Nathan is a research biologist with the U.S. Army Engineer Research and Development Center in Vicksburg, MS. While employed with the Corps, he is earning his PhD. Nathan is interested in the biological control and management of wetland invasive plant species. Specifically, he is studying flea beetle (Agasicles hygrophila) control of alligatorweed (Alternanthera philoxeroides). Historically, flea beetles have been very successful in controlling alligatorweed but an interesting phenomenon is now occurring with this system. Alligatorweed has been expanding northward but the flea beetles have lagged behind. Nathan plans to study this issue with a particular focus on biological control at species range margins.
Rachel is interested in the effects of density-dependent emigration (DDE) on the population dynamics of competing species. She is particularly interested in comparing traditional forms of DDE (where dispersal increases linearly with density) with non-tradition forms such as negative or U-shaped DDE (see Harman et al. in review). She is also interested in life-history tradeoffs at range margins using Tribolium flour beetles as a model system. Her goal is to combine experimental studies with mathematical models to understand their effects on population dynamics.
Herie is interested in roseau cane dieback in the Mississippi River Delta. She is particularly interested in developing and testing methods for restoring marsh habitats in areas of dieback as well as in newly created habitats formed from dredging the waterways.
Lori is jointly advised by Erik Aschehoug (Norwegian University of Life Sciences) and me. She has been studying plant-soil feedbacks in cogongrass (Imperata cylindrica), specifically focusing on legacy effects on native plant species. Lori recently successfully defended her thesis.
Joe is supported by our USDA grant and plays an integral role in our research on roseau cane dieback in the Mississippi River Delta. He takes care of our plants and runs our garden experiments. We’re trying to convince Joe to pursue a graduate degree.
Warwick’s dissertation focused on two main research areas: invasive plant - herbivore - predator interactions and how they vary in space (see Allen et al 2017) and direct and indirect effects of soil microorganisms on invasion success and plant-plant interactions. His research focused primarily on the wetland invader, Phragmites australis. After graduating in 2017, Warwick has moved on to a postdoc at Lincoln University in New Zealand.
Ganesh's research focused on a large-scale, biogeographic approach to studying invasive plant species. Chapters in his dissertation addressed the effects of large-scale disturbances on the proliferation and spread of the invasive plant, Phragmites australis, the ecology and evolution of latitudinal gradients in P. australis - herbivore interactions, and apparent competition between native and invasive genotypes of P. australis and how it varies with latitude.
Impact of invasive plant species on community structure. Forrest is interested in the invasion and spread of brome grass (Bromus inermis) in the tall-grass prairies of the Great Plains. His research has shown that brome is rapidly displacing native grasses, and altering the dispersal behavior and increasing the extinction risk of native insect species.
Dissertation Title: Invasion of smooth brome into North American tall-grass prairies: impact on native plant/herbivore species and mechanisms responsible for successful invasion.
For many plant speices, chemical and morphological defenses against herbivory induced upon herbivore attack. A plant's resistance to herbivory also may be influenced indirectly by its neighbors, that is, by the diversity and composition of the plant community. Amanda's objective is to examine how the efficacy of induced defenses is influenced by the context of the community. She plans to manipulate the species composition and defensive strategies (e.g., constitutive or induced defense levels) of neighboring plants and quantify their effects on the herbivory of a target plant species (soybeans) that either possess or lack the ability to induce a defense.
Mechanisms Promoting Spatial and Temporal Variability in Plant Defense
From Indidvidual Dispersal Behavior to the Multiscale Distribution of a Saproxylic Beetle.
Landscape heterogeneity and the spatial ecology of a prairie planthopper.
Adaptive oviposition behaviour in the goldenrod stem galler, Eurosta solidaginis (Diptera: Tephritidae).
Response of a Gall-forming Guild (Hymenoptera: Cynipidae) to Stressed and Vigorous Prairie Roses
Kristen examined the impact of the matrix on the efficacy of corridors and stepping stones. She also played a significant role in the development of the study on dead-wood arthropods.