长株潭城市群经济社会发展与环境压力

长株潭城市群是湖南省的核心增长极,是"资源节约型社会、环境友好型社会"社会建设综合配套改革试验区,但伴随高速的工业化发展和城市化进程,长株潭面临着严峻的资源约束和环境压力。文章从土地利用格局、经济社会发展、环境质量状况、主要污染物排放和资源能源利用等方面入手,综合分析了长株潭城市群的环境压力,主要体现在长株潭城市群城市化与土地需求的矛盾凸显,"摊大饼"的扩张模式带来生态风险;重工业和污染排放集聚,累积性污染突出;环境空气质量和地表水环境质量形势不容乐观;资源能源利用方式粗放等。结合城市群区域规划,提出了长株潭城市群在新型城镇化建设中应采取的生态环境保护措施建议。     

Monitoring the urban green spaces and landscape fragmentation using remote sensing: a case study in Osmaniye,Turkey

Urban green spaces play a significant role in management of physical activity, psychological well-being, and public health of urban residents. With the expansion of urban areas in Turkey during the past decades, urban green spaces have been fragmented and dispersed causing impairment and environmental degradation. The purpose of this study is to model urban green space distribution by focusing on the landscape fragmentation in city of Osmaniye using remote sensing and geographic information system technology. Normalized difference vegetation index (NDVI) and urban landscape ratio (ULR) were used to assess the proximity and spatial arrangement of urban green spaces within the neighbor landscapes to quantify the urban land use effect. The geospatial analysis results showed that increase in total built-up area and population has significantly decreased the urban green space cover because of high levels of landscape fragmentation in urban city center. Also, due to high levels of landscape fragmentation, approximately 45% of the Osmaniye city is estimated to become urbanized by 2030. This study demonstrated the benefits of directional vegetation index application with geospatial analyses in characterizing the environmental quality for planning and management of urban green spaces. This approach could be used for determining the future urban land development scenarios correlating with regional planning procedures.     

Performance assessment of geospatial simulation models of land-use change—a landscape metric-based approach

Performance evaluation is a critical step when developing land-use and cover change (LUCC) models. The present study proposes a spatially explicit model performance evaluation method, adopting a landscape metric-based approach. To quantify GEOMOD model performance, a set of composition- and configuration-based landscape metrics including number of patches, edge density, mean Euclidean nearest neighbor distance, largest patch index, class area, landscape shape index, and splitting index were employed. The model takes advantage of three decision rules including neighborhood effect, persistence of change direction, and urbanization suitability values. According to the results, while class area, largest patch index, and splitting indices demonstrated insignificant differences between spatial pattern of ground truth and simulated layers, there was a considerable inconsistency between simulation results and real dataset in terms of the remaining metrics. Specifically, simulation outputs were simplistic and the model tended to underestimate number of developed patches by producing a more compact landscape. Landscape-metric-based performance evaluation produces more detailed information (compared to conventional indices such as the Kappa index and overall accuracy) on the model’s behavior in replicating spatial heterogeneity features of a landscape such as frequency, fragmentation, isolation, and density. Finally, as the main characteristic of the proposed method, landscape metrics employ the maximum potential of observed and simulated layers for a performance evaluation procedure, provide a basis for more robust interpretation of a calibration process, and also deepen modeler insight into the main strengths and pitfalls of a specific land-use change model when simulating a spatiotemporal phenomenon.     

Detecting the spatial differentiation in settlement change rates during rapid urbanization in the Nanjing metropolitan region, China

Urbanization produced significant landscape changes throughout the world. China has been experiencing accelerated urbanization during the past decades. Rapid land use/land over conversion occurred nationwide in urbanization, manifesting noteworthy characteristics of landscape dynamics. In this study, we investigated the spatial differentiation in settlement change rates among 1-km² land units in the Nanjing metropolitan region, a representative rapidly urbanizing region in China. Remotely sensed detection using Landsat TM data of 1988–2006 showed that settlement increase, termed as positive growth (PG), was predominant in the study area; while settlement decrease, termed as negative growth (NG), also had a considerable proportion, which was mainly attributed to the increase of green lands and the shrink of rural settlements. Along the urban-rural gradient, PG and NG showed similar mono-peaked patterns. The urban fringe zone with a consistent width of about 4 km was identified as the hot zone of both PG and NG over the three unequal periods. For both PG and NG, high-rated changes tended to exhibit more aggregative patterns along the gradient in the urban fringe zone. Settlement changes showed apparent anisotropy across directions. The directional distribution of PG was significantly negatively correlated to the topographic variables, suggesting that the mountains constrained urban expansion in an “area-weighted inverse-distance power” form. Significant correlation between PG and NG in a time-lagged manner showed the “increase–decrease” fluctuation occurred in settlement changes, reflecting the “urban expansion–land reconfiguration” process in rapid urbanization in Nanjing.     

Seasonal variations in the relationship between landscape pattern and land surface temperature in Indianapolis, USA

This paper intended to examine the seasonal variations in the relationship between landscape pattern and land surface temperature based on a case study of Indianapolis, United States. The integration of remote sensing, GIS, and landscape ecology methods was used in this study. Four Terra's ASTER images were used to derive the landscape patterns and land surface temperatures (LST) in four seasons in the study area. The spatial and ecological characteristics of landscape patterns and LSTs were examined by the use of landscape metrics. The impact of each land use and land cover type on LST was analyzed based on the measurements of landscape metrics. The results show that the landscape and LST patterns in the winter were unique. The rest of three seasons apparently had more agreeable landscape and LST patterns. The spatial configuration of each LST zone conformed to that of each land use and land cover type with more than 50% of overlap in area for all seasons. This paper may provide useful information for urban planers and environmental managers for assessing and monitoring urban thermal environments as result of urbanization.     

Quantifying landscape pattern and connectivity in a Mediterranean coastal settlement: the case of the Urla district,Turkey

This study was aimed at analyzing and interpreting changes in landscape pattern and connectivity in the Urla district, Turkey using core landscape metrics based on a 42-year data derived from 1963 CORONA and 2005 ASTER satellite images and ten 1/25,000 topographical maps (1963–2005). The district represents a distinctive example of re-emerged suburbanization in the Izmir metropolitan area. In order to explore landscape characteristics of the study area, nine landscape composition and configuration metrics were chosen as follows: class area, percentage of landscape, number of patches, patch density, largest patch index, landscape shape index, mean patch size, perimeter area fractal dimension, and connectance index. The landscape configurations in the Urla district changed significantly by 2005 in that the process of (sub-)urbanization in the study area evolved from a rural, monocentric urban typology to a more suburban, polycentric morphology. Agricultural, maquis-phrygana, and forest areas decreased, while the built-up, olive plantation and phrygana areas increased. There was nearly a fivefold increase in the built-up areas during the study period, and the connectivity of the natural landscape declined. To prevent further fragmentation, it is important to keep the existing natural land cover types and agricultural areas intact. More importantly, a sustainable development scenario is required that contains a green infrastructure, or an ecological network planning for conservation and rehabilitation of the vital natural resources in the study area.     

Modeling land use/land cover change using remote sensing and geographic information systems: case study of the Seyhan Basin,Turkey

Land use and land cover (LULC) changes affect several natural environmental factors, including soil erosion, hydrological balance, biodiversity, and the climate, which ultimately impact societal well-being. Therefore, LULC changes are an important aspect of land management. One method used to analyze LULC changes is the mathematical modeling approach. In this study, Cellular Automata and Markov Chain (CA-MC) models were used to predict the LULC changes in the Seyhan Basin in Turkey that are likely to occur by 2036. Satellite multispectral imagery acquired in the years 1995, 2006, and 2016 were classified using the object-based classification method and used as the input data for the CA-MC model. Subsequently, the post-classification comparison technique was used to determine the parameters of the model to be simulated. The Markov Chain analyses and the multi-criteria evaluation (MCE) method were used to produce a transition probability matrix and land suitability maps, respectively. The model was validated using the Kappa index, which reached an overall level of 77%. Finally, the LULC changes were mapped for the year 2036 based on transition rules and a transition area matrix. The LULC prediction for the year 2036 showed a 50% increase in the built-up area class and a 7% decrease in the open spaces class compared to the LULC status of the reference year 2016. About an 8% increase in agricultural land is also likely to occur in 2036. About a 4% increase in shrub land and a 5% decrease in forest areas are also predicted.     

Land-cover changes in an urban lake watershed in a mega-city, Central China

Urbanization can exert a profound influence on land covers and landscape characteristics. In this study, we characterize the impact of urbanization on land cover and lacustrine landscape and their consequences in a large urban lake watershed, Donghu Lake watershed (the largest urban lake in China), Central China, by using Landsat TM satellite images of three periods of 1987, 1993 and 1999 and ground-based information. We grouped the land covers into six categories: water body, vegetable land, forested land, shrub-grass land, open area and urban land, and calculated patch-related landscape indices to analyze the effects of urbanization on landscape features. We overlaid the land cover maps of the three periods to track the land cover change processes. The results indicated that urban land continuously expanded from 9.1% of the total watershed area in 1987, to 19.4% in 1993, and to 29.6% in 1999. The vegetable land increased from 7.0% in 1987, 11.9% in 1993, to 13.9% in 1999 to sustain the demands of vegetable for increased urban population. Concurrently, continuous reduction of other land cover types occurred between 1987 and 1999: water body decreased from 30.4% to 23.8%, and forested land from 33.6% to 24.3%. We found that the expansion of urban land has at least in part caused a decrease in relatively wild habitats, such as urban forest and lake water area. These alterations had resulted in significant negative environmental consequences, including decline of lakes, deterioration of water and air quality, and loss of biodiversity.     

Assessment of Wildfire Hazards with a Semiparametric Spatial Approach

Rural households in agricultural economies are vulnerable to several environmental risks such as fires, floods, and droughts that may affect their productivity in whole or in part. These hazards are especially relevant in developing countries where farmers have few or no access to traditional risk-transfer techniques, such as insurance and finance, and where low governmental investments in rural infrastructure, risk assessment techniques, or early warning systems makes the aftermath of such hazards more expensive and results in slower recovery for those who are affected. In this paper, we use historical satellite data (Terra) of burned areas in South America to fit a semiparametric spatial model, based on kernel smoothing and on a nonlinear relationship between average time between events and damage, to assess the environmental hazard affecting the land’s productivity. The results were twofold: first, we were able to develop a spatial assessment of fire hazard, and second, we were able to evaluate how much a farmer may lose in terms of productivity per hectare due to the environmental hazard. The methodology may be easily adapted to other world regions; to different environmental hazards such as floods, windbreak, windthrow, or related land-use changes; or to integrate various environmental hazards simultaneously, as long as they can be monitored via remote sensing (e.g., satellite imagery, aerial photographs, etc).     

A multi-scale qualitative approach to assess the impact of urbanization on natural habitats and their connectivity

Habitat loss and fragmentation are often concurrent to land conversion and urbanization. Simple application of GIS-based landscape pattern indicators may be not sufficient to support meaningful biodiversity impact assessment. A review of the literature reveals that habitat definition and habitat fragmentation are frequently inadequately considered in environmental assessment, notwithstanding the increasing number of tools and approaches reported in the landscape ecology literature.This paper presents an approach for assessing impacts on habitats on a local scale, where availability of species data is often limited, developed for an alpine valley in northern Italy. The perspective of the methodology is multiple scale and species-oriented, and provides both qualitative and quantitative definitions of impact significance. A qualitative decision model is used to assess ecological values in order to support land-use decisions at the local level. Building on recent studies in the same region, the methodology integrates various approaches, such as landscape graphs, object-oriented rule-based habitat assessment and expert knowledge.The results provide insights into future habitat loss and fragmentation caused by land-use changes, and aim at supporting decision-making in planning and suggesting possible ecological compensation.     

Evaluation of urban sprawl and urban landscape pattern in a rapidly developing region

Urban sprawl is a worldwide phenomenon happening particularly in rapidly developing regions. A study on the spatiotemporal characteristics of urban sprawl and urban pattern is useful for the sustainable management of land management and urban land planning. The present research explores the spatiotemporal dynamics of urban sprawl in the context of a rapid urbanization process in a booming economic region of southern China from 1979 to 2005. Three urban sprawl types are distinguished by analyzing overlaid urban area maps of two adjacent study years which originated from the interpretation of remote sensed images and vector land use maps. Landscape metrics are used to analyze the spatiotemporal pattern of urban sprawl for each study period. Study results show that urban areas have expanded dramatically, and the spatiotemporal landscape pattern configured by the three sprawl types changed obviously. The different sprawl type patterns in five study periods have transformed significantly, with their proportions altered both in terms of quantity and of location. The present research proves that urban sprawl quantification and pattern analysis can provide a clear perspective of the urbanization process during a long time period. Particularly, the present study on urban sprawl and sprawl patterns can be used by land use and urban planners.     

平顶山地区景观格局动态特征及驱动力分析

以平顶山地区为研究对象,利用平顶山地区1992年Landsat-TM影像和2006年中巴资源卫星遥感影像,运用景观生态学原理,借助遥感和GIS技术,选取景观多样性、景观优势度、景观均匀度、景观破碎度等指标指数进行分析,揭示平顶山地区近14 a来城市景观格局演变及其驱动力。研究结果表明:交通用地、工矿及居民点和耕地用地显著增加,林地、水域显著减少;除工矿及居民点外,该地区各类型斑块数量均有增加,其中林地增加最为显著;交通用地、工矿及居民点的破碎度降低,水域、林地、耕地的景观类型破碎度增高;耕地的分维数、形状指数呈下降趋势,而林地的分维数和形状指数呈上升趋势;平顶山地区景观多样性和均匀度都呈下降趋势,而优势度和破碎度增加;景观格局变化受人为因素影响较大,人口增加、经济发展、城镇化和工业发展是平顶山地区景观格局演变的主要驱动力。     

Effect of urbanization on the structure and functional traits of remnant subtropical evergreen broad-leaved forests in South China

We investigated the effects of major environmental drivers associated with urbanization on species diversity and plant functional traits (PFTs) in the remnant subtropical evergreen broad-leaved forests in Metropolitan Guangzhou (Guangdong, China). Twenty environmental factors including topography, light, and soil properties were used to quantify the effects of urbanization. Vegetation data and soil properties were collected from 30 400-m² plots at 6 study sites in urban and rural areas. The difference of plant species diversity and PFTs of remnant forests between urban and rural areas were analyzed. To discern the complex relationships, multivariate statistical analyses (e.g., canonical correspondence analysis and regression analysis) were employed. Pioneer species and stress-tolerant species can survive and vigorously establish their population dominance in the urban environment. The native herb diversity was lower in urban forests than in rural forests. Urban forests tend to prefer the species with Mesophanerophyte life form. In contrast, species in rural forests possessed Chamaephyte and Nanophanerophyte life forms and gravity/clonal growth dispersal mode. Soil pH and soil nutrients (K, Na, and TN) were positively related to herb diversity, while soil heavy metal concentrations (Cu) were negatively correlated with herb diversity. The herb plant species diversity declines and the species in the remnant forests usually have stress-tolerant functional traits in response to urbanization. The factors related to urbanization such as soil acidification, nutrient leaching, and heavy metal pollution were important in controlling the plant diversity in the forests along the urban–rural gradients. Urbanization affects the structure and functional traits of remnant subtropical evergreen broad-leaved forests.     

Spatial Economic–Hydroecological Modelling and Evaluation of Land Use Impacts in the Vecht Wetlands Area

Wetlands provide many important goods and services to human societies, and generate nonuse values as well. Wetlands are also very sensitive ecosystems that are subject to much stress from human activities. Reducing the stress on wetlands requires a spatial matching between physical planning, hydrological and ecological processes, and economic activities. Spatially integrated modelling and evaluation can support this. The present study has developed a triple layer model that integrates information and concepts from social and natural sciences to address the analysis and evaluation of land-use scenarios for a wetlands area in the Netherlands, the Vecht area. This is the floodplain of river Vecht, located in the centre of the Netherlands. The study has resulted in a set of linked spatial hydrological, ecological and economic models, formulated at the level of grids and polders. The main activities incorporated in the system of models are housing, infrastructure, agriculture, recreation and nature conservation. The formulation of alternative development scenarios is dominated by land use and land cover options that are consistent with the stimulation of agriculture, nature or recreation. Two aggregate performance indicators have been constructed from model output, namely net present value of changes and environmental quality. The spatial characteristics of these indicators are retained in a spatial evaluation that ranks scenarios.     

Landscape indicators for rural development policies. Application of a core set in the case study of Piedmont Region

The rural landscape has long been eroded by urban and infrastructural development that has altered the system of relationships between town and country. These phenomena, including agriculture intensification, have radically changed the rural landscape, especially in terms of land use, visual and ecological diversity and biocultural heterogeneity. However, agriculture is gradually changing, moving from an exclusively productive model (highly specialised) to one more sensitive to landscape issues. In particular, the Common Agricultural Policy (CAP) has many environmental aims and, theoretically, its financial tools might be used for landscape purposes. However, the CAP does not have a “landscape dimension” and does not include assessment and integration phases with landscape policies. These issues that have arisen not only appear to be influenced by a lack of clarity on the differences between environmental and landscape orientations, but also by a shortage of indicators to identify and assess the landscape dimension in the Common Monitoring and Evaluation Framework. Here, we attempt to show that a “landscaped role” for the CAP is possible, based upon identifying the main dimensions involved, as well as verifying the effects and induced changes of rural policies. In this scenario, this paper highlights the development and testing of landscape key indicators to support the decision-makers of rural policies. The main result, in an Italian pilot case, reveals direct and indirect relations between Rural Development Programmes (RDPs) and landscape, not only in terms of negative effects, but also in relation to the real contribution of CAP towards preserving farmland and enhancing the rural landscape. Finally, these tools may also be useful in different timescales and different situations, including the improvement of current RDP spatial targeting which often seems to be ineffective compared to the requirements of landscape character areas.     

Oasis land-use change and its environmental impact in Jinta Oasis, arid northwestern China

Land use change resulted in land degradation is a focus of research on global environmental changes and plays a significant role in the stability and economic development of oases in arid regions of China. Jinta Oasis, a typical oasis of temperate arid zone in northwestern China, was investigated to assess land-use change dynamics during 1988–2003 with the aid of satellite remote sensing and GIS, and to explore the interaction between these changes and oasis environment. Six land-use types were identified, namely: cropland, forestland, grassland, water, urban or built-up land, and barren land. The results indicate that cropland, urban/built-up land, and barren land increase greatly by 30.03, 13.35, and 15.52 km², respectively; but grassland and forestland areas decrease rapidly by 58.06, and 1.76 km², respectively. These results also show that obvious widespread changes in land-use occur within the whole oasis over the study period and result in severe problems of environmental degradation (i.e. land desertification, decline of groundwater, and vegetation degeneracy).     

Analysing urban expansion and land use suitability for the city of Kahramanmaraş, Turkey, and its surrounding region

This study aimed at quantifying changes in urban area of the city of Kahramanmara? (K.Mara?) between 1948 and 2006, and analysing suitability of existing land use (LU) to the land potential. Urban change information was derived from two black-white monoscopic aerial photographs, and IKONOS and the QuickBird images acquired in 1948, 1985, 2000 and 2006, respectively. QuickBird image and soil map with 1:25,000 scale were used to analyze suitability of the current LU pattern to the land potential. The findings showed that the urban area of K.Mara? has expanded approximately 13 times during the past six decades. According to current LU and the soil map, productive and moderately productive soils were largely (73.2%) allocated for agricultural activities, which means that there was a strong consistency between the agricultural LU type and the land capability. However, widespread agriculture on the non-productive soils, and urbanization on the fertile agricultural lands were assessed as unsuitable from sustainable LU viewpoint. Considering this phenomenon, it is possible to say that rapid urban expansion has a growing pressure on the fertile agricultural soils. Monitoring LU changes, particularly urbanization, and developing effective LU plans based on the land capability were determined as the most important approaches to encourage sustainable use of land.     

Scenario Analysis for the San Pedro River, Analyzing Hydrological Consequences of a Future Environment

Studies of future management and policy options based on different assumptions provide a mechanism to examine possible outcomes and especially their likely benefits and consequences. The San Pedro River in Arizona and Sonora, Mexico is an area that has undergone rapid changes in land use and cover, and subsequently is facing keen environmental crises related to water resources. It is the location of a number of studies that have dealt with change analysis, watershed condition, and most recently, alternative futures analysis. The previous work has dealt primarily with resources of habitat, visual quality, and groundwater related to urban development patterns and preferences. In the present study, previously defined future scenarios, in the form of land-use/land-cover grids, were examined relative to their impact on surface-water conditions (e.g., surface runoff and sediment yield). These hydrological outputs were estimated for the baseline year of 2000 and predicted twenty years in the future as a demonstration of how new geographic information system-based hydrologic modeling tools can be used to evaluate the spatial impacts of urban growth patterns on surface-water hydrology.