Depth distribution of chironomids and an evaluatio

Authors: Les C Cwynar Andrew B H Rees Cy R Pedersen Stefan Engels

Publish Date: 2012/06/30

Volume: 48, Issue: 3, Pages: 517-533

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Abstract

We used 39 surface samples from Marcella Lake Yukon Territory to examine the distribution of chironomid head capsules in relation to depth and to develop a sitespecific intralake inference model for reconstructing past lake levels Ten of the 34 mostfrequently occurring taxa encountered in the surfacesediment samples are significantly related to depth We then applied the sitespecific inference model and a previously developed regional model to samples from deep and shallowwater cores from Marcella Lake The inferences were compared to an independent Digerfeldttype reconstruction of lake level history and to moisture inferences drawn from pollen data Although the sitespecific model was good in having better performance statistics than the regional model it was bad at producing depth reconstructions because most samples from the long cores lacked suitable analogues in the sitespecific training set None of the chironomidbased reconstructions was a good match to the Digerfeldttype reconstruction Inconsistencies remain between the paleohydrological inferences derived from the chironomid depth models the Digerfeldttype reconstruction and polleninferred reconstructions of past moisture regimesThanks to Josh Kurek Jesse Vermaire Bronwen Whitney Chris Lyons Katie and Kristie Richardson and Julia Gustavsen for providing help or advice at various stages of this research Dr Daniel Borcard provided helpful advice on the use of PCNM This research was supported by a Natural Sciences and Engineering Research Council of Canada NSERC Collaborative Research Opportunity Grant Cwynar PI and an NSERC Discovery grant to LCC Fieldwork was funded in part by a Northern Scientific Training Program grant to CR Pedersen Rees’ contribution to this research was supported by an NSERC Postgraduate Scholarship

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