Document Type
Report
Publication Date
10-2002
Pages
45 pp.
Abstract
Executive Summary
A study of the macrobenthic communities of the Elizabeth River watershed was initiated in summer 1999. This report presents the data from the third year of sampling in 2001. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. ( 2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will be updated annually as new data are available. (3) To produce an historical data base that will allow annual evaluations of biotic impacts by comparing trends in status within probability-based strata and trends at fixed-point stations to changes in water and/or sediment quality. During the 2001 sampling the benthic community condition of Paradise Creek of the Southern Branch of the Elizabeth River was also characterized.
The health of the benthic communities of the Elizabeth River watershed is characterized in this report by combining previously developed benthic restoration goals, the Benthic Index of Biotic Integrity (BIBI) developed for the Chesapeake Bay and probability-based sampling. A probability-based sampling design allows calculation of confidence intervals around estimates of condition of the benthic communities and allows estimates of the areal extent of degradation of the benthic communities. In summer 1999 a spatially intensive sampling occurred. The Elizabeth River watershed was divided into five sampling strata - the Mainstem of the river, the Lafayette River, the Southern Branch, Western Branch and Eastern Branch. Within each stratum 25 samples were randomly allocated in a probability-based sampling design. In 2000 and in succeeding years a single stratum, the entire Elizabeth River watershed, will be sampled with 25 random samples. In 2001 Paradise Creek was sampled as a separate stratum of 25 random samples.
Based upon probability-based sampling the estimate of benthic bottom not meeting the benthic restoration goals was 52 % in 2001, 72 % in 2000, and 64 % in 1999. In general for the Elizabeth River watershed, species diversity and biomass were below reference condition levels while abundance was above reference condition levels. Community composition was unbalanced with levels of pollution indicative species above, and levels of pollution sensitive species, below reference conditions. The level of degradation in Paradise Creek was 92% compared to 52% for the entire Elizabeth River watershed in 2001. Previously this same level of degradation was reported for the Southern Branch in the 1999 intensive sampling effort (Dauer 2000; Dauer and Llansó 2002). The higher levels of degradation in Paradise Creek were associated with extremely high abundances, low species diversity due to high dominance by a few species, and low levels of biomass and pollution sensitive species compared to the Elizabeth River watershed as a whole.
Rights
Included with kind permission of the author(s).
Repository Citation
Dauer, Daniel M., "Benthic Biological Monitoring Program of the Elizabeth River Watershed (2001) with a Study of Paradise Creek" (2002). Elizabeth River Reports. 12.
https://digitalcommons.odu.edu/chesapeakebay-archive_eriver_reports/12
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