted in the Sahara without success. Then 500 tortoises achieved what no one had expected, and the desert has begun to turn green again, visible even from space.

The Sahel region, stretching along the southern edge of the Sahara, has long endured extreme climatic conditions. Daytime temperatures frequently exceed 60°C before falling sharply at night, creating a highly hostile environment. The hardened surface crust of the soil prevents rainwater from penetrating the ground and accelerates the process of desertification. However, a project launched in 2021 may be changing this reality. It involves releasing 500 African spurred tortoises in order to make these arid landscapes more hospitable to biodiversity.

The Intervention and Its Promise

In 2021, along the southern fringe of the Sahara, specialists from the International Union for Conservation of Nature (IUCN), in partnership with Save Our Sulcata (SOS), released 500 African spurred tortoises into an almost barren landscape, reports L'Internaute. The African spurred tortoise (Centrochelys sulcata), the largest tortoise native to Africa, was selected because it excavates burrows reaching depths of between 10 and 15 metres.

These tunnels break through the hardened soil crust, allowing rainwater to infiltrate the ground and creating conditions that encourage seed germination. Five years later, satellite imagery reveals patches of green emerging across the sand, suggesting that the method is beginning to produce encouraging results.

What the Tortoises Actually Do

The tortoises' role extends well beyond digging burrows. By turning over the soil, they alter its structure, improve its ability to retain moisture, and create a more stable microclimate around the entrances to their burrows. These conditions soon attract insects and micro-organisms, while increasingly dense vegetation gradually becomes established.

For this reason, they are often described as "ecosystem engineers". Their ecological role is comparable to that of keystone species, whose activities are essential for restoring degraded ecosystems. As vegetation spreads, birds and small vertebrates begin to colonise these newly created green refuges.

A Local Success Story

Since 1992, the Village des Tortues at Noflaye, Senegal, has cared for more than 300 tortoises and has supported conservation through breeding and release programmes. Monitoring indicates a survival rate of over 80 per cent after four years, confirming that this approach can be effective over the long term.

Despite these encouraging results, the IUCN continues to classify the African spurred tortoise as Endangered, owing to habitat loss, climate change and other human-induced pressures.

Towards Lasting Ecological Resilience

The initial findings are promising, but reintroducing tortoises alone will not be enough to halt desertification. Long-term success will also depend on rainfall patterns, sustainable land management and political stability.

This project demonstrates the value of integrated ecological solutions. It builds upon traditional Sahelian farming practices, such as the half-moon water-harvesting technique, while extending their impact over much larger areas and over longer periods through the ecological work carried out by the tortoises.

See also: Ils ont planté des milliers d’arbres dans le Sahara sans succès : puis 500 tortues ont fait ce que personne n’attendait, et le désert reverdissait vu de l’espace

Photo. Claire Morel. © RSE Magazine

For the half-moon water-harvesting technique, see https://fr.wikipedia.org/wiki/Demi-lune_(agriculture)