PARENT SESSION
Oral Session 4: Biodiversity I: Communities and Function.
Presiding: C Holzapfel and D Ellsworth
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room B 110.
Ecosystem functioning during anthropogenic stress and recovery: A 20-yr whole-lake experimental investigation.
VINEBROOKE, ROLF*,1, TURNER, MICHAEL2, FINDLAY, DAVID2, PATERSON, MICHAEL2, SCHINDLER, DAVID1, 1 FRESHWATER BIODIVERSITY LABORATORY, EDMONTON, ALBERTA, CANADA2 EXPERIMENTAL LAKES AREA, WINNIPEG, MANITOBA, CANADA
ABSTRACT- Anthropogenic stressors are the current main drivers of non-random loss of global biodiversity and impairment of related ecosystem processes. However, it remains unclear whether human stressors or stress-induced changes in biodiversity best explain functional responses in real ecosystems. Here we examine patterns in biodiversity and ecosystem processes in an experimentally acid-stressed boreal lake to test whether the pH-manipulation or loss of species best explain changes in function. Strong relationships between species richness and related ecosystem processes were detected only for relatively species-poor, higher trophic levels. However, these relationships were influenced by environmental changes resulting from the acidification treatment. We corrected for the effects of the pH-manipulation by plotting ecosystem processes against the residuals of the species richness-pH relations, which negated most relationships between changes in diversity and production. The lack of significant relationships between non-random loss of biodiversity and ecosystem processes over a 20-yr period of anthropogenic stress and recovery highlights the importance of stressors and compensatory dynamics as primary determinants of the impacts of global change on freshwater ecosystems.
Key words: compensation, stressor, biodiversity, function