Biotic Responses to Restoration Efforts in a Highly Perturbed Lake: A Collaborative Success Story

Onondaga Lake in the Lake Ontario watershed was once vital to the Houdenosaunne Confederacy and the City of Syracuse, NY.  The lake experienced a century of impacts, including mercury deposition, nitrogen and phosphorus enrichment, biotic invasions and extinctions, and seepage of alkaline leachate. Upgrades to water treatment and storm sewer facilities helped to restore water chemistry.  Following closure of a soda ash facility (1986), scientists at SUNY–ESF joined N.Y. DEC, U.S.EPA, Upstate Freshwater Institute and others to assess the biota of the lake.  A Record of Decision (2005) led Honeywell International to begin restoration efforts, including isolating leachate and removing contaminated sediments.  A physical cap will provide substrate for plant growth, invertebrate colonization and fish spawning.  Biological monitoring and assessment has included  population dynamics of native and exotic fishes and recolonization rates of  macrophytes and macroinvertebrates.  Macrophyte coverage of the littoral zone has increased dramatically, in response to increased transparency and changes in sediment nutrients and stability.  The fish community, once dominated by planktivores, now includes families such as Centrarchidae, Percidae, Acipenseridae and Salmonidae.  Physical habitat to be assessed this year includes wooden “porcupines” and rocky substrate.  Creative interactions among participants provide an example for similar restoration endeavors world-wide.