The following excerpts are from:
Sustainable Land Stewardship Institute. 2003. Biological
and Physical/Habitat Assessment
of Selected Sites Within the Santa Rosa Watershed. Performed for the
City of Santa Rosa as part of Storm Water Monitoring Program. 18 p.
BMI Sampling: The technique used to describe
the BMI community and the biotic condition of the six sampling sites was the
California Stream Bioassessment Procedure (CSBP).
The California Department of Fish and Game (Harrington 1996) developed
the CSBP as standardized and cost-effective sampling, laboratory and quality
assurance procedures for the State’s bioassessment programs.
The CSBP is a regional adaptation of the U.S. Environmental Protection
Agency (EPA) Rapid Bioassessment Protocols (Barbour et al. 1999) and has been
used in various parts of the world to measure biological integrity of aquatic
systems (Davis et al. 1996).
Sampling was conducted by the City of
Santa Rosa
staff in May of 2000, 2001 and 2002. Riffle
length was measured for each of three riffles at each monitoring reach.
Using a random number table, a transect was established perpendicular to
stream flow along the upstream third of each riffle.
Starting at the downstream riffle, the benthos within a 2 ft2
area was sampled upstream of a 1 ft wide, 0.5 mm mesh D-frame kick-net.
Sampling of the benthos was performed manually by rubbing cobble and
boulder substrates in front of the net, followed by “kicking” the upper
layers of substrate to dislodge any remaining invertebrates.
The duration of sampling ranged from 60-120 seconds, depending on the
amount of boulder and cobble-sized substrate that required rubbing by hand; more
and larger substrates required more time to process.
Three locations representing any habitat diversity along each transect
were sampled and combined into a composite sample, representing a 6 ft2
area for each transect and 18 ft2 for the entire reach.
Each composite sample was transferred into a 500 ml wide-mouth plastic
jar containing approximately 200 ml of 95% ethanol.
This technique was repeated for each of three riffles in each reach.
BMI
Laboratory Analysis: The BMI samples collected in 2000 and 2001 were
processed at the EcoAnalysists Laboratory in
Moscow
Idaho
and the 2002 samples were processed by SLSI in
Chico
California
. At both laboratories, each sample
was rinsed through a No. 35 standard testing sieve (0.5 mm brass mesh) and
transferred into a tray marked with twenty, 25 cm2 grids.
All sample material was removed from one randomly selected grid at a time
and placed in a petri dish for inspection under a stereomicroscope.
All invertebrates from the grid were separated from the surrounding
detritus and transferred to vials containing 70% ethanol and 5% glycerol.
This process was continued until 300 organisms were removed from each
sample. The material left from the
processed grids was transferred into a jar with 70% ethanol and labeled as
“remnant” material. Any
remaining unprocessed sample from the tray was transferred back to the original
sample container with 70% ethanol and archived.
BMIs were then identified to a standard taxonomic level using appropriate
taxonomic keys (Brown 1972, Edmunds et al. 1976, Klemm 1985, Merritt and Cummins
1995, Pennak 1989, Stewart and Stark 1993, Surdick 1985, Thorp and Covich 1991,
Usinger 1963, Wiederholm 1983, 1986, Wiggins 1996, Wold 1974).
See
SRSI (2003) for literature citations.