Gene flow, with its counterparts natural selection, mutation and random genetic drift, are the primary architects of nature. The importance of gene flow was recognized by early evolutionary biologists and biogeographers, but only recently have we had the tools at our disposal to evaluate in detail the relative importance of gene flow in shaping natural populations. Gene flow and how it changes the character of wild and weedy populations has become a principle focus of research in my lab. Recent work has focused on the acquisition of beneficial traits by gene flow in two vastly different systems, one a tropical plant genus and its coevolved partners, and the other a domesticated crop and its weedy relatives. Our projects adopt a rare comparative geographic approach and, as such, our efforts will contribute to a broader understanding of the distribution and diversity of plant species, their histories of divergence, and the implications for the future given the accelerating rate of species introductions and extinctions.
My research program is evolving in two very different landscapes: lowland tropical rainforest of Central and South America, and agricultural fields of the upper Midwest. The tropical projects focus on biological influences in the evolution of mutualism. Among the world's most popular examples of mutualism are the defense mutualisms of Cecropia plant species and their symbionts: Azteca ants and scale insects. Although the ant-plant association is widely recognized, fundamental aspects of the system's biology are virtually unknown. For example, the number of ant or scale species that associate with Cecropia trees, or the degree of their fidelity has yet to be documented. Our specific aims in this work are to evaluate geographic variation in species associations and to document "hot" and "cold" spots of coevolution across the codistributions of interacting taxa. I am organizing a group of nearly 20 collaborators in the U.S., Central and South America to study the ecology, biogeography, phylogeny and phylogeography of these species to unravel the evolutionary and ecological mechanisms that shape their interactions in the wild. I am currently funded by the National Science Foundation Office of International Science and Education (NSF OISE) to explore potential study sites in Surinam, Guyana, Ecuador and Peru, and to establish collaborations in host countries. We anticipate resubmission of a collaborative research proposal (U of Arkansas, U of Minnesota, UC Davis, and Smithsonian) to NSF Division of Enivornmental Biology (DEB) within the year. Results of this work will have a significant impact on a growing awareness of variation among isolated populations in the nature of interspecific associations and will reveal the importance of geographic isolation on the evolution of specialization.
In contrast to our tropical projects, our temperate work involves an interdisciplinary collaboration of academic researchers and regulatory agencies to evaluate the movement of transgenes from agricultural systems to the wild. Gene movement through hybridization often creates new genetic forms that are far more variable and frequently more robust that either parent species, but the persistence of later generation hybrids or the fate of domestic genes in nature has received little systematic study. We will evaluate the fate of interspecific hybrids of canola and sexually compatible weeds in populations from western Oregon to eastern Arkansas. Our overarching goal in this work is to develop a generalized, predictive model of the changing threats of weedy species in the event of global climate change. This project recently received support from the United States Department of Agriculture (USDA) through a special initiative, "National Research Initiative: Global and climate change: invasive species and land use." Although I am sole PI on the award, the project is a collaborative effort among scientists at U of Arkansas, CSU-Fresno, U.S. EPA National Health and Environmental Effects Lab (NHERL) and North Dakota State University. This project is the first of its kind to evaluate the ecological risks of transgene escape at a broad geographic scale, and to evaluate the influence of environment on the variable rate of gene flow. As such, the results of this project will make a substantial contribution to agricultural regulatory agencies, as well as to a broader understanding of the ecological correlates of gene flow and interspecific hybridization.
My philosophy toward developing a research questions has evolved substantially during my tenure at the University of Arkansas. A sole authored publication was, in my graduate days, a symbol of authority and it served as a union card in the confederacy of ecologists. My reverence for sole authorship has turned tepid largely due to my experience as senior research associate with the National Research Council and the Environmental Protection Agency. Lidia Watrud's lab at NHEERL hosted three visiting researchers during my tenure: a population biologist, a developmental geneticist and a geographer. Her staff included a molecular plant systematist, a plant taxonomist and an entomologist. Pulling together a group of researchers with decidedly different expertise as Lidia did is exactly not what we typically do in academic research. Rather, we recruit technicians students, post-docs and colleagues with interests identical to our own. Work with the Watrud lab of the EPA has changed forever my interests in research and my research philosophy. My projects now in the tropics and in the temperate zone engage large, interdisciplinary, diverse groups of outstanding researchers working at universities, colleges, research institutes and government agencies. Junior and senior researchers, along with students bring to the table different expertise, energies and viewpoints, all of which adds new dimension to project development and planning. Research, I have found, is far more rewarding when a difficult problem finds richer, more complete resolution because diverse perspectives approach it collaboratively.
As a final note to my research statement, I am compelled to state that my interest and enthusiasm for research permeates every aspect of my work at the University of Arkansas. Results of my research, or of my colleagues' research is frequently featured in my lecture material and often forms the basis for research by undergraduate in my lab. I present lectures on current theories of ecology and evolutionary biology because I am actively researching them. I am, I believe, better able to recruit students to careers in math and science because I am an active researcher. My research further percolates through to my service commitments: board-level participation in the Organization for Tropical Studies, a commission appointment on Arkansas' Governor's Commission on Global Warming, a membership on the campus' Sustainability Council. My life as a scientist has been an interesting one, indeed, and I fully acknowledge that it is a privilege afforded me by the support of my colleagues, my department and my students.