Considering that the tigers in Bhutan have shifted to higher altitudes, tigers in Nepal could respond similarly, by moving further northwards if the environmental and ecological conditions in the Tarai region become unfavourable for survival
In the modern mainstream discourse on climate change, two questions are often peripheralised: How do animals respond to environmental stresses due to climate change and how will their modes of adaptation shape the ecosystem? This Global Tiger Day marks a fitting occasion to explore these questions in the context of tigers, especially given their vital role in keeping the health of the ecosystem.
All species respond differently to environmental changes, responses which will likely impact the availability of food and habitat significantly, ultimately changing the distribution and composition of plant and animal communities in the future. While complicated computer models may predict the general trajectories and velocities of these responses to climate change, the specific impacts on natural ecosystems remain uncertain.
Nepal’s National Biodiversity Strategy and Action Plan (NBASP) emphasises that the climate range of many species is likely to move to higher elevations from the current locations, which will have differential impacts on individual species. The key challenge for such movements under climate change will be increased interactions, and, therefore, increased conflict between the wildlife and people in areas that are not adequately protected.
Tigers are at relatively lower risk from the impacts of climate change due to their ability to tolerate fluctuations in weather conditions and high reproductive rates. They also do not rely on environmental conditions for hibernation, reproduction and migration, making them less sensitive to climatic variability. But despite these adaptive traits, the changes to their habitats and food base will pose major challenges and result in invariable effects on the ecosystem.
The tiger prey-base requires grasslands which are recharged by periodic floods. Changing land use dynamics and other external factors are unnaturally turning these grasslands into wooded grasslands, posing major threats to the core tiger habitats. Given that tigers require large areas to roam, spaces which they allocate based on prey availability (rather than habitat types), the biggest challenge they face in the coming years will result from changes in their movement.
Prolonged drought and fires could cause herbivore populations to decline, depriving the tigers of food and forcing them out of the core protected areas in search of prey.
Most of the existing tiger habitats, Shuklaphanta, Banke, Bardia, Chitwan and Parsa of the Tarai region, show an increasing annual rainfall trend with significant increase in monsoon precipitation based on an analysis of climatic data from 1971-2014. Climate projections indicate that this precipitation could be erratic, occurring as extreme weather events, which could cause floods during periods of high rainfall as evident from the two devastating floods in the last five years in Karnali, Gandaki and Babai.
Tigers are now restricted to the protected areas of the Tarai largely due to disturbances outside the core areas. Considering that the distribution of tigers in Bhutan has shifted to higher altitudes, it may be possible for tigers in Nepal to respond similarly, by moving further northwards if the environmental and ecological conditions in the Tarai region become unfavourable for survival, and if habitat connectivity and suitable habitat is maintained in these higher elevations.
The recent floods in Kaziranga National Park in Assam, India forced a tiger to flee the area. The tiger was later found sleeping on a bed inside a house. The incident highlights both the need for and the importance of higher ground for tigers. Nepal’s Chure foothills are an example of these high ground for herbivores whose management and maintenance is the key.
Given the predicted trends in climate conditions and their potential impacts on key species, it is important to integrate un/expected impacts into species conservation and protected area management plans. But because of the uncertainties associated with climate change, the plans should include ‘no-regret’ strategies that can adapt if climate change trajectories do not unfold as predicted.
By assessing climate change risks in the context of other existing threats, natural resource managers can identify those species, habitats and human communities that are relatively more vulnerable or resilient to climate change, determine why they are so, and use the information to realign management priorities.
WWF Nepal in this regard has been supporting the government in implementing climate-smart management plans in different protected areas of Nepal that take into account climate vulnerabilities of species, ecosystems and local communities within the protected areas and buffer zones. Floods and extended dry spells in recent years have impacted protected area management with significant wildlife casualties in Banke National Park, Chitwan National Park and Krishnasaar Conservation Area. Hence, an assessment of potential climate risks in protected area management is needed (which includes human communities and ecosystems). Further research and monitoring to fill knowledge gaps related to species, systems and resources within the protected areas and corridors may also be required.
Joshi is a climate and energy goal lead at WWF Nepal
A version of this article appears in print on July 29, 2019 of The Himalayan Times.