HR: 09:00h
AN: NB41A-03    [Abstracts]
TI: Developing an Eastern Canadian Diatom Index: Preliminary Considerations
AU: * Lavoie, I
EM: ilavoie@trentu.ca
AF: Trent University, 1600 West Bank Drive, Peterborough, ON K9J 7B8 Canada
AU: Campeau, S
AF: University of Quebec at Trois-Rivieres, 3351 Boul. des Forges, C.P. 500, Trois-Rivieres, QC G9A 5H7 Canada
AU: Fallu, M
AF: University of Quebec at Trois-Rivieres, 3351 Boul. des Forges, C.P. 500, Trois-Rivieres, QC G9A 5H7 Canada
AU: Dillon, P
AF: Trent University, 1600 West Bank Drive, Peterborough, ON K9J 7B8 Canada
AB: Preliminary effort on the development of a Candadian diatom index has generated questions: Is it important to account for cell size? How should rare species be treated? Should those species known to be good indicators have more weight in the analyses? Is chemistry averaged over a certain period of time better than one-time chemistry measurements? What is the seasonal and annual variability in the community structure? Should between-ecoregion or upstream-downstream variability in the parameters used to generate the index be accounted for? We are currently attempting to answer these questions. Preliminary results have allowed to conclude that (1) metrics based on relative cell volume or cell surface did not provide more information than using cell relative abundance, (2) environmental variable metrics gave the best results when expressed as average seasonal conditions and (3) a higher portion of the variance is explained when samples from the spring and the fall are kept separated. An overview of the answer to these questions will be presented as well as recommendations for the development of the index. These investigations are essential to evaluate which metric combination allows to explain the highest percent variance in diatom community structure and therefore provide the most reliable index.
DE: 1845 Limnology
DE: 1871 Surface water quality
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly