Whilst the Communities Plan has established a minimum density of 30 dwellings per hectare, to be sustainable the Urban White Paper suggested raising housing densities to at least 75 dwellings per hectare. This is achievable with terraces and perimeter blocks of town houses and flats. Reduced car parking and higher plot ratios result in more communal ‘doorstep’ spaces, such as courtyards and pocket greenspaces. This creates the potential for continuous mosaics of habitats, defining spaces and making higher density living more attractive.

The proximity of buildings to each space will create unique microclimate conditions, with varying daylight, wind, temperature and moisture levels. This will need to inform the selection of plant communities. So, for example, narrow, dark courtyards may resemble conditions on a forest floor. Designing-in the basic requirements to attract fauna will also maximise the opportunities for biodiversity. Rainwater systems can be designed to sustain wetland habitats and attenuate run-off.

Within a masterplan, plots are likely to be built out by a range of property developers. A mechanism is therefore required to encourage habitat creation. Recent experience in the new district of Bo01 in Malmo, Sweden provides a novel mechanism for encouraging this (Case Study 1, Section 4.2). Post-occupancy, landlords and residents groups can also be encouraged as part of a programme of local support and funding. This can be demonstrated by the successful courtyard greening initiatives in Berlin designed to reduce sealed surfaces (see case study 2). The configuration of communal spaces can vary considerably, influencing the potential to link habitats. At Schoneberg in Berlin networks of open courts created by urban blocks allow for continuous areas of habitat. The traditional terraced housing that is typical of industrial cities such as Manchester limits the opportunities for continuous areas of habitat. The proposed remodelling of the traditional terraced streets of Salford will see the creation of communal courtyards from private space, as well as home zone streets, creating the potential for larger areas of continuous habitat. Limiting factors may include disturbance by residents and preferences for ornamental exotics.