Trichoptera remains from early Holocene river deposits in the Great Belt, Denmark

Analyses of a sediment core from the Great Belt documented the local presen ce of fluvial deposits. The sediments consisted of silt, clay, sand and org anic detritus and they contained macroscopical remains of a mixture of terr estrial, telmatic, lacustrine and fluvial plants and animals. Most notewort hy was the abundance of remains of caddisfly larvae, totalling at least 24 species, which were dominated by fluvial species. Thus, filter-feeding hydr opsychids made up approximately 95% out of 1496 identified specimens, the d ominating species being Hydropsyche contubernalis and H. pellucidula. The p resent-day requirements of the recorded species point to a fairly fast-flow ing river, at least locally, with areas of stones (some with moss growth) a nd gravel, but also to more slowly-flowing parts with sand, fine and coarse detritus. This river may have been considerably larger than any present-da y Danish river. It appears that the fluvial deposits formed locally in conn ection with flooding of the area south of the care position. AMIS radiocarb on dating shows that the sequence was deposited very rapidly during the ear ly Holocene, about 10650 to 10250 cal. years BP. The occurrence of the lent ic Leptocerus tineiformis points to a climate at least as warm as today.