Authors: Mark P Gustafson
Publish Date: 2008/03/06
Volume: 605, Issue: 1, Pages: 235-246
Abstract
The variation in thermal regime and elevation among streams in the Sawtooth Mountains of Idaho USA was used to test hypotheses about forces structuring larval mayfly assemblages Sites above and below lakes were included to maximize variation in thermal regime Fortyfive sites were sampled for mayfly larvae and their summer thermal regime was measured Ordination methods were used to analyze variation in the mayfly assemblages Principal components analysis showed that mayfly assemblages were strongly and consistently affected by lakes within the stream system apparently through the effects of lakes on stream temperature Redundancy analysis explained 51 of the variation in assemblages and identified maximum water temperature and elevation as strong predictors of mayfly assemblages Elevation influenced assemblage structure independently of summer maximum water temperature suggesting that air temperature or some other elevationdependent feature is also important As predicted by the River Continuum Concept mayfly diversity increased with increasing maximum daily range in temperatureThe National Science Foundation Award DEB 0132983 and an ROA Supplement to that award Texas Lutheran University and Utah State University provided financial and logistical support I thank Wayne Wurtsbaugh and Bob Hall for aid in the development of the project and Wayne Wurtsbaugh for generously hosting my visit at Utah State University and commenting on the manuscript Chris Arp and Jessie Garrett provided much useful information on study sites and temperature monitoring Two anonymous reviewers provided many helpful comments on the manuscript
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