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Impact of land use and land cover changes on carbon stock in Aceh Besar District, Aceh, Indonesia

Achmad Ashfa, Ramli Ichwana, Nizamuddin Nizamuddin

Journal of Water and Land Development

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2023

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no. 57

159--166

EN

The international community affirms the critical role of forests in climate change mitigation, which includes reducing emissions from degradation and deforestation, carbon stock conservation, sustainable forest management, and increasing carbon stocks in developing countries. It relates to land use and land cover changes. This study aims to review land use and land cover changes (LULC) in two decades, namely 2000-2010 and 2010-2020, and the impact on carbon stocks. Landsat satellite imagery in 2000, 2010, and 2020 are classified into six categories: built-up area, cropland, forest, water body, bareland, and grassland. This classification uses supervised classification. The accuracy kappa coefficient values obtained for the LULC 2000, LULC 2010, and LULC 2020 maps were 89.61%, 83.90%, and 87.10%, respectively. The most dominant systematic LULC change processes were forest degradation in 2000-2020; the transition of forest to cropland (349.20 ha), forest to bareland (171.19 ha), and forest to built-up area (661.68 ha). Loss of using the forest for other uses was followed by a decrease in carbon stock. There was a high decrease in carbon stock in the forest category (11,000 Mg C∙y-1). The results showed a significant change in land use and cover. The decline in the area occurred in the forest category, which decreased from year to year. Meanwhile, the built-up area increases every year. Carbon stocks also decrease from year to year, especially forests as the most significant carbon store, decreasing in the area.

2

Estimation of impacts of land use and land cover (LULC) changes on land surface temperature (LST) within greater Imphal urban area using geospatial technique

Khan Rahul, Aribam Bindiya, Alam Wazir

Acta Geophysica

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2023

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Vol. 71, no. 6

2811--2823

EN

The rapid increase in the urbanisation process and other developmental activities across the globe have increased the land surface temperature of built-up areas which is considered as an emerging urban environmental problem. The rapid unplanned urban sprawl has influenced the land use and land cover of the urban area leading to the development of the phenomenon of Urban Heat Island. The present study highlights how land use and land cover changes have impacted the land surface temperature and urban heat islands phenomenon in the greater Imphal city of Manipur in India. The study was carried out with multi-spectral and multi-temporal satellite imageries of 1988, 2000, 2011, and 2021, respectively. The extracted information from the rectified imageries highlights a significant increase in the land surface temperature in the built-up area of the city. The findings illustrate that the maximum and minimum LST of the Imphal urban area has significantly increased from 28.77 to 31.25℃ and 10.44 to 11.47℃, respectively, for the month of February from 1988 to 2021. The increase in land surface temperature is directly attributed to the increased built-up area (24.06% to 44.85%) and reduction in the urban forest cover (28.17% to 16.65%). Cumulatively, there is a 2.44℃ and 1.03℃ rise in maximum and minimum LST over three decades. The variability in the LST shows positive correlations with the NDBI and negative correlations with NDVI. The study witnessed nearly about 0.74℃ (maximum) and 0.31℃ (minimum) decadal changes in the overall LST in the greater Imphal area.

3

Thermal stress and urban heat island effect in Jorhat urban environment as a result of changing land use and land cover

Neog Rituraj, Hazarika Jiten

Acta Geophysica

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2022

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Vol. 70, no 6

2771--2783

EN

The objective of the study is to determine the impact of land use and land cover (LULC) change on land surface temperature (LST) and thermal stress at Jorhat from 2009 to 2021. The experiment used Landsat TM (Thematic Mapper) for 2009 and OLI (Operational Land Imager)/TIRS (Thermal Infrared Sensor) for 2021 from earth.explorer.usgs.gov. Landsat data were employed to calculate the LST and LULC changes. Utilizing UTFVI (urban thermal field variance index), thermal stress over the ground surface has been computed. Thermal discomfort is computed simultaneously using the relative strain index (RSI) and net effective temperature (NET) index. Jorhat evidenced significant rise in built-up land to 281.25 hectares with reduced vegetation cover of 480.96 hectares from 2009 to 2021. These modifications caused significant rises in LST of 4.28 °C, 2.33 °C and 3.01 °C in September, October and December from 2009 to 2021. According to UTFVI from 2009 to 2021, Jorhat experienced declining ecologically excellent area with a rising proportion of ecologically worse land. In September and October 2009, the Jorhat city had just 10 days of bioclimatic discomfort and 19 days of bioclimatic comfort, as opposed to 24 and 10 days in 2021, respectively. Similarly, NET estimated 21 very hot days in October 2021, as opposed to just 9 days in 2009. Compared to 2009, there are now 6 and 4 days in December 2021 that are classified as warm or slightly hot, respectively. This leads to the conclusion that Jorhat's thermal condition is significantly impacted by changes in land use and land cover.

4

Forest cover change detection in relation to climate variability and LULC changes using GIS and RS techniques. A case of the Kafa zone, southwest Ethiopia

Lemma Dejene Beyene, Gebretsadik Kinde Teshome, Debela Seifu Kebede

Journal of Water and Land Development

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2021

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no. 51

152--162

EN

Ethiopia has lost sizable forest resources due to rapid population growth and subsequent increase in the demand for agricultural land and fuel woods. In this study, GIS and remote sensing techniques were used to detect forest cover changes in relation to climate variability in the Kafa zone, southwest Ethiopia. Landsat Thematic Mapper (TM) images of 1986 and 1990, Enhanced Thematic Mapper plus (ETM+) image of 2010 and Landsat-8 Operational Land Imager (OLI-8) image of 2018 were acquired at a resolution of 30 m to investigate spatial-temporal forest cover and land use changes. A supervised image classification was made using a maximum likelihood method in ERDAS imagine V9.2 to identify the various land use and land cover classes. Both spectral (normalised difference vegetation index – NDVI) and post classification change detection methods were used to determine the forest cover changes. To examine the extent and rate of forest cover changes, post classification comparisons were made using ArcGIS V 10.4.1. A net forest cover change of 1168.65 ha (12%) was detected during the study period from 1986 to 2018. The drop in the NDVI from 0.06–0.64 in 1986 to (–0.08)–0.12 in 2018 indicated a marked forest cover change in the study area. The correlation of NDVI values with climate data indicated the forest was not in a stable condition. The declining of the forest cover was most likely caused by climate variability in the study area.

5

Analysis of land use/land cover change in Adei watershed, Central Highlands of Ethiopia

Dinka Megersa Olumana, Chaka Degefa Dhuga

Journal of Water and Land Development

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2019

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no. 41

146--153

EN

Land use/land cover changes (LULCC) at Adei watershed (Ethiopia) over a period of 23 years (1986–2009) has been analysed from LANDSAT imagery and ancillary data. The patterns (magnitude and direction) of LULCC were quantified and the final land use/land cover maps were produced after a supervised classification with appropriate post-processing. Image analysis results revealed that the study area has undergone substantial LULCC, primarily a shift from natural cover into managed agro-systems, which is apparently attributed to the increasing both human and livestock pressure. Over the 23 years, the aerial coverage of forest and grass lands declined by 8.5% and 4.3%, respectively. On the other hand, agricultural and shrub lands expanded by 9.1% and 3.7%, respectively. This shows that most of the previously covered by forest and grass lands are mostly shifted to the rapidly expanding farm land use classes. The findings of this study suggested that the rate of LULCC over the study period, particularly deforestation due to the expansion of farmland need to be given due attention to maintain the stability and sustainability of the ecosystem.

PL

Zmiany użytkowania i sposobu pokrycia terenu w zlewni Adei (Etiopia) analizowano w ciągu 23 lat (1986–2009) z użyciem obrazów LANDSAT i dodatkowych danych. Oceniono ilościowo schemat zmian (wielkość i kierunek) oraz wykonano mapy użytkowania i pokrycia terenu po odpowiednim przetworzeniu danych. Analiza obrazów ujawniła, że badany obszar podlegał znaczącym zmianom – głównie od naturalnego pokrycia do gospodarczych agrosystemów, co wynikało z rosnącej presji ze strony człowieka i zwierząt gospodarskich. W ciągu 23 lat powierzchnie leśne i trawiaste zmalały odpowiednio o 8,5 i 4,3%, a powierzchnie użytkowane rolniczo i tereny zakrzaczone powiększyły się odpowiednio o 9,1 i 3,7%. Oznacza to, że tereny uprzednio zajmowane przez lasy i systemy trawiaste zostały zajęte przez tereny rolnicze. Przeprowadzone badania sugerują, że należy zwrócić szczególną uwagę na szybkie zmiany pokrycia powierzchni terenu, aby utrzymać stabilność i trwałość ekosystemu.