Atmospheric [CO2] over the last 800,00 years. Our lab focuses on understanding how plants adapt to changing [CO2] with respect to physiology, growth, and development. Low CO2 of the last glacial period was among the lowest levels that occurred during the evolution of land plants. Prior to the Industrial Revolution (P-I), [CO2] rose to approximately 270 ppm, and has since risen to 400 ppm over contemporary time scales as a result of greenhouse gas emissions. [CO2] is expected to reach 700-1000 ppm before the end of this century. Data from Lüthi et al. 2008 Nature.
Humans are having an ever-increasing impact on both natural and managed ecosystems. In order to predict how global change factors will ultimately affect future ecosystems, we must understand how a rapidly changing environment affects plants at the most fundamental levels. In my lab, we mainly focus on responses from the organismal level down to the physiological and molecular levels. We combine a wide variety of approaches from stable isotope ecology, quantitative genetics, genomics, and molecular biology. Our research has mainly focused on the effects of changing atmospheric CO2 concentration ([CO2]) on plants, since this factor is the primary carbon source for photosynthesis and changes in [CO2] affect plants at a global scale. We also deal with the influence of other factors such as changing temperature and precipitation regimes that interact with CO2 to affect plants.

We not only study plant responses to future environments, but we also seek to understand how past changes influenced plants. For example, we study plant responses to increasing [CO2] during contemporary time periods when [CO2] increased from 270 ppm before the Industrial Revolution (200 years ago) to a current value of 400 ppm. This increase is primarily the result of fossil fuel combustion and land use change, and represents an unprecedented rate of CO2 increase for at least the last several million years. We also investigate the effects of low [CO2] that occurred 18,000-20,000 years ago during the peak of the last glacial period. During this period, [CO2] dropped to 180-200 ppm, which is among the lowest levels that occurred during the evolution of land plants. Low [CO2] likely constrained the physiology and growth of many plants, and the legacy of low [CO2] adaptation may still influence plant responses to a higher CO2 world of today. For this work, we study ancient plants preserved in the La Brea tar pits, New Zealand bogs, and pack-rat middens. 

We have a number of active research projects that address these themes as described below:

C3 plant responses to rising atmospheric [CO2] between the last glacial period and the future. These plants show a positive response to rising CO2, as do other C3 species.  However, note that other indirect effects of rising CO2 such as more droughts and heat stress may inhibit plant growth in the future, and such responses are not accounted for here. From Gerhart et al. 2012, Tansley Review, New Phytologist.    

Current Ward Lab Projects

Current Collaborative Projects
  • Water Relations of Invasive Tamarix - with the Kansas Geological Survey
    • See Publication: Nippert, J.B., J.J. Butler Jr, G.J. Kluitenberg, D.O. Whittemore, D. Arnold, S.E. Spal, J.K. Ward. 2010. Patterns of Tamarix water used during a record drought. Oecologia 162:283-292 

  • Olive Tree and Fig Responses to Climate Change in Palestine - with Professor Basheer-Salimia
    • See Publications: Basheer-Salimia R, M Awad, JK Ward. 2012. Assessments of biodiversity based on molecular markers and morphological traits among West-Bank, Palestine fig genotypes (Ficus carica L.). American Journal of Plant Sciences : 3: 1241-1251
    • Basheer-salimia R, JK Ward. 2014. Climate change and its effects on olive tree physiology in Palestine. Review of Research 3:1-7 

  • Sustainable Agriculture - with Wes Jackson and the Land Institute

  • Responses of Alpine Plants to Low CO2 as Inferred from Ancient Marmot Teeth - with Bryan McLean and others

  • Radiocarbon Dating and Extraction Methods of Ancient Bone Collagen - with Ben Fuller, John Harris, John Southon, and others
    • See Publication: Fuller BT, SM Fahrni, JM Harris, A Farrell, JB Coltrain, LM Gerhart, JK Ward, RE Taylor, JR Southon. 2014. Ultrafiltration for asphalt removal from bone collagen for radiocarbon dating and isotopic analysis of Pleistocene fauna at the tar pits of Rancho La Brea. In press