By ERIC FREEDMAN
Capital News Service
LANSING — Replacing culverts with bridges may benefit fish because of improved connectivity of streams in a watershed, a pilot project in the Huron-Manistee National Forests shows. But doing so also creates risks of more pathways for invasive species to spread and of fine sediments that can smother fish spawning beds, a study by U.S. Forest Service and University of Notre Dame scientists cautioned. “These trade-offs need to be weighed on an individual basis,” said Nathan Evans, a doctoral student at Notre Dame and lead author of the study. “Each stream is different. The pros may outweigh the cons in one stream.