land cover dynamics
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Author(s):  
Mengistie Kindu ◽  
Degefie Tibebe ◽  
Demeke Nigussie ◽  
Thomas Schneider ◽  
Martin Döllerer ◽  
...  

2021 ◽  
Vol 930 (1) ◽  
pp. 012021
Author(s):  
S M Beselly ◽  
R D Lufira ◽  
U Andawayanti

Abstract Quantitative assessment for sustainable watershed management is essential. Hydrological parameters such as stream discharge, surface runoff, infiltration, groundwater recharge, and water quality are susceptible to the changes of the components in the river basin ecosystem. Numerous studies have shown that the Land Use Land Cover (LULC) changes such as deforestation, extensive agriculture, urbanization, and mining are recognized as the main factors to changes in LULC, which are related to the changes of the hydrological components of the river basin of all scale. This paper particularly shows the spatiotemporal variability of LULC in the Upper Brantas Basin and the effects on the river discharge variation. We showed that the changes in LULC, particularly cultivated and managed vegetation and urban/built-up area, contributed significantly to the river discharge. Particularly in the Upper Brantas Basin, it was indicated that almost half of the increased river discharge was explained by the increase of urban/built-up and the decrease in cultivated and managed vegetation area.


2021 ◽  
Vol 13 (23) ◽  
pp. 4799
Author(s):  
Daniel Sousa ◽  
Christopher Small

Aquaculture in tropical and subtropical developing countries has expanded in recent years. This practice is controversial due to its potential for serious economic, food security, and environmental impacts—especially for intensive operations in and near mangrove ecosystems, where many shrimp species spawn. While considerable effort has been directed toward understanding aquaculture impacts, maps of spatial extent and multi-decade spatiotemporal dynamics remain sparse. This is in part because aquaculture ponds (ghers) can be challenging to distinguish from other shallow water targets on the basis of water-leaving radiance alone. Here, we focus on the Lower Ganges–Brahmaputra Delta (GBD), one of the most expansive areas of recent aquaculture growth on Earth and adjacent to the Sundarbans mangrove forest, a biodiversity hotspot. We use a combination of MODIS 16-day EVI composites and 45 years (1972–2017) of Landsat observations to characterize dominant spatiotemporal patterns in the vegetation phenology of the area, identify consistent seasonal optical differences between flooded ghers and other land uses, and quantify the multi-decade expansion of standing water bodies. Considerable non-uniqueness exists in the spectral signature of ghers on the GBD, propagating into uncertainty in estimates of spatial extent. We implement three progressive decision boundaries to explicitly quantify this uncertainty and provide liberal, moderate, and conservative estimates of flooded gher extent on three different spatial scales. Using multiple extents and multiple thresholds, we quantify the size distribution of contiguous regions of flooded gher extent at ten-year intervals. The moderate threshold shows standing water area within Bangladeshi polders to have expanded from less than 300 km2 in 1990 to over 1400 km2 in 2015. At all three scales investigated, the size distribution of standing water bodies is increasingly dominated by larger, more interconnected networks of flooded areas associated with aquaculture. Much of this expansion has occurred in immediate proximity to the Bangladeshi Sundarbans.


2021 ◽  
Vol 20 (1) ◽  
pp. 1-16
Author(s):  
Vo Thanh Son ◽  
◽  
Luu The Anh ◽  
Dao Minh Truong ◽  
Trong Dai Ly ◽  
...  

Assessment of ecosystem services is vital for successful natural resource allocation; however, these have been less studied within Vietnam. This study estimated the ecosystem services value (ESV) and its change in Cham Chu nature reserve, Vietnam using a benefit transfer method. Ecosystem service values estimation and trend analyses were carried out based on land use and land cover datasets from 1986, 1998, 2007, and 2017, with their corresponding global value coefficients. The results revealed that the total value of ecosystem services in Cham Chu was approximately 64.4, 63.9, 60.7, and 63.4 million USD in 1986, 1998, 2007, and 2017, respectively. Changes have also occurred in the values of individual ecosystem service functions. From 1986 to 2017, ecosystem service functions showed significant decreases in gas regulation, pollination, biological control, water regulation, water supply, and food production of 62.9%, 51.2%, 44.4%, 24.7%, 23.1%, and 13.0%, respectively. We conclude that the loss of ESV is a result of ecological deterioration in the studied landscape, and we propose further research to examine future solutions and establish action strategies. In summary, the research approach methodology developed can be used by land managers and planners in Vietnam as a guideline to estimate the importance of ecosystem services in Vietnam.


2021 ◽  
Vol 28 (3) ◽  
pp. 429-447
Author(s):  
Mir Mehrdad Mirsanjari ◽  
Jurate Suziedelyte Visockiene ◽  
Fatemeh Mohammadyari ◽  
Ardavan Zarandian

Abstract The present study aimed to analyse changes in the land cover of Vilnius city and its surrounding areas and propose a scenario for their future changes using an Artificial Neural Network. The land cover dynamics modelling was based on a multilayer perceptron neural network. Landscape metrics at a class and landscape level were evaluated to determine the amount of changes in the land uses. As the results showed, the Built-up area class increased, while the forest (Semi forest and Dense forest) classes decreased during the period from 1999 to 2019. The predicted scenario showed a considerable increase of about 60 % in the Built-up area until 2039. The vegetation plant areas consist about 47 % of all the area in 2019, but it will be 36 % in 2039, if this trend (urban expansion) continues in the further. The findings further indicated the major urban expansion in the vegetation areas. However, Built-up area would expand over Semi forest land and Dense forest land, with a large part of them changed into built- up areas.


Author(s):  
Michael Alonzo ◽  
Jamon Van Den Hoek ◽  
Paulo J. Murillo-Sandoval ◽  
Cara E. Steger ◽  
John Aloysius Zinda

2021 ◽  
Author(s):  
Tariku Zekarias ◽  
Vanum Govindu ◽  
Yechale Kebede ◽  
Abren Gelaw

Abstract Background: Wetlands worldwide and in Ethiopia have long been subject to severe degradation due to anthropogenic factors. This study was aimed at analyzing the impact of land use/cover dynamics on Lake Abaya-Chamo wetland in 1990 – 2019. Data were acquired via Landsat TM of 1990, ETM+ of 2000, and OLI of 2010 and 2019 images plus using interview. Supervised classifications (via ERDAS14 and ArcGIS10.5) were applied to detect land use/cover classes. Change matrix model and Kappa coefficients were used for analysis of the land use/cover dynamics in the lake-wetland.Result: It was found that forest; water, shrub land, agricultural land, settlement and swamp area were the main land use/cover classes. Wetland/swamp area has continuously declined throughout 1990 – 2000, 2000 – 2010 and 2010 – 2019 where its magnitude of shrinkage in the respective periods was 11.4 % (700 ha), 16 % (867 ha) and 31.3 % (1,424 ha). While ‘settlement’ and ‘water body’ of the lake-wetland increased at progressively increasing magnitudes of changes in three periods within 1990 – 2019, ‘shrub land’ and ‘swamp’ declined at progressively increasing magnitudes of loss in the same periods Siltation, rapid population growth-led expansion of settlement and irrigation-based farming were the main drivers of the land use/cover dynamics and degradation of the lake-wetland. Conclusion: Thus, consistent mapping and integrated actions should be taken to curb the threats on the sustainability of the lake-wetland in Southern Ethiopia. To curb the impact of LULC dynamics on wetlands, the government should: formulate clear policy, institutional and legal framework on the management of wetlands.


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