News Stories

A tale of two beach plants

Published Aug. 22, 2007

   Wilmington District marine biologist Doug Piatkowski and Department of the Army intern and Regulatory Specialist Liz Hair began their search for a somewhat elusive plant about a mile west of the Coast Guard station at Wrightsville Beach.  In about three hours in sweltering heat they’ll cover roughly four miles of the beach looking for a plant that’s in danger of becoming extinct.  It’s called seabeach amaranth, and since 1993 it has been listed as threatened under the provisions of the Endangered Species Act of 1973.  A peculiar, finicky plant that looks similar to spinach, it’s threatened by erosion, flooding and regular beach foot traffic.  When they find the plant they’ll use a GPS device to record its exact location for use in maps that document the amaranth’s distribution in coastal North Carolina.  Piatkowski soon spots a lone plant. 

   “Seabeach amaranth is considered a pioneer species and usually grows between the seaward toe of the primary dune and the limit of the wave up-rush zone” he said.  “You don’t usually find the plant back in the dune field among other coastal dune plants.  Their presence is most dominant on accreting shorelines and germination occurs within stable fore-dune and/or embryo dune formations.”

   Piatkowski explained that though the amaranth is resilient to the conditions of the harsh beach-face environment, it doesn’t particularly build and stabilize dunes like other coastal dune building plants such as native sea oats.  Though there are no known dependent links between seabeach amaranth and other species, it is unknown what the consequences would be if the amaranth becomes extinct. 

   According to a statement by the Fish and Wildlife Service, seabeach amaranth is  protected because “the reduction of biodiversity reduces the ecological integrity of the environment.  All living organisms perform a function in the environment and are dependent on the functions of other organisms.  In turn, there is interconnectedness among species including humans in the environment.” 

   Just past the lone, endangered amaranth is an overabundant, invasive plant species called beach vitex that could potentially impact amaranth and its habitat.  Hair uproots a four-foot section of a vitex plant.  Its roots are shallow and add nothing to natural dune stabilization.  Tommy Socha, a plant specialist with the Wilmington District based in Charleston, has observed the growth of the vitex.  Once thought to help protect and build front beach sand dunes, it had what seemed to be the perfect prerequisites; drought resistant, tolerant of salt and blowing sand, and fast growing.  Such a plant was found in Korea and made its way to the eastern coasts of the U.S. where it’s now wreaking havoc.  Socha joined the South Carolina Exotic Plant Council and brought beach vitex to their attention. He suggested a study be done to see if this plant should be placed on the noxious plant list, or somehow keep it from being planted on the beach.  He was concerned about its growth because it had taken over and created a monoculture (a community of only one plant) by shading out native vegetation. 

   Also known as chasteberry, kolokolo kahakai, or monk's pepper, beach vitex typically grows up to eight feet in diameter and from six inches to two feet tall.  It can reach four feet tall and 12 feet wide when protected from wind and salt spray.  Socha said that beach vitex appears to be taking over primary beach dunes in South Carolina. It has been described in news articles as the "kudzu of the coast." Major efforts are underway to document the occurrence and spread of beach vitex to increase public awareness of its potential invasiveness, and to explore methods of control while restoring native beach dune.