Suzanne Stewart
Staff Writer
It became a trend years ago on social media – taking pictures of stacked rocks, either next to a stream, in the mountains or beside a trail. It may be aesthetically pleasing and impressive when the stack includes a large number of rocks, but it’s detrimental to the ecosystem of streams where those rocks play an integral role for many aquatic critters.
U.S. Forest Service fisheries biologist Kyle Tasker said a lot of fish, salamanders and macro-invertebrates rely on rocks of all sizes as part of their habitats and life cycles.
“It’s kind of a detriment to the system because those rocks play an important role in the aquatic system as they provide habitat for fish and a lot of the macro-invertebrates the fish eat and rely on,” he said. “They provide a lot of habitat for crayfish. There are also mussels that are intermixed with the stream bed materials, so they could inadvertently pick up a mussel and disturb it, thinking it was a rock.”
Rocks in streams provide shelter and are used by many water dwellers as nests for their eggs.
“A lot of fish will lay eggs on the underside of the rocks, so if you’re picking up a rock that has eggs on the underside of it and stacking it out of the water, it’s destroyed that whole clutch of eggs,” Tasker said. “Another big thing is the hellbender, which are found here in a lot of the nearby rivers – they’re a sensitive species because they’ve had so much habitat loss and degradation. They rely on those large flat rocks to nest under.
“The female will lay eggs which look somewhat like a string of pearls under the rock and then the male will guard them,” he continued. “It’s a really neat adaptation, but if you’re moving those large rocks, you could inadvertently crush a hellbender and a whole clutch of eggs.”
Smaller rocks or gravel in the streams are also very useful and should be left alone. A small species of fish known as chubs will actually built a nest with small rocks and gravel for their eggs.
“That’s a really cool thing to see – a natural process that you can see and witness – but not disrupt by moving those rocks,” Tasker said.
That’s why he suggests getting a snorkel mask when you visit any local streams and get a closer look at the habitats without disturbing them.
“It’s a fun way to spend time with the river,” he said. “You can pick up rocks and look at the macro-invertebrates on them, but then put them back in the place where you found them. I would always advise people, whatever you move, try to put it back following the Leave No Trace principles.
“I really encourage people to get out and go to rivers, and explore and recreate, but just try to resist making those rock stacks and leaving them stacked up,” he continued. Just avoid moving a lot of big rocks if you can. It has much more impact than what you expect.”
