Benthic macroinvertebrate monitoring - streambed disturbance and seasonal inundationperiod of performance: 08 01 2025 - 12 31 2027ABSTRACT summary: this project will fill key information gaps…

The U.S. Geological Survey (USGS) Office of Acquisitions and Grants awarded a Cooperative Research Units Program (CFDA 15.812) cooperative agreement totaling $308,472.64 to the CAL Poly Humboldt Sponsored Programs Foundation (HSU Foundation) for the period August 1, 2025 through December 31, 2027. This project addresses critical information gaps in benthic macroinvertebrate community dynamics by quantifying recolonization patterns in disturbed streambed areas and seasonally inundated habitats relative to perennially inundated zones. The research focuses on salmonid food availability by examining how macroinvertebrate populations respond to streambed disturbances and seasonal variation in river discharge and water temperature.

The Foundation will deliver research services through three primary tasks: (1) field sampling and data collection at three distributed river sites, with benthic samples collected biweekly during disturbance periods (mid-November through mid-April) and monthly thereafter, plus targeted sampling of seasonally inundated areas during elevated baseflow periods (mid-February through mid-June); (2) laboratory processing of samples by undergraduate and graduate students at Cal Poly Humboldt to characterize benthic density, biomass, and community composition through microscopic sorting and identification of invertebrate taxa to family or class level; and (3) analysis and reporting of findings. As required by the Cooperative Research Units Program, the project incorporates educational components for graduate student training while collaborating with USGS personnel and cooperating agency representatives to inform federal and state fish and wildlife management decisions.

Benthic macroinvertebrate monitoring - streambed disturbance and seasonal inundationperiod of performance: 08 01 2025 - 12 31 2027ABSTRACT summary: this project will fill key information gaps regarding the dynamics of benthic macroinvertebrate communities related to seasonal and disturbance-induced variation in river discharge and water temperature, through the lens of salmonid food availability. The primary objective of this project is to quantify recolonization or colonization of benthos by macroinvertebrates in disturbed areas of the perennial channel, and in seasonally inundated areas relative to the perennially inundated areas. Activities to be performed - task 1: field sampling and data collection benthic samples will be collected at three sites distributed throughout the river to characterize two disturbance and or colonization mechanisms: catastrophic drift and succession in newly and perennially available habitats. Streambed disturbance samples will be collected twice per month mid-november to mid-april, and monthly for the remaining year. Inundation samples will be collected at each site in wetted areas above the minimum winter baseflow elevation (e.g., currently 300 CFS release from lewiston DAM) twice per month starting with the onset of elevated baseflow releases from lewiston DAM (approximately mid-february through mid-june), provided increases in flow result in sufficient increases in inundated area to sample effectively.task 2: laboratory processing of field samples after sample collection in the field, undergraduate and graduate students at CAL poly humboldt (CPH), will process each sample so that benthic density (e.g., biomass M2, or equivalent), biomass, and community composition can be characterized. Samples will be sorted and individuals will be counted and identified to family for insects and class or family for non-insect taxa under a dissecting microscope.deliverables and expected outcomes -task 3: analysis and reporting analysis and reporting will primarily be the responsibility of the CPH graduate student with oversight from the project PI and graduate committee. The graduate student will be responsible for writing a masters thesis, with intention to publish in a peer-review journal. The graduate student will also be responsible for preparing and providing two presentations, one to the trinity management council responsible for flow management decision making, and one to the interdisciplinary team, which oversees is the science and monitoring branches of the trinity river restoration program.intended beneficiary(IES) -the intended beneficiaries include the trinity river restoration program, and the important federal, state, and tribal governments represented on its management council. Additional beneficiaries include the general scientific community, as the results from this project will provide information that could inform water management in settings where management decision making considers impacts to salmonid food availability.