quality index

The species listed under this fidelity scores have been derived from surveys of the Diptera of sandy exposed riverine sediments (ERS). Species surveyed were allocated to ERS fidelity classes:

Brackish grazing marsh systems are naturally poorer in species than freshwater systems, so this difference needs to be taken into account during site evaluation. As many grazing marshes are situated near the coast, their ditches often support invertebrates tolerant of salinity. Salt-tolerant invertebrate species that can be used as indicators of brackish conditions are given a score in this index, based on a scale of 0 (least tolerant of saline conditions) to 2 (dependent on at least mildly saline conditions).

The scoring system used here allocates a score to each species according to its relative rarity, then calculates the average (equivalent to a Species Quality Index or SQI) for a sample. Each of the relevant species is given a Conservation Status score of 1 to 5, as follows:

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.

This lists 71 spiders showing a high measure of naturalness from western peat bog systems, under conditions where good peatland naturalness occurs when the naturalness measure >0.5, the Spider SQI >1.8, and with sampling rules applied. The database returns a count of those matching species from the list in the sample. It is unclear how eastern bogs fare under this measure, and there is currently little overall context for it, so it should be used cautiously.

Howe (2002) summarised published data on coastal soft cliff invertebrates in Wales and the UK in general to create the index. 105 species have an association with coastal soft cliffs in the UK. These are subdivided into:

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.

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.

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.

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.