Habitat associations and breeding bird community composition within the city of Bristol, UK

Capsule: Different urban breeding bird communities are associated with different habitat types, but, although community species diversity varies significantly, total bird density does not. Aims: To investigate the association between breeding bird communities and habitats within Bristol, UK and how these communities vary in terms of species diversity and total bird abundance. Methods: Breeding density data for 70 species in the metropolitan area of Bristol, UK were subjected to de-trended correspondence analysis to identify the number of different communities present and their indicator species. These data were then used to identify patterns of habitat association with each community and differences in species richness and total bird density. Results: Three communities were identified: a rural community associated with woodland, managed grassland and inland water; a suburban community associated with buildings and residential gardens; and an intermediate community that shared some of these habitat characteristics. Species richness, but not total bird abundance, was lowest in the suburban community. Conclusion: The diversity of species in urban areas appears to be most dependent upon the availability of patches of natural and semi-natural habitats. Residential gardens support fewer species, but those species that are present may be found at high densities.

Asymmetric adjustment in the City of London office market

Earlier estimates of the City of London office market are extended by considering a longer time series of data, covering two cycles, and by explicitly modeling of asymmetric space market responses to employment and supply shocks. A long run structural model linking real rental levels, office-based employment and the supply of office space is estimated and then rental adjustment processes are modeled using an error correction model framework. Rental adjustment is seen to be asymmetric, depending both on the direction of the supply and demand shocks and on the state of the space market at the time of the shock. Vacancy adjustment does not display asymmetries. There is also a supply adjustment equation. Two three-equation systems, one with symmetric rental adjustment and the other with asymmetric adjustment, are subjected to positive and negative shocks to employment. These illustrate differences in the two systems.

Ensuring the right to the city: pro-poor housing, urban development and tenure legalization in São Paulo, Brazil

São Paulo is one of Latin America’s most modern and developed cities, yet around one-third of its 10 million inhabitants live in poor-quality housing in sub-standard settlements. This paper describes the response of the São Paulo municipal government that took office in 2001. Through its Secretariat of Housing and Urban Development, it designed a new policy framework with a strong emphasis on improving the quantity and quality of housing for low-income groups. Supported by new legislation, financial instruments and partnerships with the private sector, the mainstays of the new policy are integrated housing and urban development, modernization of the administrative system, and public participation in all decision-making and implementation processes. The programmes centre on upgrading and legalizing land tenure in informal settlements, and regeneration of the city centre. The new focus on valuing the investments that low-income groups have already made in their housing and settlements has proved to be more cost-effective than previous interventions, leading to improvements on an impressive scale.

Ownership, occupation and risk: a view of the City of London office market

Office returns in the City of London are more volatile than in other UK markets. This volatility may reflect fluctuations in capital flows associated with changing patterns of ownership and the growing linkage between real estate and financial markets in the City. Using current and historical data, patterns of ownership in the City are investigated. They reveal that overseas ownership has grown markedly since 1985, that owners are predominantly FIRE-sector firms and that there are strong links between ownership and occupation. This raises concerns about future volatility and systemic risk in a market strongly influenced by the cyclical behaviour and shocks of the international financial system.

International investment, ownership and risk in the City of London office market: an analysis of trends 1972-1997

Office returns in the City of London are more volatile than in other UK markets. This volatility may reflect fluctuations in capital flows associated with changing patterns of ownership and the growing linkage between real estate and financial markets in the City. Using current and historical data, patterns of ownership in the City are investigated. They reveal that overseas ownership has grown markedly since 1985, that owners are predominantly FIRE sector firms and that there are strong links between ownership and occupation. This raises concerns about future volatility and systemic risk.

Trends in office rents in the City of London: 1867-1959

This paper details the construction and analysis of a dataset of office lettings, which is used to produce a rent index for the City of London spanning the late nineteenth and early twentieth centuries. It advances prior research through application of a modern version of the repeat measures technique and in coverage of years where office rents have not been previously measured. Results show that there has been no real growth in rents over the period as a whole. However, there have been distinct phases of rental growth and decline that correspond with the wider economic fortunes of the City.

Effect of mountain breeze in ventilating the city under calm and neutral atmospheric environment: Interaction of airflow structures and ventilation efficiency

Many modern cities locate in the mountainous areas, like Hong Kong, Phoenix City and Los Angles. It is confirmed in the literature that the mountain wind system developed by differential heating or cooling can be very beneficial in ventilating the city nearby and alleviating the UHI effect. However, the direct interaction of mountain wind with the natural-convection circulation due to heated urban surfaces has not been studied, to our best knowledge. This kind of unique interaction of two kinds of airflow structures under calm and neutral atmospheric environment is investigated in this paper by CFD approach. A physical model comprising a simple mountain and three long building blocks (forming two street canyons) is firstly developed. Different airflow structures are identified within the conditions of different mountain-building height ratios (R=Hm/Hb) by varying building height but fixing mountain height. It is found that the higher ventilation rate in the street canyons is expected in the cases of smaller mountain-building ratios, indicating the stronger natural convection due to increasing heated building surfaces. However, there is the highest air change rate (ACH) in the lowest-building-height case and most of the air is advective into the street canyon through the top open area, highlighting the important role played by the mountain wind. In terms of the ventilation efficiency, it is shown that the smallest R case enjoys the best air change efficiency followed by the highest R case, while the worst ventilative street canyons occur at the middle R case. In the end, a gap across the streets is introduced in the modeling. The existence of the gap can greatly channel the mountain wind and distribute the air into streets nearby. Thus the ACH can be doubled and air quality can be significantly improved.

Briefing: re-engineering the city 2020–2050 – urban foresight and transition management

Cities may be responsible for up to 70% of global carbon emissions and 75% of global energy consumption and by 2050 it is estimated that 70% of the world's population could live in cities. The critical challenge for contemporary urbanism, therefore, is to understand how to develop the knowledge, capacity and capability for public agencies, the private sector and multiple users in city regions systemically to re-engineer their built environment and urban infrastructure in response to climate change and resource constraints. Re-Engineering the City 2020–2050: Urban Foresight and Transition Management (Retrofit 2050) is a major new interdisciplinary project funded under the Engineering and Physical Science Research Council's (EPSRC) Sustainable Urban Environments Programme which seeks to address this challenge. This briefing describes the background and conceptual framing of Retrofit 2050 project, its aims and objectives and research approach.

Sensors and the city: a review of urban meteorological networks

The heterogeneous nature of urban environments means that atmospheric research ideally requires a dense network of sensors to adequately resolve the local climate. With recent advances in sensor technology, a number of urban meteorological networks now exist with a range of research or operational objectives. This article reviews and assesses the current status of urban meteorological networks, by examining the fundamental scientific and logistical issues related to these networks. The article concludes by making recommendations for future deployments based on the challenges encountered by existing networks, including the need for better reporting and documentation of network characteristics, standardized approaches and guidelines, along with the need to overcome financial barriers via collaborative relationships in order to establish the long-term urban networks essential for advancing urban climate research. Copyright © 2013 Royal Meteorological Society

The impact of eBusiness on the City of London office market

The City of London is a major financial centre where the property market is heavily dependent on the space requirements of office occupiers. Technological change, however, is changing the way in which organisations conduct their business and is challenging the continued locational pull of the City. This research presents findings from a major survey of City occupiers carried out by The College research team during 2002. The research examines how the shape and form of the office property market in the City will be affected by process change in eBusiness and related technology over the next 5 years. The report, which includes an extensive literature review, examines the implications of increased homeworking and other trends for future office supply in the City. The research was funded by the Worshipful Company of Chartered Surveyors Trust (Toby Sutton Research Award), and part of the literature review by the Small Business Support Research Unit of DTI. It is essential reading for surveyors, planners, facilities managers and all those interested in the technology and property interface.