Scenario-based estimation of catchment carbon storage: linking multi-objective land allocation with InVEST model in a mixed agriculture-forest landscape

This study performed a scenario-based land allocation in a mixed agriculture-forest landscape in northern Iran to investigate how different land use policies contribute to changes in carbon storage. In pursuit of this goal, a temporal profile of the trade-off between the region's land use land cover (LULC) classes was produced using Landsat image of the year 2016. The weighted linear combination procedure was also used to map the suitability of land for agriculture, forest, urban, and rangeland based on ecological and socio-economic criteria. The suitability maps were analyzed through the Multi-Objective Land Allocation procedure under five scenarios with differing areas devoted to each LULC to generate different patterns of LULC distribution in the region. In addition, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was used to estimate the potential of LULC classes in carbon storage. The amount of carbon storage differed significantly between the scenarios, ranging from 1.29 tons/ha/year when the majority of the land was devoted to agriculture (76% of the area) to 5.40 tons/ha/year when the landscape was dominated by forest (77% of the area). The extreme conditions presented in this research may not be as likely to occur, but opens a dialog between different stakeholders and informs of a probable trend of ecosystem service loss due to agricultural land expansion.