Leicester, Leicestershire and Rutland
Surveys and mitigation for invertebrates
Leicestershire and Rutland Environmental Records Centre (LRERC)
November 2014
When are surveys needed? Invertebrate surveys are required for large‐scale built and other development (such as solar farms) that would impact adversely on high quality invertebrate habitats, such species‐rich, semi‐improved or rough grasslands; wetlands; woodland and scrub; and open habitat mosaics on previously developed land (‘brownfield’ and post‐industrial or former mining/quarrying sites). Surveys are not required for built developments impacting on land with habitats of lower value and significance to invertebrates, such as intensive arable land, improved grasslands or heavily‐used urban open spaces. Survey timing and effort Surveying a site for its invertebrate value is difficult and requires a high level of expertise. Most species of invertebrate are seasonal, with peak flying/emergence times when then can be recorded; at other times of year they will be missed in a survey. Some species only fly after disk; others are dependent on bright light conditions to fly. To gain a full picture of invertebrate use of a site would be impossible without a series of targeted surveys over several years. Natural England (NERR005, 2007) recommend 7 visits at monthly intervals between April and October. Whilst this would be appropriate to inform planning applications impacting significantly on nationally important invertebrate sites, it is not always appropriate in other situations. In most cases, LRERC requires a surveyor to carry out surveys in sufficient depth for them to confidently assess the significance of the site in a national and county‐
wide context. Several surveys visits by an acknowledged expert in entomology will always be required; it is not possible to gain a meaningful understanding of a site’s importance with one survey visit. LRERC recommend at least three survey events in early and mid‐season in order to assess the overall value of most site; however this will miss late season species such as many Grasshoppers and Dragonflies, and on sites felt to be potentially good for these species a mid to late season series of visits may be more appropriate . Very few entomologists are able to identify and survey for all species and groups of invertebrates to the same depth; most surveyors specialise in one or more invertebrate groups. This is acceptable, as surveying one group in depth is more likely to lead to an overall assessment of value that a shallow and superficial survey of a large number of groups. Survey methodologies Survey methodologies are many and varied, depending on the group being targeted ‐ pitfall trapping, sweep‐netting, beating, light‐trapping or other techniques may be used. To gain a better picture of invertebrate fauna present, a variety of techniques should be used, but the most appropriate techniques will be dependent on the surveyor’s expert assessment of the site’s needs. The report should include a section on methodology. Presentation of survey data Results of surveys should be presented as lists of species recorded on each survey event, with a note of the survey method used. The lists should be broken down into Taxon groups, with Family and Order given for each species record. Notable species should be flagged, including Red Data Book (RDB) species with their categories, Nationally Scarce (Notable) species and national Biodiversity Action plan (BAP) priority species, and for these species some conservation and habitat notes should be given, in order to inform mitigation. Mitigation recommendations The surveyor should make broad recommendations for mitigation. This could include:  Identifying key habitats and features for conservation, restoration or translocation within the site.  Habitat creation, including ‘brown roofs’.  Suitable species for planting References Natural England Research Report NERR005 (2007) Surveying terrestrial and freshwater invertebrates for conservation evaluation. Leicestershire and Rutland Environmental Records Centre Room 400, County Hall Glenfield LE3 8RA 0116 305 4108 [email protected] November 2014