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

Abstract

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 14 C 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, Barrowupon-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.

Reconstructing riverine paleo-flow regimes using subfossil insects (Coleoptera and Trichoptera): the application of the LIFE methodology to paleochannel sediments

“…A total of 49 samples of approximately 5 kg were extracted at 10-cm intervals from top to bottom of each monolith. Field sampling and processing followed Greenwood et al (2003).…”

“…Approximately 1 kg of each sample (0.5-1.0 l) was processed for aquatic insect remains following standard paraffin floatation methodology of Coope (1986) as modified by Greenwood et al (2003), and with the introduction of a 90-m-mesh sieve to retain smaller insect sclerites. A small fraction of the unprocessed sediment from each of the 49 samples was retained for determination of organic matter content by loss of mass on ignition (LOI) (Dean 1974).…”

“…Identification of fauna was achieved by comparison with standard taxonomic texts (Trichoptera : Hickin 1967;Hiley 1973;1976;Wallace 1980;Edington and Hildrew 1995;Greenwood et al 2003;Wallace et al 2003;Coleoptera: Hansen 1987;Holmen 1987;Nilsson and Holmen 1995;Harde 1998;Friday 1988). Taxonomy followed Barnard (1985) for Trichoptera and Duff (2008) for Coleoptera.…”

“…The River Trent has been the focus for several sedimentological (Brown et al 1994, Brown et al 2001, Howard 2005 archaeological (Salisbury 1992, Howard et al 2007) and paleoecological (Greenwood et al 2003 investigations. The River Trent has a catchment area of 7486 km 2 , a length of approximately 149 km and is one of the UK's most active rivers.…”

“…Trichoptera larvae have also been recognised as potential indicators of environmental and paleoflow conditions (Williams 1988), but in marked contrast to Coleoptera, only limited use has been made of them until recently (Solem and Birks 2002;Greenwood et al 2003;2006). Trichoptera larvae are found in a wide variety of aquatic environments from fast flowing open channels to lentic bodies and ephemeral pools (Bacher and Waringer 1996;Wiberg-Larsen et al 2000).…”