997 resultados para city ecology


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Changing energy requirements and dramatic shifts in food availability are major factors driving behaviour and distribution of herbivores. We investigate this in wintering East Canadian High Arctic light-bellied brent geese Branta bernicla hrota in Northern Ireland. They followed a sequential pattern of habitat use, feeding on intertidal Zostera spp. in autumn and early winter before moving to predominantly saltmarsh and farmland in late winter and early spring. Night-time feeding occurred throughout and made a considerable contribution to the birds' daily energy budget, at times accounting for > 50% of energy intake. Nocturnal feeding, however, is limited to the intertidal, possibly because of predation risk on terrestrial habitat, and increases with moonlight. The amount of Zostera spp., declined dramatically after the arrival of birds, predominantly, but not entirely, due to consumption by the birds. Birds gained fat reserves in the first 2 months but then this was dramatically lost as their major food source collapsed and their daily energy intake declined. Single birds consistently fared worse than paired birds and pairs with juveniles fared better than those without suggesting a benefit of having a family to compete for food. Many birds leave the Lough at this time of reduced Zostera spp. for other sea inlets in Ireland but some remain. Body condition of the latter gradually improved in early spring and reflected a heavy reliance on terrestrial habitats, particularly farmland, to meet the birds' daily energy requirements. However, even in the period immediately before migration to the breeding ground, the birds did not regain the amount of abdominal fatness observed in November. The dramatic changes in available food and requirements of the birds drive the major changes seen in foraging behaviour as the birds evade starvation in the wintering period.

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European hare Lepus europaeus populations have undergone recent declines but the species has successfully naturalised in many countries outside its native range. It was introduced to Ireland during the mid-late nineteenth century for field sport and is now well established in Northern Ireland. The native Irish hare Lepus timidus hibernicus is an endemic subspecies of mountain hare L. timidus and has attracted major conservation concern following a long-term population decline during the twentieth century and is one of the highest priority species for conservation action in Ireland. Little is known about the European hare in Ireland or whether it poses a significant threat to the native mountain hare subspecies by compromising its ecological security or genetic integrity. We review the invasion ecology of the European hare and examine evidence for interspecific competition with the mountain hare for habitat space and food resources, interspecific hybridisation, disease and parasite transmission and possible impacts of climate change. We also examine the impact that introduced hares can have on native non-lagomorph species. We conclude that the European hare is an emerging and significant threat to the conservation status of the native Irish hare. Invasive mammal species have been successfully eradicated from Ireland before and immediate action is often the only opportunity for cost-effective eradication. An urgent call is issued for further research whilst the need for a European hare invasive Species Action Plan (iSAP) and Eradication strategy are discussed.

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We live in a world of advanced technology, stiff global competition and rapid transformation of all facets of life and as a result architecture has not been spared. These transformations affect the social relations, cultural consumption and political economy that have influenced the manner in which people perform in and out of space in the city centres. The residents have adopted strategies for negotiating through the spaces sanitized by authorities and other agents. The public spaces provide the background materials for informal urban practices that are sometimes deemed illegal yet are necessary for animating the city spaces. Cities market themselves ecstatically beyond the baroque with a more visible presence of the contending parties through trademarks, public relations invasively advertised in streets, monuments (signature buildings or projects), and language. This paper comes out of a research carried out in Nairobi in February and March 2007. It examined how the notions of globalisation are reflected in the life in the city centre; the impacts on the quality of life of users of the city centre and how informal urbanism has developed as copying strategy to deal with the transformations due to liberalization and globalization.

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This paper examines relevant characteristics of the ‘contested city’ and the concept of ‘public space’ in that problematic context. It offers an appraisal of the historical and contemporary role of urban design in shaping social space and interrogates the feasibility of using urban design to facilitate more integrated cityscapes. It presents detailed case studies of two ‘contested cities’, Nicosia and Belfast, based on content analysis of policy and planning documents, extensive site analyses in both places, interviews and seminar discussions with policy makers, planners, community and civic leaders. The paper comprises four dimensions—conceptual, descriptive, analytical and prescriptive—and in its final section identifies core values and relevant policies for the potential achievement of shared space in contested cities.