Department of Biology

Program

Evolution, Ecology & Behavior

Research Areas

• Ecology
• Microbial Interactions and Pathogenesis

Education

Ph.D., University of California, Berkeley, 1995
Postdoctoral Fellow, WK Kellogg Biological Station, Hickory Corners, MI, 1995-98

Research Description

Research: Our lab's broad interests are in plant-environment interactions, with the goals of understanding vegetation patterns and their responses to abiotic and biotic environmental changes. Within these broad areas, we are especially interested in the importance of plant-soil and plant-microbe relationships, and the role of environmental heterogeneity. We work primarily with herbaceous systems (e.g. prairie, old-field, forest floor) using a combination of experimental and observational approaches.

The 21st Century has been dubbed "The Century of the Environment" in recognition of the importance of the world's diverse ecosystems for the continued health of our society and the increasing threats that human activities pose to this relationship. Thus, we are not only interested in testing and advancing ecological theory, but also in its application to solving environmental problems and in educational outreach.

Current research falls into three main areas:

Patterns and mechanisms of plant community diversity

Understanding patterns of species diversity is a central goal of ecology and fundamental to the management and preservation of biodiversity. Environmental heterogeneity, combined with species tradeoffs in their responses to such heterogeneity, is a classic mechanism of species coexistence. Colleagues and I are testing this hypothesis via field experiments in Michigan savanna prairie. Our work is revealing that clonal plant species capable of extensive foraging can dampen heterogeneity-diversity relationships. Other research interests in this area include examination of patterns of plant species diversity and the importance of alternative coexistence mechanisms in different community types (e.g. native prairie, successional grassland, forest understory) and exploration of the niches of native vs. exotic plant species.

Plant-microbe associations

The critical role of bacteria and fungi in such processes as decomposition and supply of mineral nutrients to plants has long been recognized. Much less is known, however, about the extent to which soil microbial composition varies among plant species or the consequences of such variation for plant processes like competition, exotic species invasions or coexistence. Current research is examining fungal endophyte, arbuscular mycorrhizal, and nitrogen-fixing associations of native prairie species, with interest in their biogeographic diversity and application to sustainable cellulosic biofuels production (http://www.indiana.edu/~cres1/biofuel.shtml). My lab is also investigating the role of plant-soil feedback in plant invasions and plant community structure, and is particularly interested in whether and how feedback changes with environmental context (e.g. competitive context, soil nutrients).  We also investigate how soil microbial community composition varies by plant species, plant nativity or other (e.g. abiotic) factors using tools such as terminal restriction fragment length polymorphism (TRFLP) analysis. For example, in one of our initial studies we used these techniques to detect significant differences in the eubacterial communities associated with field populations of native versus exotic invasive forest floor species.

Biodiversity, ecosystem functioning and global change

Increased awareness of dramatic, human-caused declines in biodiversity has reinvigorated and expanded an old debate in ecology about whether diversity promotes the stability and/or rate of ecosystem processes. The relationship between biodiversity and ecosystem functioning is a growing area of scientific research for my lab. Recent or current projects examine how vegetation richness, evenness or overall diversity affects exotic plant invasions, levels of herbivory, and native pollinator services to agricultural crops, and how microbial functional group richness affects the relationship between plant productivity and plant species diversity.

Education and outreach: Service-learning is a form of experiential or active learning ("learning by doing") that involves partnerships between students and communities. In service-learning, the service is a mechanism by which students can deepen understanding of course content and its application to the "real world," and explore their own roles and responsibilities as citizens of society.

I offer an undergraduate service-learning course, "The City as Ecosystem," that applies the principles of ecosystem ecology to sustainable design of urban and agricultural systems. A graduate service-learning course, "Science and Society," explores the many dimensions of science's intersection with society, from both personal and institutional perspectives.

Other education and outreach activity includes work with the Biology Club, Volunteers in Sustainability, and the Indiana University Architect's Office to establish green landscaping with native prairie and woodland species on campus; a research/outreach project with interdisciplinary colleagues focused on invasive species control and native plant restoration in the campus' iconic woodland "Dunn's Woods;" public presentations on ecological limits, the steady state economy, and the value of ecosystem services; and service on the City of Bloomington Environmental Commission (2001-2010). Promoting understanding of the environmental, social, and economic dimensions of human-environmental interactions is an important focus of my educational activities, and colleagues and I address this literacy in the volume "Teaching Environmental Literacy. Across Campus and Across the Curriculum," featuring essays by colleagues in Biology and many other campus units.

Select Publications

Kleczewski N M, J T Bauer, J D Bever, K Clay and H L Reynolds. 2012. A survey of endophytic fungi of switchgrass (Panicum virgatum) in the Midwest, and their putative roles in plant growth. Fungal Ecology. http://dx.doi.org/10.1016/j.funeco.2011.12.006.  

Shannon S, S L Flory and H L Reynolds. 2012. Competitive context alters plant-soil feedback in an experimental woodland community. Oecologia 169:236-243.

Smith L M and H L Reynolds. 2012. Positive plant-soil feedback may drive dominance of a woodland invader, Euonymus fortunei. Plant Ecology 213:853-860.

Bauer J T, N M Kleczewski, J D Bever, K Clay and H L Reynolds. 2012. Nitrogen-fixing bacteria, arbuscular mycorrhizal fungi and the productivity and structure of prairie grassland communities. Oecologia DOI: 10.1007/s00442-012-2363-3.

Bauer J T, SM Shannon, R E Stoops and H L Reynolds. 2012. Context dependency of the allelopathic effects of Lonicera maackii on seed germination. Plant Ecology DOI: 10.1007/s11258-012-0036-2.

Padilla F, W B Mattingly, B L Swedo, K Clay, and H L Reynolds. 2012. Negative plant-soil feedback drives seedling competitive interactions regardless of fungal endophyte infection. Journal of Vegetation Science. DOI: 10.1111/j.1654-1103.2012.01385.x.  

Reynolds H L and K Clay. 2011. Migration as an ecological process. Environmental Law 41:371-391.

Eilts J A, G G Mittelbach, H L Reynolds, and K L Gross. 2011. Resource heterogeneity, soil fertility, and species diversity: impacts of clonal species on plant communities. American Naturalist 177:574-588.

Mattingly W B, B L Swedo, H L Reynolds. 2010. Interactive effects of resource enrichment and resident diversity on invasion of native grassland by Lolium arundinaceum. Plant Ecology 207:203-212.

Glover J D, S W Culman, S Tianna DuPont, W Broussard, L Young, M E Mangan, J G Mai, T E Crews, L R DeHaan, D H Buckley, H Ferris, R Eugene Turner, H L Reynolds and D L Wyse. 2010. Harvested perennial grasslands provide ecological benchmarks for agricultural sustainability. Agriculture, Ecosystems, and Environment 137:3-12.

Reynolds H L and K A Haubensak. 2009. Soil fertility, heterogeneity and microbes: towards an integrated understanding of grassland structure and dynamics. Applied Vegetation Science 12:33-44.

Houseman G R, G G Mittelbach, H L Reynolds, and K L Gross. 2008. Perturbations alter community convergence, divergence, and formation of multiple community states. Ecology 89:2172-2180.

Swedo B L, C Glinka, D R Rollo and H L Reynolds. 2008. Soil bacterial community structure under exotic versus native understory forbs in a woodland remnant in Indiana. Proceedings of the Indiana Academy of Sciences 117:7-15.

Reynolds H L, G G Mittelbach, T Darcy-Hall, G Houseman, and K L Gross. 2007. No effect of varying soil resource heterogeneity on plant species richness in a low fertility grassland. Journal of Ecology 95:723-733.

Mattingly W B, R L Hewlate, and H L Reynolds. 2007. Species evenness and invasion resistance of experimental grassland communities. Oikos 116:1164-1170.

Reynolds H L and T K Rajaniemi. 2007. Plant interactions: competition. pp. 457-480 In: Functional Plant Ecology, Second Edition , F I Pugnaire and F Valladares (editors), CRC Press, Taylor & Francis Group, Boca Raton, FL.

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