SNH Invertebrate Site Condition Monitoring 2015: Tweedwood - Gateheugh SSSI

Quality Control

We have a very high level of confidence in this dataset. Where necessary, rare specimens were compared against reference collections, those held in the National Museums Scotland collection and identities confirmed with experts.

Method steps

1. Surveys targeted the invertebrate assemblage features of Tweedwood - Gateheugh, however other taxa were also recorded. We made two visits during mid- and late-summer to record beetles whose emergence coincide with these seasons. We installed and collected bark traps on 15 June and 24 August 2015 respectively. We beat vegetation on 15 June 2015 and carried out active searches on 15 and 16 June, and 24 August 2015 on both the Gledswood and Bemersyde estates. Details of sampling methods are included below. Bark traps - We used bark traps to sample invertebrate species that live under tree bark. A trap consisted of two layers of plastic bubble wrap (40 x 40 cm), with bubbles facing each other so as to provide artificial a^??barka^?? habitat. Dark plastic was used to cover the traps, and they were wrapped around a tree with wire at 1.5 m height. Traps were then left in situ for a minimum of four weeks to allow invertebrates to colonise this new habitat (Photo 2.2). Afterwards invertebrates between the traps and tree bark and between the bubble wrap layers were collected and the traps removed. Beating and bark brush sampling - A large, soft paint brush was used to dislodge invertebrates (particularly spiders and beetles) from bark into a tray held underneath. Trees or bushes were then gently beaten so as to dislodge further invertebrates into a white sheet at the base of the tree. Beating was also used in isolation on some occasions to dislodge invertebrates from young trees or bushes. Active searches - Appropriate microhabitats for targeted notified features were searched by hand. This involved 'grubbing' in the ground layer, overturning stones, and a range of equipment such as a^??pootersa^??, amongst other specific techniques as appropriate. Saproxylic species were sampled by surveying a variety of niches within the arboreal habitat such as dead trunks, aerial deadwood, rot holes fruiting fungi and loose bark. Wherever possible, specimens were identified in the field. If not, specimens were pinned or preserved in isopropanol for later identification in the lab with stereo- or compound-microscopes as appropriate. Voucher specimens were retained where appropriate. Where necessary, we compared specimens with museum collections to confirm identification. We focussed identification effort on the target taxa for notified features. However, non-target specimens were identified to species level as time allowed, providing a more comprehensive species list for the sites.

Tweedwood - Gateheugh SSSI