Bangladesh is home to less than 500 Phayre’s langurs and 600 capped langurs in the rainforests in the country’s northeast. Langur populations are denser in well-protected areas compared to more vulnerable regions.
A groundbreaking study conducted by a joint team of Bangladeshi and German researchers has revealed troubling evidence of hybridisation between two endangered primate species – the Phayre’s Langur (Trachypithecus phayrei) and the Capped Langur (Trachypithecus Pileatus).
The research highlights the dire implications of habitat loss and human encroachment on these species, underscoring an urgent need for conservation efforts.
Over a six-year period, from June 2017 to October 2023, the research team, led by Tanvir Ahmed, a PhD researcher from the University of Göttingen, investigated mixed-species groups in the Sylhet region. Their findings were published in the International Journal of Primatology, revealing that habitat destruction is driving the two species to interbreed, potentially compromising their genetic integrity.
“In 1997-98, Professor Dr. Mofizul Kabir observed mixed-species groups but found no hybrids. Nearly 20 years later, we were surprised to see possible hybrids in Satchari National Park,” Ahmed stated, emphasising the unexpected shift in species dynamics. The study identified three potential hybrids based on distinct physical characteristics and confirmed their status through genetic testing conducted in German laboratories.
Implications of Hybridisation
Professor Dr. Christian Roos from the German Primate Center highlighted that while hybridisation is a natural occurrence, it poses significant risks when exacerbated by human activities. “This is not just a local problem—it’s part of a broader, global challenge,” he asserted, reflecting concerns echoed by other conservationists about the interconnectedness of habitat loss and species survival.
The study found that Langur populations are denser in well-protected areas compared to more vulnerable regions like Rajkandi and Atora. Despite approximately 500 Phayre’s Langurs and 600 capped Langurs being recorded, their future remains precarious, particularly given the pressures of habitat encroachment and illegal hunting.
A call to action
The research team has called for immediate action to preserve these endangered species. They stress the need for stronger conservation policies and the establishment of wildlife corridors to facilitate genetic exchange and bolster population resilience. “If we don’t take action now, we risk losing not just two species of langurs but also a crucial part of Bangladesh’s biodiversity,” warned Ahmed.
The researchers attribute the increasing threats to human activities such as land encroachment for agriculture, illegal logging, and uncontrolled tourism. With these factors contributing to the decline in langur populations, a comprehensive conservation strategy is essential for their long-term survival.
The findings of this study serve as a critical reminder of the challenges facing biodiversity in Bangladesh. As hybridization emerges as a new threat to the Phayre’s and capped langurs, experts are urging for collaborative efforts to address the underlying issues of habitat loss and human encroachment. The research emphasizes the urgent need for effective conservation measures, not only for the langurs but for the rich biodiversity that characterizes the region.
