Grab hold of each of those ferns and give each one a tug MDMorash. They are planted too deep and will die if the rhizome stays below the gravel surface like that. It is the reason that you will often find java fern tied with a piece of fishing line to a piece of driftwood or a rock. They seem to do fine above the gravel surface on an ornament but die if you plant them the way you would think you should.