Benthic Macroinvertebrate Bioassessment in the San Joaquin River Restoration Area. Principal Investigators: Abimael León, Margarita Gordus, Karen Dulik and James Harrington California Department of Water Resources, South Central Region, Environmental Services Section
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Benthic Macroinvertebrate Bioassessment in the San Joaquin River Restoration Area
Principal Investigators: Abimael León, Margarita Gordus, Karen Dulik and James Harrington
California Department of Water Resources, South Central Region, Environmental Services Section
California Department of Fish and Game
- Most of the study sites are in “poor condition” (60%).
- The only two sites with “good condition” occur within Reach 1A and Reach 1B.
- Abundance and distribution of BMI taxa indicate a possible response to relative environmental degradation.
The study approach is consistent with California’s Surface Water Ambient Monitoring Program (SWAMP) Bioassessment Procedures (Ode 2007).
Sampling period: SWAMP index period of late May through the end of September 2010-2012 during base flow conditions
Sample size: Include at least 30 sampling reaches (sites) with 10% replication within the Restoration Area during each field season. Sites were selected after reconnaissance surveys of up to 150 random points from Reach 1 through Reach 5 (Figure 1).
Sample analysis: The Aquatic Bioassessment Laboratory will identify and quantify benthic macroinvertebrates in the samples.
Benthic macroinvertebrate (BMI) communities are both bioindicators of stream condition and a food resource for fish. These communities comprise the effects of stressors such as increased temperature, toxic chemicals, excessive nutrients and sediment loading. In addition, BMIs respond to human disturbance and physical changes in riparian vegetation and instream habitat heterogeneity.
This study addresses habitat objectives set forth in the San Joaquin River Restoration Program (SJRRP) Fisheries Management Plan. The study has been identified by the Fisheries Management Working Group (FMWG) as an ongoing need for the Program ( SJRRP 2010) As portions of the river are restored and vegetated, it is also likely that the BMIs will change, resulting in a more diverse population. Bioassessment data from BMI communities will provide information about the ecological integrity of the San Joaquin River system.
- Study results show baseline conditions of macroinvertebrate communities in the San Joaquin River Restoration Area.
- Future surveys can potentially show if restoration actions can improve existing biological conditions in the Restoration Area.
- Stream restoration actions in the Central Valley should consider ecological integrity and food production as reflected by macroinvertebrate communities.
Physical Habitat Characterization
Ode, P. R. (2007) California SWAMP Bioassessment SOP 001.
SJRRP (2010) Fisheries management plan: A framework for adaptive management in the San Joaquin River Restoration Program.
We thank State scientists for their help with field work and study logistics.
DWR staff: L. Castro, C. Collins , B. Galyon, J. Kitch, J. Morales, E. Rhyne-Christensen and F. Vang
DFG staff: M. Bigelow, B. Espino, K. Gipson, E. Guzman, S. Corcoran, M. Hubble, A. Krisch, S. Lajoie, N. McLaghlan and R. McNeal
SWRCB staff: J. Chilcott, T. J. Kopshy , S. Rutherford and B. Soto
A. Water quality
B. Habitat Complexity
C. Riparian Vegetation
D. Bank Stability
Figure 2. Central Valley B-IBI: Benthic Macroinvertebrate Index of Biotic Integrity in the San Joaquin River Restoration Area
Figure 1. Project Study Area: Macroinvertebrate survey area in the upper San Joaquin River between Friant Dam and the confluence with the Merced River
San Joaquin River at San Luis NWR