The 2015 Medal was awarded to Bai-Lian Larry Li, Professor at the University of California, USA.
B Larry Li is Professor of Ecology and Director of three research centres at the University of California, Riverside, ie the International Centre for Ecology and Sustainability, the International Centre for Arid Land Ecology, and the US Department of Agriculture – China Joint Research Centre for Agroecology and Sustainability.
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| B. Larry Li |
Professor Li has a broad inter-disciplinary background and experience in mathematical, statistical and computational modelling applications in ecological studies. Professor Li is a Fellow of the Institute for Human Ecology, USA; Chair Professor of the Chinese Academy of Science, Honorary Professor of the Russian Academy of Sciences and Fellow of the American Association for the Advancement of Science, among other important recognitions.
He currently presides over the Eco-Summit Foundation and is a member of NSF Scientific Panels. He has been the founder and editor of the prestigious International Journal on Ecological Complexity and the Journal of Arid Land. He organised many symposia and courses with other institutions, including the Max-Planck and Santa Fe institutes.
Prof Li has worked on a wide variety of ecological projects including recent involvement in energetic and thermodynamic ecological systems and restoration of ecological patterns for formations and long-term ecological research in the USA and internationally.
He has published more than 200 refereed journal articles, and numerous conference papers, in addition to 30 book chapters and eight books or edited special issues.
Following these introductory remarks, Professor Mora Mas awarded the Medal to Professor Li and invited him to give his Prigogine lecture entitled “Towards an energetically and thermodynamically-sounded approach to ecological complexity, modelling and sustainability”.
B Larry Li started his inaugural address with the following introduction:
“Life is based on cycling of matter and consumption of energy. The spatial and temporal scales of these processes transcend from the micro-world, where living cells meet their energetic demand with nutrients diffusing through the cell wall, to the planetary scale, where continental vegetation cover and oceanic biota profoundly impact the global cycles of life essentials like water and carbon. On the basis of a holistic systems view and Prigogine and Haken’s theories, my research has been focusing on addressing the following key questions: How do biological and ecological systems self-organize? What are the origins and mechanisms of emergence of scaling from individual to landscape levels (especially on emergence of dynamic scaling)? And what are the physical bases of non-equilibrium biological and ecological systems? I use mathematical, statistical, and computational modelling approaches as a way of exploring and answering these questions. These modelling approaches help identify general principles and basic mechanisms governing emerging properties of biological and ecological systems at multiple temporal and spatial scales based on energetic, thermodynamic and information considerations and allow us to have better understanding and modelling of ecological complexity, services and sustainability.
“One of my earliest English papers entitled ‘Pansystems analysis: a new approach to ecosystem modelling’ was published in Ecological Modelling in 1986. In that paper, I proposed a new pansystems approach to study complex and strongly interacting dynamic processes in ecological system, ie the social-economic-natural complex ecosystems, and a rough framework of ecological complexity – modelling complex or large-scale ecosystems. This work, to large extent, reflected in part of my earlier views to apply Prigogine’s far-from equilibrium thoughts to ecological systems.
“In this lecture, I will start with re-examination of the classic logistic equation in population ecology, from the energy conservation law. We found that there exists a conservation of energy relationship comprising the terms of available resource and population density, jointly interpreted here as total available vital energy in a confined environment. We showed that this relationship determines a density-dependent functional form of relative population growth rate and consequently the parametric equations are in the form depending upon the population density, resource concentration, and time. Thus, the derived form of relative population growth rate is essentially a feedback type, ie updating parametric values for the corresponding population density. This resource dynamics-based feedback approach has been implemented for formulating variable carrying capacity in a confined environment. Particularly, at a constant resource replenishment rate, a density-dependent population growth equation similar to the classic logistic equation is derived, while one of the regulating factors of the underlying resource dynamics is that the resource consumption rate is directly proportional to the resource concentration.
“Secondly, I will talk about energetic and thermodynamic foundation of ecological systems. A fundamental but unanswered biological question asks how much energy, on average, Earth’s different life forms spend per unit mass per unit time to remain alive. Here, using the largest database to date, for 3006 species that includes most of the range of biological diversity on the planet – from bacteria to elephants, and algae to sapling trees – we show that metabolism displays a striking degree of homeostasis across all of life. We demonstrate that, despite the enormous biochemical, physiological, and ecological differences between the surveyed species that vary over 1020-fold in body mass, mean metabolic rates of major taxonomic groups displayed at physiological rest converge on a narrow range from 0.3 to 9 W kg-1. This 30-fold variation among life’s disparate forms represents a remarkably small range compared with the 4000 to 65000-fold difference between the mean metabolic rates of the smallest and largest organisms that would be observed if life as a whole conformed to universal quarter power or third-power allometric scaling laws. The observed broad convergence on a narrow range of basal metabolic rates suggests that organismal designs that fit in this physiological window have been favoured by natural selection across all of life’s major kingdoms, and that this range might therefore be considered as optimal for living matter as a whole.
“Thirdly, I will show how we can use this foundation to scaling up, from primary producers to primary consumers, to second consumers, and so on in ecological networks. This approach opens a new view to re-examine species diversity-stability-productivity relationships in ecological systems.
“Fourthly, I will examine the emergence of scaling properties and self-organisations in ecological systems, such as species-area curve, self-thinning law, etc. My talk will also include applications of this framework to study ecotone phase transitions, biological invasion, scaling from genomes to ecosystems and global change biology.
“Based on my own study and near 35 years working experience in this field, I have been so much inspired by Prof Ilya Prigogine’s works and his thoughts. I met him in person only once, in 1992 Chaos Conference at Texas A&M University, College Station, USA; I showed him how I used his theory: nonlinear Markov non-equilibrium thermodynamic stability theory to study ecological phase transitions and predict the tree-grass dynamics of savannah in southern Texas landscapes. I believe that his work and view will continue to inspire new generations of ecologists to study not only fundamental issues of ecology but also applied ecological problems in conservation biology, biological invasion, restoration ecology, ecological monitoring and assessment, global change, and sustainable development.”
Prof Li’s excellent presentation was followed with great interest by all participants. He demonstrates a command of many disciplines, such as mathematics, statistics, computational mechanics, in addition to biology and ecosystems. His address gave a comprehensive picture of the diverse ecosystems behaviour and the importance of understanding them to achieve sustainability.
