Land Cover and Land Use Change Decreases Net Ecosystem Production in Tropical Peatlands of West Kalimantan, Indonesia

Strong climate mitigation potential of rewetting oil palm plantations on tropical peatlands

For decades, tropical peatlands in Indonesia have been deforested and converted to other land uses, mainly oil palm plantations which now cover one-fourth of the degraded peatland area. Given that the capacity for peatland ecosystems to store carbon depends largely on hydrology, there is a growing interest in rewetting degraded peatlands to shift them back to a carbon sink. Recent estimates suggest that peatland rewetting may contribute up to 13 % of Indonesia's total mitigation potential from natural climate solutions. In this study, we measured CO2 and CH4 fluxes, soil temperature, and water table level (WTL) for drained oil palm plantations, rewetted oil palm plantations, and secondary forests located in the Mempawah and Kubu Raya Regencies of West Kalimantan, Indonesia. We found that peatland rewetting significantly reduced peat CO2 emissions, though CH4 uptake was not significantly different in rewetted peatland compared to drained peatland. Rewetting drained peatlands on oil palm plantations reduced heterotrophic respiration by 34 % and total respiration by 20 %. Our results suggest that rewetting drained oil palm plantations will not achieve low CO2 emissions as observed in secondary forests due to differences in vegetation or land management. However, extrapolating our results to the areas of degraded oil palm plantations in West Kalimantan suggests that successful peatland rewetting could still reduce emissions by 3.9 MtCO2 yr-1. This result confirms that rewetting oil palm plantations in tropical peatlands is an effective natural climate solution for achieving national emission reduction targets.

Impacts of Land Use Changes on Net Primary Productivity in Urban Agglomerations under Multi-Scenarios Simulation

Land use is closely related to the sustainability of ecological development. This paper employed a patch-generating land use simulation (PLUS) model for the multi-scenario simulation of urban agglomerations. In addition, mathematical analysis methods such as Theil-Sen Median trend analysis, R/S analysis, Getis-Ord Gi* index and unary linear regression were used to study the temporal and spatial evolution characteristics of net primary productivity (NPP) for the impact of land use changes on NPP in urban agglomerations from 2000 to 2020 and to forecast the future trend of NPP. The results indicate that urban expansion is obvious in the baseline scenario and in the ecological protection scenario. In the scenario of cropland protection, the urban expansion is consistent with the land use plan of the government for 2035. The NPP in Beijing decreased gradually from northwest to southeast. The hot spot areas are concentrated in the densely forested areas in the mountainous areas of northwest. The cold spot areas are mainly concentrated in the periphery of urban areas and water areas. The NPP will continue to increase in forest and other areas under protection and remain stable in impervious surfaces. The NPP of Beijing showed a strong improvement trend and this trend will continue with the right ecological management and urban planning of the government. The study of land use in urban agglomeration and the development trend of vegetation NPP in the future can help policymakers rationally manage future land use dynamics and maintain the sustainable development of urban regional ecosystems.