HR: 14:15h
AN: NB43B-04 INVITED     [Abstracts]
TI: The use of Ordination of Invertebrate Communities to Diagnose Stress Response Type.
AU: * Reynoldson, T
EM: trefor.reynoldson@acadiau.ca
AF: Acadia University, Box 115, Wolfville, NS B4R 2P6 Canada
AB: The variety of bioassessment methods converge in attempting to determine whether the invertebrate assemblage is disturbed. Detecting a site is disturbed is the first step for most environmental agencies. The next should be to establish the cause of the disturbance and what is required and feasible to restore the site. One assessment method uses the RCA to assess sites through HMDS ordination. This method examines reference and matched test sites in ordination space, the degree of departure from the "cloud" of reference sites quantifies the disturbance. However, this method provides additional information on both the nature of the stress and degree of restoration required to recover a site. Ordination uses all the information in the community and the change in the assemblage determines the position of the site in ordination space. Therefore, sites follow different trajectories in response to nutrient enrichment compared to broad spectrum toxicants. These changes are demonstrated in mesocosm communities showing dose response diagnostic trajectories. In addition using multiple regression community ordination axis scores can be related to stressor variables and provide quantitative information on the degree of amelioration required in a stress variable to bring sites into reference condition.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly