The use of caddisfly fauna (Insecta: Trichoptera) to characterise the Late-glacial River Trent, England



Trichoptera have been utilised infrequently in palaeoecological studies despite their value as environmental indicators of freshwater habitat structure and quality, via their aquatic larvae, and catchment macroclimate conditions, via the aerial adults. Two sites, dated ca. 11 600 14C yr BP, in the middle reaches of the River Trent (England) supported caddisfly (Trichoptera) assemblages indicative of a dynamic braided river with extensive floodplain development. At the first, Barrow-upon-Trent, the caddisfly assemblage was dominated by taxa indicative of a medium to large gravel-bed river (Lepidostoma hirtum, Micrasema setiferum and taxa from the family Hydropsychidae). At the second site, Hemington, the caddisfly fauna was dominated by taxa from the families Limnephilidae and Phryganeidae. These usually occur in slow flowing and standing waters and are indicative of cut-off channels on the floodplain. Micrasema setiferum does not occur in the contemporary UK fauna and has a modern distribution across central Europe and Fennoscandia. A gridded climatology extracted for those geographical areas where M. setiferum occurs today indicated a greater degree of continentality than currently prevailing in the Trent catchment. The value of Trichoptera in palaeoecological studies is explored and a model of channel evolution for the River Trent is presented based on caddisfly data. Copyright © 2003 John Wiley & Sons, Ltd.