Temporal changes in greenspace in a highly urbanized region

Abstract

The majority of the world's population now lives in towns and cities, and urban areas are expanding faster than any other land-use type. In response to this phenomenon, two opposing arguments have emerged: whether cities should 'sprawl' into the wider countryside, or 'densify' through the development of existing urban greenspace. However, these greenspaces are increasingly recognized as being central to the amelioration of urban living conditions, supporting biodiversity conservation and ecosystem service provision. Taking the highly urbanized region of England as a case study, we use data from a variety of sources to investigate the impact of national-level planning policy on temporal patterns in the extent of greenspace in cities. Between 1991 and 2006, greenspace showed a net increase in all but one of 13 cities. However, the majority of this gain occurred prior to 2001, and greenspace has subsequently declined in nine cities. Such a dramatic shift in land use coincides with policy reforms in 2000, which favoured densification. Here, we illustrate the dynamic and policy-responsive nature of urban land use, thereby highlighting the need for a detailed investigation of the trade-offs associated with different mechanisms of urban densification to optimize and secure the diverse benefits associated with greenspaces.

Figure 1.

The proportional change, for 13 English cities, in: (a) greenspace area between 1991 and 2006 (white bars), annual average 1991–2001 (black bars) and 2001–2006 (grey bars); (b) human population between 1991 and 2001. Cities are ordered left to right, according to their geographical location from south to north.

Figure 2.

Densification across 13 cities in southern (black), central (mid-grey) and northern (light-grey) England: (a) relative change in the number of dwellings between 1981 and 2008, (b) proportional change in the number of dwellings and extent of the built-up area between 1991 and 2006. The solid line indicates y = x.