Greater one-horned rhino (Rhinoceros unicornis) mortality patterns in Nepal

Abstract

Nepal’s lowland regions provide a rich habitat for greater one-horned rhino ( Rhinoceros unicornis ) populations. However, rhinos are facing human-caused and natural threats such as habitat loss and several other forms of anthropogenic pressure that cause mortality of greater one-horned rhinos (hereafter rhino) in Nepal. Understanding these patterns of mortality can provide important information for rhino conservation. In this study, we answered three important questions to aid in rhino conservation in Nepal:1)what was the pattern of rhino mortality (increased, decreased, or no change) during 2008–2018 in Nepal? 2) Does the pattern of rhino mortality vary by season, age, and gender? And, 3) what are the major causes of rhino mortality in Nepal? We collected rhino mortality data along with age, gender, and cause of death in the period between 2008 and 2018 in Nepal from secondary sources. We found that a total of 232 cases of rhino mortalities were observed during the 11-year period. Mortality of the rhino was associated with age and cause but not with gender and season. Among the nine categories of the causes of mortality, self-fighting, natural, tiger attacks, and poaching contributed about 80 % of total mortality. Mortality due to poaching of rhinos has decreased in recent years, while mortality due to self-fighting and tiger attacks have increased. We concluded that mortality causes associated with limited space and food, and tiger population growth are increasing in recent years. Therefore, habitat expansion, translocation to new suitable habitats, and multispecies conservation policy would contribute to long-term rhino conservation in Nepal.