HR: 09:30h
AN: NB51A-05    [Abstracts]
TI: Combined impacts of global warming and pollution: impacts on food web structure and ecosystem function.
AU: * Thompson, R M
EM: thompson@zoology.ubc.ca
AF: Biodiversity Research Centre, 6270 University Blvd., Vancouver, BC V6T1Z4 Canada
AB: Effects of global species loss on ecosystem function have traditionally been extrapolated from studies which investigate the effect of random species loss or addition. Real species loss is highly patterned and clumped according to trophic position, taxonomic relatedness and interconnectedness with the remainder of the food web. Using pond microcosms, I evoked a realistic pattern of species loss using toxins and warming. Species loss was predictably highly patterned. Influences on ecosystem functions ranged from simple and linear in the case of algal productivity, through to complex and step-like in the case of bacterial decomposition. Impacts on algal productivity were mediated by effects on the rate of grazing by invertebrates. There is strong evidence from the bacterial decomposition results of an `insurance effect' whereby the presence of multiple stressors has a strong, non-additive effect on function. These results clearly show that the traditional ecotoxicological practice of studying effects of single toxins on single species may be highly misleading.
DE: 1699 General or miscellaneous
DE: 1845 Limnology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly