93,058 research outputs found

    Ten Bee Species New to Green Roofs in the Chicago Area

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    Green roofs increasingly provide habitat for many insects in urban environments. Pollinators such as bees may utilize foraging and nesting resources provided by green roofs but few studies have documented which species occur in these novel habitats. This study identified bees from 26 species, 11 genera and 5 families collected from 7 green roofs using pan trapping methods over 2 years. Ten of these species have not previously been recorded on green roofs in the Chicago region. Although the majority of bee species collected were solitary, soil-nesting, and native to Illinois, the proportion of exotic species was high compared to previous collections from Chicago area green roofs and urban parks. Urban green roofs may enhance populations of both native and exotic bees, but their ability to support the same range of native diversity recorded from other urban habitats requires further investigation

    Do looks matter? A case study on extensive green roofs using discrete choice experiments

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    Extensive green roofs are a promising type of urban green that can play an important role in climate proofing and ultimately in the sustainability of our cities. Despite their increasingly widespread application and the growing scientific interest in extensive green roofs, their aesthetics have received limited scientific attention. Furthermore, several functional issues occur, as weedy species can colonize the roof, and extreme roof conditions can lead to gaps in the vegetation. Apart from altering the function of a green roof, we also expect these issues to influence the perception of extensive green roofs, possibly affecting their acceptance and application. We therefore assessed the preferences of a self-selected convenience sample of 155 Flemish respondents for visual aspects using a discrete choice experiment. This approach, combined with current knowledge on the psychological aspects of green roof visuals, allowed us to quantify extensive green roof preferences. Our results indicate that vegetation gaps and weedy species, together with a diverse vegetation have a considerable impact on green roof perception. Gaps were the single most important attribute, indicated by a relative importance of ca. 53%, with cost coming in at a close second at ca. 46%. Overall, this study explores the applicability of a stated preference technique to assess an often overlooked aspect of extensive green roofs. It thereby provides a foundation for further research aimed at generating practical recommendations for green roof construction and maintenance

    Composition and Diversity of Avian Communities Using a New Urban Habitat: Green Roofs

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    Green roofs on buildings are becoming popular and represent a new component of the urban landscape. Public benefits of green roof projects include reduced stormwater runoff, improved air quality, reduced urban heat island effects, and aesthetic values. As part of a city-wide plan, several green roofs have been constructed at Chicago’s O’Hare International Airport (ORD). Like some other landscaping features, green roofs on or near an airport might attract wildlife and thus increase the risk of bird–aircraft collisions. During 2007–2011, we conducted a series of studies to evaluate wildlife use of newly constructed green roofs and traditional (gravel) roofs on buildings at ORD. These green roofs were 0.04–1.62 ha in area and consisted of primarily stone crop species for vegetation. A total of 188 birds were observed using roofs during this research. Of the birds using green roofs, 66, 23, and 4 % were Killdeer, European Starlings, and Mourning Doves, respectively. Killdeer nested on green roofs, whereas the other species perched, foraged, or loafed. Birds used green roofs almost exclusively between May and October. Overall, avian use of the green roofs was minimal and similar to that of buildings with traditional roofs. Although green roofs with other vegetation types might offer forage or cover to birds and thus attract potentially hazardous wildlife, the stonecrop-vegetated green roofs in this study did not increase the risk of bird–aircraft collisions

    Composition and Diversity of Avian Communities Using a New Urban Habitat: Green Roofs

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    Green roofs on buildings are becoming popular and represent a new component of the urban landscape. Public benefits of green roof projects include reduced stormwater runoff, improved air quality, reduced urban heat island effects, and aesthetic values. As part of a city-wide plan, several green roofs have been constructed at Chicago’s O’Hare International Airport (ORD). Like some other landscaping features, green roofs on or near an airport might attract wildlife and thus increase the risk of bird–aircraft collisions. During 2007–2011, we conducted a series of studies to evaluate wildlife use of newly constructed green roofs and traditional (gravel) roofs on buildings at ORD. These green roofs were 0.04–1.62 ha in area and consisted of primarily stone crop species for vegetation. A total of 188 birds were observed using roofs during this research. Of the birds using green roofs, 66, 23, and 4 % were Killdeer, European Starlings, and Mourning Doves, respectively. Killdeer nested on green roofs, whereas the other species perched, foraged, or loafed. Birds used green roofs almost exclusively between May and October. Overall, avian use of the green roofs was minimal and similar to that of buildings with traditional roofs. Although green roofs with other vegetation types might offer forage or cover to birds and thus attract potentially hazardous wildlife, the stonecrop-vegetated green roofs in this study did not increase the risk of bird–aircraft collisions

    Green Roofs Support a Wide Diversity of Collembola in Urban Portland, Oregon

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    Green roofs can help address habitat loss in urban areas by supporting plant and animal communities. To determine whether green roofs can support collembola biodiversity, we collected pitfall samples from April-June 2015 on two extensive and two intensive green roofs in urban Portland, Oregon. Twenty morphospecies were found across the roofs, indicating that green roofs support a diversity of collembola taxa. The intensive roofs were more biodiverse than the extensive, though roof type may not be the most significant factor affecting collembolan biodiversity. Each of the four green roofs were characterized by a different and unique most dominant morphospecies, and, indeed, each roof possessed a different set of top-three abundant collembola taxa. While green roofs support moderate collembola diversity, preserving natural habitat is important to maintain species richness

    Development of modular green roofs for high-density urban cities

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    Stream A: Lifecyle of implementing green roofs and green wallsMany cities are facing problems of urban heat island and lack of greenery space. Green roofs can help mitigate the adverse effects and bring the nature back to the urban area. To apply them effectively, it is important to evaluate the constraints and identify critical factors for planning and designing the green roofs. Modular green roofs have a good potential to suit high-density urban conditions because they can offer better flexibility, convenience and cost optimisation. This paper presents the research findings to develop modular green roof systems for high-density urban cities. Three different types of modular green roofs, including mat, tray and sack systems, were studied by assessing their designs and characteristics. The urban environment and typical buildings for green roof applications in Hong Kong were evaluated. Useful information was obtained to help design and select modular green roofs that can fit into high-density urban environment. In Hong Kong, the high-rise buildings have very limited roof spaces. It is usually more effective to apply green roofs to the top of medium- or low-rise buildings/structures or the intermediate podium roofs. For existing buildings, as they often have constraints on roof structural loading, it is necessary to select extremely lightweight systems. Modular green roofs can be designed to achieve this by adopting suitable vegetation and components. They can also provide greater flexibility for instant greening, future modification and maintenance. By optimising the manufacturing, nursery and installation processes, it is possible to reduce the unit cost of green roofs and allow wider spread.postprintThe 2008 World Green Roof Congress, London, 17-18 September 2008

    Feasibility of Green Roofs in the Main South Community of Worcester, Massachusetts

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    The goal of our project was to determine the feasibility of installing green roofs in two locations and determine other possible sites in Main South. Green roofs weigh 11 psf to 80+ psf. Roofs need to support their own weight, the green roof, and the code loads. Green roofs cost between 23/sfand23/sf and 31/sf. There are 47 acres of flat roofs within the 450 acres of combined sewer area in Main South. We identified 57 possible green roof sites

    Green roof - understanding their benefits for Australia

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    Summary of Actions Towards Sustainable Outcomes Environmental Issues / Principal Impacts The increased growth of cities is intensifying its impact on people and the environment through: • increased use of energy for the heating and cooling of more buildings, leading to urban heat islands and more greenhouse gas emissions • increased amount of hard surfaces contributing to higher temperatures in cities and more stormwater runoff • degraded air quality and noise impact • reduced urban biodiversity • compromised health and general well-being of people Basic Strategies In many design situations boundaries and constraints limit the application of cutting EDGe actions. In these circumstances designers should at least consider the following: • Consider green roofs early in the design process in consultation with all stakeholders to enable maximised integration with building systems and to mitigate building cost (avoid constructing as a retrofit). • Design of the green roof as part of a building’s structural, mechanical and hydraulic systems could lead to structural efficiency, the ability to optimise cooling benefits and better integrated water recycling systems. • Inform the selection of the type of green roof by considering its function, for example designing for social activity, required maintenance/access regime, recycling of water or habitat regeneration or a combination of uses. • Evaluate existing surroundings to determine possible links to the natural environment and choice of vegetation for the green roof with availability of local plant supply and expertise. Cutting EDGe Strategies • Create green roofs to contribute positively to the environment through reduced urban heat island effect and building temperatures, to improved stormwater quality, increased natural habitats, provision of social spaces and opportunity for increased local food supply. • Maximise solar panel efficiency by incorporating with design of green roof. • Integrate multiple functions for a single green roof such as grey water recycling, food production, more bio-diverse plantings, air quality improvement and provision of delightful spaces for social interaction. Synergies & references • BEDP Environment Design Guide DES 53: Roof and Facade Gardens GEN 4: Positive Development – designing for Net Positive Impacts TEC 26: Living Walls - a way to green the built environment • Green Roofs Australia: www.greenroofs.wordpress.com • International Green Roof Association: www.igra-world.com • Green Roofs for Healthy Cities (USA): www.greenroofs.org • Centre for Urban Greenery and Ecology (Singapore): http://research.cuge.com.s

    Biodiversity Impact of Green Roofs and Constructed Wetlands as Progressive Eco-Technologies in Urban Areas

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    The total amount of sealed surfaces is increasing in many urban areas, which presents a challenge for sewerage systems and wastewater treatment plants when extreme rainfall events occur. One promising solution approach is the application of decentralized eco-technologies for water management such as green roofs and constructed wetlands, which also have the potential to improve urban biodiversity. We review the effects of these two eco-technologies on species richness, abundance and other facets of biodiversity (e.g., functional diversity). We find that while green roofs support fewer species than ground-level habitats and thus are not a substitute for the latter, the increase in green roof structural diversity supports species richness. Species abundance benefits from improved roof conditions (e.g., increased substrate depth). Few studies have investigated the functional diversity of green roofs so far, but the typical traits of green roof species have been identified. The biodiversity of animals in constructed wetlands can be improved by applying animal-aided design rather than by solely considering engineering requirements. For example, flat and barrier-free shore areas, diverse vegetation, and heterogeneous surroundings increase the attractiveness of constructed wetlands for a range of animals. We suggest that by combining and making increasing use of these two eco-technologies in urban areas, biodiversity will benefit

    Investigating Biotic Interactions as a Tool to Improve the Growth of Vegetation in a Green Roof

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    Green roofs are an integral part of the urban forest and are widely used as tools in urban planning for sustainable development. One of the main reasons for the increased focus on green roofs is their social, environmental and economic benefits. Plant selection is a critical component in green roof design, as the vegetation on a roof influences the benefits obtained. Incorrect plant selection also contributes to some of the drawbacks of green roofs, such as the high ongoing cost of maintaining or replacing plants and increased water/fertiliser usage. Biotic facilitative interactions were investigated in this thesis as a means to improve plant growth on a green roof. A survey across green roofs in Sydney was used to establish the current building practices of green roofs in relation to their vegetation, substrate and physical characteristics. I also attempted to classify green roofs based on their function and investigated whether current designs provided social, environmental and ecological benefits. This was done by scoring roofs based on surveyable attributes associated with each benefit. Of the 29 green roofs surveyed across Sydney, only two roofs scored high in all three categories. Seven roofs scored high in social and environmental benefits, with four scoring high only in ecological benefits. The focus on social benefits was unexpected since most green roofs specified environmental benefits as one of their key aims. The results indicate there might be a shift in the perception of green roofs from being a tool to ameliorate urban physical characteristics to a tool that can enhance concentration, productivity and mental health in the workplace. However, care should be taken so that the focus on social benefits does not come at the expense of the other benefits
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