MACROINVERTEBRATE ASSEMBLAGES ON WOODY DEBRIS AND THEIR RELATIONS WITH ENVIRONMENTAL VARIABLES IN THE LOWER SACRAMENTO AND SAN JOAQUIN RIVER DRAINAGES, CALIFORNIA

摘要

Data from 25 site were used to evaluate associations between macroinvertebrate assem- blages on large woody debris(snags)and environmental variables in the lower San Joaquin and Sacramento River drainages in California as part of the U.S. Geological Survey's National Water Quality Assessment Program. Samples were collected from 1993 to 1995 in the San Joaquin River Drainage and in 1996 and 1997 in the Sacramento River drainage. Macroinvertebrate taxa were ag- Gregated to the family (or higher)level of taxonomic organization, resulting in 39 taxa for analyses.