城乡绿道建设探析——以广东珠三角绿道建设为例

绿道是源自欧美发达国家的先进理念,绿道建设基本不占用建设用地,符合建设低碳城市的发展要求。近几年绿道建设率先在我国广东珠三角地区开展,随后在全国各地快速发展起来,全面提升了城乡居民的生活质量,完善了城市功能,强化了地方风貌特征。文章在综合分析国内外绿道建设与研究相关文献的基础上,以广东珠三角绿道建设为例,着重对绿道建设的生态功能、游憩功能进行了探析,并针对当前绿道建设存在的问题提出建议。     

Measuring patterns and mechanism of greenway use – A case from Guangzhou,China

In the context of recent studies that have begun to establish a more quantifiable understanding of the use of urban greenways, this paper presents a preliminary investigation into the patterns in which a greenway is used and the mechanism behind the pattern of use of the greenway. Factors of the location, economic situation, environment and social background have been measured and analyzed in the use intensity model to interpret their impact on the use intensity of different sections of a greenway. The results suggest that use of the Waterfront Greenway in Guangzhou is highly impacted by population density, employment density, nearby service provision and the connectivity of the greenway to other parts of the city. In this case, the use intensity model with indicators such as location, economic, environmental and social factors has been shown to be applicable to the evaluation of the use of the greenways. Results from the case study suggest that providing greenways close to the residential zones, employment centers and key public services such as hospitals and schools will increase greenway use. The surrounding network system of a greenway must be carefully considered and designed to improve the linking of the greenway to other parts of the city, to increase the number of potential visitors to the greenway.     

The effects of urban greenway environment on recreational activities in tropical high-density Singapore: A computer vision approach

The urban greenway has been increasingly recognised as an important type of green infrastructure especially for land-scarce, densely-populated cities to efficiently provide their residents with continuous public spaces close to nature for recreation. Nevertheless, empirical studies on urban greenways and their recreational use rarely focus on high-density environment. Moreover, most research endeavours in this field are also largely confined to the subtropical climate, whereas much of the world’s future urban growth is projected to occur in the form of high-density mega-cities in much of tropical South and Southeast Asia. In view of these gaps, this study proposes a new approach that employs Computer Vision tools to examine the effects of the greenway’s physical environment on recreational activities, taking tropical Singapore as the test bed. The semantic segmentation model, PSPNet and the action detection model, ACAM are adapted and applied in conjunction with geographical information system tools to measure the greenway’s physical environment and people’s recreational activity at the human scale, and analyse their relationships. The result reveals a pattern that sees the clustering of different types of recreational activities at different time periods. It also reveals the relationships between recreational activities and specific environmental features, which were observed to have influenced the overall spatial distributions of the recreational activities. The finding also corroborates the design strategies for Singapore’s future urban greenways and offers a reference for engaging community groups to participate in the maintenance of urban greenways.     

Designing recreational trails in a forest dune habitat using least-cost path analysis at the resolution of visitor sight distance

Dune plantation forests are typically used for recreation. However, the soil and vegetation of these forests are sensitive to trampling. Therefore, recreational trails should have clearly defined boundaries. The aim of this study was to test a cell-based survey for the alignment of interpretative trails in sand dune plantation forests, where each cell of a sampling grid is surveyed in the field at a grain size of 10-m, which is an appropriate scale for both visitors and to accurately assess vegetation and stand structure. The alignment of the trail was then performed using a combined least-cost path algorithm with GIS-based land suitability analysis. Using this approach, sets of key factors for land suitability and visibility which are generally applicable to dune plantation forests were identified. Specific criteria were adopted to score and weigh each factor in this case study, where each of the 284 cells of a 10-m grid were surveyed for two weeks in a coastal urban reserve located in one of the major tourist beach resorts of the Mediterranean basin (Bibione, Northern Italy). The factors surveyed in the field were used to calculate the potential trail index, and the least-cost path method was used to optimally align the trail in order to achieve the lowest cumulative resistance value possible. The novel cell-based survey did not require the conversion of any land suitability layers to their raster counterpart grids, as the grain and resulting alignment of the trail were scaled to the neighbourhood of the users. In addition, we did not focus on the concept of the patch, as we were not interested in reclassifying the surveyed attributes, as features were originally collected at the scale of the walking paths. We conclude that the proposed method is a feasible approach, and amenable to situation where a fine-grained alignment of recreational trails is required, and/or when a careful assessment of a trails’ environmental impact is needed.     

Casual evaluation of the effects of a large-scale greenway intervention on physical and mental health: A natural experimental study in China

Many cross-sectional studies have supported the health benefits of urban greenways. However, the causal relationship between urban greenway intervention and residents’ physical and mental health remains unclear. Furthermore, the potential dose-response effect by distance to a greenway intervention remains unknown. This study explored the impact of a large-scale urban greenway intervention (construction of a 102-km-long East Lake Greenway in Wuhan, China) on the health outcomes of residents by using a natural experimental research design. We collected data before and after the intervention (in 2016 and 2019, respectively) from 1,020 participants living within a 5-km street-network distance from the entrances of this greenway. The average age of the participants was approximately 50, and most of them were married. More than half of the participants were female, currently employed, and had received a college education or above. Mixed-effects difference-in-difference (DID) models were used while controlling for individual and neighbourhood covariates. The results showed that the East Lake Greenway had a positive effect on the self-reported mental health of residents who lived within 2 km, and these benefits decreased with distance. The physical health benefit was insignificant. To increase the health benefits of urban greenways, more effort should be made to improve the accessibility of greenways and the surrounding environment. We also advocate that future natural experiments should explore the distance-varying dose-response effect of green space interventions on health outcomes.     

Modelling Habitat Suitability for Deciduous Forest Focal Species – A Sensitivity Analysis using Different Satellite Land Cover Data

We explored the usefulness of three satellite land cover data sets available to land managers in south-central Sweden for conservation planning using four deciduous forest focal resident bird species with different habitat requirements. Habitat suitability models using empirical species-specific habitat parameters and a Geographic Information System were applied to evaluate and compare the degree of consistency among three different land cover data sets. The study area encompassed 10,000 km² in a landscape mosaic of managed boreal forests and is within the distribution range of all four focal species. Although the three land cover data sets indicated similar total amounts of deciduous forest, the habitat suitability models showed that different land cover data yielded inconsistent results regarding the amount and distribution of suitable habitat within 5×5 km grid cells. Given this sensitivity to the choice of land cover data sets, the habitat suitability models showed positive relationships among the selected focal species for each land cover data set separately. As expected, decreasing amounts of suitable habitat were identified for species with higher specialisation. Thus, because habitat suitability models are an appropriate way to gain insight into the functionality and connectivity of habitat networks, land cover data must be carefully evaluated and if necessary combined with other landscape information for effective conservation planning.     

Predicting land cover change and avian community responses in rapidly urbanizing environments

We used an integrated modeling approach to simulate future land cover and predict the effects of future urban development and land cover on avian diversity in the Central Puget Sound region of Washington State, USA. We parameterized and applied a land cover change model (LCCM) that used output from a microsimulation model of urban development, UrbanSim, and biophysical site and landscape characteristics to simulate land cover 28 years into the future. We used 1991, 1995, and 1999 Landsat TM-derived land cover data and three different spatial partitions of our study area to develop six different estimations of the LCCM. We validated model simulations with 2002 land cover. We combined UrbanSim land use outputs and LCCM simulations to predict changes in avian species richness. Results indicate that landscape composition and configuration were important in explaining land cover change as well as avian species response to landscape change. Over the next 28 years, urban land cover was predicted to increase at the expense of agriculture and deciduous and mixed lowland forests. Land cover changes were predicted to reduce the total number of avian species, with losses primarily in native forest specialists and gains in common synanthropic species such as the American Crow (Corvus brachyrhynchos). The integrated modeling framework we present has potential applications in urban and natural resource planning and management and in assessing of the effects of policies on land development, land cover, and avian biodiversity.     

Road Density and Landscape Pattern in Relation to Housing Density,and Ownership,Land Cover,and Soils

Roads are conspicuous components of landscapes and play a substantial role in defining landscape pattern. Previous studies have demonstrated the link between roads and their effects on ecological processes and landscape patterns. Less understood is the placement of roads, and hence the patterns imposed by roads on the landscape in relation to factors describing land use, land cover, and environmental heterogeneity. Our hypothesis was that variation in road density and landscape patterns created by roads can be explained in relation to variables describing land use, land cover, and environmental factors. We examined both road density and landscape patterns created by roads in relation to suitability of soil substrate as road subgrade, land cover, lake area and perimeter, land ownership, and housing density across 19 predominantly forested counties in northern Wisconsin, USA. Generalized least squares regression models showed that housing density and soils with excellent suitability for road subgrade were positively related to road density while wetland area was negatively related. These relationships were consistent across models for different road types. Landscape indices showed greater fragmentation by roads in areas with higher housing density, and agriculture, grassland, and coniferous forest area, but less fragmentation with higher deciduous forest, mixed forest, wetland, and lake area. These relationships provide insight into the complex relationships among social, institutional, and environmental factors that influence where roads occur on the landscape. Our results are important for understanding the impacts of roads on ecosystems and planning for their protection in the face of continued development.     

Experimental landscape ecology

Experimentation in landscape ecology is widely conducted using diverse approaches to answer a broad range of questions. By assessing the response to controlled manipulations alternate hypotheses can be clearly refuted, model parameters quantified, and conditions are often ripe for unexpected insights. Results from landscape experiments complement the many well developed observational and modeling approaches more commonly used in landscape ecology. To better understand how landscape experimentation has been conducted and to identify future research directions, we reviewed and organized the diversity of experiments. We identified fifteen distinct landscape experiment types, which we categorized into four broad groups including (I) identifying landscape structure, (II) identifying how ecological processes vary within existing landscapes, (III) identifying how landscape structure influences ecological processes, and (IV) identifying landscape pattern formation factors. Experiment types vary along axes of scalable to real landscapes and generalizability, suitability for analysis through traditional experimental design and flexibility of experimental setup, and complexity of implementation and resource requirements. The next generation of experiments are benefiting from more explicit inclusion of scaling theories and tighter coupling between experiments and cyberinfrastructure. Future experimental opportunities for landscape ecologists include expanded collaborations among experiments, better representations of microbial-soil structure relationships at microscales, and direct evaluations of landscape interactions with global changes. The history, current practice, and future needs of landscape ecological research strongly support an expanded role of experimental approaches that complements the rich observational and modeling strengths of the field.     

Spatial relationship between human population density, land use intensity and biodiversity in the Czech Republic

We test a hypothesis about the spatial coincidence of human population density and species richness, and analyze effects of land conversion and ecosystem use on species richness and landscape diversity in human dominated Central European country, the Czech Republic. We calculated fraction of aboveground net primary productivity appropriated by humans and compared it to the species richness of vertebrate, invertebrate and plant groups and to landscape diversity index in 560 mapping grid squares with grid size approximately 130?km². Spatial correlations and regressions were established between human population density, appropriation of net primary production, land cover and biodiversity. We found positive spatial coincidence between human population density and species richness. Although the amount of net primary production was not related to species richness in general, we found significant negative spatial relationship between ecosystem use intensity and landscape diversity. As the area of the Czech Republic exhibits relatively high land use intensities, spatial patterns of human impacts have important implications for land management and biodiversity conservation in a cultural landscape.     

Multifunctionality at what scale? A landscape multifunctionality assessment for the European Union under conditions of land use change

Context

The provision of multiple ecosystem services (ES) within a landscape is commonly referred to as landscape multifunctionality. Modifying landscapes to increase multifunctionality and reduce trade-offs with concurrent services bears the potential to enhance sustainability in human-dominated landscapes. Assessing landscape multifunctionality is thus crucial for land management and planning, but lack of a clear definition and operationalization of multifunctionality impedes comparisons of different study results.

Objectives

We want to address how elements of the study design affect results of multifunctionality assessments. Furthermore, we want to quantify future multifunctionality in the European Union (EU) and indicate the role of land use change and land use diversity on multifunctionality.

Methods

We analyzed diverging scenarios depicting land use change in the EU between 2000 and 2040 for their effects on landscape multifunctionality. We tested different multifunctionality indicators at various spatial scales based on the modelling of 12 ES and biodiversity indicators.

Results

Particularly the analysis scale determines the interpretation of landscape multifunctionality. Coldspots identified by different indicators are in higher agreement than hotspots. We could not confirm links between land use diversity and landscape multifunctionality. While, at EU scale, multifunctionality slightly increases in future scenarios, agricultural intensification and (peri-)urban growth pose large threats to multifunctional landscapes.

Conclusions

The choice of indicator and analysis scale strongly determine possible interpretations of the results. Rather than focusing on the impacts of land use change on multifunctionality, it is recommended to base land use policy on the impacts of location-specific change on ES supply and demands.

     

居住区绿道网络与景观规划的融合

随着房地产业的发展,与之配套的园林环境也得到了长足的发展,居住区的园林环境也应转向关注人的生存状态和生活质量,重视居住区园林设计的生态性、娱乐性和文化性,使居住者生活在一个充满自然生机和精神文化的、人与自然和谐共存的健康住区中.现从绿色通道的概念和特征入手,通过对绿色通道在规划阶段中所扮演的角色提出了我国居住区景观规划中融合绿道网络思想的几点启示.     

Landscape changes and ecological studies in agricultural regions,Québec,Canada

Most landscape definitions in the western world are based on soil, climatic, or physiographic features and do not integrate humans as an integral part of the landscape. We present an approach where landscape types have been delineated in southern Québec, Canada based on current land use where anthropogenic and agricultural activities are concentrated as a practical application of the holistic approach in landscape definition. Landsat-TM satellite images were classified and the 27 habitat classes were regrouped into 5 general land cover classes (cash crop, dairy farming, forest, anthropogenic, wetlands) and overlaid onto soil landscape polygons to characterize natural boundary units. Cluster analyses were used to aggregate these polygons into seven agricultural types of land scape forming a gradient from urban and high-intensity cash crop farming activities to landscapes dominated by a mosaic of agriculture and forested areas. Multivariate analyses of raw data and of socio-economic and farming practices variables were used to describe the defined types of landscape and these were projected over three established land classification systems of southern Québec (Canadian ecoregions, North American Bird Conservation Initiative regions and Corn Heat Unit regions) to compare their similarity in terms of land cover and for planning of future ecological studies. Because agricultural landscapes are highly dynamic, they are bound to undergo changes in the near future. Our landscape delineation may serve as an experimental setup where land scape dynamics and wildlife populations and community structures could be monitored. Because the information we used to delineate and characterize agricultural landscape types is readily available in other countries, our approach could easily be adapted to similar data sources under and a wide variety of landscape types. This revised version was published online in July 2006 with corrections to the Cover Date.     

Generating confidence intervals for composition-based landscape indexes

Many landscape indexes with ecological relevance have been proposed, including diversity indexes, dominance, fractal dimension, and patch size distribution. Classified land cover data in a geographic information system (GIS) are frequently used to calculate these indexes. However, a lack of methods for quantifying uncertainty in these measures makes it difficult to test hypothesized relations among landscape indexes and ecological processes. One source of uncertainty in landscape indexes is classification error in land cover data, which can be reported in the form of an error matrix. Some researchers have used error matrices to adjust extent estimates derived from classified land cover data. Because landscape diversity indexes depend only on landscape composition – the extent of each cover in a landscape – adjusted extent estimates may be used to calculate diversity indexes. We used a bootstrap procedure to extend this approach and generate confidence intervals for diversity indexes. Bootstrapping is a technique that allows one to estimate sample variability by resampling from the empirical probability distribution defined by a single sample. Using the empirical distribution defined by an error matrix, we generated a bootstrap sample of error matrixes. The sample of error matrixes was used to generate a sample of adjusted diversity indexes from which estimated confidence intervals for the diversity indexes were calculated. We also note that present methods for accuracy assessment are not sufficient for quantifying the uncertainty in landscape indexes that are sensitive to the size, shape, and spatial arrangement of patches. More information about the spatial structure of error is needed to calculate uncertainty for these indexes. Alternative approaches should be considered, including combining traditional accuracy assessments with other probability data generated during the classification procedure.     

Optimizing landscape selection for estimating relative effects of landscape variables on ecological responses

Empirical studies of the relative effects of landscape variables may compromise inferential strength with common approaches to landscape selection. We propose a methodology for landscape sample selection that is designed to overcome some common statistical pitfalls that may hamper estimates of relative effects of landscape variables on ecological responses. We illustrate our proposed methodology through an application aimed at quantifying the relationships between farmland heterogeneity and biodiversity. For this project, we required 100 study landscapes that represented the widest possible ranges of compositional and configurational farmland heterogeneity, where these two aspects of heterogeneity were quantified as crop cover diversity (Shannon diversity index) and mean crop field size, respectively. These were calculated at multiple spatial extents from a detailed map of the region derived through satellite image segmentation and classification. Potential study landscapes were then selected in a structured approach such that: (1) they represented the widest possible range of both heterogeneity variables, (2) they were not spatially autocorrelated, and (3) there was independence (no correlation) between the two heterogeneity variables, allowing for more precise estimates of the regression coefficients that reflect their independent effects. All selection criteria were satisfied at multiple extents surrounding the study landscapes, to allow for multi-scale analysis. Our approach to landscape selection should improve the inferential strength of studies estimating the relative effects of landscape variables, particularly those with a view to developing land management guidelines.     

Landscape cohesion: an index for the conservation potential of landscapes for biodiversity

In urbanising landscapes, planning for sustainable biodiversity occurs in a context of multifunctional land use. Important conditions for species persistence are habitat quality, the amount and configuration of habitat and the permeability of the landscape matrix. For planning purposes, these determinants should be integrated into simple indicators for spatial conditions of persistence probability. We propose a framework of three related indices. The cohesion index is based on the ecology of metapopulations in a habitat network. We discuss how an indicator for species persistence in such a network could be developed. To translate this network index into an area index, we propose the concept of spatial cohesion. Habitat cohesion and spatial cohesion are defined and measured for single species or, at best, for species profiles. Since species differ in their perception of the same landscape, different species will rate different values of these indices for the same landscape. Because landscapes are rarely planned for single species, we further propose the index of landscape cohesion, which integrates the spatial cohesion indices of different species. Indices based on these concepts can be built into GIS tools for landscape assessment. We illustrate different applications of these indices, and emphasise the distinction between ecological and political decisions in developing and applying such tools. This revised version was published online in August 2006 with corrections to the Cover Date.     

惠州市城市绿道启动段规划设计浅析

惠州市城市绿道启动段是《珠三角区域绿道网（惠州段）规划》编制的重要组成部分,是惠州市城市绿道建设的首条示范段,规划全线利用道路两侧的人行道、非机动车道和绿化用地建设绿道,并完善升级沿途绿道环境景观。该文以城市绿道建设背景为引线,分析了城市绿道的现状概况,规划了城市绿道的整体思路,部署了城市绿道的具体设计,着力将它打造成集休闲、健身、生态于一体的绿色通道,使之成为惠州市城市绿道建设崭新的亮点、焦点和示范点。     

Integrative approach for landscape-based graph connectivity analysis: a case study with the common frog (Rana temporaria) in human-dominated landscapes

Graph-based analysis is a promising approach for analyzing the functional and structural connectivity of landscapes. In human-shaped landscapes, species have become vulnerable to land degradation and connectivity loss between habitat patches. Movement across the landscape is a key process for species survival that needs to be further investigated for heterogeneous human-dominated landscapes. The common frog (Rana temporaria) was used as a case study to explore and provide a graph connectivity analysis framework that integrates habitat suitability and dispersal responses to landscape permeability. The main habitat patches influencing habitat availability and connectivity were highlighted by using the software Conefor Sensinode 2.2. One of the main advantages of the presented graph-theoretical approach is its ability to provide a large choice of variables to be used based on the study’s assumptions and knowledge about target species. Based on dispersal simulation modelling in potential suitable habitat corridors, three distinct patterns of nodes connections of differing importance were revealed. These patterns are locally influenced by anthropogenic barriers, landscape permeability, and habitat suitability. And they are affected by different suitability and availability gradients to maximize the best possible settlement by the common frog within a terrestrial habitat continuum. The study determined the key role of landscape-based approaches for identifying the “availability-suitability-connectivity” patterns from a local to regional approach to provide an operational tool for landscape planning.     

Probabilistic patterns of inundation and biogeomorphic changes due to sea-level rise along the northeastern U.S. Atlantic coast

Context

Coastal landscapes evolve in response to sea-level rise (SLR) through a variety of geologic processes and ecological feedbacks. When the SLR rate surpasses the rate at which these processes build elevation and drive lateral migration, inundation is likely.

Objectives

To examine the role of land cover diversity and composition in landscape response to SLR across the northeastern United States.

Methods

Using an existing probabilistic framework, we quantify the probability of inundation, a measure of vulnerability, under different SLR scenarios on the coastal landscape. Resistant areas—wherein a dynamic response is anticipated—are defined as unlikely (p < 0.33) to inundate. Results are assessed regionally for different land cover types and at 26 sites representing varying levels of land cover diversity.

Results

Modeling results suggest that by the 2050s, 44% of low-lying, habitable land in the region is unlikely to inundate, further declining to 36% by the 2080s. In addition to a decrease in SLR resistance with time, these results show an increasing uncertainty that the coastal landscape will continue to evolve in response to SLR as it has in the past. We also find that resistance to SLR is correlated with land cover composition, wherein sites containing land cover types adaptable to SLR impacts show greater potential to undergo biogeomorphic state shifts rather than inundating with time.

Conclusions

Our findings support other studies that have highlighted the importance of ecological composition and diversity in stabilizing the physical landscape and suggest that flexible planning strategies, such as adaptive management, are particularly well suited for SLR preparation in diverse coastal settings.

     

Soil occupation efficiency and landscape conservation in four Mediterranean urban regions

This study investigates the relationship between soil sealing and landscape conservation in four Mediterranean regions (Athens, Barcelona, Lisbon, Rome) characterized by different patterns of urban expansion. Per-capita sealed land, a landscape conservation index and selected territorial variables were considered into a multivariate exploratory framework aimed at assessing the correlation between land-use efficiency (based on the degree of soil sealing per-capita) and the quality of suburban landscape. A population density gradient with intensity of sealed land decreasing with the distance from the central city was observed in compact urban regions such as Athens and Barcelona. A mixed urban gradient was observed in Rome and Lisbon. In all the considered cities the spatial distribution of per-capita sealed land was not correlated with the urban gradient indicating that land consumption follows place-specific patterns irrespective of landscape quality. These findings suggest that urban containment and landscape conservation are policy targets requiring environmental measures irrespective of the prevailing morphology of the urban region (compact vs dispersed). In this context, green infrastructure planning is a promising tool for landscape conservation and the containment of soil sealing within fragile and dynamic contexts such as the wildland-urban interface.