A robust ecological assessment of a development project is based on a comprehensive set of ecological information about the site. Gathering this information is generally undertaken in three steps:
- a desk based study
- an extended phase 1 habitat survey
- detailed habitatat and species surveys
Desk based study
Records of protected and notable species and non-statutory designated sites within 2km to 5km of the site should be exzamined. These records can be obtained from a number of sourcessuch as the county biological records centre, Wildlife Trusts, county species recorders, arial photography and the Multi Agency Geographical Information for the Countryside (MAGIC) website for details of statutory designated sites.
The desk based study gives an initial indication about the value of the site and should be used to design and analyse the results of the general extended phase 1 habitat survey.
Extended phase 1 habitat survey
An extended Phase 1 habitat survey can be carried out most of the year althought he winter period is generally less suitable for the survey. The aim of the survey was to identify the type, quality and extent of habitats present within the site and to identify the potential of the site to support protected or notable species.
The survey should be carried out according to the standard Phase 1 Habitat Survey methodology, extended as described by the Institute of Environmental Assessment (now the Institute of Environmental Management and Assessment) to include targeted searches for signs of protected and/or notable species, including badger Meles meles, bats, great crested newt Triturus cristatusand water vole Arvicola terrestris.
Target notes should be recorded to provide supplementary information on species composition and structure, evidence of management and on habitats too small to map. Any evidence to indicate the presence or absence of notable faunal species should also recorded.
Botanical nomenclature follows that of Stace (1997).
Further surveys
Based on the results of the extended phase 1 habitat survey combined with the results form the desk based study a series of further surveys can be designed. This may include further surveys to determine the detailed composition of the habitats that are present on the site. For smaller sites further surveys are however often restricted to surveys of protected species such as a reptile survey, a badger survey, a bat survey and great crested newts.
Assessment of effects
Value of resource
An ecological resource is defined as a species or habitat of value. Each area may have more than one feature of value that it supports (for example different habitats or populations and/or communities of species). Individual ecological resources and the features comprising that resource are evaluated according to generally accepted criteria (from Ratcliffe 1977), including designation and protection status. To attain each level of value/importance, an ecological resource or one of the features should meet the criteria set out in the table below. In some cases, professional judgement may be required to increase or decrease the allocation of specific value. This judgement is based on consideration of the following additional criteria:
- population trends
- sustainability of resource
- representativeness
- potential for substitution/re-creation
- position in the ecological unit
- biodiversity
- intrinsic value to stakeholders
Severity of impact
An “impact” is defined as any factor which may result in a change to the existing nature conservation resource. Once impacts have been determined, the severity of each impact must be assessed. The criteria utilised to determine the severity of impact are identified in the table below