RICHLAND, Wash. – 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, especially in pristine waters running through forests.
A study by the U.S. Geological Survey found that development from expanding cities can kill insects like mayflies, stoneflies and caddisflies.
The study looked at three main problems development causes:
faster flowing water,
and increasing pollution.
James Coles is an aquatic ecologist with the U.S.G.S. He said these tiny species dwindle almost as soon as people start building.
“You lose those, you lose other things,” Coles said. “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 streams in forests, like those near Portland, change faster than streams running through farmlands. Those agricultural waters are already compromised by pollution. Forest streams deliver more pristine waters to urbanized areas, where development can do harm to aquatic invertebrates, the new study found.
“When the forest land cover is removed, and then urban development comes in, we have seen a more drastic change there,” Coles said. “Things are more pristine in a forested landscape. … There’s more to lose.”
Coles says leaving more vegetation near streams can help protect the tiny species that live there.
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