Search

While urban systems are expanding at very fast rates all over the world, understanding their spatial development remains a complex and controversial issue, burdened with confusion in the literature. A common understanding of the spatial behavior of expanding urban systems needs robust conceptualization and empirical evidence. The physical growth of cities assumes different spatial patterns, usually in the form of urban sprawl resulting from multi-dimensional drivers and causing multi-dimensional economic, social and ecological impacts. The need to manage urban sprawl and its manifold adverse consequences by promoting compact urban development and urban densification/re-utilization has been widely promoted in science and policy-making. However, ensuring a high quality of life for urbanites demands integrative points-of-view for the types of compact development to promote, in particular regarding urban green spaces within densification processes. It is essential to consider the effects of compact development not only at larger scales, but also at neighborhood and household scales to pursue moderated and qualified densification, securing and (re-)developing urban green spaces and their multi-dimensional positive impacts. Urban sprawl and compact green cities require adequate and robust multi-dimensional spatially explicit indicators to support urban planners and policy makers. Through articles of this special issue, we explore in this synthesis paper the current international state of the art in developing, testing and implementing multi-dimensional ecological, economic, social and multi-scale regional, city, neighborhood indicators characterizing urban sprawl and compact green cities. The articles provide concepts and international case studies for land monitoring and planning recommendations for sustainable urban development. Such indicators give light to capture the social, economic and environmental dimensions of urban development while assessing the degree and extent of sprawl and compact green cities in a global context.

Urban and peri-urban agriculture is attracting new attention in the context of growing interests in sustainability and resilience. Although much research has been done in this field, little is known about pastoralism and its impact on urban and peri-urban settings. In this paper, we discuss the contribution of pastoral practices to urban sustainability, as well as the opportunity and need to maintain such forms of agriculture. Using Bucharest as a study area and conducting a mixed qualitative and quantitative investigation, we show that pastoral activities have a strong cultural component, contribute to short and long food supply chains, and play a role in the management of land resources. However, conflicts with urban residents may occur due to health concerns and impact on the visual quality of the landscape. We argue that active adaptation measures by both shepherds and local authorities are needed to assure the livelihood of pastoralism, particularly where it is under threat from urbanization. Our study contributes to the discussions on creating mutually beneficial relationships between agricultural activities and the urban environment for food provision, job creation and sustainable resource management. Specifically, we anticipate our study to be a starting point for more in-depth discussions on local perspectives concerning urban sustainability.

Urban areas represent the central point of sustainability initiatives which drive significant changes in cities’ planning, design and management. Given that urban areas are subject to continuous change, efficient and integrated planning and policy strategies are needed to address their complex challenges. This is why the Strategic Environmental Assessment (SEA) plays an essential role in urban planning considering the optimal investment alternatives along with the environmental protection measures. Given that the SEA process considers all impacts on social, economic, institutional and environmental factors, this process must be managed as an adaptive process. Our analysis proposes an evaluation protocol to address sustainability on its economic-environmental-social-institutional dimensions in the evaluation of environmental permits. The evaluation protocol comprised 43 items grouped into three categories (“general presentation”, “sustainability related aspects within the protection measures” and “the strength of the protection measures”). Our analysis, focused on the urban areas from Romania as case study, shows that the environmental permits address sustainability slightly below average. The environmental and institutional dimensions of sustainability achieved the highest scores while those of the economic and social dimensions were quite the opposite. This proved to be helpful in recognizing the strengths and weaknesses of such regulatory documents in terms of their environmental, social, economic and institutional sustainability. Our study contributes to the international literature given that no studies have been elaborated on the evaluation of environmental permits using an evaluation protocol.

Literature on urban ecosystem services (UESS) is vast, particularly on cultural ecosystem services. However, due to a lack of knowledge on individual urban green spaces on the site level, further research on enhanced methods is needed to underpin existing assumptions about the reasons why people are visiting urban green spaces and what kinds of ecosystem services they can expect, with a focus on recreational activities. We argue for enhanced methods to assess supply of and demand on cultural UESS that should include the direct work with urban green space users. With the overall aim of developing a Spatial Decision Support System for visiting urban green spaces, we are applying a set of different quantitative methods to gather information on peoples’ needs and perceptions as well as data on what existing green spaces offer them. We present a two-step approach 1) linking green space criteria with recreational activities (demand-side) based on a linear series of three online surveys and 2) conducting a spatial mapping of urban green space criteria based on activity-driven indicators (supply-side). In the course of exemplified indicators operationalized by using open and local authorities′ geospatial data in an explorative study in Dresden and Heidelberg (Germany), we discuss the strengths and weaknesses of the approach.

Urban green infrastructure is considered to be a key element in improving quality of life and creating an appropriate framework for sustainable cities. The most used quantitative indicator to assess urban green infrastructure is urban green space (UGS) per capita. This papeŕs aim is to analyze whether UGS is a valuable target to achieve cities’ sustainability goals. We used Romania as a case study, which should meet the target of 26 m2 of UGS per inhabitants in all cities. Aerial images were used to extract the surface of the UGS categories for a sample of 38 cities in Romania. We compared our data with three other databases (National Institute of Statistics, Environmental Protection Agencies and Urban Atlas) to check for differences. To understand the contribution of geographic and socio-economic factors to the dynamic of the UGS per capita in Romania’s cities, we used a multiple linear regression. To identify differences between cities in terms of their proportions of UGS, multiple correspondence analysis was performed. We found significant differences between the surface of UGS reported by the administrative offices and that resulting from the spatial analysis. The process of reporting UGS data currently has methodological and perspective shortcomings. Moreover, the density of the built-up space, the proximity to major transport infrastructure, the cities’ founding period and the geomorphology criteria are important predictors for the UGS. The target of 26 m2 of green area per inhabitant in all Romanian cities is not feasible and it should consider the cities’ characteristics, if you want to achieve sustainability goals. Urban green planning should focus more on the development of urban green infrastructure models that are adapted to each type of urban area.

Managing urban soil sealing is a difficult venture due to its spatial heterogeneity and embedding in a socio-ecological system. A systemic solution is needed to tackle its spatial, ecological and social sub-systems. This study develops a guideline for urban actors to find a systemic solution to soil sealing management based on two case studies in Germany: Munich and Leipzig. Legal-planning, informal-planning, economic-fiscal, co-operative and informational responses were evaluated by indicators to proof which strategy considers the spatial complexity of urban soil sealing (systemic spatial efficiency) and, while considering spatial complexity, to assess what the key management areas for action are to reduce the ecological impacts by urban soil sealing (ecological impact efficiency) and to support an efficient implementation by urban actors (social implementation efficiency). Results suggest framing the systemic solution to soil sealing management through a cross-scale, legal-planning development strategy embedded in higher European policies. Within the socio-ecological system, the key management area for action should focus on the protection of green infrastructure being of high value for actors from the European to local scales. Further efforts are necessary to establish a systemic monitoring concept to optimize socio-ecological benefits and avoid trade-offs such as between urban infill development and urban green protection. This place-based study can be regarded as a stepping stone on how to develop systemic strategies by considering different spatial sub-targets and socio-ecological systems.

Cities have become major contributors to sustainability problems and, in the meantime, seedbeds for sustainability transformation. Urban nature-based solutions, such as greening strategies that foster urban food production as a cross-cutting issue, promise to have multidimensional benefits for sustainable urban development. However, a conceptual understanding of interlinkages between nature-based solutions and their contribution to sustainability transformation is lacking. The goals of this study are twofold. First, to develop a conceptual model for testing multi-dimensional impacts of urban nature-based solutions supporting social-spatial, social-ecological and individual sustainable transformation. The model has been developed based on the concepts of place attachment, human-food connection and pro-environmental food behaviour. Second, the conceptual model is applied to the example of edible cities. Edible cities can be considered an innovative nature-based solution that provides multiple co-benefits by offering (free) food for urban residents in public spaces. A Principal Component Analysis of a survey among residents of Andernach (N = 380), one of the first edible cities in Germany revealed, in contrast to the conceptual three-dimensional model, a four-dimensional model with high construct validity and reliability. The model comprises a) place attachment, b) experiential and c) material human-food connection as well as d) pro-environmental food consumption. Items of internal emotional and philosophical human-food connection included within the pro-environmental food consumption scale suggested their important role in fostering sustainability. Results suggest that the edible city can be considered a strategy for increasing urban attractiveness and place identity, supporting social bonding and experiential human-food connection by using the edible areas for nature observation and recreation. However, although the residents are well informed about the edible city concept, most residents are not actively involved and rarely use the food provided by the edible city. Thus, they also could not answer questions related to cognitive human-food connection such as estimating the food’s taste and health quality. To strengthen material and cognitive human-food connection, policy implications of the results propose the implementation of accompanying information and participation activities. By linking nature-based solutions with sustainability transformation, this study provides conceptual and practical implications for the multidimensional benefits of innovative urban greening strategies such as edible cities.

Cities are confronted with different societal challenges calling for urban sustainability transformation (UST). Nature-based solutions (NbS) can provide actions for such challenges and strive for maximizing environmental, social and economic benefits. Edible cities, which encompass different forms of urban food production (UFP) in the city, can be seen as multifunctional NbS. However, the concept of edible cities has just recently arrived in research and its understanding as potential NbS supporting UST is still fragmented. Therefore, the study created an analytical framework, which aims at identifying and prioritizing 1) challenges that edible cities can contribute in the context of UST and 2) strategies for implementing and mainstreaming the edible city in the context of urban sustainability acceleration. The study is of explorative character and encompasses interviews with key actors from three German case studies: Andernach – a German frontrunner in implementing the edible city, Haar – follower I, which implemented the concept after learning from Andernach and Munich – follower II, where the concept of edible cities was not yet implemented but a range of bottom-up activities exist to promote the topic. Results show that edible cities can be seen as NbS that can support UST in terms of social-spatial and socio-ecological transformation, in particular promoting social cohesion and human-nature and food connection. In terms of implementing and mainstreaming, the results suggest that the edible city can be taken up by different city departments due to its multifunctionality. Furthermore, a mix of motivated bottom-up initiatives and top-down authorities paired with courage and room for experimentation on the edible city is crucial for its embedding. Apart from that, network creation with different UFP initiatives as well as with other cities is an important factor for mainstreaming edible cities. Future research shall test the transferability of the analytical framework to other NbS analyzing their potential to contribute to UST.

Environmental action plans are important instruments intended to provide sustainable solutions for the most pressing environmental issues. As they should be updated regularly, efforts to evaluate their quality are essential for enabling incremental improvements in upcoming versions. The aim of our study was to systematically evaluate the quality of Romania's Local Environmental Action Plans (LEAPs) by following a theoretical framework that includes principles from both rational and communicative approaches to assessing plan quality. We selected 32 LEAPs and applied an evaluation protocol that enabled a comprehensive assessment of the plans. Our results showed an overall moderate quality of the LEAPs. Although most plans identify many environmental problems in need of solutions, in reality additional urgent environmental problems often exist. Furthermore, LEAPs perform only moderately in identifying tools for implementation provisions and ensuring the participation of the public in the planning process, and they are even weaker in establishing goals and achieving coordination across different governmental levels. Overall the assessment reveals that plans are rarely able to craft an appealing policy message. Our findings could be used as guidance for LEAP coordinating agencies to improve the plans in the upcoming updating processes, as they identify plan weaknesses and suggest ways to achieve high quality environmental plans. Furthermore, our novel plan assessment method based on rational comprehensive and communicative approaches to plan quality evaluation can be adapted easily to other studies.

Cities can be characterized by extensive sealing limiting the supply of ecosystem services. In Europe, soil sealing is still increasing despite decreasing population. This paper shows that the management of urban soil sealing must—due to its complex driving forces, impacts, constraints of its management and different actors—be considered as a wicked problem. By using the method of response–efficiency–assessment (REA), the strategies “legal-planning”, “informal-planning”, “economic-fiscal”, “co-operative” and “informational” are assessed in their degree of efficiency as being ecologically sustainable, economically functional, institutionally accepted, supporting environmental competence and living quality. Responses were assessed by indicators using a content analysis and survey of urban actors and residents in Leipzig and Munich (Germany). Main results of the study show that no single strategy can provide an efficient solution for reducing soil sealing but rather a mix of clumsy solutions are necessary promoting: (1) stricter regulations and an increase in ecological–financial incentives, (2) stronger commitment by urban actors toward sealing reduction supported by informal-planning responses and scientific know-how, (3) information addressed to urban residents supporting self-reflection on impacts of private land consumption and (4) improved horizontal and regional co-operations taking into account cities’ responsibility for urban and global sustainability. This study provides a valuable approach on how to puzzle together clumsy solutions on the example of soil sealing management as a challenge in an urbanized world. This method can also be used for other current wicked problems like climate change.

Ecosystem services (ES) are gaining increasing attention as a promising concept to more actively consider and plan for the varied benefits of the urban environment. Yet, to have an impact on decision-making, the concept must spread from academia to practice. To understand how ES have been taken up in planning discourses we conducted a cross-case comparison of planning documents in Berlin, New York, Salzburg, Seattle and Stockholm. We found: (1) explicit references to the ES concept were primarily in documents from Stockholm and New York, two cities in countries that entered into ES discourses early. (2) Implicit references and thus potential linkages between the ES concept and planning discourses were found frequently among all cities, especially in Seattle. (3) The thematic scope, represented by 21 different ES, is comparably broad among the cases, while cultural services and habitat provision are most frequently emphasized. (4) High-level policies were shown to promote the adoption of the ES concept in planning. We find that the ES concept holds potential to strengthen a holistic consideration of urban nature and its benefits in planning. We also revealed potential for further development of ES approaches with regard to mitigation of environmental impacts and improving urban resilience.

Despite a shrinking population, soil sealing and land consumption is still increasing in Europe. In an increasingly urbanized world, scarcity of space is rising. Under the umbrella of sustainable urban land use, conflicts between residential, commercial, industrial, transport and green areas need to be solved balancing social, economic and environmental objectives. However, managing urban environments and steering soil sealing is a challenge for policymakers and planners dealing with land use conflicts due to their complex constraints and driving forces. This paper investigates which strategies can be characterized as being institutionally efficient and contributing to a reduction in urban soil sealing. The analyses are conducted in Munich and Leipzig, Germany. For the evaluation, the method of Response–Efficiency–Assessment (REA) is applied using subjective and objective indicators, which are evaluated by a content analysis and Internet survey. Strategies of the following types are assessed: legal-planning, informal planning, economic-fiscal, co-operative and informational. Results show that informal planning strategies are institutionally the most efficient due to high flexibility, high acceptance and limited reduction in local authority, which legal-planning responses lack. Current economic-fiscal responses are assessed as being the most inefficient, and there is a need for implementing new taxes, which among other things can promote the protection of fertile soils. It is concluded that local authorities need to be more aware of their authority and responsibility to limit soil sealing and to guarantee a high urban living quality. Hence, more stringent rules should be justified with proof of their effectiveness before implementation.