Human technology

As temperatures rise, exotic plants threaten Nepal’s oldest national park

When botany professor Bharat Babu Shrestha visited Nepal’s Chitwan National Park in 2013, feverfew – a flowering plant in the daisy family – was rare. Today, large areas of the park’s grasslands are covered with the invasive plant, said Shrestha, who teaches at Tribhuvan University on the outskirts of Kathmandu.

Non-native plants have spread rapidly in Nepal’s oldest national park in recent years – and part of the reason is rising temperatures as the use of fossil fuels warms the planet, the expert said. “Invasion ecology”. “Climate change appears to be conducive to the faster growth of invasive alien plants,” Shrestha said. The upsurge in exotic plants in Chitwan, a 950 km² (370 square miles) park in the plains of southern Nepal, is now crowding out grasslands and wetlands that provide food and shelter for the park’s iconic wildlife, according to officials in the park. Park. It is a problem seen in parks and reserves around the world as climate change changes the meaning of “conserving” natural areas.

“Like never before, the park is facing habitat loss at an alarming rate,” said Ananath Baral, conservation officer at Chitwan. “We are concerned about the future of wildlife. “Over the past decade, the park’s grasslands have been heavily invaded by plants such as feverfew, lantana, a climbing plant known as ‘weed’ – and Siam grass, considered one of the world’s most problematic invaders, Baral said.

As a result, in parts of the park, the grass favored by the park’s wildlife – including the one-horned rhino, deer and antelope – has partially or totally disappeared, he said. The most recent grassland mapping of Chitwan, published in 2016, shows that the area of ​​the park and its grass-covered buffer zone has decreased to 6%, from 20% in 1973 when the reserve was created.

Rising temperatures and more erratic rainfall have allowed non-native plants to thrive, said Uttam Babu Shrestha, who has looked into invasive species in Chitwan as director of the World Institute for Interdisciplinary Studies based in Kathmandu. As global temperatures are expected to continue to rise as the world struggles to reduce the use of fossil fuels, “plant invasion is likely to increase in the near future,” he warned.

Double problem

Like the grasslands, the park’s wetlands are also under stress: covered in plants that local wildlife do not eat and overwhelmed by unprecedented flooding and unpredictable droughts, biologists say.

Babu Ram Lamichhane, head of the Biodiversity Conservation Center in Sauraha, on the outskirts of Chitwan, said the combination of heavy rains and flash floods during the monsoon and prolonged dry spells in spring was degrading wetlands in Chitwan . Many ponds and ponds in the park have dried up and turned to wood or bare soil, and others have been filled with sand, silt and pebbles carried by the floodwaters, he said. “Too much and too little water are the two problems today. They threaten the rich biodiversity of the park, altering the habitat of wildlife, ”said Lamichhane. Spring 2019 has been so dry that park authorities had to install a well to pump water to the waterers used by wild buffaloes, he said. And the one-horned rhinos have left two areas on the east side of the park because the more intense dry seasons mean the swamps they live in no longer fill with water, he added.

As water sources dry up and grasslands shrink, some animals in the park have started to enter human settlements in search of better pastures and water, increasing the chances of human-land conflict. wildlife, according to park authorities. Residents of villages near the park now frequently report incidents of wildlife attacks and damage to their crops, conservation officer Baral said.

Higher costs

Trying to fix the problems is costly in labor and budget, according to Nepal’s wildlife officials. “We need to dig new ponds and build grasslands every year to keep the wildlife habitat intact,” said Haribhadra Acharya, spokesperson for the Department of National Parks and Wildlife Conservation (DNPWC). Since last July, park rangers have dug 16 new ponds and repaired 35 others in an attempt to capture and store rainwater and monsoon runoff, ranger Pushpa Deep Shrestha said. They also worked to create 2,500 hectares (6,200 acres) of new grassland in the park, he said. Maintenance efforts – which also included removing invasive weeds, uprooting trees and burning weeds – cost around 50 million Nepalese rupees ($ 420,000) – 40% of the total park development budget. said the ranger.

Five years ago, only 9.5 million Nepalese rupees were spent on maintenance works, according to the annual report of Chitwan National Park. The hard work to protect the park’s ecosystems and wildlife means climate-induced changes have so far not hurt park tourism – but Baral, the conservation officer, fears they may not be able to help. day.

Chitwan National Park brings in more than 295 million Nepalese rupees each year, or nearly 40% of the total income generated by Nepal’s 20 protected areas, according to a DNPWC report. “More than a third of tourists who come to Nepal to visit protected areas want to come here for wildlife tours and adventurous jungle safaris,” Baral said. But if the park’s animals and the habitat they need are not adequately protected, “they will stop coming,” he warned. Until a few years ago, the main concern of the park was to stop poachers. But now, “conservation of habitats is becoming difficult in a time of climate change,” said conservation biologist Lamichhane.

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