Georgian Court University
Hunting for Aliens on
(Citation: Wootton, LS.
2002. Chance Conversation Plants the Seed for NJ Sea Grant Research
Its nearly 100 degrees outside. Heat is pulsating up from the sand, adding to that
beating down from the summer sun above. To make things worse, the wind is blowing out of
the west, carrying every biting fly in New Jersey to the area of dunes where my four
dedicated student interns (Katy Bevaart, Audrey McGough, Jason Ondreika, Purvi Patel), the occasional student volunteer (Courtney Rella,
Sheetal Patel, Anna Shipman) and I (Dr. Louise Wootton, Biology) are sitting counting
plants and wondering how and why we all managed to get ourselves into this project.
So why are four students, an occasional
volunteer and one rather fraught professor traipsing over sand dunes clearly labeled
Keep off the Dunes in the height of summer?
The answer to that question starts with a
conversation between myself and Dr. Susan Halsey, director of
Louise. What do you know about Carex kobomugi? Susan asked.
Carex what? I answered. Its commonly called
Asiatic Sand Sedge replied Susan, and theyre talking about digging it up
with a backhoe at
As Im always looking for good
projects to get my students involved in research, I went home and started to look into
what was known about the species. It was a
pretty short search, since the answer was not much! I found a couple of papers describing the first
observations of the species in New Jersey, speculating that it had been accidentally introduced
to North America approximately a century ago when shipwrecks released plants used to pack
Oriental porcelain onto New Jerseys shores. I also found some reports from
Times however have changed a great deal since then, as scientists and
managers have become uncomfortably aware of the problems caused by exotic plants (think
purple loose strife or Phragmites!). This changing perception, combined with a
concern that Asiatic sand sedge was expanding in New Jersey, meant that Carex kobomugi suddenly went from a species being
cultivated for release on dunes, to being listed as one of New Jerseys top 10
most unwanted plant species and one the States coastal parks were now working
to eliminate. What became clear to me, though,
was that these management strategies were being implemented in the absence of much solid
information on the spread rates and ecological impacts of this species.
So it was, with the help of a grant from New Jersey Sea Grant and
matching funds from Georgian Courts faculty summer research program, that my four
interns, some volunteers and I set out to map all of the Carex kobomugi beds in Island Beach State Parks, so
we could compare the bed sizes with those in a survey carried out in 1985 by NJDEP. We also set up quadrats within and outside each bed
and counted the number and types of plants present to get a sense of how Carex impacts the abundance and diversity of other
plants on the dunes. Last, but not least, we
set out to see how successful the management strategies currently being implemented by the
parks have been.
To avoid the peak heat we tumbled out of bed and onto the dunes at
dawn and mapped and counted until heat or flies drove us home. We were blessed at both
So what did we find? To
be honest, the data hasnt all been crunched yet.
However the data we have looked at so far tells an interesting, and somewhat
alarming story. Relative to the 1985 survey in
IBSP, the number of Carex beds has increased
more than 300%, and the total area covered by more than 400%. Indeed, looking at the few
available data points from earlier years, its clear that the species is expanding
exponentially within our coastal dunes. Moreover,
not only are there more acres of sedge on the dunes, but in those beds present in both our
study and in 1985, stem densities of Carex have
increased by 55%, implying that the plants are becoming more vigorous over time.
What does this mean for other dune species? To some extent Carex is colonizing back dune areas in which
other dune species do not thrive. However,
numbers and diversity of other species within Carex
beds were generally lower than those in comparable plots just outside those same beds,
suggesting that the expansion of this species is significantly impacting the ecology and diversity of
coastal dunes. Since some of the other species
within the dunes, like wormwood, and sea beach amaranth are endangered or at least
Species of Concern in
The question, then, is how
to control or eradicate this species? As
mentioned at the beginning of this article, managers at
By contrast, IBSP started an
eradication program for C. kobomugi in 1999, with four beds treated to date.
Treatment in that case involves tightly controlled applications of Roundup® to individual C. kobomugi, hopefully sparing
other species of plants. This protects native species and leaves them in
place to protect the dunes from erosion. Counting
the number and types of plants in treated and untreated beds we were able to show that
this strategy does effectively spare non-target plants. The problem is that, in all cases,
even repeated herbicide application failed to completely eradicate C. kobomugi.
This suggests that, to actually eradicate this species from the dunes, a more aggressive
application of herbicide may be needed. Such a
strategy would be likely to kill everything in the area.
Moreover, from what weve seen, it is likely that even such an
aggressive strategy would require multiple chemical applications over time to be
effective. During that time the defoliated
dunes would be vulnerable to erosion, resulting in flooding and damage to ecosystems and
property currently protected by the dunes.
The logical solution to this
problem might be to change our management goals from eradication to prevention of further
expansion of the species. Then, hopefully, strategies such as those currently employed at
IBSP could be used to reduce and control existing stands. How effective such a strategy
might be strongly depends on how Carex propagates itself. Existing literature
suggests that the species grows only from runners, not from seeds. However, another of my students, Michael Cerrato,
has been working on this question for his honors thesis research. His results suggest that this species will indeed
grow from seed, if those seeds are grown at high enough temperatures. This finding means that controlling the spread of Carex
is likely to be much harder than it would have been if the seeds were indeed infertile.
As you can see then, finding
an effective management strategy for this species that wont hurt the dunes
themselves isnt going to be simple. Whats also clear, however, is that we
cant spend too much time thinking about what to do about this species, since the
longer we wait, the more of it there will be, making its removal increasingly difficult
and making the removal itself increasingly damaging to the dunes and the communities that
submitted abstracts that, if accepted will mean that I will be traveling to San Diego next
March to give a paper at a conference on invasive species in marine ecosystems coauthored
with the students. In addition, the students
and I have submitted abstracts for a poster and an oral presentation at the Coastal Zone
2003 conference in