- Researcher Shyam Thapa, who recently completed his Ph.D. in ecology, highlights flaws in traditional grassland management methods, particularly in Bardiya National Park.
- Thapa’s findings suggest the need for improved grassland management to enhance the health and numbers of tiger prey species.
- He emphasizes the importance of tailored management approaches based on grassland functionality.
- Implementing his study’s recommendations could potentially increase herbivore numbers in tiger habitats, reducing human-wildlife conflicts, Thapa says.
As winter bids adieu to the Northern Hemisphere and the mercury peaks and humidity plummets, most of Nepal’s plains and hills become tinderboxes awaiting a spark.
As officials face a gargantuan task of controlling wildfires, some authorities from Nepal’s Department of National Parks and Wildlife Conservation are themselves involved in starting fires in the name of “habitat management,” especially inside national parks in the plains. They say they believe that fires are a cost-effective tool to prevent grasslands, which provide habitat for Nepal’s iconic tigers (Panthera tigris) and their prey such as deer and chital (Axis axis), from turning into forests, and to promote the growth of fresh and nutritious grass sprouts.
But the traditional approach to grassland management may not be working, says researcher Shyam Thapa, who recently completed his Ph.D. in wildlife conservation and ecology from the University of Wageningen in the Netherlands. During his study, Thapa looked at steps that need to be taken at Bardiya National Park, home to a third of the country’s 355 tigers, so that tiger prey herbivores, such a deer, get to eat more quality grass and their health as well as numbers improve.
Mongabay’s Abhaya Raj Joshi met Thapa in Kathmandu recently to talk about the findings of his research and its implications for conservation in Nepal. The following interview has been translated from Nepali and edited for clarity.
Mongabay: With the start of the spring season in Nepal, protected area managers in Nepal launch their grassland management programs. How has human activity around the grasslands changed over the years?
Shyam Thapa: Until a few decades ago, authorities at Nepal’s national parks, such as Chitwan and Bardiya, allowed locals to visit the protected areas to cut elephant grass from designated areas for 15 days in a year. People used to make use of the sturdy grass to thatch their roofs and prepare different types of furniture.
But things have changed these days. Local people are given just three days for the job. But not many people show up, as they have become accustomed to living in concrete houses. This shift has its impact on grassland management practices in Nepal, as officials have to rely on contractors who use machines to chop off tall grasses and then set them on fire.
Mongabay: Why is it necessary to actively “manage” grassland ecosystems? Why can’t they be left in their natural condition?
Shyam Thapa: There are several reasons why we need to do that. The first reason is that the digestive system of herbivores (tigers’ prey) require fresh grass for them to absorb an optimum amount of nutrition from their food. When the grass is in its growth stage, it is tender and rich in nutrients, but as it grows older, the plant itself utilizes its nutrition for growth. The older the grass is, the less nutritious it is for herbivores such as deer.
Secondly, large patches of grasslands, especially in Bardiya, were created by human slash-and-burn-style agriculture. As they didn’t come into existence naturally, they may not sustain on their own due to various factors such as ecological succession (trees replacing grass) and the proliferation of invasive alien species. Also, in human-dominated landscapes, cattle raised by humans also helped regulate the grasslands. But human activities are no longer allowed in protected areas and these functions can’t take place naturally.
Similarly, in the distant past, the grasslands were home to an assemblage of different types of herbivores of varying sizes and appetites, such as gaurs (Bos gaurus), deer, water buffalo (Bubalus arnee) and even rhinos (Rhinoceros unicornis), to some extent. They acted as “engineers” of the grasslands by munching on the grass and not allowing it to grow tall. But in recent years, the assemblage has shrunk and we don’t see as many herbivores in the grasslands. The situation is better in Chitwan where we see different varieties of deer and the gaur and the rhinos. But in Bardiya, that’s not the case. That’s why we have also proposed that the government translocate some gaur to Bardiya.
Mongabay: What are some of the impacts of using heavy machinery for grassland management?
Shyam Thapa: We’ve seen that machines used to cut grass are heavy and they tend to trample the grass beneath them. We have observed that such trampling may be causing a mulching effect on soil. For example, on farms, people used hay to cover the land so that weeds wouldn’t grow. This approach remains effective until the hay decomposes. In the case of grasslands, the mulching effect may slow down the growth of fresh grass from underneath.
Mongabay: Could you please describe how you went about carrying out your research?
Shyam Thapa: As part of my research, we carried out experiments on different plots of grazing lawns to assess the optimal frequency of grass cutting needed for the herbivores to make full use of the nutrients available in the grassland.
We found that cutting and burning is highly effective in the short term, as highly nutritious grass grows from the ashes. But in the long run, the quality slowly deteriorates. Our findings suggested that the best approach would be to cut the grass manually four times a year so that the herbivores can get the most out of the grasslands.
Mongabay: Does this mean all the grass has to be cut four times every year?
Shyam Thapa: No, that’s not the case. Our research suggests that we should manage different grasslands based on their functional use by different herbivore species. For example, some patches may be used by herbivores as movement corridors, others as refuge against predator species. We can’t have the same blanket approach to manage all patches of grasslands.
Mongabay: So, what are some of the steps officials can take to ensure that herbivore species get the maximum nutrients they need?
Shyam Thapa: As I said earlier, we need to identify the functional role of each patch of grassland and devise our strategy accordingly. If the patch is used for grazing, it would be best to cut the grass four times, or at least three times, a year so that the animals concerned get better nutrition.
During the initial years, it might seem a lot of work and hard on resources, but as the years progress, the herbivores themselves will manage the grassland and natural processes will take over.
Similarly, we are also talking about the translocation of herbivores to their historical ranges so that the assemblage of grass eaters increases and the management of grasslands becomes easier.
Also, we can use the grass to prepare fodder for the livestock industry, which is flourishing around national parks such as Chitwan. Incinerating the grass, as is being done, only increases pollution and may have negative impacts on different species that may not be able to escape the flames during their breeding season.
Some of the suggestions have already been incorporated in the recent government-issued guidelines on wildlife habitat management. It provides a good start, but we need to do more.
We also recommend the use of manual cutting over mechanized cutting, as the money from the work goes to local communities. Yes, the safety of people doing the work is an issue, but it can be addressed if they work in groups and officials help them improve their safety measures.
Mongabay: Is it correct to say that if the measures you recommend are implemented, the number of herbivores in tiger habitats could significantly go up, thereby opening the possibility of providing for even more tigers in Nepal’s Terai grasslands?
Shyam Thapa: Yes, that’s true. Changes in grassland management regimes could help increase the density of tigers in the country and even accommodate transient tigers. This would not only mean more tigers, but also fewer incidents of negative interactions with humans.
There are some researchers who say that tigers enter human settlements as they are not getting enough to eat due to the absence of mega herbivores, especially in Bardiya.
Yes, I also believe that this could be a possibility.
Mongabay: When we talk about grassland management in tiger habitats in Nepal, we can’t leave out grasslands in India. What are some of the lessons Nepal can learn from India on this?
Shyam Thapa: The way grasslands are managed in India is similar to the way we do it here in Nepal. The only difference is that in one of the habitats, they tried out harrowing to improve the productivity of the grassland, which didn’t work out particularly well. During exchanges, they told us that the practice introduced unwanted species to the habitat and impacted the quality of the grass.
Banner image: A herd of deer in Bardiya National Park. Image by Shyam Thapa.
Conservation success leaves Nepal at a loss for dealing with ‘problem tigers’
