City-wide relationships between green spaces,urban land use and topography

The growing proportion of human populations living in urban areas, and consequent trends of increasing urban expansion and densification fuel a need to understand how urban form and land use affect environmental quality, including the availability of urban green spaces. Here we use Sheffield as a case study of city-wide relationships between urban green space extent, quality (vegetation cover and tree-cover), and gradients in urban form and topography. The total area of buildings and length of the road network are equally strong negative predictors of extent of green space, while the former predictor is a more important negative influence upon green space quality. Elevation positively influences extent of green space but negatively influences tree-cover. In contrast, slope of terrain positively influences green space quality and is the best predictor of tree-cover. Overall housing density is a more important negative predictor of extent of green space and tree-cover than the densities of individual housing types. Nevertheless, the latter are more important influences upon levels of vegetation cover. Threshold effects of densities of different housing types suggest opportunities for optimising green space quality, with implications for housing policy. Variation in ecological quality of green space may partly reflect different historical intensities of industrial activity.     

The energy and mass balance of Los Angeles County

We conducted an urban “metabolic” study of inputs and outputs of food, water, energy, and pollutants from Los Angeles County, USA. This region has been the subject of recent debate about the nature of population density and distribution as it relates to urban form and associated environmental impacts. We found that with the exception of food imports and wastewater outputs, inputs of resources and outputs of pollutants generally declined on a per capita basis from 1990 to 2000. Reductions likely reflected a combination of changes in public policy, improvements in technology and public infrastructure, and impacts of increases in population density. However, in comparison to other municipalities and urban regions, resource consumption per capita was still relatively high in some categories, particularly inputs of water and transportation energy. Per capita greenhouse gas emissions were lower in Los Angeles County than for the average of the USA as a whole but higher than previous analyses of urban areas internationally, largely due to comparatively high emissions from the transportation sector. Wastewater discharge accounted for less than 40% of water inputs excluding precipitation; however the partitioning of water outputs through other potential losses, specifically evapotranspiration, runoff, and groundwater recharge, remains highly uncertain. We suggest that more detailed information about water losses will greatly improve future mass and energy accounting for analyses of urban environmental sustainability in this semi-arid region.     

The negative effects of construction boom on urban planning and environment in Turkey: Unraveling the role of the public sector

Construction sector is usually accepted as the engine that triggers economic growth due to its strong backward and forward linkages with other sectors. On the other hand, it is also argued that increased construction activity could end up with negative economic, social and environmental impacts. The literature emphasizes the role of public sector, especially the national governments in minimizing the negative impacts of construction activity. The related arguments mostly postulate that public sector is well aware of the environmental challenges caused by construction activity and devoted to the understanding of how to improve the sustainability performance of private developers. Yet the case of Turkey provides significant evidences to question these assumptions. In this respect, this paper elaborates on the negative impacts of increased construction activity in Turkey and argues the role of public sector in intensification of the negative environmental effects through deregulation on urban planning and housing production by public agencies. The findings of the research highlight the importance of sustainable construction and verify the need for mainstreaming of sustainable construction into public policy-making at national and local levels, especially in developing countries, where most, if not all, of the future urban population growth will take place.     

Altered resources, disturbance, and heterogeneity: A framework for comparing urban and non-urban soils

We propose a framework of key concepts useful in understanding how urban soils can contribute to general ecological theory. The major factors that can cause urban soils to be different from soils in non-urban ecosystems are identified and related to the familiar state factor approach. We evaluate directly altered resource availability, and the role of stress in mediating resource availability in urban ecosystems. Modified groundwater and stream flow, and atmospheric deposition of nitrogen and base cations are particularly important resource fluxes to soils in urban ecosystems. Disturbance can be conceptualized in the same way in urban as in non-urban ecosystems. However, in addition to biophysical disturbances familiar to ecologists studying wild lands, demographically and socially mediated changes in ecosystem structure must also be considered. These changes include human migration and population structure, institutional shifts, and the effects of human health. Finally, spatial heterogeneity, including fragmentation and differential connectivity, integrates the effects of resources and disturbance, and has an effect on subsequent resource availability and susceptibility to disturbance. Layers of heterogeneity include not only the geomorphic template, but urban climate, biotic composition, buildings and infrastructure, and demographic-social patterns. The complex layering of natural and social factors that constitute urban heterogeneity permit the continuation of important ecological processes, as well as modify ecological fluxes involving soils. We present a modification of the state factor approach as an expanded framework for the study of urban soils. The understanding of urban soils can contribute to general ecological theory by testing the generality of important ecosystem drivers and their linkage with social processes in an under investigated ecosystem type that is increasing in extent and impact worldwide.     

The role of urban indicators in city management: a proposal for Croatian cities

Cities are dynamic economic and social structures that play a dominant role in both national and international economies. They are centers of population, production, consumption, and development. Cities utilize all advantages of economy of scale, proximity, and concentration. On the other hand, they produce high environmental pressures and diminish thereby the quality of life for urban residents. Indicators (environmental, economic, and governance and management) are seen as a tool that would help policy-makers in formulating urban policy that would lead cities towards sustainability and provide assistance for monitoring their development and municipal performance. The aim of this paper is to consider the role that urban indicators can play in city management. We present basic features of urban indicators that will determine their usefulness in urban management. This paper provides the framework to include environmental and economic indicators, as well as governance and management indicators, in successful urban management.     

Assessing the abundance of freshwater turtles in an Australian urban landscape

Although interest in the ecological impacts of urbanisation has increased, very little is known about its impacts on freshwater turtles in Australia. This study investigated the abundance and diversity of turtles in lakes in an urbanised subtropical landscape, Brisbane, Australia. It was found that turtles were abundant throughout the lakes surveyed, with four native species and one introduced species being detected. A total of 371 individuals were captured, 77.7% of which were Brisbane River turtle (Emydura macquarii signata). The lakes surveyed were estimated to support a population of 63–269 individuals for all species combined with most lake populations containing less than 100. Turtle demographics may be classed into three stages of population growth: recovery or nascent; intermediate; and climax. Turtle reproductive success is a major concern for the survival of turtles in urban areas. Continued monitoring is needed to establish if population declines are occurring. This study suggests that while turtles are persisting in this urban environment of Australia the pressures of urbanisation, such as habitat loss, increased predation on both nests and juveniles and pollution of waterways may pose on-going risks to their survival.     

Impacts of urban sprawl on species richness of plants,butterflies, gastropods and birds: not only built-up area matters

Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades.Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.     

Urban soil ecology as a focal point for environmental education

Direct contact with the natural world is an essential element of environmental education and a key to developing environmental literacy and a stewardship ethic. But providing this experience can be challenging in urban environments where many people believe nature only occurs “outside” the city, and urban biota are often unwelcome and perceived in negative terms. Since 80% of the United States’ population lives in or near urban areas, conservation educators and practitioners need to find ways to make nature accessible to this audience, thereby creating a public who can make informed decisions about environmental issues. Soil systems are an important, under-utilized resource for urban environmental education. Soils are ubiquitous and thus easily accessible and their communities can be effective focal points for introducing all levels of ecology, from populations to ecosystems. Soil and litter taxa are also intrinsically interesting, with discoveries of new species still being made in urban areas. By studying urban soil systems, students can develop an enhanced sense of place and an appreciation of the natural world and their connection to it thereby strengthening environmental stewardship. An important role exists for urban ecologists to work with educators to impart enthusiasm for and to augment educators’ understanding of soil systems.

Asian urban sustainability in the era of globalization

The process of achieving urban sustainable development is uncharted. We only know that plans should address the economic, environmental and social health of the city and this task can only be accomplished by approaching each of these issues at different scales. For rapidly developing world cities, “sustainability” is becoming an increasingly elusive objective, in part, because of impacts by forces beyond their borders. Using the Asia-Pacific region as a case study, a framework relates regional transnational flows to the state of the urban environment and the social conditions of linked rapidly developing cities. The “functional city system” within the Asia-Pacific increasingly is both the engine of urban growth and the force behind differentiating urban environmental and social issues. At the same time, while globalization forces have been particularly strong within cities in the Asia-Pacific, local factors also play a crucial role in urban development. Globalization driven growth has not translated into a single path of development, rather localities have demonstrated contextually specific paths.     

Interdisciplinary foundations of urban ecology

Researchers have identified urban ecology as a new field integrating social and ecological science. Critics have portrayed the field as under-theorized with negative implications for research and urban environmental planning. Unprecedented urbanization and historical bias against research integrating social and ecological systems are identified as driving this deficit. Researchers have called for new integrative approaches to address this issue. In response, this paper applies ecology’s analytic framework of “patch dynamics”, Kuhn’s concept of “normal science” and Mazoyer and Roudart’s “evolutionary series” to demographic data and historical texts to perform an analysis of interdisciplinary contributions to theory applicable in the field of urban ecology. The subsequent exploration reveals a rich history of interdisciplinary inquiry along the nature/society divide. The paper concludes that these “largely ignored” contributions offer urban ecology the opportunity to claim much broader depth as a field gaining access to precedents and innovations accomplished during the field’s early theoretical development. Drawing upon this history, a framework for ecological urban development is suggested to inform and assist contemporary research in urban ecology and planning.

Potential of decentralized wastewater management for urban development: Case of Bangkok

Decentralized wastewater management (DWWM) has recently gained much attention in wastewater management (WWM) due to its build-as-you-go principal. Rapid urban development and the widespread impact of wastewater require sustainable ways to test the DWWM approach. This paper aims to examine and discuss the potential of Bangkok’s current WWM approaches for urban development, focusing on decentralized management approaches. General WWM approaches were examined using case study research methods. Three WWM cases were selected for detailed investigation. Residential wastewater user surveys and expert interviews were used to support system performance findings of service providers and recipients, as well as to draw lessons learned. Results show that DWWM is economically and technically efficient, demonstrating potential for sustainable urban development (SUD) in the study area. The competitive cost found is a result of less sewer line, simple technology, and limited additional costs, while the high efficiency is a result of good operation and maintenance. Also the reclaimed water has been used for landscape irrigation of the urban greenery. Sustainability of the system lies in social value of public amenity it provides, and the urban planning implication that it could be an option for smart growth. The results also show that even in an inner urban area DWWM does not conflict with any SUD considerations. Thus, the study recommends using DWWM for new development within both public and private properties based on Bangkok’s case as part of long-term urban development.     

Effects of habitat fragment size and isolation on the density and genetics of urban red-backed salamanders (Plethodon cinereus)

Urban expansion is creating environmental stressors through land use change, habitat fragmentation, and habitat loss. These stressors, along with a host of others, are driving precipitous declines in vertebrate taxa around the world. Amphibians, often requiring a narrow range of environmental conditions, can be especially susceptible to the stressors of environmental change. Despite habitat loss and degradation, some amphibian species continue to persist in altered urban landscapes. The red-backed salamander (Plethodon cinereus) is one such- species and in this study, we assess how habitat patch size affects population density and genetic diversity of salamander populations in and around an urban center in Ohio, United States. Further, we examined patterns of genetic differentiation and landscape connectivity to understand gene flow between populations and tested for historic demographic bottleneck effects. Populations were sampled from 9 urban forest patches ranging in size from less than 1 ha to approximately 250 ha. There was no apparent effect of contiguous habitat patch size on salamander density nor genetic diversity, but we did observe significant genetic differentiation between 97% of pairwise population comparisons. The differentiation observed was not a result of overland distance or effective distance due to landscape resistance. There was evidence of historic bottlenecks at every site. These results suggest that density is driven by within-patch heterogeneity and that genetic diversity is affected by drivers other than patch size or contemporary population density. Our study demonstrates that red-backed salamanders can persist in wooded, urban parks, but that genetic diversity remains susceptible to demographic changes.

     

Notes on the evolution and organization of the urban ecosystem

The continual spread of human settlements over the world’s surface has transformed the natural environment on a global scale. Human’s intervention has changed primary ecosystems (protoecosystems or euecosystems) into anthropoecosystems. The spread of urban ecosystems, cultivated surfaces (agroecosystems), and various areas differentiated by their level of anthropization has facilitated the progressive reduction of euecosystems. The evolution of urban areas over the course of history with transformations of cities and surrounding territory, has created very complex mosaics. A proper study of the city, drawing together historical, cultural, social, and other factors, as well as abiotic ones (urban climate, soil, water, air), requires appropriate, uniform terminology for expressing the complex relationships existing among these factors. We therefore propose that the city (or metropolis) be considered as a set of ecosystems, a “synecosystem”. The entire urban area should be termed a “synbiotope”. It is divided into numerous partial biotopes (macro-, meso- and microbiotopes), the result of modifications wrought through the historical and cultural vicissitudes of the human population. Urban biotopes host not only humans, but also a characteristic vegetable and animal component, the “biosyncoenosis”, formed of numerous plant and animal communities, selected on the basis of the environmental conditions of the individual biotopes, which differ from each other in structure, dynamics, age, and position in the urban space. This terminology should facilitate study of the biotic component and its connection to the urban territory, as well as interpretation of results obtained in the different disciplines in terms of the human population’s quality of life.     

Pollinating animals in the urban environment

Urban environments contain habitats for flowering plants and their pollinating animal species. It is, however, unclear how the urban matrix influences plant-pollinator processes. We recorded plant diversity, floral abundance, flower visitor diversity and plot visits at 89 plant patches within the city of Zürich. The urban matrix surrounding each site was analyzed for the landscape metrics edge density and the extent of green area up to 200 m radius. The correlation between edge density and bee diversity and visitation frequency varied over the entire spatial range, while the correlation for syrphid diversity and visitation frequency levelled off at 80 m radius. In contrast, the correlations with green area were more consistent, with bee diversity levelling off after 100 m, while syrphid diversity and visits continued to increase. The variation in the correlation of bee visits was partly accounted for by the large contribution of honeybees. Plant diversity significantly affected bee diversity and visits, and syrphid visits. Floral abundance had a positive effect on bee visits and bee diversity. Syrphid diversity had a negative interaction with floral abundance and green area. The extent of green area increased bee diversity and visits, and syrphid visits, while edge density reduced visitation by bees. This study showed that plant diversity and floral abundance in urban environments promote pollinating flower visitors. The extent of green area and edge density are important urban mosaic attributes that affect pollinator abundance and visitation frequency at multiple scales.     

Social-ecological innovation: adaptive responses to urban environmental conditions

Novel approaches to natural resource management, particularly those which promote stakeholder participation, have been put forward as fundamental ingredients for establishing resilient, polycentric forms of environmental governance. This is nowhere more pertinent than in the case of the complex adaptive systems associated with urban areas. Decentralisation of urban green space management has been posited as an element thereof which, according to resilience thinking, should contribute to the adaptive capacity of cities and the ecosystem services upon which they rely. Implicit in this move towards increased adaptive capacity is the ability to manage through innovation. Although the importance of innovation towards system adaptability has been acknowledged, little work has thus far been carried out which demonstrates that innovative use of urban green space represents a form of adaptive response to environmental conditions. The current paper reports on research which maps examples of organised social-ecological innovation (OSEI) in an urban study area and evaluates them as adaptive responses to local environmental conditions which may contribute to system resilience. The results present OSEI as a coherent body of responses to local social and environmental deprivation, exhibiting diversity and adaptability according to individual contexts. The study therefore provides evidence for the importance of local stakeholder-led innovation as in the building of adaptive capacity in urban social-ecological systems.     

Restructuring for growth in urban China: Transitional institutions,urban development,and spatial transformation

This research examines government policies and urban transformation in China through a study of Hangzhou City, which is undergoing dramatic growth and restructuring. As the southern center of the Yangtze River Delta, an emerging global city region of China, Hangzhou has been restlessly searching for strategies to promote economic growth and survive the competition with Shanghai. This paper analyzes Hangzhou’s development strategies, including globalization, tourism, industrial development, and urban development, in the context of shifting macro conditions and local responses. We hold that urban policies in China are situated in the broad economic restructuring and the gradual, experiential national reform and are therefore transitional. The paper suggests that China’s urban policies are state institution-directed, growth-oriented, and land-based, imposing unprecedented challenges to sustainability and livability. Land development and spatial restructuring are central to urban policies in China. Last, while Hangzhou’s development strategies and policies to some extent reflect policy convergence across cities in China, local/spatial contexts, including local settings, territorial rescaling and land conditions, are underlying the functioning of development/entrepreneurial states.     

Use of ecological information in urban planning: Experiences from the Helsinki metropolitan area, Finland

This paper studies the use of ecological research information in urban planning focusing on Finland. Research questions addressed the importance and challenges of incorporating ecological information into the planning process, and ways to promote the use of ecological information. Fifteen key professionals from three representative development approval processes in the Helsinki Metropolitan Area were interviewed. The interviewed planners and ecologists considered ecological information important for identifying and preserving valuable urban nature and biodiversity, diminishing negative environmental impacts of construction and for enabling nature-related experiences and services for urban residents. The identified challenges for the use of the information included insufficiency, fragmented nature and lack of adequacy of information, as well as problems with the interpretation and presentation of information. In order to provide more comprehensive ecological information from urbanizing areas in Finland; there should be more coordinated efforts to produce research information that planners really need, ecologists should be more active in the process in providing ecological insights for plans, a proper and simple biodiversity valuation method should be developed, more research on the function on ecological corridors should be conducted, and biodiversity monitoring of implemented planning projects should be developed.     

Habitat origins and microhabitat preferences of urban plant species

Urban vegetation is commonly described as dominated by weedy species that are adapted to human disturbance. In this study, we determined the original (pre-agriculture) habitats of urban plant species sampled quantitatively in the spontaneous vegetation of a university campus in Halifax, Nova Scotia (eastern Canada). We sampled 11 distinct patch types corresponding to different built forms. Differences in vegetation among patch types were related in part to environmental variables such as soil moisture and light availability. The urban vegetation was dominated by species from rocky habitats such as cliffs and talus slopes, with lesser representation from grassland and floodplain habitats. When compared to a null model of species origins based on the global area and species richness of different original habitats, species from rock outcrops and grassland habitats were overrepresented in the urban vegetation. These results contrast with the received view that cities represented highly “unnatural” ecosystems: built form appears to replicate the habitat templates required by rock outcrop species. Urban ecological theory should incorporate the replication of habitat analogs by built forms in addition to the creation of ecologically novel habitats.     

对我国城市化健康发展的理论思考——城乡统筹发展的视角

本文简要回顾了我国近10年来城市化快速发展的理论和政策背景,指出快速城市化进程中存在土地、能源等自然资源过渡消耗和浪费问题,也存在重城轻乡等突出社会问题;采用人口供需平衡的方法,分析评价了我国人口城市化水平同经济发展水平、工业化水平和土地城市化的关系;对城市化加速理论进行剖析,认为我国当前工业化技术体系不适用于机器技术体系下城市化加速的经验规律,应该结合我国新型工业化的要求走资源节约型的新型城市化道路;建议适当降低城市化发展目标与速度,纠正城市化过程中＂城市偏向＂和＂以物为本＂的做法,体现国家赋予城市化带动农村发展的重任,实现城乡统筹发展。     

Planning for urban life: A new approach of sustainable land use plan based on transit-oriented development

Transit-oriented development (TOD) is an integration of transportation systems with land use and has been given priority in sustainability strategies. However, most of the existing studies on TOD emphasize the economic and environmental perspectives of sustainability, paying little attention to social equity. Moreover, despite governments worldwide are gradually trying to address unsustainable issues associated with dramatic urbanization through a framework of TOD development, the improvement of land use planning necessary to achieve variegated sustainability within a safe trajectory is not being targeted or achieved. This paper aims to establish a framework of TOD planning in China's context that could be applied beyond the concept to planning experts and policymakers on how to integrate land use planning with TOD to achieve sustainability. We further applied an empirical study of Jiaomei, China to demonstrate the application of the designed framework. The study provided a new framework for understanding sustainable transportation development with land use management as applied to the urban planning process and for exploring new paths in practice toward sustainability.