A Scottish environmental agency has slammed vandals who have destroyed a sign and cairns aimed at reducing erosion on the popular Munro, Ben Wyvis. Scottish Natural Heritage (SNH) had erected the sign at the An Cabar cairn to point walkers in the direction of the preferred route up the mountain which is aimed at protecting the fragile habitat from erosion caused by the 8000 walkers who tackle the peak every year. To try and reduce the impact on a wide area of woolly fringe moss, which provides a rare habitat for the dotterel, SNH had erected two temporary cairns at…