U.S. Department of Energy, Office of Science

Program for Ecosystem Research

Research Project   Bridging the divide: linking genomics to ecosystem responses to climatic change

Principal investigator:   Melinda Smith

Project goal

Demonstrate that genomic data can be collected from plants under field conditions and directly linked to plant physiological responses underlying climatic change impacts on ecosystem structure and functioning.

U.S. grassland

Potential extent of U.S. native grasslands (dark: tallgrass; light: shortgrass) with present climate.

Ecosystem being studied

Tallgrass prairie in the Flint Hills region of northeastern Kansas. The study system corresponds to the "bluestem-grama prairie (Andropogon-Bouteloua)" vegetation type of Kuchler (1964). This ecosystem is part of a larger grassland biome in the central United States (see map).

Results

In response to altered rainfall patterns, the prairie grass big bluestem (Andropogon gerardii) has consistently upregulated genes controlling two aspects of photosynthesis (i.e., photochemistry and carbon metabolism) crucial to ecosystem functioning.

U.S. grassland

Grassland ecosystem in the central United States.

Why this is important

The research bridges two divergent disciplines in biology: molecular biology and ecology. It is expected that this combination of disciplines will provide early indicators of biological change driven by altered precipitation and warming that can be used within ecosystem models to produce forecasts for society to consider when weighing climatic change mitigation policies. This research is also relevant to improved understanding of the fundamental controls of grassland productivity upon which livestock management depends, a key land use and economic driver in the Great Plains region.

Methods

This project takes advantage of an ongoing climatic change experiment in intact tallgrass prairie located in the Flint Hills region of northeastern Kansas, the Rainfall Manipulation Plots (RaMPs). The RaMPs experiment imposes two environmental changes associated with energy production: (1) increased temperature (1-2 degrees Celsius warming) and (2) more variable precipitation regimes defined as increased time between, and intensity of, rainfall events.

The project is focusing on the two most abundant C4 grasses in the tallgrass prairie ecosystem, Andropogon gerardii and Sorghastrum nutans, which are known from previous studies to respond differently to altered precipitation and to strongly influence community and ecosystem processes. Both are related to maize (Zea mays) for which genomic tools have been developed.

This project is attempting to directly scale responses at the genome level to ecological processes. Specifically, information on the relative changes in gene expression determined with microarray and real-time polymerase chain reaction (PCR) technologies are collected concurrently with a suite of ecophysiological responses to identify genes that are consistently up- or down-regulated in the target species in response to climatic changes. Gene-level changes are scaled to community and ecosystem level responses based on responses of the individual grass species.

remote sensing

View of the RaMPs. In the foreground is a reference plot with infrared lamps for warming.

Personnel

Melinda D. Smith, Yale University

Alan K. Knapp, Colorado State University (subaward)

Jianfa Bai, Kansas State University (subaward)

John Blair, Kansas State University (subaward)

Karen Garrett, Kansas State University (subaward)

Scot Hulbert, Kansas State University (subaward)

Jan E. Leach, Kansas State University (subaward)

Steve Travers, Kansas State University (subaward)

Philip A. Fay, University of Minnesota-Duluth (subaward)

Reference

Kuchler AW (1964) Manual to Accompany the Map: Potential Natural Vegetation of the Conterminous United States. American Geological Society (Special publication No. 36), New York.

Funding period:   August 2004 to present