History

A methodology for open space and habitat survey in London was adopted by the Mayor in his Biodiversity Strategy in 2002 and was further developed in 2004 to take account of the open space typology of PPG17 (see open space pages) and make minor modifications.

The survey methodology was first developed and used in 1984/85, when the Greater London Council commissioned the London Wildlife Trust to complete the first comprehensive survey of wildlife habitats in Greater London. It was later updated and consolidated by the London Ecology Unit and, more recently, by the GLA.  We therefore refer to this dataset as the 'GLA habitat survey' dataset.

Methods 

The GLA survey format was similar to an extended Phase I survey, a widely used habtiat survey method. There were a few small differences but the two types of survey collect essentially the same ecological information, in the same detail, with the same comprehensive coverage.

Unlike Phase I, the GLA survey method was designed particulaly with the urban setting in mind, so habitat classifications were appropriate for London. Also each site had an individual survey form, and map, to reflect the fragmented nature of green spaces in the urban setting, standardise reporting and aid comparison between sites.

Data

Information was gathered for any open space over a quarter of a hectare in area.  These units of land were referred to as 'parcels' and several parcels comprised a 'site'.  Sites and parcels were all named and given unique references.

Habitat categories were recorded as an estimated percentage cover and equivelant area within the parcel.  Open space information, such as access and facilities on site, was also gathered (comprehensively post-2004).

The paper forms were transferred to a digital format in a Geographic Information System.  Each parcel boundary is mapped and linked to its habtiat and open space records.  This forms the basis of the habitat database GiGL manage.

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