DEHRADUN: Even the strictly protected core of the Nanda Devi Biosphere Reserve, closed to trekking, mountaineering and other human activities since 1983, is feeling the effects of climate change. A new decadal monitoring report has found that landslide-prone zones in the core have nearly doubled over the past decade and that a new glacial lake is forming at an altitude of about 5,000 metres.
The findings are part of the “Nanda Devi Biosphere Decadal Monitoring Campaign 2026”, which used field surveys, satellite imagery and drone data to assess changes in the reserve’s ecology and landscape.
Nanda Devi National Park was declared a national park in 1982, and human activities were prohibited in its core zone the following year. In 1988, it was included on the UNESCO World Heritage List. Its relative isolation has made the area a natural reference point for scientists studying Himalayan ecosystems with limited direct human interference.
Decadal surveys were conducted in 1993, 2003, 2015 and 2026. The latest campaign involved the Forest Department and the Wildlife Institute of India (WII), alongside remote-sensing and other monitoring technologies.
The survey recorded at least 490 species of vascular plants, including 451 angiosperms, seven gymnosperms and more than 32 fern species. It also documented 96 lichen taxa, 20 mammal species and 125 bird species. Seventy of the lichen records are new to the park, while the beech marten was recorded there for the first time.
Blue sheep were found in seven of the nine surveyed areas, while camera traps recorded snow leopards in four areas.
The report, however, flags changes in the terrain as a growing concern. Satellite and drone data indicate that glacier melt is contributing to instability at higher elevations. Areas identified as landslide-prone have nearly doubled since the 2015 survey, while a new lake is forming behind a moraine — a natural ridge of glacial debris that the report describes as unstable.
The lake could pose a risk of a glacial lake outburst flood (GLOF), in which water breaches a natural barrier and rushes downstream. Such events can cause severe damage, as seen in the 2013 Kedarnath disaster and the 2021 Reni-Tapovan disaster.
“Several wildlife species recorded during the campaign indicate that conditions in parts of the region have improved. Reduced human activity has also helped wildlife and vegetation,” said G.S. Rawat, former director of the WII. “But the landslides and the formation of a new lake are clear signs that climate change is affecting even the most protected areas.”
The report recommends ecological monitoring of the core zone every five years and annual monitoring of the buffer zone. It also calls for round-the-clock satellite mapping of glacial lakes, with support from ISRO and the Wadia Institute of Himalayan Geology, and the installation of an early-warning system.