A MACROPHYTE-BASED RAPID BIOSURVEY OF STREAM WATER-QUALITY - RESTORATION AT THE WATERSHED SCALE

The restoration of chemically degraded rivers, lakes, and estuaries wi th large watersheds and pollution sources that are primarily diffuse i n nature requires the grading of thousands of kilometers of tributary streams. Many population- and community-oriented biomonitoring methods have been developed that avoid the cost limitations of chemical/bioma rker/bioassay approaches and the serious limitations of single-factor analysis as related to complex systems. In this study of the coastal p lain and piedmont geomorphologic provinces of the Chesapeake Bay water shed, we have demonstrated a set of quantitative measures based on ana lysis of macrophyte populations that provide statistically significant separation of streams in accordance with their state-issued water qua lity rating. Macrophytes can be abundant and diverse in lower-order st reams, and they demonstrate patterns of community structure and divers ity similar to those of other organisms developed for biomonitoring of stream degradation. Unlike organisms previously and extensively used in biomonitoring techniques, however, macrophytes are considerably eas ier to identify and quantify. In addition, macrophyte techniques provi de a range of measures of increasing sensitivity from species numbers at a few sites, to the presence/absence and abundance of indicator spe cies, and, finally, to a diversity analysis based on easily identified species at an extended number of sites. We suggest that the ease of u tilization of this methodology will allow repeated surveys of all stre ams in large water-sheds with the invertebrate, fish and diatom biomon itoring to biomarking and chemical bioassays and finally analytical ch emistry, progressively applied to verify and then identify specific po llution sources (''hot spots'') in a more limited number of problem st reams.