RESEARCH

The Marsico lab researches evolutionary ecology with an emphasis on species invasions.  Questions that inspire the most interest are those relating to how organisms with differing evolutionary histories interact in coevolved vs. novel environments.  Four research projects are currently being pursued in the lab:

Plant defense responses to coevolved, native vs. newly-associated, invasive insect herbivores.  This project involves understanding the phenotypic, chemical, and molecular underpinnings of recognition and defense by pricklypear cacti to two species of plant-boring moths.  Ph.D. student Anastasia Woodard is focused on understanding the chemical signaling between defending and non-defending host plants.  Other research includes comparing gene expression profiles of the two moth species to determine genes involved in feeding and/or counterdefense to host plant defenses.

Causes and impacts of Chinese privet invasion in forested riparian habitats.  Ph.D. student Meghan Foard is conducting dendrochronological, GIS mapping, and seed inundation studies to investigate whether Ligustrum sinense drives its own invasion through superior competition, or is a passenger riding along with habitat alteration.

The Marsico lab is collaborating with the Arkansas State University Ecotoxicology Research Facility (ERF) on a U.S. Environmental Protection Agency-funded grant to identify biological indicators of wetland water quality in the Cache River basin in the Mississippi Alluvial Plain in eastern Arkansas.  The habitats of interest are forested connected depressions that are dominated by hardwood trees and algal communities.  M.S. student David Burge is studying the algal communities in these wetlands to determine how variation in water chemistry alters the periphyton communities.

Maintaining collections, increasing their holdings with contemporary specimens, and increasing access to natural history data is critical to understanding patterns of biodiversity and shifts in spatial patterns of organisms across the landscape over time.  Since April 2010, nearly 2,000 new vascular plant vouchers have been collected through projects funded by the Arkansas Natural Heritage Commission and Shelby Farms Park Conservancy, and these vouchers are currently being accessioned into the Arkansas State University Herbarium (STAR) collection.  The Marsico lab is embarking on a project to digitize the collection of over 25,000 specimens at STAR.  Dr. Marsico recently has received funding from the National Science Foundation (NSF) for an Experiential Learning Fellowship (ELF) that provides students with financial need the opportunity to gain research and service experience on an issue of importance to the community.  Here in Jonesboro, Arkansas, the community of Master Gardeners has supported an initiative to digitize the collections in the herbarium, so that plant identification and plant conservation outreach will be more accessible and have an increased impact in the local community.  It is through this relationship with Master Gardeners and mentoring of four undergraduate students that the STAR herbarium has begun its digitization efforts.  M.A. student Kari Harris is focused on digitization and outreach to understand and promote understanding of the region’s flora.  

Undergraduate ELF students began their project in Spring 2012 and focused their efforts on accessioning 1,800 recent specimens into the collection and beginning the digitization of the collection—3,000 specimens digitized.  Ultimately, a digital STAR herbarium will provide species images and county dot maps online for use by individuals to identify plants they find in the area.

SELECT PUBLICATIONS

Woodard, A. M., G. N. Ervin, and T. D. Marsico.  2012.  Host plant defense signaling in response to a coevolved herbivore combats introduced herbivore attack.  Ecology and Evolution 2: 1056-1064.  DOI: 10.1002/ece3.224. PDF

Stewart, J. M., T. D. Marsico, D. Burge, and J. J. Hellmann.  2012. International Oaks 23: 68-75.

Marsico, T. D., L. E. Wallace, G. N. Ervin, C. P. Brooks, J. E. McClure, and M. E. Welch. 2011. Geographic patterns of genetic diversity from the native range of Cactoblastis cactorum (Berg) support the documented history of invasion and multiple introductions for invasive populations. Biological Invasions. DOI: 10.1007/s10530-010-9874-9. PDF

Marsico, T. D., J. W. Burt, E. K. Espeland, G. W. Gilchrist, M. A. Jamieson, L. Lindström, G. K. Roderick, S. Swope, M. Szűcs, and N. D. Tsutsui. 2010. Underutilized resources for studying the evolution of invasive species during their introduction, establishment, and lag phases. Evolutionary Applications 3: 203-219. PDF

Marsico, T. D. and J. J. Hellmann. 2009. Dispersal limitation inferred from an experimental translocation of Lomatium (Apiaceae) species outside their geographic ranges. Oikos 118: 1783-1792. PDF

Pelini, S. L., J. D. K. Dzurisin, K. M. Prior, C. M. Williams, T. D. Marsico, B. J. Sinclair, and J. J. Hellmann. 2009. Translocation experiments with butterflies reveal limits to enhancement of poleward populations under climate change. Proceedings of the National Academy of Sciences of the United States of America 106: 11160-11165. PDF

Marsico, T. D., J. J. Hellmann, and J. Romero-Severson. 2009. Patterns of seed dispersal and pollen flow in Quercus garryana (Fagaceae) following post-glacial climatic changes. Journal of Biogeography 36: 929-941. PDF