Aquatic invertebrates and high latitude paleolimnology

Almost all major groups of invertebrate animals may leave remains in sediments. An excellent review of animal remains (mainly invertebrates in Quaternary lake and bog deposits) was published by Frey (1964). Since that time, studies of invertebrate remains in lake sediments have undergone a tremendous development (Walker 1993). Much of this work has focussed on changes in trophic status, salinity and lake type. However, much work has also been devoted to paleoclimatic studies. Johansen (1904) was the first
to use invertebrate remains for paleoclimatic reconstruction, but his work was much criticized and debated (Johansen et al. 1906). History repeated itself when invertebrate remains were reintroduced to paleoclimatology in the 1980s (Walker and Mathewes
1987; Warner and Hann 1987; Walker et al. 1991). However, just as most terrestrial plants and animals have northern geographical range limits, so do most limnic plants and animals. As these limits are sensitive to temperature, shifts in their northern limits can be used in paleoclimatic reconstructions, although other factors may also be involved.