Land use change affects net ecosystem production in the Eastern Indian Himalayan region

Abstract

Human-driven land use changes in the Indian East Himalayan region threaten vital life-support systems by disrupting the carbon cycle, significantly affecting the global climate. Understanding net ecosystem production (NEP) is essential for evaluating the carbon sequestration potential of various managed systems, such as plantations and agroforestry. This study aimed to quantify NEP across six different land uses: natural forest, degraded forest, rubber plantation, Areca plantation, Areca agroforestry, and Piper agroforestry. This study provides the first estimates of NEP in forests, plantations, and agroforestry systems in this region. The net primary production was highest in Areca agroforestry (11.35 Mg C ha⁻¹ yr⁻¹) and lowest in Areca plantations (5.30 Mg C ha⁻¹ yr⁻¹). Carbon loss occurred through soil respiration and harvest, with annual soil respiration highest in rubber plantations (2.12 Mg C ha⁻¹ yr⁻¹) and natural forests (1.69 Mg C ha⁻¹ yr⁻¹). Harvest carbon loss was greatest in natural forests (4.80 Mg C ha⁻¹ yr⁻¹) and nearly non-existent in rubber plantations. NEP was highest in Areca agroforestry (6.99 Mg C ha⁻¹ yr⁻¹) and lowest in natural forests (1.68 Mg C ha⁻¹ yr⁻¹), as the former exhibit high NPP and lower carbon release from the system. These results indicate that Areca agroforestry are more effective carbon sinks than other land uses, including natural forests. The study concludes that the NEP of certain managed ecosystems can equal or surpass that of forest ecosystems, emphasizing their potential as nature-based solutions for climate change mitigation and their role in advancing Sustainable Development Goals, particularly SDG 13.