Plant Functional Types in Dynamic Vegetation Models for Arctic Ecosystems: Past Experiences, Future Directions
Monday, August 5, 2013: 1:30 PM-5:00 PM
101B, Minneapolis Convention Center
Stan D. Wullschleger, Oak Ridge National Laboratory
Howard E. Epstein, University of Virginia
Xiaofeng Xu, Auburn University, AL
Dynamic vegetation models used at regional to global scales simulate natural vegetation distribution and terrestrial carbon, water, and energy exchange in response to climate, soil, disturbance, and their many interactions. These models rely on the concept of plant functional types (PFT) to reduce the complexity of species diversity to a few key plant types. The challenge likely to be encountered in moving forward with modeling vegetation dynamics, however, lies in evaluating the trade-offs between simplicity in our classification of PTFs, while capturing sufficient complexity in describing differences among PFTs for major ecosystem properties and processes. In this organized oral session, speakers will discuss how PFTs have been represented in regional and global models and if and how vegetation dynamics can be improved in the future. Speakers will be encouraged to take a broad perspective on these topics, while recognizing that our goal is to target representation of PFTs in advanced high-resolution land models of Arctic terrestrial ecosystems. Such ecosystems are critically important, yet poorly represented in current global dynamic vegetation models. Thus, this session will focus on new model formulations of PFTs for high-latitude ecosystems and the field measurements and remote imagery that are required to support the development (e.g., parameterization and validation) of these next-generation models. Speakers will highlight how PFTs have historically been characterized, the sources of data used to represent PFTs in early models, and trade-offs associated with various classification schemes. Knowledge gaps will be identified. Subsequent speakers will build upon this information and discuss how the improved availability of plant functional trait data can potentially enable a more realistic and empirically-based representation of terrestrial vegetation in Earth Systems Models. One speaker will present their perspectives for how belowground processes can be incorporated into PFTs by highlighting the inclusion of important root traits (e.g., phenology, turnover) into predictive models. Furthermore, the possibilities to incorporate genetic diversity and adaptive plasticity within PFTs through probabilistic representation of key processes will be discussed. Speakers will emphasize the value of including basic ecological principles in advanced models of climate. Progress in these areas and the incorporation of new approaches to define PFTs will be of interest to many members of the ESA including taxonomists, ecologists, physiologists, statisticians, computer scientists, and other disciplines.