R.P.H. Snep

Applying landscape ecological principles in urban environments

Urban dwellers have long been interested in theinteractions between humans and nature. Already100 years ago concerns were raised about the fate ofurban flora in the rapidly expanding city of Helsinkiin Finland (Brenner 1906), but ecologists largelyignored urban areas for most of the twentieth century(Grimm et al. 2008). Lack of research has resulted inecology contributing little to solving urban environ-mental problems or providing understanding forplanning and management (Niemela¨ 1999; Grimmet al. 2008).Systematic urban ecological research started onlyabout 50 years ago. Berlin in Germany was one of thefirst cities to be studied comprehensively (Scholz1956), and urban ecological research has its longesttraditions in Central Europe and the UK (Sukopp2008). More recently, similar surge of interest hastaken place across the world. For instance, the journalLandscape Ecology has recently published numerouspapers on urban landscape ecology. With the expan-sion of cities worldwide, knowledge of the ecology ofcities integrated with social science approaches toguide the development of sustainable cities isurgently needed (Wu 2008; Grimm et al. 2008).From an ecological perspective, cities are uniquemosaics of sites which are constructed for residential,commercial, industrial, and infrastructural purposes,interspersed with green spaces. Urban green spacesare diverse, and include, for instance, parks, gardensand recreation venues. In addition to these formalgreen spaces, cities include informal green space,consisting of remnants of less modified, indigenousvegetation types, as well as specific urban habitats,such as derelict industrial sites, overgrown gardens,and ruderal sites (Breuste 2003). This mosaic ofhabitats can be fruitfully studied and understoodusing landscape ecology as a framework (Wu 2008).Landscape ecology provides approaches and meth-ods for understanding the dynamics of urban greenspaces. Urban habitat patches are small and isolatedfrom each other by a matrix of built environment.Ecological theories that have been used to examinesuch ‘‘archipelagoes’’ of urban green spaces includeisland biogeography theory (MacArthur and Wilson1967). The findings of several urban studies (e.g.,Klausnitzer 1993) of a positive relationship betweenpatch size and species richness suggest that the theoryof island biogeography could be an appropriateframework for urban ecological research as a first

The 'habitat backbone' as strategy to conserve pioneer species in dynamic port habitats: lessons from the natterjack toad ( Bufo calamita ) in the Port of Antwerp (Belgium)

Biodiversity conservation in economic areas like ports has recently become more important in the European Union due to a stricter interpretation of nature protection laws. In this study we develop a planning and design strategy—the ‘habitat backbone’—with which to support the long-term survival of pioneer species that occur in ports and have low dispersal abilities. For those species, long-term survival in port areas is uncertain because supply of their habitats (on vacant lots) is capricious and depends on land use dynamics. By gaining knowledge about spatial and temporal characteristics of these dynamics we were able to develop a solution to conserve such species. Our solution is based on the creation of permanent habitat—defined as a ‘backbone’—on (semi-) public land with an overall carrying capacity sufficient to support persistent populations. This best ensures long-term survival, and the backbone may also act as refugium. Satellite populations that emerge on adjacent vacant lots will thereby add to the persistence of the overall metapopulation. Management of permanent habitat is focused on retaining early-successional stages of vegetation. Implementing this strategy in the case of the natterjack toad in the Port of Antwerp taught us that realization of a habitat backbone is possible only if landowners, local governments and environmental NGOs cooperate. In the case at hand, such cooperation resulted in a plan that should ensure a coherent and persistent habitat network in which a chorus of some 1,400 natterjack toads could be accommodated—more than the number of toads currently observed.

Urban bird conservation : presenting stakeholder-specific arguments for the development of bird-friendly cities

Following the call from the United Nations Convention on Biological Diversity “Cities & Biodiversity Outlook” project to better preserve urban biodiversity, this paper presents stakeholder-specific statements for bird conservation in city environments. Based upon the current urban bird literature we focus upon habitat fragmentation, limited habitat availability, lack of the native vegetation and vegetation structure as the most important challenges facing bird conservation in cities. We follow with an overview of the stakeholders in cities, and identify six main groups having the greatest potential to improve bird survival in cities: i) urban planners, urban designers and (landscape) architects, ii) urban developers and engineers, iii) homeowners and tenants, iv) companies and industries, v) landscaping and gardening firms, vi) education professionals. Given that motivation to act positively for urban birds is linked to stakeholder-specific advice, we present ten statements for bird-friendly cities that are guided by an action perspective and argument for each stakeholder group. We conclude with a discussion on how the use of stakeholder-specific arguments can enhance and rapidly advance urban bird conservation action.

Ecological Models And Urban Wildlife

The promotion of urban ecological values is currently receiving a certain degree of political attention in the Netherlands, although not nearly as much as housing and jobs. In recent years, wildlife in and around cities has been studied as part of a long-term project called The Ecological City. One of the questions being studied is how cities could be provided with a sustainable network of green areas (including water bodies), i.e., areas that could house viable plant and animal populations. The present paper reviews two questions. It first discusses how the viability of animal populations can be assessed, using a specially developed spatial expert model called LARCH-city. The second question that ensues is whether such a sustainable urban ecological network can actually be developed and maintained? The first question will be answered by illustrating the functions of the LARCH expert model, and specifically its application to urban areas. Answering the second question requires linking ecological expertise with expertise in the area of planning and peoples wishes with regard to the use of and perception of urban green space. This is currently the focal point of our research. 1 Sustainability of urban green networks: the LARCH expert model Alterra Green World Research has in recent years been developing an expert model called LARCH (Landscape ecological Analyses and Rules for the Configuration of Habitat), designed to assess the sustainability of ecological and spatial networks in rural areas. Transactions on Ecology and the Environment vol 46,