A World of Water: How Aquatic Life Plays a Role in Determining Stream Health
Jason Ellis - jcellis@csuchico.edu & Jordan Kruger- jkruger2@csuchico.edu
In today’s world, the impact of humans can be seen everywhere. From areas that are heavily influenced by anthropogenic activities, to those that are more untouched. The streams that run through our lands are a great way of telling the general health of the ecosystem around them.
In our study, we focus on Big Chico Creek. It starts up in the mountainous headwaters of the Sierra Nevadas, and runs through Upper Bidwell Park before making its way into the city of Chico. This makes it an ideal stream for a study of water quality due to it going through different conditions. These conditions cause a variety of differences such as water temperature, dissolved oxygen, pollution, human impacts and much more.
Benthic macroinvertebrates are a great indicator of water quality. This is because such a variety of insects, worms, snails, crustaceans, mites and other stream dwelling creatures have such a different tolerance for water conditions. Some can live happily in streams filled with trash and a variety of human-caused runoff that negatively affects the stream. Others can only live in streams with little to no pollution. They disappear from these systems once a source of pollution develops. We used this tolerance to our advantage by sampling at two different locations on Big Chico Creek to get an idea of what is able to live in each location. The two locations chosen for this study are Upper Bidwell Park at Day Camp before the stream flows into Chico, and at a higher elevation at highway 32 in Deer Creek Canyon.
The water conditions were noticeably different with the Deer Creek Canyon having a more narrow stream, faster flow, and larger rocks/boulders. Upper Bidwell Park had a wider stream with slower flow, and smaller particulate matter. Using a D-shaped dip net to collect benthic macroinvertebrates we collected aquatic specimens from both sites and preserved them in ethanol to bring them back to the lab for analysis.
After using microscopes to identify each macroinvertebrate to a family level identification we had an idea of what differences there were between the two sites. Initially, the first thing we noticed was how much more abundant the Deer Creek Canyon location was compared to the Upper Bidwell Park location which had a significantly lower amount of specimens. Not only this, but the highway 32 location had a higher diversity of samples and individual macroinvertebrates which have a low tolerance for pollution and disturbance. These sensitive indicator species were notably absent from the Upper Bidwell Park location.
Site 1 on the left, located at Upper Park, presented a slower moving stream with lots of fine sand and a more open scheme. Site 2 on the right, located at the highway 32 crossing, contained higher quantities of boulders, swift shallow waters and little to no sand present.
This is a map of the two sights we collected from. It can be seen that the upper sight is quite different than the lower sight. There are drastic changes in elevation and topography as the creek reaches the valley, running through the city of Chico before reaching the Sacramento River.
As a result of this comparison of the two sights we found a slight difference in some groups of organisms such as mayflies at the family level with a greater difference at the family level in stoneflies and caddisflies. The group known as true flies or Diptera were fairly similar as well as the types of watermites and aquatic beetles present among both sights. Sight 2 did have greater diversity at the generic level with three species of the genus Drunella alone. Some of these differences were due to changes in elevation, however comparisons of the two communities suggests that the lower sight, sight 1, has some level of human-caused degradation that is affecting the stream’s health in that portion of Big Chico Creek.