Simulating Urban Expansion Based on Ecological Security Pattern—A Case Study of Hangzhou, China

Disordered urban expansion has encroached on a large amount of ecological land, resulting in the steady degradation of urban ecology, which has an adverse effect on the sustainable development of the region. An ecological security pattern can effectively control urban expansion, and it is of great significance to balance urban development and ecological protection. In order to analyze the impact of ecological security patterns on urban expansion, Hangzhou was taken as an example, the CA-Markov model and FLUS model were used to simulate the urban expansion pattern in 2030 under the natural development scenario and the ecological security scenario. The results showed that (1) the ecological source area in the study area is 630.90 km2 and was mainly distributed in the western mountainous area. There are 14 ecological corridors, primarily composed of valleys and rivers. Ecological nodes are mainly distributed on the north and south sides of the main urban area. (2) From 2000 to 2018, the annual increase index (AI) of construction land decreased in the northeast and southeast directions but increased in the northwest and southwest directions, and in the northeast direction the value was always the highest. Except for the southwest direction, the average annual growth rate (AGR) of construction land in the other directions decreased. At a distance from the city center of 30 km, AI was relatively higher and was increasing, while AGR was declining. At a distance of 30–45 km, both AI and AGR were increasing, indicating that the focus of construction land was moving outwards. (3) From 2018 to 2030, under both natural development scenario and ecological security scenario, construction land would keep expanding, but the construction land area, proportion, AI, and AGR of the latter would both be smaller than the former, indicating that the ecological security pattern can effectively curb urban expansion. Because of a large amount area of ecological sources, the expansion of construction land in the southwest direction would be constrained, especially under the ecological security scenario. The methods and results of this study can provide theoretical and application references for urban planning and green development in metropolises.

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Mapping 20 Years of Urban Expansion in 45 Urban Areas of Sub-Saharan Africa

Remote Sensing ◽

10.3390/rs13030525 ◽

2021 ◽

Vol 13 (3) ◽

pp. 525

Author(s):

Yann Forget ◽

Michal Shimoni ◽

Marius Gilbert ◽

Catherine Linard

Keyword(s):

Case Studies ◽

Urban Areas ◽

Urban Expansion ◽

Local Population ◽

Sub Saharan Africa ◽

Annual Growth Rate ◽

Urban Dynamics ◽

Mapping Approach ◽

Sub Saharan ◽

The Impact

By 2050, half of the net increase in the world’s population is expected to reside in sub-Saharan Africa (SSA), driving high urbanization rates and drastic land cover changes. However, the data-scarce environment of SSA limits our understanding of the urban dynamics in the region. In this context, Earth Observation (EO) is an opportunity to gather accurate and up-to-date spatial information on urban extents. During the last decade, the adoption of open-access policies by major EO programs (CBERS, Landsat, Sentinel) has allowed the production of several global high resolution (10–30 m) maps of human settlements. However, mapping accuracies in SSA are usually lower, limited by the lack of reference datasets to support the training and the validation of the classification models. Here we propose a mapping approach based on multi-sensor satellite imagery (Landsat, Sentinel-1, Envisat, ERS) and volunteered geographic information (OpenStreetMap) to solve the challenges of urban remote sensing in SSA. The proposed mapping approach is assessed in 17 case studies for an average F1-score of 0.93, and applied in 45 urban areas of SSA to produce a dataset of urban expansion from 1995 to 2015. Across the case studies, built-up areas averaged a compound annual growth rate of 5.5% between 1995 and 2015. The comparison with local population dynamics reveals the heterogeneity of urban dynamics in SSA. Overall, population densities in built-up areas are decreasing. However, the impact of population growth on urban expansion differs depending on the size of the urban area and its income class.

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The Construction of Ecological Security Patterns in Coastal Areas Based on Landscape Ecological Risk Assessment—A Case Study of Jiaodong Peninsula, China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182212249 ◽

2021 ◽

Vol 18 (22) ◽

pp. 12249

Author(s):

Yichen Yan ◽

Hongrun Ju ◽

Shengrui Zhang ◽

Guokun Chen

Keyword(s):

Ecological Risk ◽

Principal Component ◽

Coastal Areas ◽

Ecological Security ◽

Ecological Planning ◽

Land Utilization ◽

The North ◽

Jiaodong Peninsula ◽

Security Pattern ◽

Landscape Ecological

Increasing land utilization, population aggregation and strong land–sea interaction make coastal areas an ecologically fragile environment. The construction of an ecological security pattern is important for maintaining the function of the coastal ecosystem. This paper takes Jiaodong Peninsula in China, a hilly coastal area, as an example for evaluating landscape ecological risk within a comprehensive framework of “nature–neighborhood–landscape”, based on spatial principal component analysis, and it constructs the ecological security pattern based on the minimum cumulative resistance model (MCR). The results showed that the overall level of ecological risk in the study area was medium. The connectivity between the areas of low landscape ecological risk was relatively low, and the high risk areas were concentrated in the north of the Peninsula. A total of 11 key ecological corridors of three types (water, green space and road corridors) and 105 potential corridors were constructed. According to the ecological network pattern, landscape ecological optimization suggestions were proposed: key corridors in the north and south of Jiaodong Peninsula should be connected; urban development should consider current ecological sources and corridors to prevent landscape fragmentation; and the ecological roles of potential corridors should be strengthened. This paper can provide a theoretical and practical basis for ecological planning and urban master planning in coastal areas in the future.

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Carbon Emission and Urban Construction Land Expansion in China: Evidence from Co-Integration Tests and Impulse Response Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.1883 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 1883-1888

Author(s):

Wen Wen Qiu

Keyword(s):

Urban Development ◽

Impulse Response ◽

Carbon Emission ◽

Industrial Structure ◽

Urban Expansion ◽

Response Analysis ◽

Causality Test ◽

Construction Land ◽

Urban Construction ◽

The Impact

Using co-integration analysis, Granger causality test, and impulse response analysis in an integrated way, this paper makes empirical study of the impact on China’s carbon emission by its urban construction land expansion. The result shows that there is a long-run equilibrium relationship between carbon emission and urban construction land expansion in China, with the latter being the Granger cause of the increase in carbon emission. However, the impact process shows a lagging nature. The impact effect is not so evident in a short term, but is rather significant in a long term (five to ten years). To reduce its carbon emission, China should optimize its urban development mode and control the scale of urban development reasonably, especially focusing on the economical and intensive use of land and upgrading of industrial structure, so as to reduce energy consumption by its urban expansion, check excessive increase in carbon emission, and promote the sustainable urbanization.

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Cause and mechanism of the Seti River flood, 5th May 2012, western Nepal

Journal of Nepal Geological Society ◽

10.3126/jngs.v46i0.31576 ◽

2013 ◽

Vol 46 ◽

Author(s):

Shreekamal Dwivedi ◽

Yojana Neupane

Keyword(s):

Disaster Preparedness ◽

Flash Flood ◽

Seismic Station ◽

Source Area ◽

Western Slope ◽

The North ◽

Outburst Floods ◽

Hourly Rainfall ◽

Inaccessible Area ◽

The Impact

A catastrophic flash flood has occurred in the Seti River in the morning of May 5, 2012. An attempt has been made to find out the cause of the flood which originated form very remote inaccessible area lying in the Western slope of the Annapurna IV peak. Comparative Analysis of the Landsat ETM satellite images of 20th April, 2012 and 6th May, 2012 revealed that the area of about 32000 square meter of the southern ridge 1.5 kilometer away from the Annapurna IV peak failed in the north western direction. The impact of descending mass of the failed mountain from 6850 meters to 4500 meters almost vertically pulverized the ice, sediment and rock. The impact even triggered seismicity at 9:09.56 AM, local time which was recorded all over the 21 stations of National Seismological Centre. The closest seismic station at Dansing which is 32 km. south west from the area recorded the high signals for 70 minutes which corresponds to the duration of the debris flow. Lab analysis of the flood water sample revealed the density of the flow as 1.88 gm/cc. Analysis of the satellite based hourly rainfall GSMaP NRT from the period form 20th April-6th May 2012 revealed that there were just 4 occurrences of rainfall which amounted less than I mm/hour in the source area of the avalanche. The rainfall > 6mm/hour which occurred in the Kharapani area on 4 May was localized rainfall which did not extend to the avalanche area. Lack of systematic disaster preparedness caused huge loss of life and property even though the early warning message was received from the Ultralight pilot who was flying close to the area. The avalanche triggered high intensity floods which have similar characteristics to glacier lake outburst floods (GLOFs) have emerged as a new hazard in the Himalaya.

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Suzhou Urban Expansion and its Fractal Characteristic Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.209-211.499 ◽

2012 ◽

Vol 209-211 ◽

pp. 499-502

Author(s):

Gang Fang ◽

Juan Yang ◽

Qi Li

Keyword(s):

Fractal Dimension ◽

Urban Landscape ◽

Urban Expansion ◽

Fractal Model ◽

City Development ◽

Characteristic Analysis ◽

Construction Land ◽

The North ◽

Urban Construction ◽

Expansion Speed

The Suzhou urban expansion as the research object, used the 1987,2000,2005 and2009 Landsat TM / ETM+ multi-objective remote sensing images to acquire the Suzhou urban landscape map, from the urban expansion speed, urban expansion strength, urban expansion elasticity coefficient, and the urban expansion direction to analyze the urban expansion dynamic changes, and then used the fractal model to calculate the Suzhou construction land fractal dimension and stability indexes in 1987-2009, and explored the relationship between the urban construction complexity and stability and the fractal dimension. The results show that, with the urbanization process accelerated, the construction land area in Suzhou City continued to increase, the urban expansion strength further enhanced, the urban expansion speed further accelerated, the city development direction mainly toward the north and south, southeast and northwest. The 1987-2009 urban construction land fractal dimension showed increasing -- reducing -- increasing trend, the urban construction land shape become more and more irregular, the urban construction land complexity increased, the urban construction land plaque stability decreased gradually.

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Analysis of ecological security pattern of rare earth mining areas in South China based on MCR model

Journal of Geography and Cartography ◽

10.24294/jgc.v3i1.1304 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Hengkai Li ◽

Yuting Liu ◽

Qin Li ◽

Xiuli Wang

Keyword(s):

Rare Earth ◽

South China ◽

Source Area ◽

Local Area ◽

Mining Area ◽

Ecological Security ◽

Security Pattern ◽

Landscape Ecological ◽

Landscape Ecological Security ◽

The Rare Earth

The rare earth mining area in South China is the main production base of ionic rare earth in the world, which has brought inestimable economic value to the local area and even the whole nation. However, due to the lack of mining technology and excessive pursuit for economic profits, a series of environmental problems have arisen, which is a great threat to the ecosystem of the mining area. Taking Lingbei rare earth mining area in Ganzhou as an example, this paper discriminated and analyzed such aspects as the ecological source, ecological corridor and ecological nodes of the mining area based on the landscape ecological security pattern theory and the minimum cumulative resistance model (MCR) method, and constructed a landscape ecological security pattern of the mining area during the 2009, 2013 and 2018. The results show that: i) The patch area of the ecological source of rare earth mining area is small, mainly concentrated in the east and west sides of the mining area. ii) During the selected year, the ecological source area, ecological corridors, radiation channels and the number of ecological nodes in the rare earth mining area are increasing, indicating that the landscape ecological security of the rare earth mining area has been improved to some extent, but it remains necessary for relevant departments to make a optimized planning to further reconstruct the ecological security pattern of the rare earth mining area.

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Analysis of the Urban Expansion for the Akure, Ondo State, Nigeria

International Letters of Social and Humanistic Sciences ◽

10.18052/www.scipress.com/ilshs.75.41 ◽

2017 ◽

Vol 75 ◽

pp. 41-55 ◽

Cited By ~ 1

Author(s):

Edward Echidime Eke ◽

Michael A. Oyinloye ◽

Isaac Oluwadare Olamiju

Keyword(s):

Control Mechanism ◽

Urban Expansion ◽

Satellite Image ◽

Spatial Dynamics ◽

Rapid Expansion ◽

Annual Growth Rate ◽

Master Plan ◽

Comparison Analysis ◽

Ondo State ◽

The Impact

- African cities are experiencing uncontrolled expansion. The focus of this paper is to evaluate the impact of urban expansion on landuse types of Akure for the period of 1972 to 2009 . In analyzing the u rban expansion of the cit y, 1972 MSS, 1986 Landsat Thematic TM and Landsat Enhanced Thematic Mapper Plus (ETM + ) images for 2002 and 2009 satellite image captured from googleearth website were used in a post classification comparison analysis to map the spatial dynamics of landuse / land cover changes and identify the urban expansion of Akure. Questionnaire was also used to determine the factors responsible for the expansion of Akure. The findings showed a rapid expansion in the built-up are a of Akure from 1.00% in 1972 to 2.46% in 1986, 2.46% in1986 to 3.90% in 2002 with an annual growth rate of 10.63% and 3.66% due to increasing population of Akure within these periods respectively. Prediction made showed that the built-up of A kure would expand to 2.66 % in 2022 . Th e study recommends review of the outdated 1980 master plan and development control mechanism that will guide the rapid expansion that had been accompanied by loss of vegetation in Akure.

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Technical Methodologies for The Assessment of the Impacts of Reclamation Projects on Marine Ecology

10.21203/rs.3.rs-343113/v1 ◽

2021 ◽

Author(s):

Yurong Ouyang ◽

Lin Wu ◽

Juanjuan Dai ◽

Yaojian Wu ◽

Ling Cai ◽

...

Keyword(s):

Ecosystem Services ◽

Coastal Wetland ◽

Marine Ecosystems ◽

Ecological Assessment ◽

Marine Ecology ◽

Ecological Security ◽

Wetland Ecosystems ◽

Security Pattern ◽

And Control ◽

The Impact

Abstract The present article introduces the concept of ecological assessment of reclamation projects. In addition, considering the impact of reclamation projects on marine ecosystems, we built a framework that takes into account structure, function, and ecosystem services for the assessment of the impact of reclamation projects on marine ecology. Moreover, this study explored different technical methods for ecological assessment of reclamation projects, with an emphasis on those that evaluate the impacts of reclamation on the structure of marine ecosystems. The present research provides technical support for the recognition and diagnosis of marine ecology problems that are the result of reclamation projects, introduces a guideline for the development of ecological restoration projects, assists in protecting coastal wetland ecosystems, promotes the scientific and reasonable management and control of reclamation, and helps maintaining the regional marine ecological security pattern.

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