BAS utilizes a variety of sampling procedures to meet monitoring and assessment objectives with an emphasis placed on standardization. Currently, the default standardized benthic sampling and habitat assessment protocol in California is outlined by the State Board's Surface Water Ambient Monitoring Program (SWAMP). BAS has experience applying the SWAMP sampling procedure to a variety of waterbody types from large river systems such as the Merced to small urban streams. BAS currently provides assistance to clients for SWAMP field sampling projects. BAS also has experience with targeted riffle sampling approaches as well as the deployment of substrate basket samplers and Hester-Dendy plate samplers.
Sample processing consists of four main phases including sample inventory, organism fixed-count subsampling, organism identification to standard taxonomic level, and database entry. These steps are outlined in detail in the BAS standard operating procedures. Each step includes cross referencing sample identity and/or quality control measures to assure sample integrity throughout the process. Quality control is performed on 10 percent of remnant samples and the percentage of organisms recovered is tracked on a Shewhart chart.
All identified organisms are archived by taxon for each project and a subset of processed samples is routinely submitted to a qualified laboratory for evaluation of taxonomic and enumeration accuracy and conformance to standard taxonomic effort.
Currently, interlaboratory quality control cost is borne by the client and implemented at the discretion of the client. BMI data are entered and stored in a relational database. Taxonomic lists are produced from database queries and transferred to spreadsheets where biological metrics are calculated. BAS also uses the SWAMP Taxonomy Template for reporting bioassessment data.
Work products include taxonomic lists, suites of metric values, and the voucher collection of identified BMIs.Voucher collections of identified invertebrates are stored for four years after product submittal. After four years the client has the option of taking possession of the voucher collection or authorizing BAS to discard the voucher collection. BAS will notify client prior to taking any action regarding the voucher collection.
Supplemental products include generation of indices of biotic integrity where appropriate and exploratory analyses utilizing the ordination procedure, nonmetric multidimensional scaling. Ordination supplements biological metrics by graphically orienting sample units in relative space according to the relative similarity of taxonomic composition: distances between sample units plotted on a graph decrease with increasing taxonomic similarity. Ordination facilitates the identification of patterns in data including the identification of relationships between environmental variables and taxonomic composition. In contrast, multimetric indices use biological metrics to characterize sample units. The objectives of multimetric indices are to integrate distinct attributes of biological assemblages and to provide biological signals with high signal-to-noise ratios that respond across stressor gradients.
For SWAMP compatible BMI taxonomic data, BAS will coordinate with the client to assure data quality standards and appropriate formatting.