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The term invertebrate applies to animals that do not have backbones, such as insects, spiders and worms. In the UK alone invertebrates number over 30,000 terrestrial and freshwater species and 7,000 marine species. Many invertebrate species are in decline as a result of being slow to disperse into new locations and being extremely sensitive to environmental change. As a result, the invertebrate diversity of a site is an extremely useful indicator of the habitat quality of a site or the success of a management plan.

Marmalade hoverfly

The marmalade hoverfly (Episyrphus balteatus)

Applied Ecology Ltd is experienced in undertaking terrestrial and aquatic invertebrate surveys and subsequent laboratory-based sample sorting and species identification using microscopes.

Our invertebrate specialists have many years’ experience from a variety of entomological backgrounds to provide expertise on a variety of taxonomic groups.

Conservation status

Some invertebrates such as the stag beetle (Lucanus cervus) are becoming rare due to habitat degradation and fragmentation, whilst other species have suffered due to their symbiotic relationships with species that are in decline themselves.

Stag beetle (Lucanus cervus)

Stag beetle (Lucanus cervus)


A large number of British invertebrates are protected under the Wildlife and Countryside Act (1981) (as amended).  Species listed under Schedule 5 may be protected under one, some or all of the following parts of Section 9:

  • Section 9, Part 1 – intentional killing, injuring, taking
  • Section 9, Part 2 – possession or control (live or dead animal, part or derivative)
  • Section 9, Part 4 (a) – damage to, destruction of, obstruction of access to any structure or place used by a scheduled animal for shelter or protection
  • Section 9, Part 4 (b) – disturbance of animal occupying such a structure or place
  • Section 9, Part 5 (a) – selling, offering for sale, possessing or transporting for the purpose of sale (live or dead animal, part or derivative)
  • Section 9, Part 5 (b) – advertising for buying or selling live or dead animal, part or derivative

Click HERE for a full listed of species listed under Schedule 5.

The NERC Act (2006) also lists close to 400 invertebrate species that are Species of Principle Importance under Section 41.  Section 40 of the same Act requires every public body in the exercising of its functions (in relation to Section 41 species) to ‘have regard, so far as is consistent with the proper exercise of those functions, to the purpose of conserving biodiversity’.  This makes the listed invertebrates a material consideration in the planning process, requiring a detailed ecological survey before planning permission can be granted. In addition, local authority planning departments must meet the requirements of the Planning Policy Statement 9 (PPS9), which requires planners not only to protect biodiversity, but where possible to enhance it.

Stag beetle larvae

Stag beetle larvae

Several hundred invertebrate species are also UK BAP priority species of conservation concern.

Many UK invertebrates are also listed as Red Data Book (RDB) species, which contains species that are of international concern categorised by their danger of extinction in the short, medium and long term.


Survey licences are not normally required to complete general invertebrate surveys in terrestrial and aquatic habitats.  However, if the survey is specifically targeting species with full protection under the Wildlife and Countryside Act (1981) (see above) and may result in an offence being committed, the relevant statutory nature conservation organisation may be able to issue a species specific survey licence to avoid committing an offence.


A general invertebrate survey of a site for terrestrial invertebrates would typically employ the use of a range of survey methods including for example:

  • Direct observation.
  • Hand searching.
  • Sweep-netting.
  • Beating of woody vegetation.
  • Trapping.
  • Sieving of leaf litter.
  • Extraction of insects from leaf litter using extractors or water funnels.

Collected specimens are either identified in the field and released or (more frequently) preserved for subsequent sorting and species identification using a microscope.

Fairy shrimp (Chirocephalus diaphanous)

Fairy shrimp (Chirocephalus diaphanous)

A variety of survey methods and approaches are available to sample invertebrates from aquatic habitats such as ponds, lakes, rivers, streams and ditches.  In practice, however, the approach that is used is dictated by the physical nature of the habitat being surveyed (e.g. its accessibility to the surveyor), and the objective of the survey.  Standard general survey methods of shallow water habitats are frequently based on national biological water quality monitoring protocols that use a pond-net to sweep and/or “kick sample” the aquatic habitats present within a stream or river reach or around a pond margin.  In less accessible deeper water habitats, alternative methods may be necessary including the use of dredges, grabs or air-lift sampling equipment operated from boats.


The presence of a rare and/or protected invertebrate species within a site could be of material planning concern, and efforts should be made to protect and conserve important invertebrate habitats within the development where practicable.  For flowing water habitats, for example, statutory consultees such as the Environment Agency in England and Wales, and SEPA in Scotland will require development to be set back from the edge of rivers and streams to protect the aquatic habitat and its riparian zone.  In situations where it is not possible to preserve or maintain important habitats in situ, replacement habitats would probably need to be created as part of landscaping proposals and/or existing habitats better managed as compensation for habitat loss and damage.

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