Scientists recently looked at what urban development is doing to streams in Portland and eight other U.S. cities. They found that urban development can mean trouble for invertebrate species.
That’s especially true in pristine waters running through forests. Development from expanding cities can make streams flow faster. It also changes habitat and increases pollution.
A study by the U.S. Geological Survey found that all that can kill insects like mayflies, stoneflies and caddisflies.
James Coles is an aquatic ecologist with the U.S.G.S. He says these tiny species dwindle almost as soon as people start building.
“You lose those, you lose other things," Coles says. "Most people, I think, get most excited about the fish. But the fish have to have something to eat, and generally the basis for a lot of the fish are the invertebrates."
Coles says leaving more vegetation near streams can help protect the tiny species that live there.