Study shows biodiversity value of ‘Green Infrastructure’

Last year’s Natural Environment White Paper called for the creation of ‘green infrastructure’ as a tool to conserve and enhance biodiversity in the UK. Defining what this would entail, the report concluded that in addition to the conservation of existing protected areas and measures to enhance the wider rural landscape, the integrity of an effective national ecological network will be dependent on the existence of green spaces and corridors within urban areas.

The theory that habitat, or ‘green’, corridors enhance biodiversity within otherwise inhospitable landscapes has long been accepted amongst ecologists, but the body of supporting evidence for this assumption remains relatively sparse.

A study published this week, however, adds new support to the theory; researchers studying the abundance and diversity of spiders, ground beetles and rove beetles in domestic gardens near Paris, France found that gardens connected by green corridors to other gardens and ‘source’ habitat patches supported a significantly higher species diversity compared to relatively isolated gardens.

In addition, the research revealed that the community composition in connected gardens was similar to that found in corridors, indicating that these wildlife highways help maintain ecological community structure.

The authors conclude that connecting corridors should be an essential part of the wide-scale planning of green spaces in urban areas.

Positively, the recently reviewed National Planning Policy Framework for the UK contains an explicit requirement for planning policies to consider “…designated sites of importance for biodiversity [and] the wildlife corridors and stepping stones that connect them” – the work of Vergnes, Le Viol and Clergeau suggests that (at least for invertebrates) this approach could greatly enhance the diversity and resilience of ecological communities.

Reference: Vergnes, A., Le Viol, I., Clergeau, P. (2012) Green corridors in urban landscapes affect the arthropod communities of domestic gardens. Biological Conservation. 145: 171–178. Doi:10.1016/j.biocon.2011.11.002.