Walking along the shore of Black Point Pond in Chilmark, Richard Johnson of Sheriff's Meadow Foundation is nearly dwarfed by a thick stand of 12-foot high reeds.

Also called phragmites, the reeds are an invasive species that have formed a dense monoculture over what was once an open diverse habitat of native pondshore plants. Dead reeds crunch beneath his boots, covering the ground so virtually nothing else can grow through.