Spatial heterogeneity of ecosystem services and their valuation across himalayas: a systematic literature review and meta-analysis

Abstract

The Mountain Ecosystems, such as the Himalayan region, not only provide numerous Ecosystem Services (ESs) to millions of people living in mountainous areas but also provide essential ES to those living downstream. However, there is often an uneven distribution of ES availability and its value across different regions. Therefore, a better understanding of the spatial heterogeneity of ES is required for efficient and sustainable management of ES. This study thoroughly reviews literary data to examine ES’s spatial distribution and economic values across the Western, Central, and Eastern Himalayas. The literature was searched in the Scopus online database using the Boolean method from specific keywords such as ‘Ecosystem Services’ AND ‘Himalayas’. A systematic review of 76 of the most relevant literature sources yielded 31 unique ES divided into three categories: Provisioning (PES), Regulating (RES), and Cultural (CES). The distribution of reviewed literature is relatively balanced across the Himalayas (Western: 30.26%, Central: 32.89%, Eastern: 36.84%); however, the analysis identified a bias towards PES (43.54%), highlighting a need for increased research focus on RES (36.48%) and CES (19.98%). Notably, water-related services such as PES9 (Surface water used as a material (non-drinking purposes)) and PES8 (Surface water for drinking) have been ranked highest in all regions of the Himalayas yet have not been comprehensively studied in terms of their quantification and valuation. Furthermore, while most literature focused on the identification of ES (73.68%), there is a significant lack of attention to quantification (39.47%) and valuation (23.68%) of ES in the region. The average economic values for PES, RES, and CES were 446.75 USD/ha/year, 1128.81 USD/ha/year, and 457.51 USD/ha/year, respectively, indicating higher valuation for RES. This underlines the need for a more balanced research approach that includes identifying and thoroughly quantifying and valuing all types of ES in the Himalayas.