Environmental Management
D. Frianto; E. Sutrisno; A. Wahyudi; E. Novriyanti; W.C. Adinugroho; A.S. Yunianto; H. Kurniawan; H. Khotimah; A. Windyoningrum; I.W.S. Dharmawan; H.L. Tata; S. Suharti; H.H. Rachmat; E.M. Lim
Abstract
BACKGROUND AND OBJECTIVES: Efforts to enhance carbon stocks and boost carbon absorption potential are essential for climate change mitigation. Peatland ecosystems, known for their high organic content, are particularly vulnerable to environmental management. The study aimed to examine the alterations ...
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BACKGROUND AND OBJECTIVES: Efforts to enhance carbon stocks and boost carbon absorption potential are essential for climate change mitigation. Peatland ecosystems, known for their high organic content, are particularly vulnerable to environmental management. The study aimed to examine the alterations in land use and land cover that occurred between 1998 and 2022, spanning a 24-year duration. Additionally, it sought to assess the associated variations in carbon stocks within the designated Kepau Jaya specific purpose forest area. The area under investigation encompasses a peatland ecosystem that has experienced substantial changes in land cover and land use. This study investigated the fluctuations in carbon stock caused by these alterations and provides valuable perspectives on the potential of agroforestry systems to promote a wider range of land uses. Additionally, it highlights their role in ecosystem restoration initiatives and the better management of forest peatland regions.METHODS: A spatial analysis was conducted on Landsat 5 and 8 satellite images by using shapefile data stored within the Google Earth Engine platform. Data analysis was carried out using Classification and Regression Tree, a decision tree algorithm used in machine learning for guided classification. Furthermore, purposive sampling was utilized to gather socioeconomic data, followed by the implementation of a benefit-cost analysis.FINDINGS: The results revealed significant changes in the land cover within the Kepau Jaya specific purpose forest area over a 24-year period, with forested areas and open areas decreasing by 23.15 hectares per year and 16.94 hectares per year respectively, and oil palm plantation areas expanding by 40.10 hectares per year. From 1998 to 2022, there has been a consistent annual decline in carbon stocks, resulting in a reduction of 1,933.11 tons of carbon per year. The changes in land use and cover are closely linked to this decline. In an effort to increase plant species diversity in the area and support the gradual transition away from monoculture, a participatory agroforestry scheme was implemented by intercropping Coffea liberica and Shorea balangeran between oil palm rows in a 2-hectare oil palm plantation block within the agroforestry demonstration plot. According to measurements taken at breast height, the aboveground biomass of these species was measured, leading to projected estimates of carbon stocks in Kepau Jaya specific purpose forest area reaching 19,455 tonnes of carbon by the year 2030, with Coffea liberica contributing 4,148 tonnes carbon and Shorea balangeran contributing 15,307 tonnes carbon. CONCLUSION: The study area experienced a substantial reduction in forest cover, whereas the extent of oil palm areas expanded significantly. The findings underscore the need for proactive measures to strengthen the governance of specific-purpose forest areas through community empowerment and the establishment of demonstration plots to promote agroforestry development. The results of this study provide insights for long-term forest rehabilitation strategies aimed at fostering sustainable forest management that yields environmental and socio-economic benefits in the long run.
Environmental Management
B.H. Narendra; O. Setiawan; R.A. Hasan; C.A. Siregar; , Pratiwi; N. Sari; A. Sukmana; I.W.S. Dharmawan; R. Nandini
Abstract
BACKGROUND AND OBJECTIVES: Flooding is the most frequent hydrological disaster which greatly impacts humans and the environment. Lombok, a small tropical island, experiences severe flooding almost yearly. Flood susceptibility mapping is important to determine the priority watershed in implementing flood ...
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BACKGROUND AND OBJECTIVES: Flooding is the most frequent hydrological disaster which greatly impacts humans and the environment. Lombok, a small tropical island, experiences severe flooding almost yearly. Flood susceptibility mapping is important to determine the priority watershed in implementing flood mitigation action, including improving the spatial planning in watershed management. Several methods of determining flood susceptibility require the support of long data series and a variety of monitoring equipment in the field where not every region has the resource capacity. Compared to other methods that require the support of long data series and a large number of evenly distributed monitoring equipment, the geomorphometric parameters and land use/cover in a watershed are closely related to the hydrological responses and are potentially applicable in flood susceptibility mapping. This research aimed to classify the watershed flood susceptibility on a small island based on the geomorphometric characteristics and land use/land cover of the watershed.METHODS: This study was carried out on Lombok Island, located in southern Indonesia, representing a small island in the tropical region. Watershed classification was carried out using 24 geomorphometric variables and land use/land cover, representing aspects of the river network, geometry, texture, and watershed relief. The principal component analysis approach was carried out to determine the most significant variable, and the weight of each variable was determined using the weighted sum approach method. Then, compound values were calculated based on the weighted values and preliminary ranking to indicate the flood susceptibility levels, which were divided into five classes.FINDINGS: The analysis found that the variables most related to flood events are the total number of rivers, relief ratio, elongation ratio, river density, stream frequency, and dry agricultural land use. These most related geomorphometrics indicate that the watersheds with higher flood susceptibility have low rock permeability, relatively low infiltration capacity, and relatively high surface runoff, thus triggering flooding. The flood susceptibility mapping classified 16 watersheds as having very high flood susceptibility. This research shows that analysis of the geomorphometric characteristics and land use/land cover can be relied upon to determine the flood susceptibility level, which is useful in spatial planning and flood disaster mitigation.CONCLUSION: Geomorphometric characteristics and land use/land cover can be used to determine a watershed's hydrological characteristics or behaviour. Based on the geomorphometric characteristics of the watersheds on Lombok Island, some identifying variables that are highly related to flood processes were obtained. Based on these characteristics, watersheds with high and very high flood susceptibility levels have low rock permeability, relatively low potential infiltration capacity, and relatively high surface runoff potential. Flooding still occurs despite good forest cover because the geomorphometric characteristics of the watershed also play a major role in flood events.
