Showing papers on "Urban ecosystem published in 2018"

Extraction of Urban Water Bodies from High-Resolution Remote-Sensing Imagery Using Deep Learning

Abstract: Accurate information on urban surface water is important for assessing the role it plays in urban ecosystem services in the context of human survival and climate change. The precise extraction of urban water bodies from images is of great significance for urban planning and socioeconomic development. In this paper, a novel deep-learning architecture is proposed for the extraction of urban water bodies from high-resolution remote sensing (HRRS) imagery. First, an adaptive simple linear iterative clustering algorithm is applied for segmentation of the remote-sensing image into high-quality superpixels. Then, a new convolutional neural network (CNN) architecture is designed that can extract useful high-level features of water bodies from input data in a complex urban background and mark the superpixel as one of two classes: an including water or no-water pixel. Finally, a high-resolution image of water-extracted superpixels is generated. Experimental results show that the proposed method achieved higher accuracy for water extraction from the high-resolution remote-sensing images than traditional approaches, and the average overall accuracy is 99.14%.

The role of socio-economic factors in planning and managing urban ecosystem services

Abstract: How green spaces in cities benefit urban residents depends critically on the interaction between biophysical and socio-economic factors. Urban ecosystem services are affected by both ecosystem characteristics and the social and economic attributes of city dwellers. Yet, there remains little synthesis of the interactions between ecosystem services, urban green spaces, and socio-economic factors. Articulating these linkages is key to their incorporation into ecosystem service planning and management in cities and to ensuring equitable outcomes for city inhabitants. We present a conceptual model of these linkages, describe three major interaction pathways, and explore how to operationalize the model. First, socio-economic factors shape the quantity and quality of green spaces and their ability to supply services by influencing management and planning decisions. Second, variation in socio-economic factors across a city alters people’s desires and needs and thus demands for different ecosystem services. Third, socio-economic factors alter the type and amount of benefit for human wellbeing that a service provides. Integrating these concepts into green space policy, planning, and management would be a considerable improvement on ‘standards-based’ urban green space planning. We highlight the implications of this for facilitating tailored planning solutions to improve ecosystem service benefits across the socio-economic spectrum in cities.

Linking ecosystem services, urban form and green space configuration using multivariate landscape metric analysis.

Abstract: Landscape metrics represent powerful tools for quantifying landscape structure, but uncertainties persist around their interpretation. Urban settings add unique considerations, containing habitat structures driven by the surrounding built-up environment. Understanding urban ecosystems, however, should focus on the habitats rather than the matrix. We coupled a multivariate approach with landscape metric analysis to overcome existing shortcomings in interpretation. We then explored relationships between landscape characteristics and modelled ecosystem service provision. We used principal component analysis and cluster analysis to isolate the most effective measures of landscape variability and then grouped habitat patches according to their attributes, independent of the surrounding urban form. We compared results to the modelled provision of three ecosystem services. Seven classes resulting from cluster analysis were separated primarily on patch area, and secondarily by measures of shape complexity and inter-patch distance. When compared to modelled ecosystem services, larger patches up to 10 ha in size consistently stored more carbon per area and supported more pollinators, while exhibiting a greater risk of soil erosion. Smaller, isolated patches showed the opposite, and patches larger than 10 ha exhibited no additional areal benefit. Multivariate landscape metric analysis offers greater confidence and consistency than analysing landscape metrics individually. Independent classification avoids the influence of the urban matrix surrounding habitats of interest, and allows patches to be grouped according to their own attributes. Such a grouping is useful as it may correlate more strongly with the characteristics of landscape structure that directly affect ecosystem function.

Homogenization of plant diversity, composition, and structure in North American urban yards

Abstract: Urban ecosystems are widely hypothesized to be more ecologically homogeneous than natural ecosystems. We argue that urban plant communities assemble from a complex mix of horticultural and regional species pools, and evaluate the homogenization hypothesis by comparing cultivated and spontaneously occurring urban vegetation to natural area vegetation across seven major U.S. cities. There was limited support for homogenization of urban diversity, as the cultivated and spontaneous yard flora had greater numbers of species than natural areas, and cultivated phylogenetic diversity was also greater. However, urban yards showed evidence of homogenization of composition and structure. Yards were compositionally more similar across regions than were natural areas, and tree density was less variable in yards than in comparable natural areas. This homogenization of biodiversity likely reflects similar horticultural source pools, homeowner preferences, and management practices across U.S. cities.

Mapping Urban Green Infrastructure: A Novel Landscape-Based Approach to Incorporating Land Use and Land Cover in the Mapping of Human-Dominated Systems

Abstract: Common approaches to mapping green infrastructure in urbanised landscapes invariably focus on measures of land use or land cover and associated functional or physical traits. However, such one-dimensional perspectives do not accurately capture the character and complexity of the landscapes in which urban inhabitants live. The new approach presented in this paper demonstrates how open-source, high spatial and temporal resolution data with global coverage can be used to measure and represent the landscape qualities of urban environments. Through going beyond simple metrics of quantity, such as percentage green and blue cover, it is now possible to explore the extent to which landscape quality helps to unpick the mixed evidence presented in the literature on the benefits of urban nature to human well-being. Here we present a landscape approach, employing remote sensing, GIS and data reduction techniques to map urban green infrastructure elements in a large U.K. city region. Comparison with existing urban datasets demonstrates considerable improvement in terms of coverage and thematic detail. The characterisation of landscapes, using census tracts as spatial units, and subsequent exploration of associations with social–ecological attributes highlights the further detail that can be uncovered by the approach. For example, eight urban landscape types identified for the case study city exhibited associations with distinct socioeconomic conditions accountable not only to quantities but also qualities of green and blue space. The identification of individual landscape features through simultaneous measures of land use and land cover demonstrated unique and significant associations between the former and indicators of human health and ecological condition. The approach may therefore provide a promising basis for developing further insight into processes and characteristics that affect human health and well-being in urban areas, both in the United Kingdom and beyond.

Current and historical land use influence soil-based ecosystem services in an urban landscape

Abstract: Urban landscapes are increasingly recognized as providing important ecosystem services (ES) to their occupants. Yet, urban ES assessments often ignore the complex spatial heterogeneity and land-use history of cities. Soil-based services may be particularly susceptible to land-use legacy effects. We studied indicators of three soil-based ES, carbon storage, water quality regulation, and runoff regulation, in a historically agricultural urban landscape and asked (1) How do ES indicators vary with contemporary land cover and time since development? (2) Do ES indicators vary primarily among land-cover classes, within land-cover classes, or within sites? (3) What is the relative contribution of urban land-cover classes to potential citywide ES provision? We measured biophysical indicators (soil carbon [C], available phosphorus [P], and saturated hydraulic conductivity [Ks ]) in 100 sites across five land-cover classes, spanning an ~125-year gradient of time since development within each land-cover class. Potential for ES provision was substantial in urban green spaces, including developed land. Runoff regulation services (high Ks ) were highest in forests; water quality regulation (low P) was highest in open spaces and grasslands; and open spaces and developed land (e.g., residential yards) had the highest C storage. In developed land covers, both C and P increased with time since development, indicating effects of historical land-use on contemporary ES and trade-offs between two important ES. Among-site differences accounted for a high proportion of variance in soil properties in forests, grasslands, and open space, while residential areas had high within-site variability, underscoring the leverage city residents have to improve urban ES provision. Developed land covers contributed most ES supply at the citywide scale, even after accounting for potential impacts of impervious surfaces. Considering the full mosaic of urban green space and its history is needed to estimate the kinds and magnitude of ES provided in cities, and to augment regional ES assessments that often ignore or underestimate urban ES supply.

CityScope: A Data-Driven Interactive Simulation Tool for Urban Design. Use Case Volpe

Abstract: MIT City Science Group (CS) studies the interaction of social, economic and physical characteristics of urban areas to understand how people use and experience cities with the goal of improving urban design practices to facilitate consensus between stakeholders Long-established processes of engagement around urban transformation have been reliant on visual communication and complex negotiation to facilitate coordination between stakeholders, including community members, administrative bodies and technical professionals City Science group proposes a novel methodology of interaction and collaboration called CityScope, a data-driven platform that simulates the impacts of interventions on urban ecosystems prior to detail-design and execution As stakeholders collectively interact with the platform and understand the impact of proposed interventions in real-time, consensus building and optimization of goals can be achieved In this article, we outline the methodology behind the basic analysis and visualization elements of the tool and the tangible user interface, to demonstrate an alternate solution to urban design strategies as applied to the Volpe Site case study in Kendall Square, Cambridge, MA

Social acceptance and perceived ecosystem services of urban agriculture in Southern Europe: The case of Bologna, Italy.

Abstract: Urban agriculture has become a common form of urban land use in European cities linked to multiple environmental, social and economic benefits, as well as to diversified forms (from self-production allotments to high-tech companies). Social acceptance will determine the development of urban agriculture and specific knowledge on citizens’ perception is required in order to set the basis for policy-making and planning. The ecosystem services provided by urban agriculture can be determinant in this process. The goal of this paper is to evaluate the social acceptance and the perceived ecosystem services of urban agriculture in the city of Bologna (Italy), as an example of a Southern European city. In particular, we evaluated the preferences for urban land uses, for different typologies of urban agriculture and for the resulting products, the perceived provision of ecosystem services and the willingness to engage in new initiatives. A survey that investigated these topics (including open questions, closed questions and Likert-scale evaluation) was performed on the citizens of Bologna (n = 380) between October and November 2016. Results showed that urban agriculture is widely accepted by the inhabitants of Bologna, particularly regarding vegetable production. Although intensive farming systems were the least preferred forms to be implemented in Bologna, citizens highly accepted a large variety of urban agriculture goods, with preference for those obtained from plants as compared to animal products. The willingness-to-pay for urban food products was mostly the same as for conventional ones, although the participants recognised the social values, proximity and quality of the former. Socio-cultural ecosystem services were perceived as more valuable than environmental ones. Policy-making recommendations can be extracted from the results to facilitate the development of urban agriculture plans and policies.

Land use history and seed dispersal drive divergent plant community assembly patterns in urban vacant lots

Abstract: Summary Despite high levels of disturbance and habitat modification, urban ecosystems still host substantial levels of biodiversity. The processes that maintain existing levels of diversity, however, remain understudied. Identifying the links between urban ecological processes and patterns has, therefore, become a fundamental research goal to support urban biodiversity and ecosystem functioning. We conducted a study to determine how the diversity and composition of urban plant communities is affected by spatially and temporally variable land use legacies. We constructed a chronosequence of vacant lot properties covering a range of 3-22 years since demolition, in an urban neighborhood in Baltimore, Maryland (USA). Surveys of herbaceous plant species abundance were conducted during the summers of 2012 and 2013 in sections of each vacant lot where the building previously stood (the ‘building footprint’) and sections of the lot that was previously a backyard or garden (the ‘remnant garden’). We found divergent patterns in plant community composition between areas of vacant lots with varying land use histories. This includes significant shifts in the functional composition of biotically-vectored seed dispersal strategies, as well as an increase in seed mass and terminal velocity trait values of plant communities in building footprints over time. Additionally, we found that plant communities in different sections of the same vacant lot tended to become more functionally dissimilar in seed dispersal strategies over time. In contrast, we found no significant changes in taxonomic diversity over time for any of our measures. Policy implications. Our study suggests that regional-scale patterns of seed dispersal interact with diverse land use legacies to structure the plant communities of urban vacant lots. Although it has been suggested that highly altered local environmental conditions and competition from introduced species limit native plant diversity in urban environments, we find seed dispersal to be a more significant driver of urban plant community assembly patterns. Implementing management strategies that focus on habitat connectivity and enhancing species pools via seeding may present an effective strategy for promoting more successful establishment of diverse plant communities in urban environments. This article is protected by copyright. All rights reserved.

A Gardener's Influence on Urban Soil Quality

Abstract: Gardens are hot spots for urban biodiversity and provide habitats for many plant and animal spe- cies, both above- and below-ground. Furthermore, gardens provide a wide range of ecosystem services, including carbon (C) storage and nutrient cycling. Although the soil is the foundation of sustainable gardens providing those ecosystem services, very little is known about the conseque- nces of garden management on soil quality. Here we present a comprehensive assessment of urban garden soil quality, including biotic and abiotic site characteristics combined with land-use history and garden management information in a multivariate evaluation. A set of 44 soil quality indicators was measured at 170 sites of 85 gardens in the city of Zurich, Switzerland, comprising contrastingly managed garden habitats along a gradient of urban density. Taken together, our results show that garden management was the driving factor that influenced soil quality and soil functions. Eco-physiological soil quality indices were useful to identify differences in disturbance and intensity of soil use, showing highest microbial (microbial biomass (Cmic)/soil organic carbon (SOC)) and lowest metabolic (qCO2) quotients in perennial grass sites compared to annual vegetable sites. Despite the intensity of soil disturbance in annual vegetable and flower beds, the highest endogeic earthworm biomass and diversity were found in those habitats. Whereas decomposition of green tea bags was higher in grass sites. Soil heavy metal contents varied considerably and could not be linked with garden management practices, but with spatial patterns of industry and traffic. We conclude that understanding soil quality in urban ecosystems needs multi-indicator frameworks to capture the complexity of soil characteristics and the influencing factors in space and time. This study contributes to a better understanding of urban gardens and enhances the development of sustainable soil management strategies aimed at long-term improvement of soil quality and related ecosystem services in cities.

Consumer demand for urban forest ecosystem services and disservices: Examining trade-offs using choice experiments and best-worst scaling

Abstract: Many studies value urban ecosystem service benefits using residents’ willingness to pay and supply-side analyses of ecosystem attributes. But, few studies account for consumer demand and ecosystem disservices. To address this gap we surveyed 1052 homeowners eliciting consumer demand for key urban forest ecosystem attributes and service-disservice levels in both their properties and surrounding neighborhood. We use an approach integrating focus group, field data, and surveys to identify consumer preferences and trade-offs between urban forest ecosystem structure-functional attributes and their level of services and disservices. This method, called best worst choice, produces more estimates of utility while reducing the likelihood of introducing biases associated with human cognitive tendencies. Results indicate that consumer choices for property value were highest followed by tree condition, a structural proxy for minimizing disservices, and tree shade, a functional proxy for temperature regulation. We also found evidence of trade-offs in demand for different ecosystem services, significant scale effects, and that willingness to pay for ecosystem disservices was negative. Findings suggest that management, and studies that value and map ecosystem services, using fixed scales should account for end-user demand and functional traits, as consumers can discern trade-offs in benefits and disservices across different cognitive and spatial scales.

Empowering Citizens Toward the Co-Creation of Sustainable Cities

Abstract: Urban ecosystems are becoming one of the most potentially attractive scenarios for innovating new services and technologies. In parallel, city managers, urban utilities, and other stakeholders are fostering the intensive use of advanced technologies aiming at improving present city performance and sustainability. The deployment of such technology entails the generation of massive amounts of information which in many cases might become useful for other services and applications. Hence, aiming at taking advantage of such massive amounts of information and deployed technology as well as breaking down the potential digital barrier, some easy-to-use tools have to be made available to the urban stakeholders. These tools integrated in a platform, operated directly, or indirectly by the city, provide a singular opportunity for exploiting the concept of connected city whilst promoting innovation in all city dimensions and making the co-creation concept a reality, with an eventual impact on government policies.

Widespread loss of intermediate soil horizons in urban landscapes.

Abstract: Soils support terrestrial ecosystem function and therefore are critical urban infrastructure for generating ecosystem services. Urbanization processes modify ecosystem function by changing the layers of soils identified as soil horizons. Soil horizons are integrative proxies for suites of soil properties and as such can be used as an observable unit to track modifications within soil profiles. Here, in an analysis of 11 cities representing 10 of the 12 soil orders, we show that urban soils have ∼50% fewer soil horizons than preurban soils. Specifically, B horizons were much less common in urban soils and were replaced by a deepening of A horizons and a shallowing of C horizons. This shift is likely due to two processes: (i) local management, i.e., soil removal, mixing, and fill additions, and (ii) soil development timelines, i.e., urbanized soils are young and have had short time periods for soil horizon development since urbanization (decades to centuries) relative to soil formation before urbanization (centuries to millennia). Urban soils also deviated from the standard A-B-C horizon ordering at a much greater frequency than preurban soils. Overall, our finding of common shifts in urban soil profiles across soil orders and cities suggests that urban soils may function differently from their preurban antecedents. This work introduces a basis for improving our understanding of soil modifications by urbanization and its potential effects on ecosystem functioning and thereby has implications for ecosystem services derived from urban landscapes.

Nature Based Strategies for Urban and Building Sustainability

Abstract: Nature Based Strategies for Urban and Building Sustainability reviews the current state-of-the-art on the topic. In the introduction, the editors review the fundamental concepts of nature elements in the built environment, along with the strategies that are necessary for their inclusion in buildings and cities. Part One describes strategies for the urban environment, discussing urban ecosystems and ecosystem services, while Part Two covers strategies and technologies, including vertical greening systems, green roofs and green streets. Part Three covers the quantitative benefits, results, and issues and challenges, including energy performances and outdoor comfort, air quality improvement, acoustic performance, water management and biodiversity. Provides an overview of the different strategies available to integrate nature in the built environmentPresents the current state of technology concerning systems and methodologies on how to incorporate nature in buildings and citiesFeatures the latest research results on operation and ecosystem servicesCovers both established and new designs, including those still in the experimental stage