Saint Xavier University
Department of Biological Sciences

Ecology and Evolution Lab

D. Liane Cochran-Stafira, Ph.D.

Sarracenia purpureaWyeomyia smithii

LCS out-standing in her field

Associate Professor
Department of Biological Sciences
Office:  S223
Voice Mail: 773-298-3514
Fax:  773-298-3536

Adjunct Research Professor
Department of Biological Sciences
Northern Illinois University
DeKalb, Illinois   


  • B.S.  Elmhurst College
  • M.S. DePaul University
  • Ph.D. Northern Illinois University,  Advisor Carl N. von Ende
  • Post Doctoral Research/Teaching Fellowship:  The  University of Chicago, Mentors:  Mathew Leibold and Ellen Simms
  • my cv
Frequently Taught Courses Other SXU Courses
  • BIOL 206  Microbiology
  • BIOL 302  Systematics and Ecology of Algae (ACCA Course at Morton Arboretum)
  • BIOL 3xx   Plant Community Ecology - at Morton Arboretum, ACCA College Botany Program
  • Applied MUS  Cello, private instruction
Other Activities

Research Interests:

Sarracenia purpurea
Sarracenia purpurea

photo by L. Cochran-Stafira

At the heart of my research is an interest in how species interactions influence the structure and dynamics of ecological communities.  Much of my work focuses on the direct and indirect effects of predation and competition on species diversity.  While I don't restrict myself to any single group of organisms, I was trained as both a microbiologist and an aquatic biologist, and I tend to focus mainly on small aquatic invertebrates and the microbial communities on which they feed.  I have been studying the inquiline community of the carnivorous pitcher plant Sarracenia purpurea as a model system for developing and testing theoretical concepts in community ecology.  In a world in which habitat fragmentation poses a serious threat to the future of biodiversity, the need to integrate local population and community processes with regional processes such as patch dynamics has become paramount.  The concept of the metacommunity was developed in an effort to link community ecology theory at the local level with regional and global models at larger spatial scales.  One of the major problems confronting this line of research has been the lack of a suitable natural model system.  Currently, I am focusing on developing the pitcher community as a model for studying metacommunity dynamics.  Part of this work involves a collaboration with Professor Laurens Mets at the University of Chicago.  We are developing a DNA fingerprinting method that will allow us to study dispersal rates of the bdelloid (asexual) rotifer Habrotrocha rosa as a first step towards constructing a mathematical model of pitcher metacommunity dynamics.

Another area of interest involves testing the species redundancy hypothesis using Sarracenia purpurea pitcher communities.  Recently, much attention has been focused on the relationship between biodiversity and ecosystem function.  How important are the actual species to the maintenance of ecosystem productivity, community resilience, etc?  The species redundancy hypothesis proposes that ecosystems show little change in function until many species are lost, suggesting that there is a high level of species functional redundancy.  I propose to experimentally test this hypothesis using the detritus-based ecosystem that is found within the pitchers of S. purpurea.  This project will involve both laboratory and field experiments in which the species composition of each trophic level will be varied.  Data will be then collected on a number of ecosystem functions including productivity (measured as species abundance and total biomass) and rates of nitrogen and phosphorous release from insect prey.

Beginning in the summer of 2002, I'll be adding a new dimension to the pitcher plant work by looking at the coevolution of the plant and its inquilines.  The species composition of the inquiline community of S. purpurea remains remarkably constant throughout the geographic range of the host plant.  (For more information on the biogeography of the pitcher plant inquiline community, visit Tom Miller's web site at Florida State University.)  However, it has has never been convincingly demonstrated that the plant-inquiline relationship is mutualistic.  The recent literature provides a number of tantalizing clues that suggest possible coevolution of the inquiline community with their host plant, but for a claim of "coevolution" or mutualism to be invoked, it is necessary to first demonstrate fitness benefits of the associations for the partners involved.  This project will look for those fitness benefits, and will ultimately ask the question of whether an entire community can evolve (a controversial quest indeed - but one worth investigating).

I employ a combination approach in which laboratory and field experiments as well field census data are combined to investigate the dynamics of the pitcher system at all levels, from the population dynamics and dispersal rates of individual consumer taxa such as rotifers, to the larger scale changes in protozoan and bacterial community diversity.

Interested in joining my lab?
Students who wish to work in my lab will be expected to be creative thinkers and independent, hard workers.  As I said, I'm not wedded to the idea of only working with pitcher plant communities.  It is possible for you to work on other organisms; however, your project must have some relevance to the theoretical issues that unify my own research projects.  I will expect that students approach their work as potentially publishable, not as simply an easy way to earn a credit or two (believe me - it's not all that easy).  Students who feel they are ready to jump right in can begin a research project immediately.  Others can join initially as field/lab assistants to get their feet wet.  They can then switch to a project later on after they've gained some experience.

If you think you're interested, please read the abstracts I've provided.  Then contact me and we'll talk about opportunities in my lab. 

Some representative abstracts from presentations at the Annual Meetings of the Ecological Society of America (ESA)

ESA 2008
ESA 2006
ESA 2005
ESA 2003
ESA 2001
ESA 2000

Sample publications:

Ellison, A.M., N.J. Gotelli, J.S. Brewer, D.L. Cochran-Stafira, J.M. Kneitel, T.E. Miller, A.C. Worley, and R. Zamora. 2003. The evolutionary ecology of         carnivorous plants.  Advances in Ecological Research 33: 1-74.  PDF

Cochran-Stafira, D.L., J.T. Wootton, and C.A. Andrews.  2001.  Multi-species Interactions: Indirect Effects.  Pages 155-171, in Tested studies for laboratory     teaching, Volume 23.  Proceedings of the 23rd Workshop/Conference of the Association for BiologyLaboratory Education (ABLE).  ( PDF)

Cochran-Stafira, D.L., and C.E. von Ende.  1998.  Integrating bacteria into food webs:  studies with Sarracenia purpurea inquilines.  Ecology                 79:880-898.  PDF

Cochran-Stafira, D.L., and M.J. Starzyk.  1989.  Membrane filter-fluorescent antibody technique for the detection of the genus Thermus in water.  Microbios         60:159-165.

Cochran-Stafira, D. L., and R.A. Andersen.  1984.  Diatom flora of a kettle-hole bog in relation to hydrarch succession.  Hydrobiologia.  109: 265-273. 

Current student projects:   I'm looking for talented, energetic, inquisitive students to join my lab.  If this describes you, contact me !
Jeries al-Sahoury - see ESA 2014 abstract

Matthew Sheedy - 

Past student projects:
David  Andersen 
Rob Lindgren  
Araceli Gonzalez - see ESA 2009 abstract
Yvonne Stokes - see ESA 2006 abstract
Christina Cocanig - see ESA 2005 abstract
Kristen Sandoval - see ESA 2005 abstract
Eva Yakimova - see ESA 2003 abstract  
Yvonne Stokes graduated from SXU in May, 2002 with a  B.S. in Botany.  Seems like the pitcher plant bug infected her though, and she continues her studies of the Effects of Competition on Pitcher Production and Morphology in Sarracenia purpurea as a graduate student at Governor's State University.  (abstract
Cedric Williams and Danielle Moore worked together on a project entitled Testing the species redundancy hypothesis using Sarracenia purpurea pitcher communities.  Cedric dealt with the ecological theory, and Danielle was pretty much up to her elbows in the microbiology of the system.  Cedric graduated from SXU in May, 2002, with a B.S. in Biology.  He is now a student in the School of Pharmacy at the University of Illinois Chicago Medical Center.  Danielle graduated in 2003 with her B.S. in Biology, and is currently working as a laboratory technician.  (abstract). 

Last updated  Janurary 11, 2014

This site is authored and maintained by Liane Cochran-Stafira

Saint Xavier University