Green roofs conservation

Recently our elegant 1920s Zoo-shop roof became one of three principal sites for a major study into invertebrate biodiversity on green roofs.

Shop green roof
London Zoo shop green roof experiment
Although green roofs have well known energy conservation value and many other environmental benefits, there has been very little research into their biodiversity conservation potential, especially as a mitigation measure for the loss of species-rich ‘brownfield’ sites through increasing urban development.

A surprisingly large number of rare invertebrates, and other wildlife species such as the black redstart, find refuge on green roofs and their development presents a conservation challenge. If the roofs of new developments and more of our existing urban buildings were to have such green roofs the conservation and environmental gains would be tremendous. For example in Greater London alone, buildings cover a remarkable 24,000 hectares or 16% of the overall area.

The remit of this three year PhD study by Gyongyver Kadas of Royal Holloway, University of London is to investigate how green roof design factors influence biodiversity profiles, and how these factors can be manipulated to optimise the biodiversity profiles associated with urbanised brown field habitats.

Working in close liaison with the University of Wadenswil (Switzerland) and the Green Roof Laboratory initiative, this research is focusing on important invertebrate groups highlighted in the UK Biodiversity Action Plan and English Nature’s Species Recovery Programme. These include beetles, spiders, wasps and bees such as the brown-banded carder bee Bombus humilis and the ground nesting mining bees Andrena florea and Lasioglossum pauperatum.

In addition to studying species associations with different green roof designs, the research will investigate associated colonisation and succession patterns over a number of years. The London Zoo study involves forty five 4 m² compartments (see main photograph) which will be testing different design factors; orientation, substrate type, depth and micro-topographical profiles.

This research is also assisting our efforts to better understand our native species presence on the London Zoo site and, of course, will help inform how we can further incorporate such green initiatives in our own developments, such as the brown roof on our Komodo Dragon House.

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