Resort Municipality of Whistler via The Canadian Press Western toads are seen near Whistler, B.C., in this undated handout photo.

WHISTLER, B.C. — Some very small creatures are forcing some big changes in a popular section of the Resort Municipality of Whistler, B.C., as an annual migration begins to peak.

The municipality has closed the Lost Lake access road, a parking lot and the events lawn, and says other closures are possible as thousands of western toadlets make their trek from the lake into the surrounding forest.

The dime-sized amphibians are native to British Columbia and listed as a species of special concern.

They breed in the lake where tadpoles mature, then spend most of their time in the forest, meaning as many as 40,000 of the tiny toads have to hop across beaches, trails, lawns and roads during the August migration.

The municipality says busy Lost Lake beach and the beach lawn are still open but could be closed if high numbers of toads start hopping in that direction.