Invertebrates
ECOSA use a number of specific techniques to survey for terrestrial and aquatic invertebrates, to identify scarce species and key habitat areas. Our project experience includes creation of species inventories for Statutory and Non-statutory designated sites, and numerous surveys for proposed development sites including roads and housing developments.
For further details on the legal protection of invertebrates and survey methods please see links below.
- Status
- Protection Under UK Legislation
- Survey Methods
- Pitfall Trap Survey
- Sweep Netting Survey
- Light Trap Survey
- Grubbing Survey
- Survey Timing
Status
Invertebrates beetles, flies, bees, wasps, ants, bugs, butterflies, moths, mayflies, dragonflies, damselflies, spiders, crayfish, shrimp, slugs, snails and grasshoppers and many more. are a group of animals that have no backbone. On a world scale huge numbers of invertebrates have been lost as a result of habitat destruction. The exact number of species lost is unknown. In the UK once familiar species such as bumblebees and many moths and butterflies have suffered huge recent declines.
Protection Under UK Legislation
A number of invertebrates are offered full protection under the Wildlife & Countryside Act, 1981 (as amended) This legislation makes it illegal to:
- intentional kill, injure, or take a scheduled animal;
- damage, destroy, or obstruct access to any structure or place used by a scheduled animal for shelter or protection; and
- disturb of any scheduled animal occupying such a structure or place.
Survey Methods
There are a number of techniques for surveying invertebrates. ECOSA select the most suitable technique, depending on the sites habitat type and the nature and status of the species to be surveyed for.
Pitfall Trap Surveys
The pitfall trapping technique involves the use of a ground pit into which invertebrates fall and cannot escape. The trap is filled with an aqueous solution designed to trap, kill and preserve invertebrates. This technique is useful for sampling ground dwelling species. As this method results in the death of invertebrates this techniques should only be employed at a site for one season, and no more often than every three years.
Sweep Netting Surveys
Sweep netting involves the use of a strong net for 'sweeping' through low herbage, bushes and tree foliage, in order to dislodge any invertebrates within the vegetation. The invertebrates are then caught within the net bag. The surveyor can then records and release the catch.
Light Trap Surveys
This method is effective way of surveying moths. Light traps emit high levels of ultra violet light which attracts moths. Moths attracted to the trap are caught alive within the main body of the trap. The surveyor can then record and release the catch.
Grubbing Surveys
Grubbing involves direct searching techniques, whereby the surveyor will search, sieve, beat and dig to record invertebrate species.
Survey Timing
In order to cover all the activity periods for all the species, survey work ideally needs to extend from April until September. However, basic assessments of the potential of the on site habitat to support important communities of invertebrates can be carried out throughout the year.
