Boko Haram conflict zone hides huge bird haven – study

[ILORIN, NIGERIA, SciDev.Net] One of Africa’s most insecure regions is also home to one of its largest waterbird populations, despite decades of conflict that have made the area nearly impossible to study, according to new research calling for greater conservation efforts to protect them.

Lake Chad now supports an estimated 2.48 million waterbirds—the highest number ever recorded there—according to the study, published in the Proceedings of the National Academy of Sciences (PNAS).

The researchers combined aerial surveys with statistical modelling to estimate wildlife populations across the transboundary wetland shared by Nigeria, Niger, Chad and Cameroon, including an area of high insecurity due to the long-running Boko Haram insurgency.

The team directly counted more than 76,000 birds by air and concluded that the actual total was likely more than 30 times larger—a leap questioned by some independent scientists.

The researchers say the findings support the case for urgent international protection and long-term conservation planning for the wetland, coordinated by national governments and European partners. They recommend the establishment of a protected area and World Heritage status for Lake Chad.

“Before this study, Lake Chad was already known as possibly one of the three most important waterbird hotspots in Africa and perhaps the world,” said Pierre Defos du Rau, a research officer at the French Biodiversity Agency (OFB) and first author of the paper.

“But for security reasons, the biodiversity of this area of global concern had not been comprehensively surveyed since 2008. It was becoming a huge gap in our knowledge of migratory birds, not only African birds but also birds coming from Europe to spend the boreal winter in the Sahel.”

Surveying a conflict zone

To minimise security risks, researchers conducted an aerial survey rather than fieldwork on the ground.

In January 2022, a small aircraft flew across the eastern half of Lake Chad, the only area considered safe enough to survey, for eight days, with a skilled bush pilot at the controls.

The flight plan was shared only with airport authorities, and the team used a single observer to keep the aircraft light and manoeuvrable. Daily security assessments helped secure permissions and refuelling access.

“The first step was to avoid flying over the most insecure areas within Lake Chad,” Defos du Rau told SciDev.Net.

“The second step was to find a pilot experienced and skilful enough. This brilliant pilot is Jaime Dias, from the Wings for Conservation Foundation.”

Researchers surveyed the lake using narrow flight lines and a technique called distance sampling, which adjusts for animals missed further from the plane.

Because the western half of the lake remained inaccessible due to insecurity linked to the militant Islamist Boko Haram insurgency, the team used satellite-based statistical models to estimate bird populations there, based on habitat characteristics, conflict indicators and wildlife densities observed in the surveyed area.

“These species-specific models were then used to predict species abundance over the unsurveyed half,” Defos du Rau explained.

‘The refuge effect’

The researchers suggest that increased rainfall has expanded the lake’s water surface, creating more habitat for waterbirds. But they also believe that conflict-related displacement may have reduced hunting pressure, allowing wildlife populations to recover—a phenomenon known as the “refuge effect”.

Ugoline Godeau, a research engineer at the Mediterranean wetlands research institute Tour du Valat and the paper’s second author, said refuge effects occur when insecurity causes people to avoid certain areas, reducing disturbance and creating better conditions for wildlife.

Leo Zwarts is a waterbird ecologist at Altenburg & Wymenga Ecological Consultants, in the Netherlands, who was not involved in the study. He suggests that communities displaced by violence may have unintentionally created quieter habitats where birds could forage more freely.

“Almost all waterbirds are shy and avoid people,” Zwarts told SciDev.Net. “It is therefore not surprising that the authors found a refuge effect in their analysis.”

Food security and poaching

As well as being relevant for conservation, experts say the findings also have implications for health and food security of local populations.

Co-author Clémence Deschamps, of OFB, noted that migratory waterbirds have long been an important food source for communities in the Sahel.

“If these resources are carefully monitored and exploited sustainably, they could contribute to the food security of the millions of Lake Chad people,” she said.

However, careless harvesting can be detrimental to both the bird populations and human health.

“In particular, the use of poison to capture wildlife is a particularly worrying practice with likely huge impacts on consumers’ health,” said Deschamps.

“These poaching practices should absolutely be investigated.”

Knowledge gaps

The researchers acknowledge that the study was limited because they could not directly survey the western half of the lake.

“We used statistically cautious approaches to conservatively estimate wildlife abundances for these areas,” Godeau said.

She also noted that a single observer cannot perfectly track thousands of birds and that artificial intelligence “is not yet ready to correctly identify dozens of species at once, in flight, against a variable background”.

Zwarts says using modelling to try to complete the picture may be the only alternative in high-risk areas but “that is also where the weakness lies”.

“A lot can easily go wrong there. This is not a criticism of this work but a general problem in this type of analysis.”

Zwarts also questioned part of the explanation offered for the apparent growth in bird numbers, arguing that seasonally flooded margins around the lake—important feeding areas for many waterbirds—may play a more important role than the lake’s overall size.

“My hypothesis,” he said, “is that the size of the floodplain zone, and not the size of the lake, is crucial for most waterbirds in Lake Chad.” He added that much about how hydrology, seasonal flooding and conflict interact to shape the ecosystem remains poorly understood.

Defos du Rau stressed that the researchers do not encourage similar surveys in other high-risk zones unless truly necessary. “It may not be advisable to duplicate such surveys in other insecure areas without extreme caution and local support and guarantees,” he said.

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.