In reply to brian a:
> (In reply to Sambo) why not
Vegetation type probably.
2.1 Habitat
Recent research has identified the three NVC vegetation communities in which most breeding sites of the highland midge C. impunctatus occur:
1. The Sphagnum sub-community of Betula pubescens - Molinia caerulea woodland (W4);
2. Molinia caerulea - Potentilla erecta mire (M25);
3. Juncus acutifolius sub-community of Juncus effusum / acutifolius - Gallium palustre rush pasture (M23).
The common features of the breeding habitat seem to be the presence of Sphagnum spp., the rushes, J. articulatus and J, acutiflorus or the purple moor grass M. caerulea. These plants characterise soils with a high enough water content for the development of the larvae. This habitat is not uncommon in the West Highlands.
Research is based on Scotland but to summarise: it's bogs!