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Taxonomic group

Subclass: Acari

Diagnostic features

Mites are arachnids, invertebrates with four pairs of legs (at least as adults). Mites differ from the spiders in that they only have one main body segment (spiders have bodies divided into two distinct sections). Terrestrial mites are often found in stream samples, but freshwater species are often revealed by their good swimming ability and the presence of swimming hairs on the legs.

Typical habitats

Swimming mites are often abundant in ponds and wetlands, but other non-swimming species live on the beds of slow-flowing waters.


Some mites are parasites, attaching themselves to other invertebrates, while others feed on plants or decaying organic matter.

Indicator value

  • Hard bottom: 5
  • Soft bottom: 5.2

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

Mites are found in almost all freshwater habitats and therefore they may have limited indicator value. They have been assigned tolerance values of 5 (hard bottom sites) and 5.2 (soft bottom sites).