Tuesday morning at The Nature Conservancy’s McCarran Ranch Preserve, thirteen children from Mrs. Akers and Mrs. Brisbane’s 4th & 5th grade classes briefly crossed paths with a beaver. It swam by just before lunch-time, as the students from the Sierra Expeditionary Learning School were seated in a circle under a patch of bare winter cottonwood trees near the Truckee River, in the middle of a lesson on macroinvertebrates.
“What do you think macroinvertebrate means?” asked Jennifer Robinson, instructor for the local outdoor science education group Sierra Nevada Journeys, writing the word on a small whiteboard in front of the group. “A macaroni-invertebrate?” one boy whispered. Robinson broke the term down into smaller pieces: if a vertebrate is an animal with a backbone, then an invertebrate is the opposite: an animal without a backbone. Macro (no relation to macaroni) means something that can be seen with your bare eye, unlike something micro, which might require a microscope. “So,” Robinson continued, “altogether, a macroinvertebrate is….”
”A beaver!” [aaah!]
The kids jumped to their feet and ran to the river’s edge, mostly arriving too late to see the beaver, but excited for the close encounter.
Sierra Nevada Journeys, a Reno-based non-profit organization, runs environmental education programs for 2nd-6th grade classes. During the school year, SNJ groups make regular visits to sites such as Oxbow Nature Study Area and McCarran Ranch, where students get to explore science lessons in the real world and hopefully make important connections.
On Tuesday, the students’ task was to learn how to assess water quality by collecting and analyzing macroinvertebrates. A macroinvertebrate, to resume our previous lesson, is something with no backbone that is big enough to see with our bare eyes — in this case, tiny stream insects that live on the underside of rocks along the edge of the Truckee River. Though this seemed a hefty assignment for a bunch of 4th and 5th graders, Robinson led them through the process in a series of stages — first observing the environment, then capturing macroinvertebrates, then assessing the catch-of-the-day and discussing what it all meant.
I was impressed with the way Robinson led the students through the activities and questions without telling them the answers, letting them explore and figure things out on their own while guiding them to the right conclusions.
“Certain species of macroinvertebrates are very sensitive to changes in their environment, and other species are more tolerant,” explained Robinson. In a river, macroinvertebrates might experience floods (disturbance), drought, changes in temperature, predation, pollution, and more. “Which kinds of species do we hope to find today — sensitive or tolerant?” asked Robinson.
“Both,” replied one student (a solid answer). However, after some discussion, the group settled on the decision that if they were interested in water quality, they would hope to find higher numbers of sensitive species than tolerant species. If all they found were very tolerant species, then that might indicate that conditions in the river were too polluted or disturbed for the sensitive species to survive.
Using blue aquarium nets, the students collected macroinvertebrates and clam shells from the river, then met again to discuss their findings. Overall, the catch-of-the-day consisted mostly of mayfly larvae, considered “sensitive”, so that indicated good things for our water quality. In drawings and written observations, students reported astutely that the water looked pretty clear, but also kind of dirty, with some trash. Finally, you’ll be glad to know, at least two students concluded that the water at McCarran Ranch looked better than the water in India or China.
Bonus: Sierra Nevada Journeys is going to be contributing to Truckee River Guide by sharing all the data that they collect with their students. Awesome!
A big thanks to Jennifer Robinson, Sean Hill, the other Sierra Nevada Journeys instructors, and Mrs. Akers and Mrs. Brisbane’s classes for letting me tag along for the day at McCarran Ranch! If you’re interested in volunteering with Sierra Nevada Journeys or want more information on the program, contact Sean Hill through their website at http://sierranevadajourneys.org/.
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