Persistent evidence for a dramatic decline in langurs (Semnopithecus spp.) in Nepal and elsewhere: Science data and personal experiences converge on a landscape-scale

Abstract

Langurs (Semnopithecus spp.) were once very common and play an important spiritual and ecological role, e.g. for well-being and seed dispersal in forested landscapes. But now they are dramatically declining in many parts of Nepal. From our reviews and rapid assessments in several sites of the HKH region, the prime reason for this decline remains multi-facetted and uncertain, but it is likely that global economy plays a role and that langurs have been hunted down as a natural source of meat for those people across Asian borders who believe in ethno-medical practices when consuming these animals for treating tuberculosis, arthritis, and other health problems. A wider demand exists for such medications. Stress (‘Ecology of Fear’), infection by parasites, as well as viral and bacterial infections might be other underlying factors of the landscape-wide decline of this species population. However, more study is needed while population remnants are found in protected areas and inaccessible areas, often in relation to water like river valleys. Despite years of study and many publications, the best-available public data for this species remain very few (only 11 geo-referenced records with GBIF.org). In addition to effective conservation policies and a good framework to achieve, we recommend rigorous surveys and open access data compilations -ideally with predictive modelling in support - to quickly inform the current population estimate and range-wide status. Education programs are also critical to increase the awareness among local hunters and communities for the conservation of langurs and other primates in Nepal and beyond. The langur seems to be a typical victim of globalization and its wider neoliberal repercussions; here we ask for relevant conservation improvements.