Adaptation to and mitigation of climate change in the Bangsri Micro-watershed, East Java, Indonesia

Abstract

Land use change in the Bangsri sub-catchment of the Brantas basin in East Java during the past three decades has increased both local and global climate vulnerability, by degrading soils and contributing to net greenhouse gas emissions, respectively. Our study aimed to estimate land use change and its impact on net carbon emissions, as well as to formulate strategies for adaptation to and mitigation of climate change downstream of a National park. We analyzed land cover changes from satellite imagery and measured carbon stocks in biomass, necromass and soil (0 to 30 cm) pools. Satellite imagery of land cover in 1994, 2001, 2011 and 2017 showed a decrease in natural forest area and an increase in the area of shrubs, agroforestry, production forests and annual crop land. Net CO2 emission increased from 2.4 to 6.4 Mg ha-1 year-1 in the periods 2001 to 2011 and 2011 to 2017, respectively. Sand mining is the most destructive land use pattern in the area, as it leaves soil profiles stripped of their topsoil. Vulnerability to less reliable rainfall has been addressed by the common creation of small reservoirs and the abundant use of irrigation for vegetables growing under partial shade in the agroforestry zone.