Showing papers on "Urban ecosystem published in 2011"

Coupling biogeochemical cycles in urban environments: ecosystem services, green solutions, and misconceptions

Abstract: Urban green space is purported to offset greenhouse-gas (GHG) emissions, remove air and water pollutants, cool local climate, and improve public health. To use these services, municipalities have focused efforts on designing and implementing ecosystem-services-based “green infrastructure” in urban environments. In some cases the environmental benefits of this infrastructure have been well documented, but they are often unclear, unquantified, and/or outweighed by potential costs. Quantifying biogeochemical processes in urban green infrastructure can improve our understanding of urban ecosystem services and disservices (negative or unintended consequences) resulting from designed urban green spaces. Here we propose a framework to integrate biogeochemical processes into designing, implementing, and evaluating the net effectiveness of green infrastructure, and provide examples for GHG mitigation, stormwater runoff mitigation, and improvements in air quality and health.

Ecosystem services and urban heat riskscape moderation: water, green spaces, and social inequality in Phoenix, USA

Abstract: Urban ecosystems are subjected to high temperatures—extreme heat events, chronically hot weather, or both—through interactions between local and global climate processes. Urban vegetation may provide a cooling ecosystem service, although many knowledge gaps exist in the biophysical and social dynamics of using this service to reduce climate extremes. To better understand patterns of urban vegetated cooling, the potential water requirements to supply these services, and differential access to these services between residential neighborhoods, we evaluated three decades (1970–2000) of land surface characteristics and residential segregation by income in the Phoenix, Arizona, USA metropolitan region. We developed an ecosystem service trade-offs approach to assess the urban heat riskscape, defined as the spatial variation in risk exposure and potential human vulnerability to extreme heat. In this region, vegetation provided nearly a 25°C surface cooling compared to bare soil on low-humidity summer days; the ma...

Mapping an urban ecosystem service: quantifying above‐ground carbon storage at a city‐wide scale

Abstract: Summary 1. Despite urbanization being a major driver of land-use change globally, there have been few attempts to quantify and map ecosystem service provision at a city-wide scale. One service that is an increasingly important feature of climate change mitigation policies, and with other potential benefits, is biological carbon storage. 2. We examine the quantities and spatial patterns of above-ground carbon stored in a typical British city, Leicester, by surveying vegetation across the entire urban area. We also consider how carbon density differs in domestic gardens, indicative of bottom-up management of private green spaces by householders, and public land, representing top-down landscape policies by local authorities. Finally, we compare a national ecosystem service map with the estimated quantity and distribution of above-ground carbon within our study city. 3. An estimated 231 521 tonnes of carbon is stored within the above-ground vegetation of Leicester, equating to 3AE16 kg C m )2 of urban area, with 97AE3% of this carbon pool being associated with trees rather than herbaceous and woody vegetation. 4. Domestic gardens store just 0AE76 kg C m )2 , which is not significantly different from herbaceous vegetation landcover (0AE14 kg C m )2 ). The greatest above-ground carbon density is 28AE86 kg Cm )2 , which is associated with areas of tree cover on publicly owned ⁄ managed sites. 5. Current national estimates of this ecosystem service undervalue Leicester’s contribution by an order of magnitude. 6. Synthesis and applications. The UK government has recently set a target of an 80% reduction in greenhouse gas emissions, from 1990 levels, by 2050. Local authorities are central to national efforts to cut carbon emissions, although the reductions required at city-wide scales are yet to be set. This has led to a need for reliable data to help establish and underpin realistic carbon emission targets and reduction trajectories, along with acceptable and robust policies for meeting these goals. Here, we illustrate the potential benefits of accounting for, mapping and appropriately managing aboveground vegetation carbon stores, even within a typical densely urbanized European city.

Urban Ecology: Patterns, Processes, and Applications

Abstract: SECTION 1 - ECOLOGY IN CITIES: MAN-MADE PHYSICAL CONDITIONS SECTION 2 - ECOLOGY IN CITIES: PATTERNS OF URBAN BIODIVERSITY SECTION 3 - ECOLOGY IN CITIES: PROCESSES AFFECTING URBAN BIODIVERSITY SECTION 4 - ECOSYSTEMS, ECOSYSTEM SERVICES, AND SOCIAL SYSTEMS IN URBAN LANDSCAPES SECTION 5 - URBAN DESIGN, PLANNING, AND MANAGEMENT: LESSONS FROM ECOLOGY

Temporal changes in greenspace in a highly urbanized region

Abstract: The majority of the world's population now lives in towns and cities, and urban areas are expanding faster than any other land-use type. In response to this phenomenon, two opposing arguments have emerged: whether cities should ‘sprawl’ into the wider countryside, or ‘densify’ through the development of existing urban greenspace. However, these greenspaces are increasingly recognized as being central to the amelioration of urban living conditions, supporting biodiversity conservation and ecosystem service provision. Taking the highly urbanized region of England as a case study, we use data from a variety of sources to investigate the impact of national-level planning policy on temporal patterns in the extent of greenspace in cities. Between 1991 and 2006, greenspace showed a net increase in all but one of 13 cities. However, the majority of this gain occurred prior to 2001, and greenspace has subsequently declined in nine cities. Such a dramatic shift in land use coincides with policy reforms in 2000, which favoured densification. Here, we illustrate the dynamic and policy-responsive nature of urban land use, thereby highlighting the need for a detailed investigation of the trade-offs associated with different mechanisms of urban densification to optimize and secure the diverse benefits associated with greenspaces.

Integrating sciences to sustain urban ecosystem services

Abstract: Effective water management within urban settings requires robust multidisciplinary understanding and an appreciation of the value added to urban spaces by providing multifunctional green-blue spaces. Multifunctional landscapes where ecosystem service provisions are 'designed-in' can help 'transition' cities to more sustainable environments which are more resilient to changing future conditions. With benefits ranging from the supply of water, habitat and energy to pollutant removal, amenity and opportunities for recreation, urban water bodies can provide a focal point for reconnecting humans and nature in otherwise densely built-up areas. Managing water within urban spaces is an essential infrastructure requirement but has historically been undertaken in isolation from other urban functions and spatial requirements. Increasingly, because of the limits of space and need to respond tonewdrivers (e.g. mitigationofdiffusepollution), more sustainableapproaches tourbanwater manage- ment are being applied which can have multiple functions and benefits. This paper presents a review of ecosystem services associated with water, particularly those in urban environments, and uses the emerging language of ecosystem services to provide a framework for discussion. The range of supporting, provisioning, regulating and cultural ecosystem services associated with differing types of urban water bodies are identified. A matrix is then usedtoevaluatetheresultsofaseriesofsocial,ecologicalandphysicalsciencestudiesco-locatedonasinglestretch of a restored urban river. Findings identify the benefits of, but also barriers to, the implementation of a transdisci- plinary research approach. For many, transdisciplinary research still appears to be on the edge of scientific respectability. In order to approach this challenge, it is imperative that we bring together discipline specific exper- tise to address fundamental and applied problems in a holistic way. The ecosystem services approach offers an exciting mechanism tosupport researchers in tackling researchquestionsthat require thinking beyond traditional scientific boundaries. The opportunity to fully exploit this approach to collaborative working should not be lost.

Monitoring Urban Sprawl Using Remote Sensing and GIS Techniques of a Fast Growing Urban Centre, India

Abstract: India's urban population has grown tremendously in the last four decades from 79 million in 1961 to 285 million in 2001. This fast rate of increase in urban population is mainly due to large scale migration of people from rural and smaller towns to bigger cities in search of better employment opportunities and good life style. This rapid population pressure has resulted in unplanned growth in the urban areas to accommodate these migrant people which in turn leads to urban sprawl. It is a growing problematic aspect of metropolitan and bigger city's growth and development in recent years in India. Urban sprawl has resulted in loss of productive agricultural lands, open green spaces, loss of surface water bodies and depletion of ground water. Therefore, there is a need to study, understand and quantify the urban sprawl. In this paper an attempt has been made to use Shannon's entropy model to assess urban sprawl using IRS P-6 data and topographic sheet in GIS environment for one of the fastest growing city of South India and its surrounding area. The built-up area of the city has increased from 135 km2 in 1971 to 370 km2 in 2005. The study shows that there is a remarkable urban sprawl in and around the twin city between 1971 and 2005 because 215 km2 of agricultural land has lost to built-up land during this period. As a result the urban ecosystem has changed in the last four decades.

Urban agriculture : growing healthy, sustainable places

Abstract: Urban agriculture is rising steadily in popularity in the United States and Canada - there are stories in the popular press, it has an increasingly central place in the growing local food movement, and there is a palpable interest in changing cities to foster both healthier residents and more sustainable communities. The most popular form of urban agriculture, community gardening, contributes significantly to developing social connections, building capacity, and empowering communities in urban neighborhoods. Older, industrial cities such as Cleveland, Detroit, and Buffalo, with their drastic loss of population and their acres of vacant land, are emerging as centers for urban agriculture initiatives - in essence, becoming laboratories for the future role of urban food production in the postindustrial city. Because urban agriculture entails the use of urban land, it has implications for urban land-use planning, which is controlled and regulated by municipal governments and planning agencies. This PAS Report provides authoritative guidance for dealing with the implications of this cutting-edge practice that is changing our cities forever.

Ecological processes in urban landscapes: mechanisms influencing the distribution and activity of insectivorous bats

Abstract: Urbanisation affects indigenous fauna in many ways; some species persist and even increase in urban areas, whereas others are lost. The causative mechanisms determining changes in distributions and community structure remain elusive. We investigated three hypothesized mechanisms, which influence success or failure of the insectivorous bat assemblage across the urban landscape of Sydney, Australia; landscape heterogeneity (diversity of land uses), productivity (as indexed by landscape geology) and trait diversity. We present data on species richness and activity (bat passes per night) collected systematically using ultrasonic bat detectors from randomly selected landscapes (each 25km ). Landscapes were categorized into classes including 'urban', 'suburban' and 'vegetated', where suburban sites were additionally stratified based on geology, as a proxy for productivity. Four landscape elements were sampled within each landscape, including remnant bushland (>2ha), riparian areas, open space/parkland and residential/built space. We found that there was significantly greater bat activity and more species of bat in areas on fertile shale geologies (p<0.05), supporting the productivity, rather than the heterogeneity hypothesis. Within landscapes, there was no significant effect of the landscape element sampled, although bushland and riparian sites recorded greater bat activity than open space or backyard sites. Using general linear mixed models we found bat activity and species richness were sensitive to landscape geology and increasing housing density at a landscape scale. Using an RLQ analysis a significant relationship was found between these variables and species traits in structuring the community present (p<0.01). Specifically, open-adapted bats were associated with areas of greater housing density, while clutter-adapted bats were uncommon in urban areas and more associated with greater amounts of bushland in the landscape. Overall we found greater support for the productivity and traits hypotheses, rather than the heterogeneity hypothesis. The degree of urbanisation and amount of bushland remaining, in combination with landscape geology, influenced bat activity and mediated the trait response. Our findings reflect global trends of species diversity and abundance in urban landscapes, suggesting that processes affecting bat species distribution in urban ecosystems may be predictable at a landscape scale. © 2011 The Authors. 2

Socio‐ecohydrology and the urban water challenge

Abstract: Urban water systems are highly engineered. However, hydrology and ecology are still closely linked in semi-arid urban ecosystems in which surface characteristics, vegetation, and water flows are all highly transformed. Although these systems are human-dominated, there are many uncertainties in the water budgets of semi-arid cities, because evapotranspiration, runoff, groundwater recharge, and leakage are poorly constrained. Decision-making, governance, and socioeconomic factors play important roles in determining urban hydrologic budgets. We offer a framework to integrate these factors in studies that combine biophysical and social dimensions of the urban water system using the example of western US cities, which are facing critical issues in water supply and demand, and which can benefit from a more comprehensive understanding of the factors that determine water consumption, distribution and availability. Because of the severity of the water crisis in the western US, and the biophysical, institutional, and cultural barriers to developing and implementing new water management practices, this region provides useful lessons for addressing water challenges in other regions. Copyright © 2011 John Wiley & Sons, Ltd.

Wall ecology: A frontier for urban biodiversity and ecological engineering

Abstract: Walls are extensive, ubiquitous urban ecosystems that can act as habitat for a range of different species and support non-standard cosmopolitan assemblages. Most investigations into wall ecology have focused on botanical surveys rather than testing hypotheses, but it is apparent that walls can be surprisingly diverse. They also have the potential to be ecologically engineered to encourage a greater diversity and range of species. This review considers the development of wall ecology, highlighting the key characteristics of walls that have been found to influence their ability to support species, with a focus on higher plants. It then examines the kinds of plant assemblages that are found on walls and the broader role of walls within urban biodiversity, before discussing the potential for ecological engineering of walls. Some progress has recently been made in the latter area with the installation of living walls and the physical engineering of wall materials, but much more needs to be done to effectively ...

Climate Change and Health in the Urban Environment: Adaptation Opportunities in Australian Cities

Abstract: Urban populations are growing rapidly throughout the Asia-Pacific region. Cities are vulnerable to the health impacts of climate change because of their concentration of people and infrastructure, the physical (geographical, material, and structural) attributes of the built environment, and the ecological interdependence with the urban ecosystem. Australia is one of the most highly urbanized countries in the region and its already variable climate is set to become hotter and drier with climate change. Climate change in Australia is expected to increase morbidity and mortality from thermal stress, bacterial gastroenteritis, vector-borne disease, air pollution, flooding, and bushfires. The cost and availability of fresh water, food, and energy will also likely be affected. The more vulnerable urban populations, including the elderly, socioeconomically disadvantaged groups, and those with underlying chronic disease, will be most affected. Adaptation strategies need to address this underlying burden of disease and inequity as well as implement broad structural changes to building codes and urban design, and infrastructure capacity. In doing so, cities provide opportunities to realize "co-benefits" for health (eg, from increased levels of physical activity and improved air quality). With evidence that climate change is underway, the need for cities to be a focus in the development of climate adaptation strategies is becoming more urgent.

The ecology of urban areas and their functions for species diversity

Abstract: Despite the appearance of an enormous number of publications about urban ecology and species diversity, many issues are simply opened up rather than explained. The ecological complexity of urban areas, i.e., the variety of determinants and the spatial and temporal dynamic of cities, preclude simple starting points and lines of explanation. Therefore, we lack sufficient comparisons between various cities, especially comparisons on a global level. If cities are to be compared by appropriate indicators, and if they are to be evaluated with respect to urban biodiversity, then models are necessary that help us understand and mirror the causal relationships between urban areas and biological diversity. Three approaches, also representing a multiscaled view of urban areas, are presented that are suitable for developing applicable models and indicators for monitoring ecological systems: the embedded city, the urban matrix, and urban patches. The embedded city represents a globally useful concept, because the relationship between cities and their regions can be applied as an indicator to all regions. The lack of sufficient description of the urban matrix makes comparisons between cities difficult and causes scientists to underestimate the importance and function of the matrix for urban biodiversity. Urban patches are often investigated in urban studies about plants and animals. Therefore, much existing data can be used, and several criteria describing the functions of patches for biodiversity are available. In particular, the first two approaches should be researched more intensively.

Urban wildscapes and green spaces in Mombasa and their potential contribution to climate change adaptation and mitigation

Abstract: Well-planned urban green landscapes, including wildscapes and green spaces, have the potential to contribute to climate change adaptation and mitigation. Yet for cities in low-income countries, the value of these urban landscapes in climate change response strategies is often disregarded and remains largely unexploited and unaccounted for. This paper discusses the potential role of urban green landscapes as a "soft engineering" climate change response strategy, and calls for the pursuance of management practices that preserve and promote the use of these urban spaces. It does so by combining theoretical arguments with an empirical example based on an innovative and novel approach to landscape rehabilitation, the Lafarge Ecosystems Programme, in the coastal city of Mombasa, Kenya. The paper finds that a well-managed system of green landscapes in resource-poor urban areas can generate net social benefits under a range of future scenarios. It further finds that climate change adaptation and mitigation responses can be initiated by a range of stakeholders operating at all scales. Such hard infrastructural responses, although necessary in some cases, can present a number of challenges and costs that bring us to question both the effectiveness and efficiency of such solutions relative to the techno-institutional and financial barriers faced by low-income countries. Furthermore, the devastation of New Orleans by Hurricane Katrina in 2005, with the failure of the levee system, demonstrated that hard protection can also fail, with tragic consequences. (2) For low-income countries this emphasizes the need to explore less expensive but multi-beneficial strategies. One such strategy for urban areas is the provision and protection of blocks of contiguous land and improvements in the connectivity of areas of natural resource or ecological value, with the aim of establishing a network of natural areas and working landscapes. This ecosystems approach or "soft

Green Space Changes and Planning in the Capital Region of China

Abstract: Green space plays an important role in complex urban ecosystems and provides significant ecosystem services with environmental, aesthetic, recreational and economic benefits. Beijing is the capital city of China and has a large population of about 15.81 million. Construction of green spaces is an important part of sustainable development in Beijing. To attain the sustainable development of Beijing as a capital city, an international city, a historical cultural city, and a living amenity city, this article attempts to develop a comprehensive plan of green space development both at the municipal and regional levels. At the municipal level of Beijing, based on the study of green space changes, and taking physical geographic conditions and historical context into account, we propose to establish green barriers in the mountainous area, and plan a comprehensive green space pattern composed of one city, two rings, three networks, eight water areas, nine fields, and several patches in the plain area. At the regional level of the Capital Circle Region, integrating the characteristics and causes of main environmental issues, we design a macroscopic pattern—“barriers by mountains in the northwest,” “seaward open spaces in the southeast,” “grassland-forest-field-coast zones,” and “green-blue symphony”—for ecological restoration and green space construction. Finally, we discuss the principles necessary to implement green space planning considering adaptation to local conditions, composite function exploitation, interregional equity and integrated planning.

Are soils in urban ecosystems compacted? A citywide analysis

Abstract: Soil compaction adversely influences most terrestrial ecosystem services on which humans depend. This global problem, affecting over 68 million ha of agricultural land alone, is a major driver of soil erosion, increases flood frequency and reduces groundwater recharge. Agricultural soil compaction has been intensively studied, but there are no systematic studies investigating the extent of compaction in urban ecosystems, despite the repercussions for ecosystem function. Urban areas are the fastest growing land-use type globally, and are often assumed to have highly compacted soils with compromised functionality. Here, we use bulk density (BD) measurements, taken to 14 cm depth at a citywide scale, to compare the extent of surface soil compaction between different urban greenspace classes and agricultural soils. Urban soils had a wider BD range than agricultural soils, but were significantly less compacted, with 12 per cent lower mean BD to 7 cm depth. Urban soil BD was lowest under trees and shrubs and highest under herbaceous vegetation (e.g. lawns). BD values were similar to many semi-natural habitats, particularly those underlying woody vegetation. These results establish that, across a typical UK city, urban soils were in better physical condition than agricultural soils and can contribute to ecosystem service provision.

Urban sustainability, urban ecology and the Society for Urban Ecology (SURE)

Abstract: The majority of people worldwide live in cities and towns and their numbers continue to increase. Cities and towns offer an attractive living environment for the majority of people, but more knowledge is needed about the dynamics of this man-made environment, i.e. about the extremely changed natural conditions and about urban areas as living space. With increased urbanization worldwide, an urban perspective is progressively needed to understand human-nature interactions to improve research, design, planning, and management of cities, towns and urban regions. Mismatches between spatial and temporal scales of ecological process on the one hand, and social scales of monitoring and decision making on the other have not only limited our understanding of ecological processes in urban landscapes, they have also limited the integration of urban ecological knowledge into urban planning (Breuste et al. 2011). An ecocity is understood as:

The effects of air pollution on urban ecosystems and agriculture

Abstract: Over half the global population live in cities, with this proportion rising rapidly. Yet relatively little attention has been paid to the health of urban ecosystems, which are subject to more severe stresses in many cases than their rural counterparts. In this paper, the importance of urban ecosystems, including agriculture, is emphasised, with particular consideration given to the impacts of air pollution. Techniques for studying these impacts are fumigations, filtrations, transect studies and the use of chemical protectants, examples of which are considered for both the developed and developing world. Sulphur dioxide (SO2) and coal smoke formerly dominated the developed world and remain a growing problem in the developing countries. In both regions, the ‘modern’ pollutants, in the form of nitrogen oxides (NO x ), ozone (O3) and fine particulate matter (PM10), are also major problems for urban vegetation. Despite generally lower pollutant levels in the developed world, there is evidence that both crops a...