Deforestation in Bangladesh is forcing two endangered langur species to interbreed, putting their very existence at risk. This study reveals the devastating consequences of habitat loss and the urgent need for conservation efforts.
Hybridization to Extinction
Scientists have found that Phayre’s langurs (Trachypithecus phayrei) and capped langurs (Trachypithecus pileatus) in northeast Bangladesh are being driven to mate with one another as a result of the destruction of their forest homes. This surprising turn of events poses an imminent danger to the existence of these two primates.
Eight of the 98 langur groups taken into account in the study published in the International Journal of Primatology, contained a mix of Phayres and capped langurs and in three cases some individuals even appeared to be hybrids between these two. These chicks are proven to have been taken by a capped langur mother and fathered by a Phayre’s langur, following genetic analysis. In addition, a fertile male hybrid was obtained and later a female hybrid gave birth to pups as well.
Zoologist and lead author of the study, Tanvir Ahmed, says this is particularly concerning because any fertile hybrids suggest that if gene flow were to occur between the two species it would have a lasting effect on their genetic makeup, possibly driving one or both of them to extinction.
Unsustainable Mixing Linked to Habitat Loss
Rather, as the researchers suggest, this alarming shrinkage is the likely consequence of human activities that cause deforestation and habitat fragmentation along with hunting and trapping of primates leading to “a thinning of the populations and limiting individual movement between local populations.”
The copying effect is more likely when animals are disturbed to the point that their habitats resemble a giant salad bowl, with different bits of organisms tossed together in new and strange ways. As senior author Christian Roos notes, this is not a parochial problem. When habitats are eradicated, the animals there must interbreed with others to survive and inevitably die out, or at least one of them — if not both as a result.
It also found that the population density of langurs was significantly higher in well-protected forests than in poorly protected forests. Nevertheless, these forests are usually too small, too isolated, and too fragmented to maintain the species over the long term.
Conclusion
The plight of the Phayre’s langurs and capped langurs in Bangladesh serves as a grim testament to everything that can go awry when habitat loss befalls wildlife populations and the imminence of the need for earnest conservation initiatives. Drastic measures without too much delay are needed, ranging from the protection of forests over the establishment of dispersal corridors to continuous research for understanding hybridization and implementing appropriate conservation strategies that last long enough in time to save these endangered primates. If actions are not taken urgently, then one must wonder if some of these unique species will undergo irreversible genetic changes or even extinction, thus drastically reducing the biodiversity of Bangladesh.
