Urban Development Intensity Research Articles

Compact cities or sprawling suburbs? Optimising the distribution of people in cities to maximise species diversity

Abstract Conservation of biodiversity in urban environments depends on species’ responses to the intensity of urban development. “Land sharing” and “land sparing” represent alternate ends of a gradient that conceptualises a trade‐off between the human population and biodiversity. We used a linear optimisation procedure to (a) identify the optimal allocation of land for people and nature, (b) assess whether the optimal allocation is closer to land sparing or land sharing and (c) examine how this might change under scenarios of human population growth. We surveyed birds in 28 landscapes, each 25 ha in size, along a gradient of human population density (zero to c. 1,600 persons/25 ha) in the Greater Melbourne region, Australia. Species’ responses to population density were estimated using generalised additive models (GAMs). These relationships were then used to determine the optimal allocation of land among different categories of population density based on maximising a community index, the geometric mean of relative abundance (G) of bird species. Human population density was an important driver of the reporting rate for 28 species. Response curves differed among “urban avoider,” “urban adapter” and “urban exploiter” species. For the current human population in the study area, the optimal allocation of land included elements of both land sharing and land sparing. However, for scenarios of increased population size, optimal allocation converged upon a land sparing design. Synthesis and applications. Urban areas represent a mosaic of land uses that offer habitats of differing quality. Land sharing, based on sustaining biota among residential areas, performed poorly under all scenarios due to its inability to support species that depend on natural or seminatural habitat. To sustain more than a homogenised avifauna in urban regions, large tracts of natural vegetation are needed within, or adjacent to, the urban environment. Protecting natural areas on urban fringes will be critical to the safeguarding of nature in the future as urban populations and land‐use inevitably expand.

Structural Impact Relationships Between Urban Development Intensity Characteristics and Carbon Dioxide Emissions in Korea

The goal of this study is to analyze the interrelated direct and indirect impacts of urban development intensity (UDI) characteristics on carbon dioxide (CO2) emissions in Korea. The study also compares the main arguments and analysis results of previous studies on cities that are effective in reducing CO2 emissions. To do this, factors attributable to the UDI characteristics of Korea were selected, and CO2 emissions were calculated. Then, the impact of UDI characteristics on CO2 emissions was analyzed using the partial least squares structural equation model. The main results show that the physical, spatial, and socio-demographic characteristics of UDI have a direct impact on CO2 emissions, and physical, economic, and city-type characteristics indirectly affect CO2 emissions. As a result, we reach the following conclusions: (i) dense urban forms reduce CO2 emissions; (ii) economic characteristics of UDI have impact on total CO2 emissions, having both negative and positive effects; and (iii) medium and small cities have higher per capita CO2 emissions than do large cities.

Is Urban Land Development Driven by Economic Development or Fiscal Revenue Stimuli in China?

Since the reform and opening-up, urban land development in China mainland has been increasing dramatically with significant regional differences. Using the panel data of municipal districts in 246 cities at the prefectural or higher levels in Chinese mainland from 2004 to 2014, based on the analysis of the differences in land development intensity in municipal districts, a model of factors affecting land development is built to verify whether the urban land development is driven by economic development or fiscal revenue from the perspectives of economic development and fiscal revenue. The conclusions are as follows: first, the intensity of land development varies significantly among municipal districts. The difference in the intensity of land development increases with the increase of city scale. The difference in the intensity of land development in central China is lower than that in eastern and western China. Second, the primary factors affecting the intensity of urban land development are economic growth, population urbanization, and population density. Finally, land transfer revenues also drive the land development in cities at the prefectural or higher levels to a considerable extent, which is proposed as “land finance” (local governments rely on the sale of land use rights to obtain extra-budgetary income to maintain local fiscal expenditure) in the literature.

长三角城市群碳排放与城市用地增长及形态的关系

PDF HTML阅读 XML下载 导出引用 引用提醒 长三角城市群碳排放与城市用地增长及形态的关系 DOI: 10.5846/stxb201707101242 作者: 作者单位: 浙江大学公共管理学院土地科学与不动产研究所,浙江大学公共管理学院土地科学与不动产研究所,浙江大学公共管理学院土地科学与不动产研究所,浙江大学公共管理学院土地科学与不动产研究所,浙江大学环境与资源学院农业遥感与信息技术应用研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上项目（41771244）；国家留学基金（201706320200）；中央高校基本科研业务费专项资金资助；浙江大学文科教师教学科研发展专项项目 Relationships between carbon emission, urban growth, and urban forms of urban agglomeration in the Yangtze River Delta Author: Affiliation: Institute of Land Science and Property, School of Public Affairs, Zhejiang University,,Institute of Land Science and Property, School of Public Affairs, Zhejiang University,, Fund Project: National Natural Science Foundation of China（Grant No.41771244）; China Scholarship Council (Grant No.201706320200); supported by “the Fundamental Research Funds for the Central Universities”; supported by “the Teaching and Research Development Funds for Humanities and Social Sciences of Zhejiang University” 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市是一种重要的碳源，城市扩张过程中的用地面积增长和空间特征变化均会影响城市碳排放。分析1995-2015年长三角城市群碳排放重心转移，查明碳排放和城市用地增长的脱钩状态时空变化，并通过构建面板数据模型探究城市形态对碳排放的影响，得出以下结论：（1）1995-2015年长三角城市群碳排放重心经历了西南向-西北向-东南向-西北向的转移过程，这种转移过程与其相应时期内部分城市的工业发展与产业结构调整有关；（2）1995-2015年，长三角城市群碳排放与城市用地增长的脱钩状态存在着显著的时空异质性。研究区由以扩张负脱钩为主变化为以弱脱钩为主，2005年以后，区域之间的脱钩差异开始缩小，总体来看研究区脱钩状态趋向于同质。至2015年，近70%的城市已达到了脱钩，其中上海等城市实现了强脱钩；（3）连续完整的地块在区域内的主导程度会对城市碳排放产生负向的影响，而城市用地斑块的破碎化程度和聚集程度对碳排放有着正向的影响，且相对而言，聚集程度的正向影响更为显著。 Abstract:Cities are one of many carbon sources. According to the Intergovernmental Panel on Climate Change (IPCC) AR5, CO2 emissions from fossil fuel combustion and industrial processes contributed about 78% to the total Green House Gas (GHG) emission increase between 1970-2010. Total annual anthropogenic GHG emissions have increased by about 10GtCO2-eq between 2000-2010. The increase directly came from energy (47%), industry (30%), transport (11%), and building (3%) sectors, which mainly exist in cities. Urban expansion and urbanization can affect urban carbon emission. Studies show that there is a long-term and stable relationship between urbanization and carbon dioxide emissions. The relationships between urban carbon emissions and indicators, including urban development intensity, urban land use, and the industrial sector, are studied extensively. During urban expansion, the quantitative and spatial features of urban lands can both affect carbon emissions. Therefore, urban form was added to the possible factors influencing carbon emissions in this study, which may be different from previous research that has focused on the relationship between urban growth and carbon emissions. However, in some related research, when urban form has been added to the indicators, the objects were residents or the transport sector, and they lacked quantitative indicators to verify the conclusions. The definition of "urban form" in this study was landscape pattern which was characterized by landscape metrics, and the study area consisted of 13 cities in the Yangtze River Delta. In this study, we analysed the shift of the gravity center from 1995-2015 for carbon emissions of the study area, and defined the decoupling index as well as analysing the temporal-spatial changes of the decoupling relationships between carbon emissions and urban growth in the study area. We also built panel data models to estimate the impact of urban forms on carbon emissions. Based on that, the conclusions are as follows:(1) The shift of the gravity center from 1995-2015 for carbon emissions of the study area was southwest-northwest-southeast-northwest. The shift may be related to the development of industry and change of industrial structure in some cities during this period. (2) There was a significant temporal-spatial heterogeneity in the decoupling relationships between carbon emissions and urban growth from 1995-2015. The leading decoupling relationship between carbon emissions and urban growth of the study area changed from expansive negative decoupling to weak decoupling from 1995-2015. The difference of decoupling relationships between cities narrowed after 2005 and the overall decoupling relationship of the study area became homogeneous. In 2015, almost 70% of cities reached the decoupling state and the decoupling states of Shanghai, Shaoxing, and Taizhou were strong. (3) Urban carbon emissions can be negatively influenced by the dominance of complete patches, and positively influenced by the degree of fragmentation and aggregation of urban patches. Carbon emissions can be more sensitive to the more aggregative distribution of the urban patches. This study analysed the relationship between carbon emissions and urban growth, as well as exploring how urban form can affect carbon emissions. The conclusions could provide scientific references for the policy making of low-carbon development strategies and land use and urban planning of urban agglomeration in the Yangtze River Delta. 参考文献 相似文献 引证文献

Establishment of an Improved Floor Area Ratio with High-Resolution Satellite Imagery

An Improved Floor Area Ratio (IFAR) which can describe the intensity of urban land development was proposed and estimated by means of remote sensing technique. The paper intent to conduct a quick and high-precision estimation of the index based on building shadows in high-resolution images. Firstly, the spectral characteristics of shadows were analyzed to establish a ratio band SR which would enhance shadow information. The object-oriented method was used to achieve the extraction of shaded areas. Secondly, GIS method was used to estimate the shadow length and building height. The inspection of the building height between the estimation result and the filed measured data showed an accuracy of 90%. Finally, the gross floor area of each building was calculated by multiplying the storeys with the basement area. Thiessen polygons were built by assuming the centroid of the basement area as a point. The IFAR of each building was the ratio of the gross floor area to the corresponding polygon. The IFAR have more abundant connotations by taking more information into consideration. The remote sensing tool can well extract the proposed index accurately on a very large scale.

Evaluating Urban Land Carrying Capacity Based on the Ecological Sensitivity Analysis: A Case Study in Hangzhou, China

Abstract: In this study, we present the evaluation of urban land carrying capacity (ULCC) based on an ecological sensitivity analysis. Remote sensing data and geographic information system (GIS) technology are employed to analyze topographic conditions, land-use types, the intensity of urban development, and ecological environmental sensitivity to create reasonable evaluation indicators to analyze urban land carrying capacity based on ecological sensitivity in the rapidly developing megacity of Hangzhou, China. In the study, ecological sensitivity is grouped into four levels: non-sensitive, lightly sensitive, moderately sensitive, and highly sensitive. The results show that the ecological sensitivity increases progressively from the center to the periphery. The results also show that ULCC is determined by ecologically sensitive levels and that the ULCC is categorized into four levels. Even though it is limited by the four levels, the ULCC still has a large margin if compared with the current population numbers. The study suggests that the urban ecological environment will continue to sustain the current population size in the short-term future. However, it is necessary to focus on the protection of distinctive natural landscapes so that decision makers can adjust measures for ecological conditions to carry out the sustainable development of populations, natural resources, and the environment in megacities like Hangzhou, China.

Impact of land revenue on the urban land growth toward decreasing population density in Jiangsu Province, China

Although land conveyance fees have accounted for a large portion of local governments' fiscal revenues and have been associated with rapid urban land expansion in China during the past two decades, little attention has been paid to the effect of land revenue on urban development intensity in China. This study focuses on the linkage between land revenue and urban land growth toward a decreasing population density (sparse pattern), termed “sparse effect” of land revenue in this study. A classification approach, based on the rate of demographic and urban land growth, was used to categorize urban land growth in Jiangsu Province, China. By dummy coding those categories, the dependent variable was generated and the multilevel logit model was used to examine the “sparse effect”. From 2000 to 2010, 63 analytical units experienced a sparse pattern. Local governments showed some land management behaviors specific to land revenue, including newly-converted-land-prioritized and employment-land-prioritized, which resulted in “expansive effect” of land revenue on urban land growth. Taking advantage of the hukou system (household registration), land revenue cast the “selective absorbing effect” on population. The study indicated that the “expansive effect” together with “selective absorbing effect” of land revenue has resulted in the “sparse effect”, which could be weaker in a poor, less-developed region.

Using trail cameras to estimate free‐ranging domestic cat abundance in urban areas

The domestic cat Felis catus is one of the most ecologically harmful invasive species on earth. Predation by free‐ranging cats poses a serious global threat to small vertebrates and is a leading source of anthropogenic mortality for birds and small mammals in North America. However, little is known about the size of cat populations, especially in urban areas where both cats and wildlife are abundant. Methods to quantify free‐ranging cat populations are needed to understand the magnitude of threats facing wildlife populations and to inform decisions about prioritizing conservation and cat population management. We assessed the utility of trail cameras and sight—resight analysis for estimating free‐ranging cat abundance in a small urban area (Stillwater, OK, USA). We also evaluated whether relationships exist between cat abundance and both urban development intensity and human population density. Even with relatively large cat populations, we identified the vast majority (∼96.5%) of individual cats in both day‐time and night‐time photos. We found no relationship between cat abundance and either urban development intensity or human population density. This finding combined with the large numbers of cats observed suggests that cats may be abundant in our study area regardless of urban context. Sampling freeranging cat populations across a broad range of urbanization intensities that capture a variety of human behaviors and/or cat management policies is needed to shed light on the drivers of cat population abundance. Trail cameras show promise as a highly useful tool for achieving this objective in the context of wildlife conservation management.

Assessing the impact of urban development on net primary productivity during 2000–2010 in Taihu Basin

Urbanization causes ecological problems around the world. Sustainable urban development requires a better understanding of impacts of urban pattern on an ecosystem. Taihu Basin as a representative region has experienced rapid development process over the past decade, while ecological effects of different development patterns were rarely examined. Taking net primary production (NPP) as an indicator of vegetation functions, NPP loss caused by urban development was investigated at 1-km grid level from 2000 to 2010. Our main finding is that urban development has encroached approximately 7499.50 km2, about 34.54 % of the total cropland, and incomplete development activities in rural areas have reduced more NPP than surrounding urban areas. The results revealed that urban development intensity has increased in most of the northern and eastern regions, which is far beyond the original urban boundary. Urban development patterns have varied effect on the ecosystem. Low levels of urban development and land utilization can affect a broader area than a highly developed urban area, while the latter has greater effects on average. In the context of rapid urbanization, reasonable city planning, effective land use policies and regulations must be implemented to realize sustainable development.

Research on the Relationship between Urban Development Intensity and Eco-Environmental Stresses in Bohai Rim Coastal Area, China

To realize sustainable urban development that minimizes environmental impacts, the relationship between urban development intensity and eco-environmental stresses should be clearly revealed. This paper focused on the Bohai Rim coastal area, where cities have experienced significant development in the last decade. An index system was developed to quantify the comprehensive urban development intensity (CDI) and comprehensive eco-environment stresses (CES). Remote sensing imagery and statistical data were used to provide indices for CDI and CES. Spatiotemporal analysis was carried out on the correlation between the two indices. The coupling between the CDI and CES was then investigated to explore the urban development characteristics of each city in the study area, its development level, and the trend of urban development. Results showed that human activities surrounding urban development were partly dependent on the use of ecological resources to a certain degree, and that the degree of dependence increased with year. To promote a sustainable level of urban development, the government should focus on not only the high development intensity, but also the high quality of the eco-environment. Dalian was a good model of how to achieve a balance between the two.

Spatiotemporal trends of urban heat island effect along the urban development intensity gradient in China

Urban heat island (UHI) represents a major anthropogenic modification to the Earth system and its relationship with urban development is poorly understood at a regional scale. Using Aqua MODIS data and Landsat TM/ETM+ images, we examined the spatiotemporal trends of the UHI effect (ΔT, relative to the rural reference) along the urban development intensity (UDI) gradient in 32 major Chinese cities from 2003 to 2012. We found that the daytime and nighttime ΔT increased significantly (p<0.05, mostly in linear form) along a rising UDI for 27 and 30 out of 32 cities, respectively. More rapid increases were observed in the southeastern and northwestern parts of China in the day and night, respectively. Moreover, the ΔT trends differed greatly by season and during daytime in particular. The ΔT increased more rapidly in summer than in winter during the day and the reverse occurred at night for most cities. Inter-annually, the ΔT increased significantly in about one-third of the cities during both the day and night times from 2003 to 2012, especially in suburban areas (0.25<UDI≤0.5), with insignificant trends being observed for most of the remaining cities. We also found that the ΔT patterns along the UDI gradient were largely controlled by local climate-vegetation conditions, while that across years were dominated by human activities. Our results highlight the strong and highly diverse urbanization effects on local climate cross China and offer limitations on how these certain methods should be used to quantify UHI intensity over large areas. Furthermore, the impacts of urbanization on climate are complex, thus future research efforts should focus more toward direct observation and physical-based modeling to make credible predictions of the effects.

Tree Productivity Enhanced with Conversion from Forest to Urban Land Covers.

Urban areas are expanding, changing the structure and productivity of landscapes. While some urban areas have been shown to hold substantial biomass, the productivity of these systems is largely unknown. We assessed how conversion from forest to urban land uses affected both biomass structure and productivity across eastern Massachusetts. We found that urban land uses held less than half the biomass of adjacent forest expanses with a plot level mean biomass density of 33.5 ± 8.0 Mg C ha-1. As the intensity of urban development increased, the canopy cover, stem density, and biomass decreased. Analysis of Quercus rubra tree cores showed that tree-level basal area increment nearly doubled following development, increasing from 17.1 ± 3.0 to 35.8 ± 4.7 cm2 yr-1. Scaling the observed stem densities and growth rates within developed areas suggests an aboveground biomass growth rate of 1.8 ± 0.4 Mg C ha-1 yr-1, a growth rate comparable to nearby, intact forests. The contrasting high growth rates and lower biomass pools within urban areas suggest a highly dynamic ecosystem with rapid turnover. As global urban extent continues to grow, cities consider climate mitigation options, and as the verification of net greenhouse gas emissions emerges as critical for policy, quantifying the role of urban vegetation in regional-to-global carbon budgets will become ever more important.

Variation in ecosystem services across an urbanization gradient: A study of terrestrial carbon stocks from Changzhou, China

Ecosystem services in urban areas are regarded as multiple environmental benefits fostered by urban–rural landscapes. A wide range of ecosystem services have been largely affected by land use and cover change in urban areas, leading to significant variation of ecosystem services, such as terrestrial carbon stocks across a gradient of urbanization. Urban areas are critical for terrestrial carbon dynamics owing to both considerable amount of biomass and soil carbon stored in cities and significant losses in carbon stocks from urban land use and cover change. We used Changzhou, a typical fast-growing city in China, as a case study, and estimated biomass and soil carbon stored in land covers using the InVEST model. We also quantified gradient changes in terrestrial carbon stocks in response to urban land use and cover change along two sample transects as a function of distance from the urban center. We found that carbon densities decreased with increasing intensity of urban development. Gradient transect analyses revealed an overall trend of increasing carbon stocks from the urban center to peri-urban areas as a direct result of land use and cover change driven by policy-oriented urban planning, which led to both infilling of empty areas within the urban center and sprawling of urban land toward peri-urban areas. As recent growth trends continue, the expansion of urban land markedly decreased areas previously dominated by green open spaces, making urban land use and cover change and losses in carbon stocks an increasingly important component of regional carbon dynamics. We proposed measures to mitigate these negative effects of urbanization on carbon stocks both for densely built-up areas and for rapidly urbanizing peri-urban areas.

Quantifying the relationship between urban development intensity and carbon dioxide emissions using a panel data analysis

As a factor associated with urban management and planning, urban development intensity (UDI) could in fact form the basis for a new rationale in coordinating urban sustainable development and reducing CO2 emissions. However, existing literature engaging in the task of quantifying the impacts of urban development intensity on CO2 emissions is limited. Therefore, the goal of this study is to quantify the relationship between urban development intensity and CO2 emissions for a panel made up of the five major cities in China (Beijing, Shanghai, Tianjin, Chongqing and Guangzhou) using time series data from 1995 to 2011. Firstly, this study calculated CO2 emissions for the five selected cities and presented a comprehensive index system for the assessment of the level of urban development intensity based on six aspects (land-use intensity, economic intensity, population intensity, infrastructure intensity, public service intensity and eco-environmental intensity) using locally important socioeconomic variables. Panel data analysis was subsequently utilised in order to quantify the relationships between urban development intensity and CO2 emissions. The empirical results of the study indicate that factors such as land-use intensity, economic intensity, population intensity, infrastructure intensity and public service intensity exert a positive influence on CO2 emissions. Further, the estimated coefficients suggest that land-use intensity is the most important factor in relation to CO2 emissions. Conversely, eco-environmental intensity was identified as having a major inhibitory effect on CO2 emission levels. The findings of this study hold important implications for both academics and practitioners, indicating that, on the path towards developing low-carbon cities in China, the effects of urban development intensity must be taken into consideration.

Effects of land use and cover change on terrestrial carbon stocks in urbanized areas: a study from Changzhou, China

Land use and cover change is the key factor affecting terrestrial carbon stocks and their dynamics not only in regional ecosystems but also in urbanized areas. Using the typical fast-growing city of Changzhou, China as a case study, this paper explored the relationships between terrestrial carbon stocks and land cover within an urbanized area. The main objectives were to assess variation in biomass and soil carbon stocks across terrestrial land covers with different intensities of urban development, and quantify spatial distribution and dynamic variation of terrestrial carbon stocks in response to urban land use and cover change. On the basis of accurate spatial datasets derived from a series of Landsat TM images during the years 1986 to 2011 and reliable estimates of urban biomass and soil carbon stocks using the InVEST model, our results showed that carbon stocks per unit area in terrestrial land covers decreased with increasing intensity of urban development. Urban land use and cover change and sealing of the soil surface created hotspots for losses in carbon stocks. Total carbon stocks in Changzhou decreased by about 30% during the past 25 years, representing a 1.5% average annual decrease. We suggested potential policy measures to mitigate negative effects of land use and cover change on carbon stocks in urbanized areas.

Spatiotemporal trends of terrestrial vegetation activity along the urban development intensity gradient in China's 32 major cities

Terrestrial vegetation plays many pivotal roles in urban systems. However, the impacts of urbanization on vegetation are poorly understood. Here we examined the spatiotemporal trends of the vegetation activity measured by MODIS Enhanced Vegetation Index (EVI) along Urban Development Intensity (UDI) gradient in 32 major Chinese cities from 2000 to 2012. We also proposed to use a new set of concepts (i.e., actual, theoretical, and positive urbanization effects) to better understand and quantify the impacts of urbanization on vegetation activities. Results showed that the EVI decreased significantly along a rising UDI for 28 of 32 cities (p<0.05) in linear, convex or concave form, signifying the urbanization impacts on vegetation varied across cities and UDI zones within a city. Further, the actual urbanization effects were much weaker than the theoretical estimates because of the offsetting positive effects generated by multiple urban environmental and anthropogenic factors. Examining the relative changes of EVI in various UDI zones against that in the rural area (ΔEVI), which effectively removed the effects of climate variability, demonstrated that ΔEVI decreased markedly from 2000 to 2012 for about three-quarters of the cities in the exurban (0.05<UDI≤0.25) and suburban (0.25<UDI≤0.5), and only half of the cities in the urban (0.5<UDI≤0.75) and urban core (0.75<UDI≤1). The stable or even increasing tendencies of ΔEVI in the urban and urban core of many cities could primarily be attributed to the importance of positive effects derived from the urban environment and the improvement of management and maintenance of urban green space. More work is needed to quantify mechanistically the detailed negative and positive effects of urban environmental factors and management practices on vegetation activities.

The influence of concrete on the geochemical qualities of urban streams

The geochemical signature of freshwater streams can be used to determine the extent and nature of modification to stream water geochemistry due to urban development. This approach used the Gibbs (1970) diagram as a model for evaluation of changes to ionic composition linked to urban development. In this multi-year study, the geochemistry of 21 waterways in the Georges River catchment, Sydney, were monitored and compared with the level of urban development as measured by sub-catchment imperviousness and directly connected imperviousness. The results reflect a strong relationship between the intensity of sub-catchment urban development and stream geochemistry. All major geochemical attributes increased with escalating levels of urban development. The largest increase was for bicarbonate, which increased 18 times from a mean of 6.4 mg L–1 at non-urban streams to a mean of 118 mg L–1 at urban streams. Similarly, mean concentrations of calcium increased by 14 times (from 2 to 27.9 mg L–1). Mean salinity was enriched in the most urban streams, compared with non-urban streams, by more than 6 times. We attribute this, in part, to the influence of urban geology, notably concrete stormwater infrastructure. Changes in stream geochemistry due to urban development are an important element of the urban stream syndrome.

Exploring on Urban Land Development Intensity based on Artificial Neural Network Methods

A modest development intensity for urban land benefits both ecological protection and living spaces improvement. It is an important indicator for urban land development intensity (ULDI) to measure the city livable and sustainable development. As an example of Chongqing Metropolitan Area, firstly, spatial database about land development intensity and its driving factors was established in sample regions, and BP artificial neural network methods were used to construct the land development intensity simulation model based on data driven in urban area with the help of MATLAB7 software. Secondly, two different scheme and algorithm were adopted to simulate land development intensity. Artificial neural network methods were detected by comparing the difference between real development intensity and the simulation results. Lastly, the land development intensity in Chongqing Metropolitan Area (9 districts ) was simulated. Meanwhile, the results were compared by using the methods of neural network forecasting model and the multiple linear regression model with a wider range. The results shows that: (1) BP artificial neural network method is a good way to simulate the ULDI; (2) it is important to choose the reasonable driving factors and training algorithm; (3) the research scale has a certain impact on the results. Although the BP artificial neural network method can not explicitly explain the relationship between land development intensity and its driving factors in urban area, when data is sufficient, it is better to evaluate the ULDI than the method of regression analysis.

快速城市化地区景观生态安全时空演化过程分析——以东莞市为例

Based on the pressure-state-response conceptual framework,an evaluation system is proposed to study landscape ecological security dynamics from 1988 to 2005 in Dongguan City,a fast-growing city in Guangdong Province,China.The pressure index,which describes the pressure that human activities exert on the environment,consists of urban development intensity,population density,distance to major transportation routes,distance to nearest city center and distance to nearest town center.The landscape security state index,which relates to the quality of the environment,is composed of landscape patch density,ecological service value,and landscape vulnerability.The response index,which reflects the reaction of human beings to landscape dynamics,is defined as adjusted intensity of natural reserve districts,forest,park,and crop lands.The evaluation units are Landsat TM pixels and the fundamental data set is obtained by classifying raw TM data.Transportation and city-center location data are obtained from topographic maps.Population,environmental protection,planning,and other data are obtained from the Dongguan statistical yearbook and the Dongguan Department of Environmental Protection.The results for Dongguan City indicate that the pressure index was 0.317,0.394,and 0.472 in 1988,1997 and 2005 respectively,which means the landscape pressure increased from 1988 to 2005.The landscape security state indicator was 0.473,0.406 and 0.365 in 1988,1997 and 2005,which means landscape security became more insecure.The response to ecological security dynamics was steady from 1988 to 2005.The weighted sum of the pressure index,the landscape security state index,and the response index is the integrated ecological security index which was 0.497,0.436 and 0.395 in 1988,1997 and 2005.In short,ecological security declined from 1988 to 2005.The districts with middle-low ecological security expanded outwards from primarily town center locations in 1988 to outlying urban areas and along major transportation routes by 2005.The high ecological security districts,which consist of reservations,forest land,parks,and rivers,were steady from 1988 to 2005.The study indicates that the pixel evaluation unit based on 1 km×1 km neighborhoods is useful for calculating urban development intensity and landscape patch density,and in smoothing the ecological security grade boundary.

A spatial panel ordered-response model with application to the analysis of urban land-use development intensity patterns

This paper proposes and estimates a spatial panel ordered-response probit model with temporal autoregressive error terms to analyze changes in urban land development intensity levels over time. Such a model structure maintains a close linkage between the land owner’s decision (unobserved to the analyst) and the land development intensity level (observed by the analyst) and accommodates spatial interactions between land owners that lead to spatial spillover effects. In addition, the model structure incorporates spatial heterogeneity as well as spatial heteroscedasticity. The resulting model is estimated using a composite marginal likelihood (CML) approach that does not require any simulation machinery and that can be applied to data sets of any size. A simulation exercise indicates that the CML approach recovers the model parameters very well, even in the presence of high spatial and temporal dependence. In addition, the simulation results demonstrate that ignoring spatial dependency and spatial heterogeneity when both are actually present will lead to bias in parameter estimation. A demonstration exercise applies the proposed model to examine urban land development intensity levels using parcel-level data from Austin, Texas.