Counting Mayflies at McCarran Ranch

What can we learn about the Truckee River from a bunch of 5th graders? Enthusiasm, for one. Last Thursday at The Nature Conservancy’s McCarran Ranch Preserve, birds chirped, the river bubbled, thunderclouds loomed, and 90 students from the 5th grade class at Alice Smith Elementary temporarily drowned out the peaceful sounds of nature as they stalked pelicans, lizards and macroinvertebrates in the river channel, during their Sierra Nevada Journeys “Hands in the River” program.

Macroinvertebrates — tiny organisms without backbones that are big enough to see with the naked eye — are a crucial part of the Truckee River food chain, and include the mayflies, caddisflies, stoneflies, midges, dragonflies, damselflies, waterboatmen, and other groups. Most go through several life phases. Mayflies, for example, hatch from an egg to a larvae, then spend their larval phase feeding on the algae that grows on rocks. During their third life phase  (biologists call a subimago and fly-fishermen call a dun), Mayflies try to avoid becoming trout-food, and during their final life stage (biologists call it an imago, fly-fishermen a spinner), they mate, lay eggs, and die. Hatches happen at different times of year, depending on the species, so relative abundances may shift throughout the year.

Three types of people pay attention to macroinvertebrates: Fly fishermen, scientists, and kids.  Fly fishermen can tell you which macroinvertebrates the fish are biting. Scientists can tell you what the presence or absence of certain species of macroinvertebrates means for the health of a water body. And kids tend to cross paths with macroninvertebrates simply by being low to the ground, inquisitive, and somewhat less squeamish than adults. (Somewhat).

Dry toes. Naturalists at work, McCarran Ranch. May 21, 2015.

Since March, Jennifer Robinson, instructor for Sierra Nevada Journeys, has been sharing macroinvertebrate data with Truckee River Guide, all collected by 5th grade students at McCarran Ranch Preserve (for more information on the Sierra Nevada Journeys program, see a previous blog post, All Hands in the River at McCarran Ranch).

Below is some of the data that the kids have collected this spring. The Sierra Nevada Journeys curriculum focuses more on exploration than on advanced species identification, and it may be too soon to observe any noticeable trends, but with so many eyes on the river, they’re bound to uncover some interesting things. For example, they’ve found invasive Asian clams (Corbicula fluminea) on every visit, but have yet to see a New Zealand mud snail (Potamopyrgus antipodarum) at McCarran Ranch.

Instructor Sean Hill leads a group of Sierra Nevada Journeys students at McCarran Ranch. May 21, 2015.

First catch of the day. McCarran Ranch, May 21, 2015.

Last Thursday, hoping to get a few photos of data collection in action, I tagged along with Sean Hill, who is an instructor and Director of Education at Sierra Nevada Journeys. “What do you see out here that reminds you of something?” Hill asked the kids in his group. Some saw trees that reminded them of people, some saw birdhouses that reminded them of birdhouses at home. One boy saw a pelican. “It reminds me of a story that someone told me, of how those are the birds that bring babies,” the boy said.

Down by the river, nobody kept their feet dry, and the kids hopped from rock to rock collecting minnows, clamshells and aquatic insects from the river channel. Two students captured a crayfish, and everyone screamed.

A student from Alice Smith Elementary School holds a cup full of macroinvertebrate surprises. May 21, 2015.

A student from Alice Smith Elementary School examines her crayfish catch at McCarran Ranch, May 21, 2015.

Wet feet. Students from Alice Smith Elementary explore the Truckee River at McCarran Ranch. May 21, 2015.

Sierra Nevada Journeys runs trips to McCarran Ranch during spring and fall months, so it will be interesting to see how (and if) populations of macroinvertebrates in the river change over time. Updates will be posted to a Sierra Nevada Journeys page, located here. Stay tuned as we see what they find!

Thanks to The Nature Conservancy for maintaining McCarran Ranch Preserve as an awesome space for exploring, and to Sierra Nevada Journeys for sharing the data that they collect. An extra-big thanks this week goes to Dylan Kuhn, cofounder of Postmatic (a great new WordPress plugin for bloggers), who spent time over Memorial Day weekend working to make the wildlife map on this site searchable. Check it out!