Seepages are very small, flowing waterbodies. They are characterised by generally slow rates of flow, and by being extremely shallow, sometimes no more than a film of water over the substrate. This means that they are most often associated with the uppermost sections of waterbodies, being transitional to streams and rivers as they gather water lower in the catchment. They are also very often derived from springs.
The Index of Ecological Continuity (IEC) for beetles was originally developed as a means of producing a simple statistic which could be used in grading a site for its significance to the conservation of saproxylic (wood-decay) beetles based on ecological considerations rather than rarity. Several important sites have been designated as a result of this approach to interpreting site species lists as saproxylic assemblages of ecological significance.
Exposed riverine sediments (ERS) occur within river systems at the juncture of the aquatic and terrestrial, and consist of poorly vegetated alluvial deposits of silts, sands and gravels, which are habitat for a wide range of rare and highly specialised beetles. The fidelity scores used in Pantheon originate from Bates 2005 (see link below) who worked in collaboration with Adrian Fowles, who had developed a previous set of scores.
The term "coarse woody debris" (CWD) is used to denote the input of fallen trees and other woody matter into watercourses. CWD may consist of entire trees, root boles, trunks, logs, branches and other pieces of wood that can accumulate within river systems, either submerged or partially submerged in the water.
This index uses only the extant invertebrate fauna of acid mires in England. It should be noted that the acid mire fidelity grade assigned to each species refers to its fidelity to the whole range of acid mire habitats.