Research in the Leege Lab
Georgia Southern University
Department of Biology

My research focuses on conservation ecology with regards to plant population and community ecology and threats to biodiversity. In particular, I am interested in the ecology of rare and invasive plants and how they interact to influence each other's population dynamics. My students and I use field and greenhouse observations and experiments to answer questions about the role of herbivores, invaders and other disturbances in regulating plant population and community dynamics. My research is based primarily in the southeastern U.S. and in Michigan.

I have openings in my lab for graduate students at the masters level and for undergraduate research projects that address these or similar questions.

 

Relict trillium adult subadult and juvenile. Photo taken by Christopher Heckel.

 1. Threats to Endangered Trillium reliquum

With the Trillium system, I ask the question, how do populations of endangered species respond to threats by invasive plants and deer? With funding from the Department of Natural Resources, we have constructed deer exclosures and removed Lonicera japonica (Japanese honeysuckle, an invasive vine) from multiple sites across the range of trillium in Georgia and are monitoring population and community dynamics.

Funding
Georgia Department of Natural Resources, Sigma Xi (2), Garden Club of America: Catherine Beattie Fellowship (2), Marie Mellinger Grant, Georgia Southern University: COST Academic Excellence (2), Student Faculty Research Award, COST COUR, etc.

Students who have worked on this project
Graduate students: Christopher Heckel, Jacob Thompson
Undergraduates: D. Josh Parris

Publications / Presentations
Heckel, Christopher and L.M. Leege. 2006. Life history and reproductive biology of the endangered Trillium reliquum. Plant Ecology (online first: printed volume forthcoming.)

March 2006. "The impacts of white-tailed deer herbivory and Lonicera japonica on the population dynamics of Trillium reliquum." Jacob S. Thompson* and L.M. Leege. at Georgia Academy of Science Annual Meeting at Georgia Perimeter College, Lawrence, GA. Best graduate student paper in Biological Sciences.

August 2004. "The effects of invasive vine encroachment on the population dynamics of an endangered herb." Newsworthy and Late-breaking contributed paper with Christopher D. Heckel. Ecological Society of America Annual Meeting. Portland, OR.

March 2004. "Impacts of exotic invasive vines on a population of the endangered Trillium reliquum." Contributed paper with Christopher D. Heckel. Georgia Academy of Science Annual Meeting. Berry College, GA. Best graduate student paper in Biological Sciences.

November 2003. "Impacts of exotic invasive vines on a population of the endangered Trillium reliquum." Poster presentation with Christopher D. Heckel. Invasive Plants in Natural and Managed Systems: Linking Science and Management and 7th International Conference on the Ecology and Management of Alien Plant Invasions, Fort Lauderdale, FL.

 

 

 2. Threats to Endangered Baptisia arachnifera

Hairy rattleweed (Baptisia arachnifera) occurs in only two counties in the world - in Wayne and Brantley Counties in southeast Georgia's coastal plain. The legume is highly endangered due to habitat loss (conversion to timber land). It also loses a good share of its seed crop each year to a natural seed predator.

None of its remaining habitat is on public land and therefore this species has no formal protection.

With funding from the Department of Natural Resources and US Fish and Wildlife, we are monitoring its population dynamics on timber land and in one privately owned site to determine the effects of human and natural threats.

Funding
US FIsh and Wildlife, Department of Natural Resources.

Students who have worked on this project
Jacob Thompson, Amy Squire (UGA), D. Josh Parris

Presentations/Publications

 

Redbay galls are initiated each spring by psyllids. (Photograph by L. Leege)

3. Interactions between the redbay tree(Persea borbonia) and its psyllid leaf galler (Trioza magnoliae)

The leaves of redbay trees are very commonly infested with galls that are produced in response to the jumping plant louse, Trioza magnoliae. In my lab, we are interested in the fitness cost of the galls to this evergreen tree. We are also investigating patterns of gall distribution in sites of varying resource availability.

In collaboration with Dr. Norman Schmidt of GSU's Department of Chemistry, we have also begun to quantify levels of defensive chemicals in redbay.

We have done field work on this system at George L. Smith state park, Herty Preserve on the GSU campus, and on three of the Georgia barrier islands.

Students who have worked on this project
Charlie Bridges, Leonard Brown, Ben Churcher, April Edwards, Susan George, Elaine Giles, R. Brooke Hastings, Christine Mayo (Department of Chemistry), BJ Newell, Julie Powell

Presentations/Publications
Leege, Lissa M. 2006. The relationship between psyllid leaf galls and redbay (Persea borbonia) fitness traits in sun and shade. Plant Ecology 84(2): 203-212.

Leege, L.M. and R. B. Hastings. 2002. Biological constraints to reproductive success in populations of coastal and inland redbay (Persea borbonia). Georgia Journal of Science 60(1).

Leege, L.M. and C. Bridges. 2000. The Distribution of Galls on Redbay Leaves in Sand Dune and Maritime Forest Habitats: is Life Really Better at the Beach? Georgia Journal of Science 58 (1): 49.

Spring 2005 "The concentration of essential oils of redbay (Persea borbonia) with respect to seasonal changes." Poster presentation with Sara Calvarese and Norman E. Schmidt at 37th Annual Southeast Regional American Chemical Society Undergraduate Research Conference, Mississippi State University.

 

 

Cakile edentula in fruit and flower on the shore of Lake Huron, MI.
(Photograph by F. D'Arcangelo)

4. Effect of herbivory across ontogeny of sea rocket (Cakile edentula), a dune annual

With the sea rocket system, I ask the question, how do plants in nitrogen-poor environments allocate their resources to growth, reproduction and defense in order to optimize their fitness? In my lab, we are investigating resource allocation across the life cycle as well as fitness effects of herbivory at different stages of the plant's life. We are also doing comparative work between Great Lakes and Georgia barrier island Cakile edentula populations.

Sea rockets produce glucosinolates, a class of compounds that are not used in primary metabolism and are thought to serve a defensive function for plants in the mustard family. Glucosinolates are responsible for the "hot" taste in radishes and mustard. We are quantifying these compounds and determine how plant allocation to this type of chemical defense varies across the life of a plant.

Funding
GSU

Students who have worked on this project
Emily Bankard (Michigan State University), Dourinina Beal, Karen Brown , Brent Ginn, Daisy Kangeter

Presentations/Publications
July 2004 "When should a plant defend or grow? Herbivory and glucosinolate concentrations through the life of a beach annual, Cakile edentula". Contributed paper with DH Kangeter, BT Ginn, and KR Brown. Ecological Society of America Annual Meeting. Portland, OR.

Brown, K.R., B.T. Ginn, L.M. Leege. 2001. Effects of Herbivore Damage on Growth and Reproduction in Cakile edentula. Georgia Journal of Science 59(1):25.


 

Wild horses on Cumberland beach.

 5. Feral horse effects on plant communities at Cumberland Island
A growing wild horse population (more than 200 individuals) lives on Cumberland Island. The horses graze on the island in the salt marsh and in the sand dunes as well as in pasture land. This grazing and trampling may be altering the structure and composition of plant communities in these habitats.

Since 1999, we have worked with the park service to monitor feral horse impacts to these communities and are interested in determining the ability of a large, non-native herbivore to alter plant community structure.

Funding
National Park Service Challenge Cost Share Grant
Georgia Southern University

Students who have worked on this project
Master's student: Peter Dolan
Undergraduates: Quiana Manning, LaChieka Miller, Trey Yearwood

Presentations/Publications
Dolan, P and L.M. Leege. 2002. Feral horses in dune and saltmarsh habitats on Cumberland Island. Georgia Journal of Science 60(1).

Dolan, P. and L.M. Leege. 2001. Feral Horse Impacts on the Saltmarsh of Cumberland Island. Georgia Journal of Science 59(1):51.


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Department of Biology, Georgia Southern University

last modified: 1/9/07