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Invertebrate scoping survey
A invertebrate scoping survey is generally carried out when the presence of certain habitats and features on a site have been identified as having potential significant value for invertebrates. This is usually highlighted as part of a Preliminary Ecological Appraisal.
All areas of the site are walked during an invertebrate scoping survey and features appraised for their invertebrate potential. Features such as open grassland, bare ground, ponds, woodland fringe and hedgerow structure, are all inspected and evaluated for their potential to hold invertebrate assemblages of importance, or be of interest to specific, significant species.
Presence/absence invertebrate surveys
Invertebrate survey methodology depends upon the species or group of species requiring surveying. Effective surveying often involves using a combination of different sampling methodologies.
For terrestrial invertebrates sweep netting, spot sampling, beating, grubbing, pitfall trapping, light traps, malaise traps and suction sampling may be used. For aquatic invertebrates kick sampling and pond netting are the methods most often used.
The targeted sampling of invertebrates can determine the quality and robustness of a habitat or a feature on site, which can have a direct bearing on the type and level of mitigation that may be required.
Interpreting invertebrate survey results
The results of an invertebrate survey may be as simple as identifying whether a targeted notable species is present and, if so, how it is using the site.
However, more commonly the survey will establish the invertebrate assemblage present using analytical software such as Invertebrate Species-habitats Information System (ISIS).
This information is used to advise on the most appropriate mitigation approach taking the project design into account.
Timing of surveys
- An initial habitat appraisal for invertebrates can be undertaken as part of a Preliminary Ecological Appraisal. The appraisal can be undertaken at any time of year although the most optimal time would be from April - September;
- An invertebrate scoping survey should be undertaken by an experienced surveyor at any time of year, although it is best completed between April and September;
- Presence/absence invertebrate surveys - due to the large diversity of invertebrates and their varied habitats, surveys can be one off surveys carried out within a specific month of the year or a series of surveys carried out between spring and late summer. The number and timing of surveys will depend upon the species or species groups being surveyed and the objective of the survey.
Mitigation and compensation
Mitigation or compensation for invertebrates is generally habitat-based.
Retaining habitat suitable for invertebrates to protect populations of uncommon invertebrates in situ is considered best practice.
Compensatory habitats can be created if necessary and best practice would be to have established prior to any modification or destruction of existing habitat of value.
Re-created habitats should be designed around the specialist requirements of the targeted invertebrate. It is rarely the case that protected invertebrate species are translocated although should this be necessary a relevant licence from Natural England may be required.
Legislation
Many invertebrates are protected under the Wildlife and Countryside Act 1981 (as amended) and the Natural Environment and Rural Communities Act 2006 (NERC Act) as well as an increasing number that are listed as UK Biodiversity Action Plan (BAP) priority species and of principal importance under the NERC Act. This places a duty on planning authorities “to have regard” for those species when determining planning permission.
Sites of high interest for invertebrates are largely protected from damage through their inclusion within protected habitats/areas such as:-
- Sites of Special Scientific Interest (SSSI);
- Special Areas of Conservation (SAC);
- National Nature Reserves (NNR);
- Local Nature Reserves (LNR);
- County Wildlife Sites (CWS).
Note
The above information is based on standard guidelines and current UK legislation. Every site is unique so please contact a Torc Ecology consultant who will advise on the best survey approach in relation to the project requirements.
Facts about invertebrates!
There are more than 32,000 terrestrial and freshwater invertebrates and over 7000 marine invertebrate species in the UK.
Invertebrates play a vital role in underpinning many day to day ecological processes and the invertebrate diversity of a site is a useful indicator when appraising habitat features at a site or landscape level.
Many invertebrate species are critically endangered, are legally protected, or are identified as a priority species for conservation action.
