The Multihabitat Approach of USEPA’s Rapid Bioassessment Protocols: Benthic Macroinvertebrates

Abstract

The multihabitat approach to sampling for bioassessment is not a new concept, but has been described in detail in the USEPA Rapid Bioassessment Protocols Although there are variations on this technique, the basic approach is to sample the major aquatic habitats in proportion to each representation in the stream reach. Both fish and benthic macroinvertebrates are sampled in this manner. The primary advantage of the multihabitat approach is to sample representative stream habitats that will address habitat altered systems and provide an indication of impairment from both chemical and non-chemical stressors. This technique has been shown to collect representative samples of the stream reach and to be highly precise among and within sampling crews. Four questions are addressed in this paper: (1) What are the strengths and limitations of the method for low-gradient streams; (2) What are the performance characteristics (i.e., accuracy, precision, sensitivity) of the method; (3) What is the relative ability of the method to distinguish natural variability (i.e., temporal, spatial) from human disturbance; (4) How would the method be implemented for low-gradient streams.