PARENT SESSION
Long-Term Monitoring to Assess Recovery of Aquatic Ecosystems.
John Smith, Michael Ryon
Wednesday, November 15, 2000
1:20 PM to 5:20 PM
RH Center Ballroom
(380) Assessing long-term recovery in contaminated streams using multiple chemical and biological endpoints.
Adams, S. Marshall1, 1
ABSTRACT- The recovery process of aquatic ecosystem is complex, occurring over multiple levels of organization and over different time scales. In aquatic systems, stress and disturbance may affect several levels of organization from the sub-organismal to the ecosystem-level, and the consequences and mechanisms of stress are different at each hierarchical level. Assessing the biological recovery process in East Fork Poplar Creek (EFPC) over a 13 year period has involved studies with ambient toxicity testing, bioaccumulation monitoring, periphyton analysis, benthic macroinvertebrate surveys, biomarker measures of individual fish health, and fish community analysis. Depending on the particular endpoints used to assess recovery, different conclusions were reached regarding the effectiveness of remedial activities on the recovery process in EFPC. The long-term temporal patterns of chl a in periphyton, invertebrate community structure, bioindicators of fish health, and fish community metrics were similar over the study period but over time displayed some differences in spatial patterns along the gradient of the stream. Results from the bioaccumulation and the ambient toxicity testing indicated that, in several cases, temporal patterns in recovery were different from those demonstrated by the biological endpoints. Whereas information on chemical loading and biological exposure can help provide the basis for identifying the mechanistic basis of recovery, biological endpoints, and particularly those at higher levels of organization, are key for understanding the dynamics and ecological significance of recovery. The complexity of aquatic systems and their variable recovery dynamics suggests that no single approach for assessing aquatic system recovery is adequate and that a suite of chemical and biological endpoints are required for a more complete understanding of ecosystem status during both the recovery and the post-disturbance period.
Key words: Stream recovery, Multiple endpoints, Temporal patterns, Biomonitoring