ZOOBENTHIC SUCCESSION OF CONSTRUCTED WETLANDS IN THE FORT MCMURRAY, ALBERTA OIL SANDS REGION.

C.L. Leonhardt and J.J.H. Ciborowski. Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 3P4

We assessed the successional phenology of benthic invertebrate community development in three classes of wetlands formed in oil sands mining areas. We characterised and ordinated benthic community composition with respect to time since reclamation, using Principal Components Analysis followed by Discriminant Function Analysis (DFA). Our goal is to produce a scale against which progress towards achievement of a "natural state" can be measured. We sampled 18 wetlands, aged 1 to 28; Six low-conductivity (< 650 μS cm^-1), and 8 intermediate salinity wetlands (1,250-2,400 μS cm^-1) contained natural surface waters. Seven saline wetlands (1,250-4,600 μS cm^-1), built on mine waste materials contained natural surface water plus oil sands process-affected water (OSPW). Invertebrate family and chironomid generic richness both increased with wetland age. Young wetlands (< 7 y) of each class were dominated by different midge subfamilies. Communities of older wetlands (>13 y) became more similar, and were increasingly characterized by gastropods, oligochaetes, dragonflies and mayflies. DFA indicated that OSPW-affected wetlands were characterized by fewer Chironomini but more Tanypodinae and Tanytarsini. Gastropods most effectively characterized reference zoobenthic communities, but chironomid genera effectively demonstrate initial stages of convergence.