October 18, 2010 – "Biological Networks and the Scaling of Plant Form, Function, Diversity, and Ecology"
Brian Enquist, Department of Ecology and Evolutionary Biology, University of Arizona & The Santa Fe Institute
Ecology needs a predictive theoretical framework to understand and integrate how plants and ecosystems respond in changing world. However, is it possible to predict attributes of plant function, diversity, or even ecosystem performance from more general first principles? I will discuss new insights from Metabolic Scaling Theory (MST). MST is based on how the geometry of vascular networks underlies individual-level scaling relations for how plants use resources, fill space, and grow. The theory invokes a few key principles – space-filling, biomechanics, and minimization of resource transport costs within hierarchical vascular networks. MST postulates that these principles have primarily shaped the evolution of plant form, function, diversity, and ecology. Recent applications include linking how key functional traits interact to regulate variation in relative growth rates, leaf functioning, and how functional traits covary with each other. These then scale up to determine emergent properties in ecology and the functional trade-off axes that help define plant diversity. Lastly, this talk will also show how functional diversity in plants can then be 'scaled up' to predict emergent scaling behavior across diverse forests, including size–frequency distributions, spacing relations, canopy configurations, mortality rates, population dynamics, successional dynamics, and resource flux rates. The theory uniquely makes quantitative predictions for both leaf-level and forest-level scaling exponents and normalizations. A major strength of the theory is that it endeavors to explain a lot with a little. MST is based on a small number of principles and parameters but it makes many quantitative predictions and unifies diverse features of (i) the structure and function of plants; and (ii) plant ecology, community ecology, and ecosystem dynamics.
Professor Enquist, a broadly trained plant ecologist, investigates how functional constraints at the level of the individual (anatomical and physiological) influence larger scale ecological and evolutionary patterns. His lab uses both theoretical, computational, biophysical and physiological approaches to address integrative questions related to (1) the evolution of form and functional diversity; (2) the origin of allometric relationships (how characteristics of organisms change with their size) and the scaling of biological processes - 'from cells to ecosystems'; (3) the evolution of life-history and allocation strategies; and (4) community ecology and macroecology. His research also includes the monitoring of long-term dynamics of growth and change within a tropical forest in the Area de Conservation, Guanacaste, Costa Rica.
He is the recipient of an NSF Young Investigators CAREER Award; a Young Investigator Mercer Award from the Ecological Society of America; and a Costa Rican Fulbright Fellow.