Georgian Court University
sand sedge, Carex kobomugi, was accidentally introduced to North America
approximately a century ago and is now found along much of the Northeast coast of the
During the summers of 2002 and 2003 and again in 2008 and 2009, Dr. Louise Wootton and her students mapped all existing stands of this species at Island Beach State Park (IBSP) and the Sandy Hook Unit of Gateway National Recreation Area (SHU). We are now hard at work surveying where and how much of this species is found on the coastal dunes elsewhere in New Jersey, and building a GIS database based on the results of these surveys.
Our research so far shows that the total area occupied by Carex kobomugi at IBSP increased by about 300% between 1985 and 2003 and doubled again between 2003 and 2008, with 48 acres now affected by the species at that Park. At Sandy Hook things are even more severe, with an increase of 780% between 1985 and 2003 and a further 300% increase in affected areas between 2003 and 2008, with more than 54 acres of dunes in this park now being affected. What this means is that more than 20% of the total primary and secondary dune areas of these parks is now occupied by this invasive sedge rather than native species.
Combining our numbers with the published data from Shisler et al. (1987), Small (1954) and Stalter (1980) it is clear that the expansion rate of C. kobomugi in both of these areas has been approximately exponential (Figure 1, above). Our research also showed that this expansion is a potentially serious problem, since we found that abundances of native species were reduced by 50 to 75% within C. kobomugi stands (Wootton et al. 2005). The species is also negatively impacting native species richness and species diversity, particularly in the more pristine areas studied (Wootton et al. 2005).
As a result, we are now strongly of the opinion that management of this species to remove it from affected areas and to prevent its invasion of new areas is urgently needed in New Jersey. To learn more about exactly why we think this, we are sharing the introduction to a recent grant proposal submitted to NOAA for consideration for funding for a major restoration effort in New Jersey's dunes.
While the current expansion of C. kobomugi clearly has a negative ecological impact, the species is an important dune stabilizer, so its control or removal does need to be carried out with care. Thus, when in 1999 IBSP started a removal project, they used highly localized applications of Roundup® so as to spare non-target plants, leaving them in place to hold the dunes. In 2002 and 2003 my students and I assessed the treated stands for remaining C. kobomugi and for native plant abundances. We found that after 1 year of treatment, Roundup® applied in this way reduced, but did not eliminate, C. kobomugi. Continued monitoring of dunes that have been treated in this way, as well as active pursuit of alternative management strategies are of great importance to our understanding of the best way to combat the ongoing expansion of this species.
Click here to read our initial proposal for this project
Click here to see some pictures of us at work
Read more about what we've found so far:
Aronson J, Floret C,
LeFloch E, Ovalle C, Pontanier R. 1993. Restoration and rehabilitation of
degraded ecosystems in arid and semi-arid lands. Restoration Ecology 1:8-17.
Aronson J, Floret C, LeFloch E, Ovalle C, Pontanier R. 1993. Restoration and rehabilitation of degraded ecosystems in arid and semi-arid lands. Restoration Ecology 1:8-17.
JK, Wargo RN, Jordan RA. 1987. Evaluation of Japanese sedge, Carex kobomugi,
for use in coastal dune planting and stabilization. New Jersey Agriculture
Experiment Station Publication number P-40502-03-87
JA. 1954. Carex kobomugi at
R. 1980. Carex kobomugi Ohwi at
Wiedemann AM, Pickart A. 1996. The Ammophila problem on the Northwest Coast of North America. Landscape and Urban Planning 34: 287-99.
L, Halsey S, Bevaart K, McGough A, Ondreika J and Patel P.
2005. When Invasive Species Have
Benefits as Well as Costs: Managing Carex kobomugi (Asiatic sand sedge) in
Biological Invasions. 7:1017-27.
Biological Invasions. 7:1017-27.
Author: Louise Wootton. Ph.D. Last updated June 17, 2009