Dan Kjar Daniel KjarAssistant Professor of Biology
Elmira, New York
Ph.D. Georgetown University
M.S. Georgetown University
B.S. Northern State University
Doctoral dissertation: Studies on the ants, alien and native plants, and ant sampling methods in a U.S. National Park
Master's thesis: Variation in terrestrial arthropod and vascular plant diversity in a Mid-Atlantic low deciduous forest
Undergraduate senior thesis: Behavioral implications of sub-saturated atmospheric water uptake in Thermobia domestica (Thysanura)
My graduate research was focused on the impacts of alien invasive plants on terrestrial arthropod populations. In particular I studied alien plants and the ant community of a national park, Dyke Marsh Wildlife Preserve (DMWP), part of the George Washington Memorial Parkway. Ants are important ecosystem engineers and changes to the abundance or species composition may have far reaching implications for all arthropod and plant communities in a forest habitat. Understanding the impact of alien vegetation on arthropods and other taxa may be critical in determining the current and future health of natural areas. Alien plants appear to rapidly reduce riparian forests along the Potomac River to mats of various alien vine species, in particular, Kudzu and Porcelainberry. Although many studies have addressed alien arthropod impacts on native arthropod and plant communities, few studies have addressed the impact of alien plants on arthropod communities and no study that I am aware of has specifically addressed alien plant impacts on native ant communities. My study has produced interesting and unexpected results that I will be publishing shortly.
Briefly, I found that in the DMWP forest, alien-plant cover was negatively correlated with the distance of sampling sites from the Potomac River. Therefore, invasion of alien plants in this forest may be the result of land clearing during flooding, propagule pressure from the river, or both. Further, the amount of cover and species richness of native plants was negatively correlated with the amount of alien-plant cover, suggesting the alien plants are negatively affecting native plants.
Pitfall trapping resulted in higher ant abundance in samples and greater ant species for a given sampling effort than soil-core samples. On the other hand, soil-core samples resulted in a higher species-per-ant ratio than pitfall-trap samples but quickly reached a species-richness asymptote at 15 ant species. In this study random site selection using GIS and GPS resulted in more ant species per pitfall-trap hour than a previous study in the same forest with the same number of pitfall traps randomly distributed within four 100-m2 non-random locations.
Total ant richness was positively correlated with the amount of alien-plant cover, suggesting increasing amounts of alien plants can increase ant richness. The incidence of the less-common and forest-ant species was positively correlated with the amount of alien-plant cover and not correlated with total-plant cover. Therefore, the increased incidence of the less-common ant group is probably not the result of general habitat changes due to total-plant cover. These findings suggest increased resource availability due to alien-plant presence, disturbed habitat, or some other factor correlated with alien-plant cover in the forest has led to increased ant richness in sites with greater alien-plant cover.
I also investigated associations among invasive alien vegetation and alien arthropods. Dyke Marsh's millipede and centipede communities are dominated by two alien millipedes (Ophyiulus pilosus, Oxidus gracilis) and one alien centipede (Pachymerium ferrugineum). I have found only one definitive alien ant species (others may be suspected introductions or tramp species). Vollenhovia emeryi is native to Japan, and in 1986 Stefan Cover found the first record in the U.S. in Rock Creek Park, Washington, D.C. Researchers in Philadelphia found this species in 1993. I found V. emeryi 8 years later (2002) at Dyke Marsh Wildlife Preserve further south along the Potomac River. This is probably the first known record of this ant in Virginia. Ted Suman, that same year, collected V. emeryi across the river from Dyke Marsh at Fort Washington, also likely a first record for that state. In 2004 I placed a pitfall trap next to my lab at Georgetown University and caught 10 V. emeryi in 48 hours. During early June of 2005 I collected an entire nest of V. emeryi from this location near the Georgetown Observatory and deposited it with Ted Schultz at the Smithsonian's National Museum of Natural History. The colony is currently thriving under the care of Eugenia Okonski in the Schultz lab.
Searching for Vollenhovia emeryi on the Potomac River.
Along with my field research, I also collaborate with John Pickering at the University of Georgia and others on www.discoverlife.org. One project we are working on is a web enabled matrix key to all of the ants of North America. This will be the first key to all of the species found in North America in 56 years (Creighton 1950). Currently we are in the process of producing high quality digital images of every described North American ant species. We use Automontage software and various other tools to image pinned type and other specimens across the country and I worked on the ants under Ted Schultz's care at the Smithsonian Institution's National Museum of Natural History. This is a collaborative effort with Brian Fisher's lab at the California Academy of Sciences, and Stefan Cover at the Harvard University Museum of Comparative Zoology to produce a standard, comprehensive ant image database, and share information and images among the three groups. In the last year this effort has expanded to the ants of many other parts of the world. The Discoverlife IdNatureguide is a matrix based key and will make a major advance in biodiversity studies, allowing people without extensive training in ant taxonomy or access to revisions and books, that are long out of print, to identify and report ant species. We presented the key to the ants of North America to E. O. Wilson as a birthday gift during a meeting in February 2005.
This is an example of my work at the Smithsonian. This is a Camponotus cerberulus. Click on a thumbnail to enlarge.
Northern State University 9/95-9/99 B.S. cum laude Biology
Georgetown University 9/00-10/02 M.S. Biology
Georgetown University 9/00-12/05 Ph.D. Biology
Invitations, Honors and Fellowships:
- Graduate Teaching Fellow, Georgetown University
Graduate Courses Completed:
"Studies on the ants, alien and native plants, and ant sampling methods in a U.S. National Park." presentation and defense of Ph.D. dissertation, Georgetown University, Washington D.C., 1 December 2005
"Alien plants in an eastern riparian forest: is there an impact on ants and native plants?" presentation to the Washington Biologists' Field Club, Smithsonian National Zoological Park, Washington, D.C., 22 April 2005
"The Ants of Dyke Marsh Preserve: Are Alien Plants Changing the Native Ant Community?" Presentation to the Entomological Society of Washington, Smithsonian National Museum of Natural History, Washington, D.C., 3 March 2005
"Using Coldfusion, Discoverlife.org, and the internet to monitor and identify species: Demonstrations of a literature database, a sampling event database, online matrix keys, and realtime mapping of species information online." Presentation to National Park Service employees from the Rock Creek Park and the Center for Urban Ecology, Rock Creek Park, Washington, DC, 11 February 2005
"Ant Community Changes Associated with Introduced Plant Species." poster presented at the Center for Biodiversity and Conservation's 9th annual spring symposium on invertebrate conservation at the American Museum of Natural History, New York, NY, 25-26 March 2004
"Arthropods of the Washington, D.C., Area, Emphasizing Dyke Marsh Wildlife Preserve and Rock Creek Park." poster presented at the National Park Services Spotlight on National Park Resources meeting at the University of the District of Columbia, Washington, D.C., 24 March 2004
"Alien Invasion In The U.S. Capital: Arthropod and Plant Community Changes Associated With Introduced Plant Species." poster presented at the 7 th International Conference on the Ecology and Management of Alien Plant Invasions, Ft. Lauderdale, FL, 3-7 November 2003
"Are Aggressive Alien Plants Changing Native Arthropod Communities in Dyke Marsh Wildlife Preserve?" brownbag presentation to the Georgetown University Biology Department, Washington, D.C., 23 October 2003
"Arthropod Variation in a Forest Choked and Strangled with Invasive Alien Vegetation." presentation to the Friends of Dyke Marsh, Huntley Meadows Park Visitors Center, Alexandria, VA, 29 January 2003
"The Possible Impact of Alien Invasive Plants on the Terrestrial-Arthropod Community in the Dyke Marsh Wildlife Preserve, Virginia." poster presented at the American Institute of Biological Sciences conference, Washington, D.C., March 2002
"Variation in Terrestrial Arthropod and Vascular Plant Diversity in a Mid-Atlantic Low Deciduous Forest Rampant with Alien Plants." presentation of Master's thesis research to the Department of Biology, Washington, D.C., October 2002
"The Biodiversity Database of the Washington, D.C., Area: What Is It, and How Do You Use It?" short presentation to the Entomological Society of Washington, Smithsonian National Museum of Natural History, Washington, D.C., 7 November 2002
"Changing Natural Washington, D.C.: Arthropod and Plant Biodiversity in a Forest Choked and Strangled by Alien Invasive Plants." poster presented to the symposium A Capital View of Botany: Our Changing D.C. Flora, The Botanical Society of Washington, U.S. National Arboretum, Washington, D.C., 8 December 2001
"Changes in Terrestrial Arthropod Abundance and Diversity are Associated with Different Levels of Invasive Alien Plants in an Eastern Low Forest." Brownbag presentation to the Georgetown University Biology Department, 28 September 2001
"The Biodiversity Database of the Washington, D.C., Area: Current and Future Applications of an Online Database of Biodiversity." presentation to the Washington Biologists' Field Club, Smithsonian National Zoological Park, Washington, D.C., April 2001
"Arthropod Diversity and Distribution in Dyke Marsh Wildlife Preserve (DMWP), George Washington Memorial Parkway National Park , Virginia." poster presented at the American Institute of Biological Sciences conference, Washington, D.C., March 2001
Publications:Kjar, D. S. and E. M. Barrows. 2004. Arthropod Community Heterogeneity in a Mid-Atlantic Forest Highly Invaded by Alien Organisms. Banisteria. 24: 26-37
Kjar, D. S. and E. M. Barrows. Alien- and native-plant correlations and environmental disturbances in a U.S. National Park. (in prep)
Kjar, D. S. An evaluation of species sampling efficacy using field studies and computer modeling. (in prep)
Kjar, D. S. The ant community of an Easter U.S. riparian deciduous forest. (in prep)
Kjar, D. S. Correlation of Native-ant-species incidence with alien-plant cover in a U.S. National Park forest. (in prep)
Kjar, D. S., S. P. Cover, and T. R. Suman. A first record of the Japanese Ant Vollenhovia emeryi (Formicidae: Myrmicinae) in Virginia, and previously unpublished records of this ant in three U.S. Eastern States. (in prep)
This website is an online database of arthropod species caught or observed in the Dyke Marsh Wildlife Preserve. This database includes 29 species of Formicidae.
Barrows, E. M. and D. S. Kjar. 2004. Arthropods of Dyke Marsh Wildlife Preserve, Virginia: A Searchable Online Database (ADMWPD). Website.http://data.georgetown.edu/faculty/barrowse/nps/dmwp.cfm
I designed this website as an online, searchable collection of images and information on the biodiversity of the Washington, D.C., Area. It has over 2000 webpages, 5000 digital images, and many pages of information on local biota. This database is linked to the other databases produced by our lab, allowing images and information to be seamlessly integrated into species lists produced for the national park service. This website receives over 12,000 hits per month.
Barrows, E. M. and D. S. Kjar. 2004. Biodiversity Database of the Washington, D.C., Area (BDWA). Website. http://biodiversity.georgetown.edu
This website is an online searchable database of over 12,000 species found in an extensive and ongoing literature search funded by the National Park Service.
Barrows, E. M., D. S. Kjar, C. R. Bird, B. Q. Chung, T. Q. Chung, and M. R. Minor. 2004. Arthropods of the Washington, D.C., Area: A Searchable Online Database (AWDCAD). Website. http://data.georgetown.edu/faculty/barrowse/nps