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This paper positions urban ecology as increasingly conversant with multiple perspectives and methods for understanding the functions and qualities of diverse cities and urban situations. Despite progress in the field, we need clear pathways for positioning, connecting and synthesising specific knowledge and to make it speak to more systemic questions about cities and the life within them. These pathways need to be able to make use of diverse sources of information to better account for the diverse relations between people, other species and the ecological, social, cultural, economic, technical and increasingly digital structures that they are embedded in. Grounded in a description of the systemic knowledge needed, we propose five complementary and often connected approaches for building cumulative systemic understandings, and a framework for connecting and combining different methods and evidence. The approaches and the framework help position urban ecology and other fields of study as entry points to further advance interdisciplinary synthesis and open up new fields of research. [ABSTRACT FROM AUTHOR]

Green roofs provide multiple benefits including reducing the urban heat island effect, absorbing stormwater and air pollution, and serving as habitat for wildlife. However, many cities have not taken advantage of green roofs as a nature-based solution. In New York City (NYC), approximately 20% of the landscape is covered by buildings, thus rooftops present a substantial opportunity for expanding green infrastructure. Spatial data on green roofs are critical for understanding their abundance and distribution, what filters may drive spatial patterns, and who benefits from them. We describe the development of a green roof dataset for NYC based on publicly available data and classification of aerial imagery from 2016. Of the over one million buildings in NYC, we found only 736 with green roofs (<0.1%), although there may have been others we did not detect. These green roofs are not evenly distributed in NYC - they are most common in midtown and downtown Manhattan, while most other areas have few to none. Green roofs tend to be more prevalent in parts of NYC with combined sewer systems, but some such areas, and those with the most heat-vulnerable communities, have few if any despite their potential to help ameliorate stormwater and urban heat challenges. Though green roofs are providing some benefits within NYC, we anticipate they are filtered based on dynamics of infrastructure, institutions, and perceptions, rather than targeted to address climate and weather-related challenges. There is substantial opportunity in NYC to increase green roofs, and equity of them. The dataset we developed is publicly available and can serve as a baseline for tracking these assets through time, while supporting further research, conversations, and policies related to the benefits and distribution of green roofs. The underlying methods can also be applied to help fill similar data gaps in other cities. [ABSTRACT FROM AUTHOR]

In this perspective, we present how three initial landmark papers on urban sustainability research contributed to the larger sustainability science scholarship and paved the way for the continued development of urban sustainability research. Based on this, we propose three conceptual innovation pathways to trace the progression of urban sustainability science: First, urban sustainability from a system's perspective, meaning that urban sustainability requires integrative solutions to work in the tripled social-ecological-technological system setting. Second, urban sustainability from a (people and place) relational perspective, meaning urban sustainability is a contested and dynamic social-ecological contract of cities. As a governance mission, urban sustainability requires evidence from research that can inform coordinated action to bridge people, places, meanings, visions and ecosystems. Third, urban sustainability from a transformative science perspective, meaning that for urban sustainability to be achieved and progressed, deep transformations are required in systems, relations, policies and governance approaches. Our proposal for the future of urban sustainability science centres on emphasizing the relevance and policy applicability of systems' thinking, value and place thinking and transitions/transformations thinking as fundamental to how knowledge is co-produced by research science, policy and society and becomes actionable. [ABSTRACT FROM AUTHOR]

Global urbanization over the last century has concentrated people, infrastructure, and economic activity in cities, pushing them to the front lines of damaging impacts of climate change and other social and economic shocks, including COVID-19. This knowledge frontier is key to standardize the diverse knowledge of NBS and strengthen knowledge translation with more rigorous examination of emerging NBS types and designs. NBS needs to be a key component of recommendations in the next Intergovernmental Panel on Climate Change report for climate adaptation in cities and to formulate pathways for nature-positive futures that can be taken up in national and local level agendas where climate resilience planning is rapidly taking place. [Extracted from the article]

Nature-based solutions offer an exciting prospect for resilience building and advancing urban planning to address complex urban challenges simultaneously. In this article, we formulated through a coproduction process in workshops held during the first IPCC Cities and Climate Science Conference in Edmonton, Canada, in March 2018, a series of synthesis statements on the role, potential, and research gaps of nature-based solutions for climate adaptation and mitigation. We address interlocking questions about the evidence and knowledge needed for integrating nature-based solutions into urban agendas. We elaborate on the ways to advance the planning and knowledge agenda for nature-based solutions by focusing on knowledge coproduction, indicators and big data, and novel financing models. With this article, we intend to open a wider discussion on how cities can effectively mainstream nature-based solutions to mitigate and adapt to the negative effects of climate change and the future role of urban science in coproducing nature-based solutions. [ABSTRACT FROM AUTHOR]

Weather-related disasters are on the rise. The causes, whether driven by climate change or changes in exposure and vulnerability of social-ecological-technological systems are still uncertain. Here, we address this issue with an in-depth study of the variability in climate-related extreme events which have impacted New York City (NYC) over the past 140 years. NYC has not historically been viewed as a particularly hazard prone region. However, this perspective is changing, particularly after the disastrous consequences of Hurricane Sandy (2012). We constructed a systematic database of impactful climatic events and assessed multi-sector impacts. Results indicate that hazards have systematically affected the city, with heat waves as the deadliest events and hurricanes as the costliest. We analyzed climatic hazard trends focusing on heat waves and flooding only, since data for these events are available over the full-time frame of the study. We then examined impacts of the most severe of these two hazards using data from The New York Times. Our analyses show that flooding and heat wave extreme events have regularly affected the city over its history with a trend toward increasing mean number of hazards per decade. We highlight a trend of decreased mortality due to heat waves over time and increase in the impacts of heavy precipitation, primarily related to the expansion of the transportation system and potentially to climate change over this time period. We suggest that, especially in urban areas of developed countries such as NYC, changes in built up infrastructure may be the primary drivers of risk to natural hazards. [ABSTRACT FROM AUTHOR]

Urbanization is one of the biggest social transformations of modern time, driving and driven by multiple social, economic, and environmental processes. The impacts of urbanization on the environment are profound, multifaceted and are manifested at the local, regional, and global scale. This article reviews recent advances in conceptual and empirical knowledge linking urbanization and the environment, focusing on six core aspects: air pollution, ecosystems, land use, biogeochemical cycles and water pollution, solid waste management, and the climate. We identify several emerging trends and remaining questions in urban environmental research, including ( a) increasing evidence on the amplified or accelerated environmental impacts of urbanization; ( b) varying distribution patterns of impacts along geographical and other socio-economic gradients; ( c) shifting focus from understanding and quantifying the impacts of urbanization toward understanding the processes and underlying mechanisms; ( d) increasing focus on understanding complex interactions and interlinkages among different environmental, social, economic, and cultural processes; and ( e) conceptual advances that call for articulating and using a systems approach in cities. In terms of governing the urban environment, there is an increasing focus on public participation and coproduction of knowledge with stakeholders. Cities are actively experimenting toward sustainability under a plethora of guiding concepts that manifests their aspirational goals, with varying levels of implementation and effectiveness. [ABSTRACT FROM AUTHOR]

Cities and urbanized regions are complex, dynamic, and highly integrated systems linking social, ecological, and technical infrastructure domains in ways that create deep challenges for good governance, policymaking, and planning. The combination of impacts from climate change in cities, air pollution, rapid population growth, multiple sources of development pressure and overall urban system complexity make it difficult for decision-makers to develop and guide development trajectories along more livable, equitable, and at the same time, more resilient pathways. Advancing urban sustainability and resilience agendas requires expanding the scope of inter- and trans-disciplinarity approaches, moving beyond the historically separate social–ecological and socio-technical approaches to jointly study social–ecological–technical infrastructure systems in cities. We take urban complexity as a given and suggest that in both research and practice we need to better capture and understand feedbacks, interdependencies, and non-linearities which create uncertainties and challenge the efficacy of governance practices to achieve normative goals for society. Here, we explore new methods, tools, and approaches to advance our understanding of urban system complexity through a series of journal special issue articles that examine urban structure–function relationships, urban sustainability transitions, green space availability, social–ecological memory, functional traits, and urban land use scenarios. [ABSTRACT FROM AUTHOR]

Urban ecology is a field encompassing multiple disciplines and practical applications and has grown rapidly. However, the field is heterogeneous as a global inquiry with multiple theoretical and conceptual frameworks, variable research approaches, and a lack of coordination among multiple schools of thought and research foci. Here, we present an international consensus on how urban ecology can advance along multiple research directions. There is potential for the field to mature as a holistic, integrated science of urban systems. Such an integrated science could better inform decisionmakers who need increased understanding of complex relationships among social, ecological, economic, and built infrastructure systems. To advance the field requires conceptual synthesis, knowledge and data sharing, cross-city comparative research, new intellectual networks, and engagement with additional disciplines. We consider challenges and opportunities for understanding dynamics of urban systems. We suggest pathways for advancing urban ecology research to support the goals of improving urban sustainability and resilience, conserving urban biodiversity, and promoting human well-being on an urbanizing planet. [ABSTRACT FROM AUTHOR]

Urban futures that are more resilient and sustainable require an integrated social-ecological system approach to urban policymaking, planning, management, and governance. In this article, we introduce the Urban Biodiversity and Ecosystem Services (URBES) and the Cities and Biodiversity Outlook (CBO) Projects as new social-ecological contributions to research and practice on emerging urban resilience and ecosystem services. We provide an overview of the projects and present global urbanization trends and their effects on ecosystems and biodiversity, as a context for new knowledge generated in the URBES case-study cities, including Berlin, New York, Rotterdam, Barcelona, and Stockholm. The cities represent contrasting urbanization trends and examples of emerging science-policy linkages for improving urban landscapes for human health and well-being. In addition, we highlight 10 key messages of the global CBO assessment as a knowledge platform for urban leaders to incorporate state-of-the-art science on URBES into decision-making for sustainable and resilient urban development. [ABSTRACT FROM AUTHOR]

We review the current state of knowledge about urban ecosystem services in New York City (NYC) and how these services are regulated, planned for, and managed. Focusing on ecosystem services that have presented challenges in NYC-including stormwater quality enhancement and flood control, drinking water quality, food provisioning and recreation-we find that mismatches between the scale of production and scale of management occur where service provision is insufficient. Adequate production of locally produced services and services which are more accessible when produced locally is challenging in the context of dense urban development that is characteristic of NYC. Management approaches are needed to address scale mismatches in the production and consumption of ecosystem services. By coordinating along multiple scales of management and promoting best management practices, urban leaders have an opportunity to ensure that nature and ecosystem processes are protected in cities to support the delivery of fundamental urban ecosystem services. [ABSTRACT FROM AUTHOR]

The world has become urban; cities increasingly shape our worldviews, relation to other species, and the large-scale, long-term decisions we make. Cities are nature, but they need to align better with other ecosystems to avoid accelerating climate change and loss of biodiversity. We need a science to guide urban development across the diverse realities of global cities. This need can be met, in part, by shifts in urban ecology and its linkages to related sciences. This perspective is a "synthesis of syntheses", consolidating ideas from the other articles in the Special Section. It re-examines the role of urban ecology, and explores its integration with other disciplines that study cities. We conclude by summarizing the next steps in the ongoing shift in urban ecology, which is fast becoming an integral part of urban studies. [ABSTRACT FROM AUTHOR]

This perspective emerged from ongoing dialogue among ecologists initiated by a virtual workshop in 2021. A transdisciplinary group of researchers and practitioners conclude that urban ecology as a science can better contribute to positive futures by focusing on relationships, rather than prioritizing urban structures. Insights from other relational disciplines, such as political ecology, governance, urban design, and conservation also contribute. Relationality is especially powerful given the need to rapidly adapt to the changing social and biophysical drivers of global urban systems. These unprecedented dynamics are better understood through a relational lens than traditional structural questions. We use three kinds of coproduction—of the social-ecological world, of science, and of actionable knowledge—to identify key processes of coproduction within urban places. Connectivity is crucial to relational urban ecology. Eight themes emerge from the joint explorations of the paper and point toward social action for improving life and environment in urban futures. [ABSTRACT FROM AUTHOR]

This paper builds on the expansion of urban ecology from a biologically based discipline—ecology in the city—to an increasingly interdisciplinary field—ecology of the city—to a transdisciplinary, knowledge to action endeavor—an ecology for and with the city. We build on this "prepositional journey" by proposing a transformative shift in urban ecology, and we present a framework for how the field may continue this shift. We conceptualize that urban ecology is in a state of flux, and that this shift is needed to transform urban ecology into a more engaged and action based field, and one that includes a diversity of actors willing to participate in the future of their cities. In this transformative shift, these actors will engage, collaborate, and participate in a continuous spiral of knowledge → action → knowledge spiral and back to knowledge loop, with the goal of co producing sustainable and resilient solutions to myriad urban challenges. Our framework for this transformative shift includes three pathways: (1) a repeating knowledge → action → knowledge spiral of ideas, information, and solutions produced by a diverse community of agents of urban change working together in an "urban sandbox"; (2) incorporation of a social–ecological–technological systems framework in this spiral and expanding the spiral temporally to include the "deep future," where future scenarios are based on a visioning of seemingly unimaginable or plausible future states of cities that are sustainable and resilient; and (3) the expansion of the spiral in space, to include rural areas and places that are not yet cities. The three interrelated pathways that define the transformative shift demonstrate the power of an urban ecology that has moved beyond urban systems science and into a realm where collaborations among diverse knowledges and voices are working together to understand cities and what is urban while producing sustainable solutions to contemporary challenges and envisioning futures of socially, ecologically, and technologically resilient cities. We present case study examples of each of the three pathways that make up this transformative shift in urban ecology and discuss both limitations and opportunities for future research and action with this transdisciplinary broadening of the field. [ABSTRACT FROM AUTHOR]

The narrative of urban sustainability transformations epitomises the hope that urban governance can create the conditions to plan and govern cities in a way that they contribute to local and global sustainability and resilience. So far, urban governance is not delivering: novel governance approaches are emerging in cities worldwide, yet are unable to transform conventional policymaking and planning to allow for innovative, co-beneficial and long-term solutions and actions to emerge and institutionalise. We present a capacities framework for urban transformations governance, starting from the need to fulfil distinct output functions ('what needs to happen') for mobilising and influencing urban transformation dynamics. The framework helps to diagnose and inform urban governance for responding to disturbances (stewarding capacity), phasing-out drivers of path-dependency (unlocking capacity), creating and embedding novelties (transformative capacity) and coordinating multi-actor processes (orchestrating capacity). Our case study of climate governance in New York City exemplifies the framework's applicability and explanatory power to identify conditions and activities facilitating transformation (governance), and to reveal gaps and barriers of these vis-à-vis the existing governance regime. Our framework thereby functions as a tool to explore what new forms of urban transformation governance are emerging, how effective these are, and how to strengthen capacities. • Existing urban governance is unable to address persistent problems. • Effective governance support of transformation lies in collective capacities. • We develop a framework of four capacities for urban transformation governance (UTG). • We use the framework to explain the development of UTG capacities in New York City. • The framework enables explaining, evaluating and supporting UTG. [ABSTRACT FROM AUTHOR]

Abstract Climate change actions in cities worldwide are driving deep changes in urban governance. We ask whether new capacities for transformative climate governance are emerging in two cities that have experimented with urban climate governance: Rotterdam, the Netherlands, and New York City (NYC), United States. Transformative climate governance creates the conditions for developing integrated and innovative climate mitigation and adaptation policies and interventions that respond to and shape urban transformation dynamics and contribute to sustainability and resilience. The comparison of capacities for transformative climate governance in Rotterdam and NYC offers insights into the emerging features of urban climate governance vis-à-vis existing urban governance regimes: how urban climate governance is driven and delivered, what new governance conditions emerge, and whether these conditions enable transformative climate governance. In both cities, an integrated, experimental and inclusive approach to climate governance is emerging, which crosses multiple policy sectors and domains (e.g. transport, energy, health, justice), involves a variety of actors and facilitates innovative solutions. Envisioning, long-term goal and knowledge integration, experimentation and tapping into coalitions for change help to provide the basis (including guiding principles, urgency, actor networks, innovative solutions) for transformative climate governance. However, these transformative approaches tend to be still subordinate to business-as-usual interests and policy and planning approaches, which favour isolated, incremental and short-term responses. The challenge for strengthening transformative climate governance will be to develop rigorous institutional and organisational conditions that decisively stipulate a prioritisation of climate change across scales and sectors, provide action mandates and enable wider coordination, collaboration and learning. Highlights • Climate governance activities in cities drive deep changes in urban governance. • Transformative climate governance (TCG) supports desirable urban transformations. • Capacities for TCG manifest in new institutional, knowledge and network conditions. • Visioning, goal and knowledge integration and experimentation create TCG capacities. • Top-down institutional and organisational conditions need to be strengthened for TCG. [ABSTRACT FROM AUTHOR]

Urban landslides are increasing globally, mainly caused by human-induced changes in hillsides. Most of these events have caused low-intensity damages to housing and infrastructure. A total of 2038 locations of landslides in the hydrological year of 2010 were used to model landslides' occurrence in the metropolitan region of São Paulo—Brazil—using a social–ecological–technological system's approach, which enables the analysis of urban landslides as the outcome of dynamic socioeconomic and infrastructural conditions alongside climatic and geophysical conditions. A multi-step model approach was used to select the best set of variables related to landslides' occurrence and assess their importance. The value of AUC of the model was 0.9087, denoting the high level of discrimination achieved. Antecedent rainfall played the most important role, followed by terrain slope. Informal settlements, associated with poor constructive practices and a lack of municipal inspection on civil works and buildings, as well as the number of households, which stands for built density and greater alteration in hillsides, yielded a slightly lower contribution. Other variables showed a marginal contribution. These results reinforce the role of local ordinances aimed at restricting occupation in steeper slopes and public policies to promote adequate housing and constructive practices. Future climate projections to MRSP point to the increase in intense rainfall days, making disasters caused by landslides a major source of risk. [ABSTRACT FROM AUTHOR]

The understanding of urban social-ecological systems requires integrated and interdisciplinary methods. This paper explores differences in the accessibility of urban green spaces (UGS) based on urban morphology. In contrast to other comparative analyses that followed simplified quantification of UGS provision and/or omitted the impact of morphological properties of urban space, this study proposes three improvements. First, it uses the share of UGS in the service area of 300 m walking distance around each residential building in a city as a measure of UGS provision. Second, it includes the potential physical accessibility of UGS as warranted by key actors, such as owners or managers, who decide whether UGS are open or not to potential users. Third, it links UGS accessibility and heterogeneous urban structures. We developed a mixed-methods analysis that combines multiple data sources regarding UGS, the spatial distribution of residential buildings, and street networks. We conducted our analysis in five case-study cities (Barcelona, Halle, Lodz, Oslo, and Stockholm). Our findings suggest that the urban structures where the human-environment interaction transformed the space (such as in the core city areas) are characterized by limited UGS in the service area. Urban structures that are less transformed by human activity (especially suburbia) have the highest share of selected UGS in the service area. In addition, even if the share of UGS in the service area is high, many of them might have limited physical accessibility. In the broader sense, this highlights that social-ecological processes are linked to urban form and cannot be separated in an analysis. Therefore, social-ecological systems could be better understood through the lens of urban morphology. [ABSTRACT FROM AUTHOR]

This paper presents a typology of ecological injustice hotspots for targeted design of nature-based solutions to guide planning and designing of just cities. The typology demonstrates how the needs and capabilities of nonhuman nature can be embedded within transitions to multi- and interspecies relational futures that regenerate and protect urban social-ecological systems. We synthesise the findings of previous quantitative and qualitative analyses to develop the Ecologically Just Cities Framework that (1) works as a diagnostic tool to characterise four types of urban ecological injustices and (2) identifies nature-based planning actions that can best respond to different types of place-based ecological injustices. [ABSTRACT FROM AUTHOR]

Present and future urbanization together with climate change and other uncertainties make urban quality of life a critical issue, and one that will need constant attention and deliberation. Across cities and contexts, urban ecosystems in the form of green and blue infrastructure, have the potential to contribute to human well-being as well as supporting biodiversity, and to do so under diverse conditions. However, the realization of this potential depends not only on the green and blue infrastructure itself, the well-being benefits are outcomes of the structures and processes of the entire urban system. Drawing on theory and insights from social-ecologicaltechnological systems (SETS) research and resilience assessments, we describe how a systemic understanding of the generation and delivery of green and blue infrastructure benefits may inform cross-sectoral strategies and interventions for building resilience around this particular aspect of human well-being. Connecting SETS to non-academic discourse and practice, we describe the urban system in terms of three systemic controlling variables: infrastructure, institutions, and the perceptions of individual beneficiaries, which we call filters, and how these can be used in different participatory processes to assess and build resilience around green and blue infrastructure and its benefits. To ground the conceptual and theoretical framework in real world complexity and make it operational in practice we discuss three case studies applying the framework in Barcelona, Halle, and Stockholm. All cases share the same general three-step process but their individual combinations of methods and adaptions of the filters framework are designed to fit with three necessarily unique collaborative, transdisciplinary processes. The cases are discussed in terms of outcomes and output, the ways they made use of the conceptual framework, and the challenges they faced. This exploratory work points to a new way of engaging with urban resilience--the strength of the approach is that it is not limited to the identification of specific interventions or policy options, nor trying to prevent change; rather it focuses on how to move with change and build resilience through constant balancing of different types of SETS change. Our study reinforces the growing understanding of how well-being benefits positioned as emergent outcomes of internal SETS interactions offers leverage for mainstreaming green and blue infrastructure throughout diverse governance processes and sectors. [ABSTRACT FROM AUTHOR]

Understanding opportunities as well as constraints for people to benefit from and take care of urban nature is an important step toward more sustainable cities. In order to explore, engage, and enable strategies to improve urban quality of life, we combine a social-ecological-technological systems framework with a flexible methodological approach to urban studies. The framework focuses on context dependencies in the flow and distribution of ecosystem service benefits within cities. The shared conceptual system framework supports a clear positioning of individual cases and integration of multiple methods, while still allowing for flexibility for aligning with local circumstances and ensuring context-relevant knowledge. To illustrate this framework, we draw on insights from a set of exploratory case studies used to develop and test how the framework could guide research design and synthesis across multiple heterogeneous cases. Relying on transdisciplinary multi- and mixed methods research designs, our approach seeks to both enable within-case analyses and support and gradually build a cumulative understanding across cases and city contexts. Finally, we conclude by discussing key questions about green and blue infrastructure and its contributions to urban quality of life that the approach can help address, as well as remaining knowledge gaps both in our understanding of urban systems and of the methodological approaches we use to fill these gaps. [ABSTRACT FROM AUTHOR]

Urban green and blue space interventions may bring about unintended consequences, involving trade-offs between the different land uses, and indeed, between the needs of different urban inhabitants, land users, and owners. Such trade-offs include choices between green/blue and non-green/blue projects, between broader land sparing vs. land sharing patterns, between satisfying the needs of the different inhabitants, but also between different ways of arranging the green and blue spaces. We analyze investment and planning initiatives in six case-study cities related to green and blue infrastructure (GBI) through the lens of a predefined set of questions--an analytical framework based on the assumption that the flows of benefits from GBI to urban inhabitants and other stakeholders are mediated by three filters: infrastructures, institutions, and perceptions. The paper builds on the authors' own knowledge and experience with the analyzed case-study cities and beyond, a literature overview, a review of the relevant city documents, and interviews with key informants. The case studies indicate examples of initiatives that were intended to make GBI benefits available and accessible to urban inhabitants, in recognition of GBI as spaces with diverse functionality. Some case studies provide examples of trade-offs in trying to plan and design a green space for multiple private and public interests in densely built-up areas. The unintended consequences most typically resulted from the underappreciation of the complexity of social-ecological systems and--more specifically--the complexity of the involved infrastructures, institutions, and perceptions. The most important challenges addressed in the paper include trade-offs between the different ways of satisfying the residents' different needs related to the benefits from ecosystem services, ensuring proper recognition of the inhabitants' needs and perceptions, ecogentrification, caveats related to the formalization of informal spaces, and the need to consider temporal dynamics and cross-scale approaches that compromise different goals at different geographical scales. [ABSTRACT FROM AUTHOR]

In New York City (NYC), the early period of the COVID-19 pandemic in the spring of 2020 induced a significant shift in the use and accessibility of urban green spaces (UGS). To understand the impact of COVID-19 on the access to UGS, we conducted a spatial analysis of geographic access to UGS and perceived access based on data collected from a social survey deployed from May 13 to June 15, 2020. We examine geographical accessibility to UGS and how this compares to perceived accessibility, or the ease which residents feel they can access a UGS. We further explored the correlation between spatial access to UGS and fifteen social vulnerability variables including economic status, household composition, minority status, and housing type for different zip codes. The results show that geographical proximity variables can predict a number of the perceived access variables, particularly those related to COVID-19 measures. Although lower-income communities were found to have higher spatial access to UGS, many of the same communities, including people living in crowded and multi-unit buildings, on average only have access to smaller green spaces, suggesting an uneven distribution of larger quality parks. This observation is further confirmed by survey results. These findings have implications for policies surrounding the distribution of UGS and whether equitable access is provided to NYC residents, with implications for similar patterns that may exist in other cities. • We compare geographical access to urban green spaces (UGS) with perceived access. • Geographical accessibility can predict perceived concerns regarding social distancing. • UGS environmental justice implications are related to perceptions of UGS qualities. • We overlap COVID-19 vulnerabilities with the availability of UGS at the zip code level. • Many working-class neighborhoods are highly impacted by COVID-19 and have smaller UGS. [ABSTRACT FROM AUTHOR]

As cities face increasing pressure from densification trends, green roofs represent a valuable source of ecosystem services for residents of compact metropolises where available green space is scarce. However, to date little research has been conducted regarding the holistic benefits of green roofs at a citywide scale, with local policymakers lacking practical guidance to inform expansion of green roofs coverage. The study addresses this issue by developing a spatial multi-criteria screening tool applied in Barcelona, Spain to determine: 1) where green roofs should be prioritized in Barcelona based on expert elicited demand for a wide range of ecosystem services and 2) what type of design of potential green roofs would optimize the ecosystem service provision. As inputs to the model, fifteen spatial indicators were selected as proxies for ecosystem service deficits and demands (thermal regulation, runoff control, habitat and pollination, food production, recreation, and social cohesion) along with five decision alternatives for green roof design (extensive, semi-intensive, intensive, naturalized, and allotment). These indicators and alternatives were analyzed probabilistically and spatially, then weighted according to feedback from local experts. Results of the assessment indicate that there is high demand across Barcelona for the ecosystem services that green roofs potentially might provide, particularly in dense residential neighborhoods and the industrial south. Experts identified habitat, pollination and thermal regulation as the most needed ES with runoff control and food production as the least demanded. Naturalized roofs generated the highest potential ecosystem service provision levels for 87.5% of rooftop area, apart from smaller areas of central Barcelona where intensive rooftops were identified as the preferable green roof design. Overall, the spatial model developed in this study offers a flexible screening based on spatial multi-criteria decision analysis that can be easily adjusted to guide municipal policy in other cities considering the effectiveness of green infrastructure as source of ecosystem services. Unlabelled Image • The article addresses the question of where to build green roofs most effectively with regard to citizen needs. • A spatial multi-criteria screening tool for the creation of green roofs is developed. • Ecosystem service deficits are spatially defined by combined social-ecological evaluation criteria. • Finally, the optimal green roof design for an effective ecosystem service provision is determined. [ABSTRACT FROM AUTHOR]

The circumstances under which different ecosystem service benefits can be realized differ. The benefits tend to be coproduced and to be enabled by multiple interacting social, ecological, and technological factors, which is particularly evident in cities. As many cities are undergoing rapid change, these factors need to be better understood and accounted for, especially for those most in need of benefits. We propose a framework of three systemic filters that affect the flow of ecosystem service benefits: the interactions among green, blue, and built infrastructures; the regulatory power and governance of institutions; and people's individual and shared perceptions and values. We argue that more fully connecting green and blue infrastructure to its urban systems context and highlighting dynamic interactions among the three filters are key to understanding how and why ecosystem services have variable distribution, continuing inequities in who benefits, and the long-term resilience of the flows of benefits. [ABSTRACT FROM AUTHOR]

Understanding why some parks are used more regularly or intensely than others can inform ways in which urban parkland is developed and managed to meet the needs of a rapidly expanding urban population. Although geolocated social media (GSM) indicators have been used to examine park visitation rates, studies applying this approach are generally limited to flagship parks, national parks, or a small subset of urban parks. Here, we use geolocated Flickr and Twitter data to explore variation in use across New York City's 2143 diverse parks and model visitation based on spatially-explicit park characteristics and facilities, neighborhood-level accessibility features and neighborhood-level demographics. Findings indicate that social media activity in parks is positively correlated with proximity to public transportation and bike routes, as well as particular park characteristics such as water bodies, athletic facilities, and impervious surfaces, but negatively associated with green space and increased proportion of minority ethnicity and minority race in neighborhoods in which parks are located. Contrary to previous studies which describe park visitation as a form of nature-based recreation, our findings indicate that the kinds of green spaces present in many parks may not motivate visitation. From a social equity perspective, our findings may imply that parks in high-minority neighborhoods are not as accessible, do not accommodate as many visitors, and/or are of lower quality than those in low-minority neighborhoods. These implications are consistent with previous studies showing that minority populations disproportionately experience barriers to park access. In applying GSM data to questions of park access, we demonstrate a rapid, big data approach for providing information crucial for park management in a way that is less resource-intensive than field surveys. Highlights • We analyze geographic human visitation dynamics in all New York City parks using Twitter and Flickr data • Park visitation increases with proximity to public transportation, water bodies, athletic fields and impervious surfaces • Park visitation decreases with green space and proportion of minority ethnicity and minority race in neighborhoods of parks • Location-based social media data can be used as a rapid indicator for citywide park visitation to inform management [ABSTRACT FROM AUTHOR]

Research on urban ecosystems rapidly expanded in the 1990s and is now a central topic in ecosystem science. In this paper, we argue that there are two critical challenges for ecosystem science that are rooted in urban ecosystems: (1) predicting or explaining the assembly and function of novel communities and ecosystems under altered environmental conditions and (2) refining understanding of humans as components of ecosystems in the context of integrated social-ecological systems. We assert that these challenges are also linchpins in the further development of sustainability science and argue that there is a strong need for a new initiative in urban systems science to address these challenges and catalyze the next wave of fundamental advances in ecosystem science, and more broadly in interdisciplinary and transdisciplinary science. [ABSTRACT FROM AUTHOR]

Defining landscape structure and key relationships between landscape structure and function is challenging in urban areas characterized by density and patchy spatial patterns. In order to trace the spatial and temporal patterns of urban landscape structures, compare patterns across cities, or inform urban design principles, we need to classify the landscape in a way that captures context and landscape heterogeneity, but can be broadly applied across different cities or landscape variations within a city. In this study, we introduce a simple and reproducible approach for classifying the structure of urban landscapes (STURLA) that utilizes heterogeneous, composite classes which represent combinations of built and natural features, and examine the response of a landscape function – surface temperature. This classification approach is unique in that it develops composite (as opposed to homogeneous) classes, which are defined a posteriori, based on compositions of adjacent structural elements that emerge in the urban landscape, using a cellular grid to define units of analysis. We test the separability of classes that emerge from this approach, and find that it is possible to discern classes – comprised of the mix of land and building covers common in urban areas – which have meaningfully distinct temperature signatures. This classification approach may be extended to multiple cities and ecological indicators in order to offer insight into the relationship between urban landscape structure and ecosystem response, in a way that accounts for interactions among different types of urban landscape surfaces. We suggest that this approach can support spatial prioritization of landscape function needs in urban development and design approaches for improving particular types of functioning, such as reductions in urban heat. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of urban ecosystem services is a necessary requirement for adequate planning, management, and governance of urban green infrastructure. Through the three-year Urban Biodiversity and Ecosystem Services (URBES) research project, we conducted case study and comparative research on urban biodiversity and ecosystem services across seven cities in Europe and the United States. Reviewing > 50 peer-reviewed publications from the project, we present and discuss seven key insights that reflect cumulative findings from the project as well as the state-of-the-art knowledge in urban ecosystem services research. The insights from our review indicate that cross-sectoral, multiscale, interdisciplinary research is beginning to provide a solid scientific foundation for applying the ecosystem services framework in urban areas and land management. Our review offers a foundation for seeking novel, nature-based solutions to emerging urban challenges such as wicked environmental change issues. [ABSTRACT FROM AUTHOR]

The article focuses on the aspects of considering workspaces to improve the ecosystem-service (ES) assessment combined with decision-support tools in urban systems. It explores the aspects of the research frontiers discovered by researchers which include the complex dynamic of ES considering space and time, the association between ES provision and human well-being, and the determination of technological potential to enhance or substitute ES.

This study introduces a novel approach to classifying urban structure using land cover and building height. The goal of the study was to improve comparability of urban structure–function relationships across cities through development of a novel classification framework that can facilitate urban studies of ecological patterns and processes. We tested the suitability of the classification in two very different urban settings – continental Berlin and coastal New York City. Using Landsat temperature data as an ecological function variable, we compared how urban structures in both cities relate to temperature. Results show that in both cities a large range of urban structure classes show similar trends with respect to land surface temperature, despite differences in climate and structure of the two cities. We found that approximately 68% of the area of Berlin and 79% of the area of New York City can be represented with the same fifteen urban structure classes. Results indicate that these common classes share very similar temperature patterns and may indicate broader utility of the classification framework. Among the classes which have the most dissimilar temperature trends between the two cities, we find large differences in inner-class composition and neighboring classes. Findings also show that the presence of water has a strong influence on temperature regulation, as classes containing water have the lowest surface temperatures, indicating a need for prioritizing aquatic ecosystems in urban planning and management. [ABSTRACT FROM AUTHOR]

Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world's population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio-physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy. [ABSTRACT FROM AUTHOR]

Cellular automata (CA) models have increasingly been used to simulate land use/cover changes (LUCC). Metaheuristic optimization algorithms such as particle swarm optimization (PSO) and genetic algorithm (GA) have been recently introduced into CA frameworks to generate more accurate simulations. Although Markov Chain Monte Carlo (MCMC) is simpler than PSO and GA, it is rarely used to calibrate CA models. In this article, we introduce a novel multi-chain multi-objective MCMC (mc-MO-MCMC) CA model to simulate LUCC. Unlike the classical MCMC, the proposed mc-MO-MCMC is a multiple chains method that imports crossover operation from classical evolutionary optimization algorithms. In each new chain, after the initial one, the crossover operator generates the initial solution. The selection of solutions to be crossed over are made according to their fitness score. In this paper, we chose the example of New York City (USA) to apply our model to simulate three conflicting objectives of changes from non-urban to low-, medium- or high-density urban between 2001 and 2016 using USA National Land Cover Database (NLCD). Elevation, slope, Euclidean distance to highways and local roads, population volume and average household income are used as LUCC causative factors. Furthermore, to demonstrate the efficiency of our proposed model, we compare it with the multi-objective genetic algorithm (MO-GA) and standard single-chain multi-objective MCMC (sc-MO-MCMC). Our results demonstrate that mc-MO-MCMC produces accurate simulations of land use dynamics featured by faster convergence to the Pareto frontier comparing to MO-GA and sc-MO-MCMC. The proposed multi-objective cellular automata model should efficiently help to simulate a trade-off among multiple and, possibly, conflicting land use change dynamics at once. • This paper presents a multi-objective CA land use/cover change model. • The model uses a novel multi-objective Markov chain Monte Carlo (MO-MCMC). • We compare MO-MCMC with a multi-objective genetic algorithm (MO-GA). • We apply our model to simulate the expansion of multi-density urban areas in New York. • The results show that the MO-MCMC outperformed MO-GA in terms of accuracy and speed. [ABSTRACT FROM AUTHOR]

The urban heat island effect creates warmer and drier conditions in urban areas than in their surrounding rural areas. This effect is predicted to be exacerbated in the future, under a climate change scenario. One way to mitigate this effect is to use the urban green infrastructure as a way to promote the cooling island effect. In this study we aimed to model, with a high spatial resolution, how Mediterranean urban parks can be maximized to be used as cooling islands, by answering the following questions: i) which factors influence the cooling effect and when?; ii) what type of green spaces contributes the most to the cooling effect?; iii) what is the cooling distance of influence? To answer these questions we established a sampling design where temperature and relative humidity were measured in different seasons, in locations with contrasting characteristics of green and grey cover. We were able to model the effect of green and grey spaces in the cooling island effect and build high spatial resolution predicting maps for temperature and relative humidity. Our study showed that even green spaces with reduced areas can regulate microclimate, alleviating temperature by 1–3 °C and increasing moisture by 2–8%, on average. Green spaces with a higher density of trees were more efficient in delivering the cooling effect. The morphology, aspect and level of exposure of grey surfaces to the solar radiation were also important features included in the models. Green spaces influenced temperature and relative humidity up to 60 m away from the parks' limits, whereas grey areas influenced in a much lesser range, from 5 m up to 10 m. These models can now be used by citizens and stakeholders for green spaces management and human well-being impact assessment. Unlabelled Image • Urban planning needs high spatial resolution information to mitigate the urban heat island effect. • Land-cover type (green and grey spaces) and urban morphology strongly influence the cooling island effect. • Parks with high density of trees reduce temperature (1-3° C) and increase relative humidity (2-8%) mostly during summer. • Tree canopy area influences temperature and relative humidity as far as 60 m. [ABSTRACT FROM AUTHOR]