Ph.D., Ecology, University of Chicago
Post-doc., Ecology, Loyola University Chicago
M.S., Biology, Florida International University
B.S., Biology, Florida International University
A.A., Biology, Miami-Dade Community College
Volesky, L.A., S. Iqbal, J.J. Kelly, and P. Geddes. 2018. Relationships of native and exotic Phragmites australis to wetland ecosystem properties. Wetlands 38(3):577-589. DOI 10.1007/s13157-018-1001-1.
Geddes, P. 2015. Experimental evidence that subsidy quality affects the stability of recipient planktonic communities. Aquatic Sciences 77(4):609-621.
Geddes, P., T. Grancharova, J. J. Kelly, D. Treering, and N. C. Tuchman. 2014. Effects of invasive Typha x glauca on wetland ecosystem properties are influenced by time since invasion. Aquatic Ecology 48:247-258.
Lishawa, S.C., K.J. Jankowski, P. Geddes, D.J. Larkin, A.M. Monks, and N.C. Tuchman. 2014. Denitrification in a Laurentian Great Lakes coastal wetland invaded by hybrid cattail (Typha × glauca). Aquatic Sciences 76:483-495.
Larkin, D. M. Freyman, S. Lishawa, P. Geddes and N.C. Tuchman. 2011. Mechanisms of dominance by the invasive hybrid cattail Typha X glauca. Biological Invasions 14(1):65-77.
Mitchell, M.M, S. Lishawa, P. Geddes, D. Larkin, D. Treering, and N.C. Tuchman. 2011. Time-dependent impacts of cattail invasion in Great Lakes coastal wetlands. Wetlands 31:1143-1149.
My research interests focus on two broader themes: 1) Invasive plant species and the mechanisms that underlie successful invasions in wetlands, and 2) Ecological interactions in communities. Under theme No. 1, I’m interested in how plant invasive species’ traits (such as rapid growth, large biomass, large litter deposition, and even genotype) trigger a cascade of effects that span from their interaction with co-occurring native species all the way up to ecosystem-level processes. Within this topic, I am exploring two important wetland plant invaders: cattails (Typha spp.) and common reed (Phragmites spp.). I also combine molecular tools (microsatellite markers) to answer ecological questions, mostly related to the identification of hybridizing invasive plant species. Under theme No. 2, I’m interested in: a) how communities respond to external disturbances (e.g., invaders, pollutants, urbanization), and b) how aquatic communities are fueled, either via primary production, detritus, or external inputs (i.e., spatial subsidies).
Northeastern Illinois University
5500 North St. Louis Avenue
Chicago, IL 60625