Patterns of plant communities along vertical gradient in Dhauladhar Mountains in Lesser Himalayas in North-Western India

Mustaqeem Ahmad; Sanjay K Uniyal; Daizy R Batish; Harminder P Singh; Vikrant Jaryan; Sonia Rathee; Padma Sharma; Ravinder Kumar Kohli

doi:10.1016/j.scitotenv.2020.136919

Patterns of plant communities along vertical gradient in Dhauladhar Mountains in Lesser Himalayas in North-Western India

Sci Total Environ. 2020 May 10:716:136919. doi: 10.1016/j.scitotenv.2020.136919. Epub 2020 Jan 24.

Authors

Mustaqeem Ahmad¹, Sanjay K Uniyal², Daizy R Batish³, Harminder P Singh⁴, Vikrant Jaryan⁵, Sonia Rathee⁶, Padma Sharma⁴, Ravinder Kumar Kohli⁷

Affiliations

¹ High Altitude Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176 061, India; Department of Environment Studies, Panjab University, Chandigarh 160 014, India.
² High Altitude Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176 061, India.
³ Department of Botany, Panjab University, Chandigarh, India. Electronic address: daizybatish@yahoo.com.
⁴ Department of Environment Studies, Panjab University, Chandigarh 160 014, India.
⁵ Department of Botany, Sant Baba Bhag Singh University, Village Khiala, Padhiana, Jalandhar, Punjab 144 030, India.
⁶ Department of Botany, Panjab University, Chandigarh, India.
⁷ Department of Botany, Panjab University, Chandigarh, India; Central University of Punjab, Mansa Road, Bathinda 151 001, India.

PMID: 32059324
DOI: 10.1016/j.scitotenv.2020.136919

Abstract

Mountains are definitely the most rugged, yet frail resources and biodiversity-rich regions of the world. Environmental variables directly affect species composition, growth patterns, and the ecosystem resulting in a drastic change in the vegetation composition along ascending elevations. The present study investigated vegetation composition, nestedness, and turnover in plant communities along a vertical gradient (2000 to 4000 m) in Dhauladhar Mountains, Lesser Himalayas, India. We determined how α-diversity pattern and nestedness-related processes or turnover (β-diversity) causes dissimilarity in plant communities' composition along the vertical gradient. Overall, 21 permanent plots (20 × 20 m²) at every 100 m interval from 2000 to 4000 m were established. A sampling of shrubs and herbaceous species was done by marking sub-plots of 5 × 5 m² and 1 × 1 m², respectively, within permanent plots. We observed an inverted hump-shaped pattern for evenness index (E), a unimodal hump-shaped pattern for Shannon index (H'), Margalef's richness index, and β-Whittaker (β_w) diversity, and mild-hump-shaped pattern for Simpson index (λ) across the elevational gradient. Turnover (β_sim) and the nestedness-resultant component of β-diversity (β_sne) significantly differed across the elevational gradient. The observed β-diversity patterns revealed that the species replacement rate was less in the mid-altitude communities as compared to lower and higher altitude communities. It was largely attributed to the ecotonic nature of mid-altitudes, which benefited mid-elevational communities rather than low or high altitude communities. Besides lower altitudes, the increased human interference has led to disturbance and subsequent homogenization of flora across the mid-altitudes. With respect to this, the present study signifies the need for preserving the mid-altitudinal communities, without undermining the importance of conserving the low and high altitude communities.

Keywords: Mid-altitudes; Nestedness; Richness; Species replacement rate; Turnover rate; β-Diversity.

MeSH terms

Altitude
Ecosystem*
India
Plants