Print PageAsiatic sand sedge (Carex kobomugi), an invasive species, is spreading across dunes all along the Atlantic coast leading to diversity loss and native species declines, particularly endangered species. The sedge also alters geomorphology of dunes impeding their ability to protect coastal communities. It has been suggested that the sedge is relatively intolerant of burial, while growth of native species, like American beach grass (Ammophila breviligulata), is actually stimulated by active sand accretion. No work has definitively shown the impact of beach nourishment (burial) on sedge invasion.
We compared sand burial tolerance of both Asiatic sand sedge and American Beach Grass in a mesocosm experiment at Island Beach State Park in New Jersey. Five sand depth treatments were established at three sites in the park from no burial (control) up to 24 inches in 6-inch increments. Each 1-square meter plot contained equal numbers of both the sedge and beach grass shoots within them. Biweekly, the number of emerging shoots was quantified and the health of the emerging shoots were assessed.
Results/Conclusions
After one full growing season, deep burial (greater than 18 inches) impeded the emergence and survival of the sedge the most. Lower depths had no effect on the sedge’s survival. To contrast, American beach grass was not affected by burial regardless of depth of sand applied. Currently, efforts to control the invasive involve hand pulling or herbicide application, both which are costly, labor intensive and may have harmful effects on the dune communities. Should the deep burial of the dunes by beach nourishment continue to smother the sedge through a second growing season, the traditional harmful methods of sedge control could be abandoned. However, in the next year if the sedge is able to emerge from deep burial and persist, then beach nourishment simply provides new niches with little resistance for the sedge to invade.
