Georgian Court University

Dr. Wootton's Carex kobomugi Research Projects
Summer 2005

Project 1: Monitoring the recovery of Carex kobomugi on dunes previously sprayed with Roundup®

Project 2:  Examination of the Impact of the Invasive Carex kobomugi on Native Dune Plant Populations in Pristine and Disturbed Areas of Sandy Hook in Gateway National Recreational Area  (Thesis work of Mr. Jim Burkitt)

Project 3: Mapping the presence of Carex kobomugi in New Jersey's Coastal Dunes

Project 1: Monitoring the recovery of Carex kobomugi on dunes previously sprayed with Roundup®

wpe9.jpg (11744 bytes)In 2002 and 2003 my students and I mapped all existing stands of this species at Island Beach State Park (IBSP). We found that the area occupied by Carex kobomugi at IBSP increased by about 300% since 1985 (Shisler et al. 1987), and now occupies more than 22 acres within the park. The species is widespread in coastal dunes throughout the state, and we have recorded expansion rates in excess of 750% over the same period in some areas. We also showed that this expansion is a potentially serious problem, as abundances of native species were reduced by 50 to 75% within C. kobomugi beds. Carex also negatively impacts native species richness and species diversity, particularly in more pristine areas (Wootton et al. in press).   

While C. kobomugi has a negative ecological impact, the species is an important dune stabilizer, so its control or removal needs to be carried out with special care. Thus when in 1999 IBSP started a removal project, it used highly localized applications of Roundup®, sparing non-target plants to continue to stabilize the dunes. However, no monitoring program was put into place to assess the effectiveness of this program, or effects on species in the surrounding areas. In 2002 and 2003 my students and I assessed treated and nearby, untreated Carex beds and the immediately surrounding areas for C. kobomugi and native plant abundances. We found that after 1-2 years of treatment, Roundup® applied in this way reduced, but did not eliminate, C. kobomugi, while having no significant effects on native plant abundance or  diversity. The spray program was discontinued in 2003 due to financial cuts at the NJ DEP.  The question is, will the areas previously treated recover their native species or will the invasive species return to its former abundance over time? 

Proposed Study

wpeA.jpg (17498 bytes)Monitoring:  If the spray program worked as intended, the area of dune infested with Carex should decrease after treatment and should stay low or decrease over the long term. In addition there should be no difference between changes in communities surrounding treated areas and those surrounding nearby control (untreated) Carex beds (i.e. no unintended effects on surrounding communities). The only way to determine whether this is the case is to maintain careful monitoring of treated areas. Such monitoring can also provide information about differences in effectiveness or impact of spray treatments carried out in different seasons, or with different frequencies. Such information should prove valuable to park managers in terms of guiding future treatment efforts. Thus in the summer of 2005 my students and I intend to remap the perimeters of treated stands using differential GPS units. We will then resample quadrats within each treated stand, counting the densities of each species encountered.  We will also sample areas immediately outside the affected areas in order to provide comparison with native (un-impacted) dune systems. We will carry out similar assessments of untreated (“control”) stands of Carex kobomugi in the vicinity of each treated bed. This will allow us to distinguish inter-annual variability versus treatment effects on bed size and relative abundances of target and non-target species within these stands.  It will also allow us to gauge the patterns of recovery within the sprayed beds.  

Projected audiences

wpeC.jpg (70392 bytes)Managers and Park Officials:  Invasive species are widely agreed to be a major problem both ecologically and economically throughout the world. However, there are few models for the management of such species. Carex is a good candidate for the study of techniques that are, or are not, effective in managing such species and why. The species is widespread enough, and its spread is damaging enough, to make its management desirable in and of itself. It is not, however, at the point where its extent is so great that any management effort is essentially unrealistic, as in the case of Phragmites and some other invasive species. We are also fortunate in having the cooperation of Park Managers and the State DEP in our studies. This means we are able to try different management strategies and to monitor their success under relatively controlled field conditions, and at spatial scales large enough to make the results of this study large enough for the results to be good indicators of the effectiveness of those strategies in the “real world”. As in the past, all results from this study will be shared with park officials so that they can be used to guide future management decisions. Finally, the species is of particular interest in terms of management in that it has an interesting, unusual property:  Most invasive species are unambiguously negative, and their removal is simply a matter of finding something that works and applying it as widely as feasibility and economics allow. However C. kobomugi has positive ecosystem effects, in terms of its role as a dune stabilizer, as well as its negative effects in terms of the loss of native species and decline in overall diversity within dune ecosystems. Management of this species thus presents special challenges, and solutions to those challenges may prove useful in managing other invasive species that have positive as well as negative ecosystem functions.

College Students: Another important benefit of this project will be the experience it will provide for the students involved. Participation in this study will provide the students with the opportunity to 1) learn marketable skills such as plant identification, GPS mapping and GIS data management, 2) obtain research experience, 3) build their resumes and 4) learn the processes involved in scientific research. It is my philosophy that students should be involved in all aspects of research. Students are encouraged to collaborate in the planning of the research objectives and the strategies to be applied to meet those objectives. They are clearly invaluable in the data collection phase, since most of the research proposed here is extremely labor intensive. The students then are expected to help with data analysis and preparation of scientific presentations and publications. 

Measurement of Project Effectiveness

Monitoring:  Another objective of this study will be the on-going monitoring of the areas that have been treated with Roundup thus far, as well as any that are treated in 2004.  dGPS maps will be used to document the size and shape of treated beds, as well as that of nearby untreated (control) beds. These maps and outcomes of the quadrat surveys will be compared with those made in previous seasons, and the results will be shared with park officials and any other interested parties.

 Project 2:  Examination of the Impact of the Invasive Carex kobomugi on Native Dune Plant Populations in Pristine and Disturbed Areas of Sandy Hook in Gateway National Recreational Area

The following is the text from an early draft of Jim's thesis proposal:

wpeB.jpg (7025 bytes)Project Objectives 

1. Locate and identify pristine and disturbed habitats on Sandy Hook using GIS technology to assess maps of land-use within the Park, as well as visual observations of the proposed sites. 

2. Assess species composition, distribution, richness and diversity within and surrounding one large, medium and small bed in an area impacted by human traffic (human disturbance sites). 

3.  Assess species composition, distribution, richness and diversity within and surrounding one large, medium and small bed in an area impacted by high levels of physical disturbance (wind and wave energy : naturally disturbed sites).   

4. Assess species distribution, richness and diversity within and surrounding one large, medium and small bed in a more pristine area (sheltered from both human and high energy natural disturbances). 

5. Incorporate data on native plant population composition, richness and diversity and invaded areas into GIS to determine the relationship between invaded areas versus non-invaded areas, as well as pristine areas versus disturbed areas. 

6. Use data collected in this study, as well as data previously collected by this group, to investigate the impacts of C. kobomugi on native plant populations.  

Materials and Methods 

wpeE.jpg (20770 bytes)Objective 1: Using 2004 aerial photographs provided by the Monmouth County Information Services viewed through using GIS software (ArcMap 9.0) as well as observations from my own field experience in the Park, disturbed and pristine areas of Sandy Hook will be identified.  Hunan-disturbed areas will be defined as areas that are within a 50 meter buffer of roads, trails, or other human impacted areas, such as parking lots.  Naturally disturbed areas will be identified as those experiencing high levels of wind and wave energy (usually associated with spits and other oceanward-extending promontories.  Pristine areas will be defined as areas that have little to no human use, and which are also relatively sheltered from wind and wave energy. These areas will are likely to be located in the wildlife management areas of the Park where human impact is minimal.  

Objectives 2 and 3: Once the invaded areas of Sandy Hook are mapped, and the disturbed and pristine areas have been identified, a small, medium and large bed will be chosen within each area for further analysis. To analyze the impacts of C. kobomugi on native dune plant species, counts of the types and numbers of plants within 1m2 quadrats will be used to assess the species abundances, distributions and diversities within the invaded areas. To assess what the native populations might have been like in the absence of the invasive species, quadrat samples will also be counted in a five meter buffer surrounding the areas occupied by C. kobomugi. Species richness in each quadrat will be determined by totaling up the number of different species within the invaded area, as well as within the native populations in the five meter buffer. Species diversity will be calculated using the Shannon-Weiner Diversity Index.                                     

Objective 4: Once species composition, richness and diversity are determined in each of the small, medium and large beds in the pristine and human and naturally disturbed areas, that data will be entered into ArcMap 9.0 and analyzed to show patterns of distribution of C. kobomugi, patterns of species diversity and patterns of species richness within each area. These patterns will be displayed using a triangulated integrated network (TIN) to create contour maps of the different species abundances or parameters (diversity, species richness etc.). The TIN will allow for further analysis of the invaded C. kobomugi beds based on the composition and distribution of the dune vegetation.

Objective 5 and 6: Use field data and GIS data to determine the overall impact of C. kobomugi on the native plant populations.

Expected Results and Benefits of Study 

This study will allow us to build a much stronger understanding of the impact of C. kobomugi on native plant populations. By choosing beds of different sizes we will be able to look for the influence of edge effects on the impact of the invasive species upon native plants.  Similarly, by choosing sites in areas experiencing different levels and types of disturbance we will be able to assess the influence of those disturbances upon the effect of Carex on native species.  Based on our previous observations we expect that the impact of the invasive species to be greatest in the largest beds in the most pristine areas, and to be less strong in smaller beds, and those in more disturbed habitats.  However, until these hypotheses have been systematically tested, as in this study, it is impossible to know how reliable those expectations may turn out to be.  Ultimately, this research will provide park managers with a more definitive and thorough understanding of the effect that invasion by C. kobomugi has on native dune plant populations.  This, in turn, should guide and inform development of more successful management plans for this invasive species in the future.

wpe10.jpg (92485 bytes)Project 3: Mapping the presence of Carex kobomugi in New Jersey's Coastal Dunes

One objective for the 2005 research season is to expand the monitoring program beyond the gates of the parks studied so far, to determine the degree of infestation of dunes throughout Coastal New Jersey. To do this we will use GPS mapping to create a GIS database of the size and shape of infested areas to provide a reference for monitoring patterns in subsequent spread rates and directions of this invasive species.  We are currently working to contact municipalities in order to obtain the requisite permits to allow us to go forward on this portion of the research.