Flow regulation has significant impacts on river ecosystems including aquatic vegetation, benthic macroinvertebrates, and salmonids (Caldwell et al., 2018). The Trinity River is an example of a flow-regulated river that has experienced a decline in fish populations and ecological health (Beechie et al., 2015). This study uses benthic macroinvertebrates (BMIs) as indicators of fish habitat quality. We compare the abundance and composition of BMI communities before and after a rain event that inundated marginal habitat. Samples were collected at marginally- and perennially-inundated sites on the Trinity River in Junction City, California in January and February 2020. The resulting data illuminated that there was not a significant (p-value=0.27) increase in BMI abundance or diversity in marginal habitats post-inundation. This non-significant result may be attributed to the small sample size and high variability in the data. As we learn more about how flow regimes affect BMI abundance and diversity within marginal habitats, dam managers can be more informed on managing flow regimes to promote more healthy fisheries.
Environmental Science and Management