Chesapeake Bay benthic community restoration goals

Benthic macroinvertebrate assemblages have been an integral part of the Chesapeake Bay monitoring program since its inception due to their ecological importance and their value as biological indicators. The condition of benthic assemblages reflects an integration of temporally variable environmental conditions and the effects of multiple types of environmental stresses. As such, benthic assemblages provide a useful complement to more temporally variable chemical and water quality monitoring measures. While assessments using benthic monitoring data have been useful for characterizing changes in environmental conditions at individual sites over time, and for relating the condition of sites to pollution loadings and sources, the full potential of these assessments for addressing larger management questions, such as What is the overall condition of the Bay? or How does the condition of various tributaries compare? has not yet been realized. Regional-scale assessments of ecological status and trends using benthic assemblages are limited by the fact that benthic assemblages are strongly influenced by naturally varying habitat elements, such as salinity, sediment type, and depth. Such natural variability confounds interpretation of differences in the benthic community differences as simple responses to anthropogenic environmental perturbations. An additional limitation is that different sampling methodologies used in various programs often constrain the extent to which the benthic data can be integrated for a unified assessment. The objective of this project was to develop a practical and conceptually sound framework for assessing benthic environmental conditions in Chesapeake Bay that would address the general constraints and limitations just described. This was accomplished by standardizing benthic data from several different monitoring programs to allow their integration into a single, coherent data base. From that data base a set of measures (Chesapeake Bay Benthic Restoration Goals) was developed to describe characteristics of benthic assemblages expected at sites having little evidence of environmental stress or disturbance. Using these goals, benthic data from any part of the Bay could be compared to determine whether conditions at that site met, were above, or were below expectations defined for reference sites in similar habitats

Effect of reductions in numbers of taxa on the AZTI Marine Biotic Index (AMBI).

<p>Effect of reductions in numbers of taxa on the AZTI Marine Biotic Index (AMBI).</p

Percentages of taxa with BRI tolerance scores which have CO1 sequences available in the Barcode Of Life Database.

<p>Taxa were segregated into six categories along the disturbance gradient by BRI tolerance scores. The total number of taxa with tolerance scores in each category are presented above the bar indicating sequence availability. Barcodes were available for 163 of 462 taxa with tolerance scores.</p

Application of the Presence AMBI and AMBI to outfall monitoring data from 1972 to 1995 at Los Angeles County Station 6C (2.2 km from the outfall) and Station 0C (14.7 km from the outfall).

<p>Application of the Presence AMBI and AMBI to outfall monitoring data from 1972 to 1995 at Los Angeles County Station 6C (2.2 km from the outfall) and Station 0C (14.7 km from the outfall).</p

Pearson correlation coefficients (r) between benthic indices and measures of pollution at Los Angeles County Stations 6C and 0C from 1972 to 1995.

<p>Organic nitrogen is a measure of eutrophication and the mean ERM <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040875#pone.0040875-Long1" target="_blank">[17]</a> quotient is a measure of sediment contamination. For each of eight measured metals, the ERM quotient measures the ratio of the observed concentration to the value at which biological effects are likely, and the mean ERM quotient for the eight metals is an integrated measure of the likelihood of contaminant effects.</p

Presence AMBI assessment categories, assessment thresholds, and percentage of samples in agreement with abundance AMBI assessment category in the 493 sample calibration data.

<p>Presence AMBI assessment categories, assessment thresholds, and percentage of samples in agreement with abundance AMBI assessment category in the 493 sample calibration data.</p

Relationship between Presence BRI (BRI-P) and the original abundance BRI.

<p>Vertical and horizontal lines indicate assessment thresholds for the BRI <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040875#pone.0040875-Smith1" target="_blank">[12]</a> and BRI-P (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040875#pone-0040875-t001" target="_blank">Table 1</a>), respectively.</p

Application of the Presence BRI and BRI to 1990 seasonal outfall monitoring data at Orange County Station 0 (adjacent to the outfall) and Station Con (8 km from the outfall).

<p>Application of the Presence BRI and BRI to 1990 seasonal outfall monitoring data at Orange County Station 0 (adjacent to the outfall) and Station Con (8 km from the outfall).</p