As the global population urbanizes, dramatic changes are expected in city lighting and the urban form, which may threaten the functioning of urban ecosystems and the services they deliver. However, little is known about the ecological impact of lighting in different urban contexts. Movement is an important ecological process that can be disrupted by artificial lighting. We explored the impact of lighting on gap crossing for Pipistrellus pipistrellus, a species of bat (Chiroptera) common within UK cities. We aimed to determine whether the probability of crossing gaps in tree cover varied with crossing distance and lighting level, through stratified field surveys. We then used the resulting data on barrier thresholds to model the landscape resistance due to lighting across an entire city and explored the potential impact of scenarios for future changes to street lighting. The level of illumination required to create a barrier effect reduced as crossing distance increased. For those gaps where crossing was recorded, bats selected the darker parts of gaps. Heavily built parts of the case study city were associated with large and brightly lit gaps, and spatial models indicate movement would be highly restricted in these areas. Under a scenario for brighter street lighting, the area of accessible land cover was further reduced in heavily built parts of the city. We believe that this is the first study to demonstrate how lighting may create resistance to species movement throughout an entire city. That connectivity in urban areas is being disrupted for a relatively common species raises questions about the impacts on less tolerant groups and the resilience of bat communities in urban centres. However, this mechanistic approach raises the possibility that some ecological function could be restored in these areas through the strategic dimming of lighting and narrowing of gaps.
Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city’s brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas.
Although intergroup contact can reduce prejudice, opportunities to experience such contact are often constrained by systems of segregation. Work on this problem has focused on divisions entrenched within institutions of residence, education and employment. Our research employed a complementary approach, which treated segregation as the outcome of individuals' movements over time within everyday life spaces. Taking as a case study Catholics' and Protestants' use of public environments in north Belfast, we used GPS tracking technology, combined with GIS analytics, to explore the time geography of residents' activity space use over a two-week period (Study 1). We also conducted a field survey to explore how psychological factors shaped their willingness to use activity spaces beyond their own communities (Study 2). Analysis based on around 1000 hours of raw movement data revealed that north Belfast is marked by high levels of segregation, expressed via residents' limited use of public spaces, facilities and pathways located in outgroup areas. However, use of shared spaces is also common, with Catholics spending more time in such spaces than Protestants. Structural equation modelling suggested that residents' self-reported willingness to use activity spaces outside their own communities was associated with both negative and positive intergroup contact-relationships partially mediated by realistic threat, symbolic threat, and anxiety over interaction across sectarian lines. Both kinds of contact and realistic threat were also associated with the time residents actually spent in spaces beyond their own communities. Opportunities for integrating psychological and geographic research on contact and segregation are highlighted.
Individual exposure to air pollution depends not only upon pollution concentrations in the surrounding environment, but also on the volume of air inhaled, which is determined by an individual's physiology and activity level. This study focuses on journey-time exposure, using network analysis in a GIS environment to identify pedestrian routes between multiple origins and destinations throughout the city of Lancaster, North West England. For each segment of a detailed footpath network, exposure was calculated accounting for PM2.5 concentrations (estimated using an atmospheric dispersion model) and respiratory minute volume (varying between individuals and with slope). For each of the routes generated the cumulative exposure to PM2.5 was estimated, allowing for easy comparison between multiple routes. Significant variations in exposure were found between routes depending on their geography, as well as in response to variations in background concentrations and meteorology between days. Differences in physiological characteristics such as age or weight were also seen to impact journey-time exposure considerably. In addition to assessing exposure for a given route, the approach was used to identify alternative routes that minimised journey-time exposure. Exposure reduction potential varied considerably between days, with even subtle shifts in route location, such as to the opposite side of the road, showing significant benefits. The method presented is both flexible and scalable, allowing for the interactions between physiology, activity level, pollution concentration and journey duration to be explored. In enabling physiology and activity level to be integrated into exposure calculations a more comprehensive estimate of journey-time exposure can be made, which has potential to provide more realistic inputs for epidemiological studies.
This paper focuses on the methods used in a project which set out to capture the movements and to consider the wellbeing of 30 teenagers on their journeys to and from school. A mobile phone linked to a GPS receiver was used to automatically log travel patterns whilst the respondents added 'blog' images and text about how they felt on the journey. Follow up interviews further explored the data. The paper shows that by using a range of methods the young people became involved in the project in different ways providing a rich picture of contingent and complex school journeys.
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