Diamesa

Chertoprud, Mikhail V., Palatov, Dmitry M. & Dimante-Deimantovica, Inta, 2017, Macrobenthic communities in water bodies and streams of Svalbard, Norway, Journal of Natural History 51 (47 - 48), pp. 2809-2825 : 2817

1. Diamesa community. This community is typical of rocky bottoms of streams and small rivers, occupying them almost completely. All samples were dominated by Diamesa chironomids. Other taxa are usually not represented. There are several species of the Diamesa genus in the surveyed area. They are not always recognizable by the larvae. We distinguish three subtypes:

1.1. Diamesa gr. arctica , Diamesa aberrata . Found on rocky bottoms of streams and small rivers, usually in those with predominance of ice feed. One of the two species of the Diamesa genus usually dominates, but the species of the arctica group are not always identifiable. Hence, it is possible that even more species of this group can be found.

1.2. Diamesa bertrami , D. gr. arctica . Found at rocky-pebbly bottoms of small streams fed by groundwater. These habitats are distinguished by slightly increased temperature and salinity at lower currents, as well as by poor development of vegetation. Lods-Crozet et al. (2007) has already described such associations. According to them D. aberrata and D. bohemani Goetghebuer dominate in glacial streams, and D. bertrami and D. arctica dominate in non-glacial streams.

1.3. Diamesa gr. aberrata . This species is found on mixed substrates (small stones, pebbles, moss and vegetation) of the brooks at the outlet of lakes and flooded areas, springs and limnocrenes (small ponds fed by springs), in places with lower currents.

Other hard-bottom communities are usually associated with silted rocky and pebbly bottoms in lakes. Here are five additional dominants. The dominant depends on the size and feed of the water body, on the nature and extent of stone silting and, most likely, on some other extra factors.