Authors: Michelle Mohr*, California State University Dominguez Hills, Raju Bista, California State University Dominguez Hills, Parveen Chhetri, California State University Dominguez Hills
Keywords: Treeline ecotone; Population dynamics; Age structure; Recruitment pattern; Treeline advance
Session Type: Poster
Presentation File: Download
Climate change will have a strong influence on vegetation communities, particularly on the transition zone communities such as the treeline ecotone. The population structure and dynamics of long-lived treeline species can be utilized as an indicator of climate change. This study was conducted at the treeline ecotone of the Dhorpatan Hunting Reserve, western Nepal to understand the population dynamics of Betula utilis (Himalayan Birch). Two transects (120 × 20 m) were established in north-east facing slope of the Rugakharka area in reserve. We enumerated all individuals of B. utilis and applied dendroecological techniques to obtain age information in the transects. The population age structure was analyzed to investigate the regeneration dynamics at treeline ecotone. The B. utilis population showed the reverse J-shaped age distribution indicative of undisturbed old-growth forests with sustainable regeneration. The age structure is mostly dominated by young individuals; however, their mortality was found to be very high. Significant negative relationships between recruitment and temperatures of March month was discovered. A significant positive relationship was found between the recruitment and August precipitation of the region. There is less of a chance for population densification in the near future until the seedling mortality rate is reduced. This may occur as temperatures continue to rise.