Impact of Climate Change on Vegetation in High Altitudes of North Western Himalaya: A Case Study of Pinus wallichiana from Pangi Valley, Himachal Pradesh

Abstract

Climate change is one of biggest challenge to the world in 21st century. Climate is changing from Last Glacier Maxima (LGM), but after industrialization the rate of climate change has rapidly increased. Increase in CO2 level from 280 PPm (1960) to 495 PPm (2019) and global average surface temperature from 0.6 to 0.90 C (1.1 to 1.6° F) between 1906 and 2005, double increase in temperature for the last 50 years and the rise in global average surface temperature (1.50C) have caused rapid increase in the rate of climate change. The sub-alpine and alpine regions are very sensitive, and are also experiencing even greater increase in temperature. Therefore, the present study is an attempt to assess the Pinus wallichiana population in Pangi Valley of Himachal Pradesh, North Western Himalaya in relation to climate change. Circumference at Breast Height (CBH) class was taken as a criterion to assess the shift in Pinus wallichiana population along an altitudinal gradient. Shifting of vegetation was assessed on the basis of size class distribution of species in different size classes with respect to altitude. Survival rate and stress tolerance of seedlings and saplings in alpine region was assessed based on dry needles stage (%) and number of dead seedlings and saplings present in each quadrat. The study established a decrease in size class from temperate to sub – alpine region. Even, saplings and seedlings were recorded in the lower fringes of alpine region. The statistical analysis indicated that the seedlings of Pinus wallichiana showed maximum positive significant correlation with altitude (r= 0.321), indicating thereby, with increase in altitude the seedlings density also increased. Saplings of Pinus wallichiana also showed maximum positive significant correlation with altitude (r= 0.302), indicating thereby, with increase in altitude the saplings density also increased. Trees density in size class 100-150cm of Pinus wallichiana showed maximum negative significant correlation along an altitudinal gradient (r= -0.377), indicating thereby, with increase in altitude, the density of trees with diameter 100-150cm decreased. Seedlings of Pinus wallichiana showed maximum positive significant correlation with saplings (r= 0.962), indicating thereby, saplings density was dependent on seedlings density. The study also revealed that the survival rate decreased with the increasing altitude. The study clearly revealed the altitudinal shift of Pinus wallichiana in Pangi valley. This could be due to less snow fall, rainfall and increase in maximum and minimum temperature in Pangi valley, and can be related to the climate change. Regular monitoring of the temperate, sub – alpine and alpine vegetation in Pangi valley in relation to climate change is suggested to understand the vegetation dynamics and impact of climate change on vegetation and also on other natural resources.