Authors: Parveen Chhetri*, Department of Earth Science and Geography, California State University, Dominguez Hills, Raju Bista, Department of Earth Science and Geography, California State University, Dominguez Hills, Narayan P Gaire, Tribhuvan University, Krishna B Shrestha, Department of Biological Sciences, University of Bergen
Topics: Biogeography, Mountain Environments
Keywords: Treeline, Population dynamics, Recruitment pattern, Climate change, Nepal, Himalayas
Session Type: Virtual Paper
Start / End Time: 8:00 AM / 9:15 AM
Room: Virtual 32
Presentation File: No File Uploaded
World climate is changing at an unprecedented rate, and the Himalayan region is one of the hotspots for change. Changing climate is impacting the forest ecosystem, particularly along the upper transition treeline ecotone zone. The population structure and regeneration dynamics of long-lived treeline species can be utilized as an indicator of climate change. To understand the population dynamics of three dominant treeline species Abies spectabilis (Himalayan Silver Fir), Pinus wallichiana (Blue Pine), and Betula utilis (Himalayan Birch) from the Nepal Himalayas, this study was conducted at the treeline ecotone of the Makalu Barun National Park, eastern Nepal; Annapurna Conservation Area, central Nepal; and Dhorpatan Hunting Reserve, western Nepal, respectively. A total of eight study plots of variable length, three plots each in Makalu and Manang and two plots in Dhorpatan, were established. We enumerated all individuals within the study transects and applied dendroecological techniques to obtain age information. The population age structure was analyzed using static life table and survivorships curves to investigate the regeneration dynamics at treeline ecotone. All three species showed the reverse J-shaped age distribution indicative of undisturbed old-growth forests with sustainable regeneration. Young individuals mostly dominate the age structure; however, their mortality was found to be very high. There is less chance for population densification in the near future until the seedling mortality rate is reduced. This may occur as temperatures continue to rise.