|Citation||Limnotek Research and Development. 2010. Cheakamus River benthic community monitoring for water license requirements: Cheakamus River Monitoring Program #7, Final Report. Prepared for BC Hydro.|
|Abstract/Description or Keywords||Statistical modeling was used to examine the importance of flow and other
habitat attributes on the abundance and composition of benthic communities in the
Cheakamus River. The modeling was recognized by a Consultative Committee (CC) of
the Cheakamus water use plan as a useful tool to support future decisions on water
release from the Daisy Dam. The study answered two management questions raised by
1. What habitat attributes best determine the composition, abundance, and
biomass of benthic invertebrates in the Cheakamus River?
2. Among all habitat attributes, what is the relative importance and magnitude of
effect of flow in determining the composition, abundance, and biomass of
benthic communities in the Cheakamus River?
Benthic invertebrate and periphyton count and biomass data were collected from
five stations downstream of the Daisy Dam along with measurements of up to 53 habitat
variables. The sampling occurred during all seasons in 2009. The data were appended
to similar measurements from 1996 and 1999. Multiple regression analysis was used to
develop models that were used to identify and rank the most important attributes of
habitat and food web interactions that determined each of six dependent variables.
Those dependent variables, also known as endpoints, were as follows:
1. Benthic invertebrate biomass,
2. An index of benthic invertebrate abundance called the Cheakamus
benthos index (CBI),
3. Benthic invertebrate diversity,
4. Periphyton biomass,
5. Periphyton diversity,
6. Biovolume of Didymosphenia geminata (Didymo), a stalked diatom that
formed large mats in 2009 and could potentially affect water quality .
Stomach contents of juvenile salmonids and resident rainbow trout were also examined
to determine the extent of links between benthos produced in the Cheakamus River and
food that is ingested by fishes.
Best fit of the multiple regression models to the data occurred with one to eight
predictor variables describing flow metrics, temperature, turbidity, elevation, presence of
Didymo, riparian vegetation, food web interactions, and flow variance. All predictor
variables were independent and the models were computationally stable. The selected
predictors explained 54-68% of observed variance of the biological metrics among all
years, seasons, and locations.
|Regional Watershed||Howe Sound & Sunshine Coast|
|Sub-watershed if known||Cheakamus River|