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

Program Affiliation: Evolution, Ecology and Behavior | Microbiology | Plant Biology

Research Groups Affiliation: Ecology | Microbiology | Plant Biology

Phone: 812/855-0792
Fax: 812/855-6705
Email Heather

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:

Soil resource heterogeneity and 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. As a direct test of the heterogeneity hypothesis, colleagues and I have established a field experiment to manipulate levels and heterogeneity of soil resources in a southwestern Michigan savanna prairie community. Other research interests related to vegetation diversity include evaluating the importance of alternative coexistence mechanisms over a range of community types (e.g. native prairie, successional grassland, forest understory).

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. Recent or current projects examine whether plants can niche partition nitrogen or phosphorus by form (e.g. NO3-, amino acid) or source (e.g. inorganic vs. organic) and how this varies with plant species nativity and microbial associations. My lab is also investigating how soil microbial composition varies by plant species, plant nativity or other (e.g. abiotic) factors. Some of this work uses the nucleic acid technique, terminal restriction fragment length polymorphism (TRFLP) analysis, coupled with web-based research tools. 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 involved with nutrient cycling or energy flow. The relationship between biodiversity and ecosystem functioning is a growing area of scientific research for my lab. Recent projects have examined the relationship between the evenness (equitability of species abundances) of native prairie communities and the ability of exotic plant species to invade these communities and the relative importance of native plant species richness (i.e. the number of species in a community) versus perturbations to plant resources in determining the vulnerability of nutrient-poor grassland to invasion

To learn more about these and other research projects in our lab, please visit the lab website!

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 service-learning courses in ecosystem ecology and in a graduate course entitled "Science and Society." Other education and outreach activity includes work with the Biology Club and the Indiana University Architect's Office to establish green landscaping with native prairie and woodland species on campus, public presentations on the value of ecosystem services, and service on the City of Bloomington Environmental Commission.

Houseman G R, G G Mittelbach, H L Reynolds, and K L Gross. (in press). Perturbations alter community convergence, divergence, and formation of multiple community states. Ecology.

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.

Vogelsang K M, H L Reynolds, and J D Bever. 2006. Mycorrhizal fungal identity and richness determine the species diversity and productivity of a tallgrass prairie system. New Phytologist 172:554-562.

Reynolds H L, K M Vogelsang, A E Hartley, J D Bever, and P A Schultz. 2006. Variable responses of old-field perennials to arbuscular mycorrhizal fungi and phosphorus source. Oecologia 147:348-358.

Reynolds H L, A E Hartley, K M Vogelsang, J D Bever, and P A Schultz. 2005. Arbuscular mycorrhizal fungi do not enhance nitrogen acquisition and growth of old-field perennials under low nitrogen supply in greenhouse culture. New Phytologist 167:869-880.

Gross, K L, G G Mittelbach, and H L Reynolds. 2005. Grassland invasibility and diversity: responses to nutrients, seed input, and disturbance. Ecology 86:476-486.

Rajaniemi, T K and H L Reynolds. 2004. Root foraging for patchy resources in eight herbaceous plant species. Oecologia 141:519-525.

Reynolds, H L, A Packer, J D Bever, and K Clay. 2003. Grassroots ecology: plant-microbe-soil interactions as drivers of plant community structure and dynamics. Ecology 84:2281-2291.