Simon Levin Proposal abstracts

Defense Advanced Research Projects Agency (DARPA)
Microstates to Macrodynamics: A New Mathematics of Biology PI: Simon Levin with 15 Co-PIs: Peter Bates, Robert Bryant, Timothy Buchman, Jim Damon, Charlie Epstein, Michael Deem, Herbert Edelsbrunner, Richard Lenski, Jack Morava, Lior Pachter, Olivier Pourquie, Sorin Popescu, Bernd Sturmfels, Joshua Weitz, Ned Wingreen The past decade has witnessed an explosion of interest in what mathematics can contribute to biology, and indeed a growing recognition that the power and promise of mathematical approaches must force a revolution in biological research and training. Mathematics is finally being recognized as providing indispensable tools for any biological scientist. However, mathematics is not new to biology: Mathematical constructs have for a century been at the core of such fields as population genetics, ecology, epidemiology and, more recently, neurobiology. In recent years, its successes have expanded to include cell biology, immunology, physiology and, especially, sequence analysis. Such successes have just scratched the surface; the integration of mathematics into biology is still in its infancy, and the time is right to build upon the successes of the past in order to elucidate the fundamental laws of biology through the power of mathematical analysis. This proposed project will foster collaborations among leading mathematicians and biologists, building a community of researchers who will develop the new mathematics of biology, and discover fundamental unifying principles. This could not have been achieved a decade ago and may not happen for decades without a structure and program to bring these disparate groups together in dialogue and collaboration. We have thus assembled a unique team of experimental biologists eager to contribute to the development of mathematical foundations of their subject, and mathematicians eager to help create the mathematical tools that can shed new insights on these problems. The central biological questions involve scaling from cells to organisms to populations to ecosystems, with attention to robustness, collective phenomena, as well as the structure and dynamics of complex networks. The mathematical tools will be drawn from a wide spectrum, from dynamical systems to algebraic statistics to differential topology, from the deterministic to the stochastic, with full expectation that novel formalisms will be established as the project develops. This project, relying on leaders from mathematics and biology, will initiate a new dialogue unconstrained by past approaches and aim to fundamentally change the landscape of biology.

Defense Advanced Research Projects Agency (DARPA)

Microstates to Macrodynamics: A New Mathematics of Biology
PI: Simon Levin with 15 Co-PIs: Peter Bates, Robert Bryant, Timothy Buchman, Jim Damon, Charlie Epstein, Michael Deem, Herbert Edelsbrunner, Richard Lenski, Jack Morava, Lior Pachter, Olivier Pourquie, Sorin Popescu, Bernd Sturmfels, Joshua Weitz, Ned Wingreen

The past decade has witnessed an explosion of interest in what mathematics can contribute to biology, and indeed a growing recognition that the power and promise of mathematical approaches must force a revolution in biological research and training. Mathematics is finally being recognized as providing indispensable tools for any biological scientist. However, mathematics is not new to biology: Mathematical constructs have for a century been at the core of such fields as population genetics, ecology, epidemiology and, more recently, neurobiology. In recent years, its successes have expanded to include cell biology, immunology, physiology and, especially, sequence analysis. Such successes have just scratched the surface; the integration of mathematics into biology is still in its infancy, and the time is right to build upon the successes of the past in order to elucidate the fundamental laws of biology through the power of mathematical analysis.

This proposed project will foster collaborations among leading mathematicians and biologists, building a community of researchers who will develop the new mathematics of biology, and discover fundamental unifying principles. This could not have been achieved a decade ago and may not happen for decades without a structure and program to bring these disparate groups together in dialogue and collaboration. We have thus assembled a unique team of experimental biologists eager to contribute to the development of mathematical foundations of their subject, and mathematicians eager to help create the mathematical tools that can shed new insights on these problems. The central biological questions involve scaling from cells to organisms to populations to ecosystems, with attention to robustness, collective phenomena, as well as the structure and dynamics of complex networks. The mathematical tools will be drawn from a wide spectrum, from dynamical systems to algebraic statistics to differential topology, from the deterministic to the stochastic, with full expectation that novel formalisms will be established as the project develops. This project, relying on leaders from mathematics and biology, will initiate a new dialogue unconstrained by past approaches and aim to fundamentally change the landscape of biology.

The Andrew W. Mellon Foundation
The Emergence and Evolution of Ecosystem Functioning PIs: Simon A. Levin, Lars O. Hedin, Stephen W. Pacala Other faculty: Henry S. Horn, François Morel, Ignacio Rodriguez-Iturbe, Daniel Sigman, Bess Ward For decades, the disciplines of population biology and ecosystems science have developed with inadequate contact between them, seemingly addressing distinct problems on different scales. That situation has changed dramatically in the past decade, even as ecosystems science has become more global in scope, and as much of population biology has relied increasingly on molecular techniques. Indeed, the need to deal with phenomena across these distinct levels of organization and complexity has made more obvious, and more urgent, the importance of finding ways to scale, from the small scale to the large, and from the individual to the biosphere. The time is ripe for innovative, integrative approaches to such integration from theoretical as well as empirical perspectives. Princeton certainly is not alone in its attention to these problems, but has unique capabilities to develop novel approaches in understanding and conceptualizing the dynamics of diverse systems. Our group has over the past year and a half developed strong partnerships reaching from autecology and population biology to hydrology and biogeochemical cycling, and involving both theoretical and empirical approaches. We propose to use this foundation to further develop a collaborative training and research program at the interface between population biology and biogeochemical cycling, with central focus on training graduate students and postdoctoral fellows. In this way, we expect to develop a cadre of young scientists well-grounded in both disciplines, and with the interdisciplinary perspectives that are necessary for future intellectual leadership in ecology and biogeochemistry. The general themes of this project will involve an understanding of community and ecosystem structure and functioning, across systems and across scales. We shall particularly be interested in grasslands, temperate and tropical forests, and marine coastal and off-shore systems. In all of this research, the work will be soundly based in empirical work, but also closely linked to the development of theoretical and quantitative models. . In particular, we will build on techniques we have long been developing for modeling spatially distributed populations, and for scaling from microscopic to macroscopic phenomena. Many of these techniques, and many of the empirical patterns that we will address, have been developed under prior Mellon funding.
Dynamics of South Africa Vegetation PIs: Simon A. Levin, Lars O. Hedin, Ignacio Rodriguez-Iturbe, Stephen W. Pacala The vast parks and other natural areas in South Africa provide unique opportunities to explore fundamental ecological questions at the interface between population biology and ecosystems science. Of special interest is the elucidation of the nature of ecosystems as complex adaptive systems in which macroscopic patterns arise as the collective consequences of interactions at much lower levels of organization, and feed back to affect those interactions. This project seeks to establish a partnership between South African ecologists and researchers at Princeton University with expertise in ecosystems science, hydrology, and the modeling of complex systems. The primary mechanism for achieving this partnership will be through the graduate students and other researchers working on the dynamics of South African ecosystems, linking population biology, hydrology, and nutrient cycling.

The Andrew W. Mellon Foundation

The Emergence and Evolution of Ecosystem Functioning
PIs: Simon A. Levin, Lars O. Hedin, Stephen W. Pacala
Other faculty: Henry S. Horn, François Morel, Ignacio Rodriguez-Iturbe, Daniel Sigman, Bess Ward

For decades, the disciplines of population biology and ecosystems science have developed with inadequate contact between them, seemingly addressing distinct problems on different scales. That situation has changed dramatically in the past decade, even as ecosystems science has become more global in scope, and as much of population biology has relied increasingly on molecular techniques. Indeed, the need to deal with phenomena across these distinct levels of organization and complexity has made more obvious, and more urgent, the importance of finding ways to scale, from the small scale to the large, and from the individual to the biosphere.

The time is ripe for innovative, integrative approaches to such integration from theoretical as well as empirical perspectives. Princeton certainly is not alone in its attention to these problems, but has unique capabilities to develop novel approaches in understanding and conceptualizing the dynamics of diverse systems. Our group has over the past year and a half developed strong partnerships reaching from autecology and population biology to hydrology and biogeochemical cycling, and involving both theoretical and empirical approaches. We propose to use this foundation to further develop a collaborative training and research program at the interface between population biology and biogeochemical cycling, with central focus on training graduate students and postdoctoral fellows. In this way, we expect to develop a cadre of young scientists well-grounded in both disciplines, and with the interdisciplinary perspectives that are necessary for future intellectual leadership in ecology and biogeochemistry.

The general themes of this project will involve an understanding of community and ecosystem structure and functioning, across systems and across scales. We shall particularly be interested in grasslands, temperate and tropical forests, and marine coastal and off-shore systems. In all of this research, the work will be soundly based in empirical work, but also closely linked to the development of theoretical and quantitative models. . In particular, we will build on techniques we have long been developing for modeling spatially distributed populations, and for scaling from microscopic to macroscopic phenomena. Many of these techniques, and many of the empirical patterns that we will address, have been developed under prior Mellon funding.

Dynamics of South Africa Vegetation
PIs: Simon A. Levin, Lars O. Hedin, Ignacio Rodriguez-Iturbe, Stephen W. Pacala

The vast parks and other natural areas in South Africa provide unique opportunities to explore fundamental ecological questions at the interface between population biology and ecosystems science. Of special interest is the elucidation of the nature of ecosystems as complex adaptive systems in which macroscopic patterns arise as the collective consequences of interactions at much lower levels of organization, and feed back to affect those interactions. This project seeks to establish a partnership between South African ecologists and researchers at Princeton University with expertise in ecosystems science, hydrology, and the modeling of complex systems. The primary mechanism for achieving this partnership will be through the graduate students and other researchers working on the dynamics of South African ecosystems, linking population biology, hydrology, and nutrient cycling.

The David and Lucile Packard Foundation
Managing for Resilience: Science to Advance Ecosystem-Based Management in the Sea of Cortes PIs: Simon Levin and Heather Leslie The overall goal of this project is to generate and synthesize scientific knowledge in order to contribute to the implementation of marine ecosystem-based management (EBM) efforts in the Sea of Cortes region of Mexico and elsewhere. We have three main objectives: 1) To investigate the coupled dynamics of the social and ecological coastal marine systems of the region; 2) To conduct a regional resilience assessment; and 3) To synthesize the project results in ways that are relevant and useful for policymakers, managers, and other stakeholders. We will achieve these objectives through three activities. First, we will conduct a case study to test the utility of resilience theory and participatory assessment for guiding coastal conservation and development initiatives. Second, we will develop conceptual and quantitative models of the region's coupled social and ecological systems, in order to better understand the connections between the two systems and to forecast the consequences of future changes in coastal and marine ecosystems of the region. Finally, we will synthesize key theoretical and empirical information and provide a practical framework for implementing marine EBM. In addition to publications, outcomes will include workshops for scientists and other stakeholders, a symposium on marine EBM and resilience at an upcoming major scientific meeting, and regular communication with others working on marine EBM initiatives in the region and elsewhere. We anticipate that these activities will advance scientific understanding of the region and contribute to the long-term sustainability of the coupled ecological and human systems of the Sea of Cortes.

The David and Lucile Packard Foundation

Managing for Resilience: Science to Advance Ecosystem-Based Management in the Sea of Cortes
PIs: Simon Levin and Heather Leslie

The overall goal of this project is to generate and synthesize scientific knowledge in order to contribute to the implementation of marine ecosystem-based management (EBM) efforts in the Sea of Cortes region of Mexico and elsewhere. We have three main objectives: 1) To investigate the coupled dynamics of the social and ecological coastal marine systems of the region; 2) To conduct a regional resilience assessment; and 3) To synthesize the project results in ways that are relevant and useful for policymakers, managers, and other stakeholders. We will achieve these objectives through three activities. First, we will conduct a case study to test the utility of resilience theory and participatory assessment for guiding coastal conservation and development initiatives. Second, we will develop conceptual and quantitative models of the region's coupled social and ecological systems, in order to better understand the connections between the two systems and to forecast the consequences of future changes in coastal and marine ecosystems of the region. Finally, we will synthesize key theoretical and empirical information and provide a practical framework for implementing marine EBM. In addition to publications, outcomes will include workshops for scientists and other stakeholders, a symposium on marine EBM and resilience at an upcoming major scientific meeting, and regular communication with others working on marine EBM initiatives in the region and elsewhere. We anticipate that these activities will advance scientific understanding of the region and contribute to the long-term sustainability of the coupled ecological and human systems of the Sea of Cortes.

The National Science Foundation
Collaborative Research: Co-Organization of River Basin Geomorphology and Vegetation PIs: Simon Levin, Ignacio Rodriguez-Iturbe, Rafael Bras Physical and ecological processes of the earth surface are intrinsically coupled. Yet very little is known on how this coupling produces self-organized patterns in landforms, soils and plant communities. Our hypothesis is that: River basins organize through local non-linear interactions (between vegetation, soils and topography) in such a way that identifiable global patterns emerge on the 3-D structure of the river network and on the organization of vegetation. The above hypothesis suggests a vegetation-modulated erosion in response to stochastic climatic forcing that involves a co-organization of the structure of the river network and the vegetation of the basin. Modeling will be used within the context of data from two different grass dominated sites. The co-evolution of landscape morphology and its vegetation patterns will be studied under stochastic climate forcing, and constant and varying tectonic uplift (or base level drop). The major questions to be addressed are: 1) Are there any large-scale signatures of vegetation organization in river basins? 2) Is there any global strategy in the organization of landscape morphology and its vegetation cover? 3) What is the impact of climate or uplift fluctuations on vegetation self-organization and erosion rates on a complex adaptive topography? 4) What is the effect of disturbances such as fire and grazing on the co-organization? Intellectual Merits: Validation of the proposed hypothesis would lead to an improved understanding of the local mechanisms leading to the self-organization of vegetation patterns; the role of landscape topography in mediating the stochastic nature of local interactions; and the degree of coupling between ecological and physical landscape processes constrained over a complex terrain. A model will be developed to adaptively evolve landscape topography, and resulting spatial heterogeneities in soil moisture, and vegetation patterns under stochastic climate forcing. It will provide a framework to assess the sensitivity of the dynamic Eco-Hydro-Geomorphic system to fluctuations and changes in the forcing mechanisms (i.e., climate, tectonic processes), natural and anthropogenic landscape disturbances, and short- and long-term land and water management. Modeling results can be used as a guide to design future field and theoretical work. Broader Impacts: On the educational side, this project will contribute to the formation of "a new generation of scientists with essential cross-disciplinary experience and perspectives" (Newman et al, 2006). The results will have a broader relevance to an expanding body of work in grasslands and other water limited regions of the US and the world. It will also provide added scientific and operational value to the ongoing ecosystem monitoring efforts in grasslands in the United States. In addition, the potential payoff of this type of research "includes broad social and economic benefits, addressing serious issues related to water supply and quality as well as ecosystem health and diversity in water-limited environments" (Newman et al, 2006). This is a highly interdisciplinary project that will combine research results from different branches of earth sciences (i.e., ecology, geomorphology, hydrology) under the umbrella of a physically-based numerical framework.

The National Science Foundation

Collaborative Research: Co-Organization of River Basin Geomorphology and Vegetation
PIs: Simon Levin, Ignacio Rodriguez-Iturbe, Rafael Bras

Physical and ecological processes of the earth surface are intrinsically coupled. Yet very little is known on how this coupling produces self-organized patterns in landforms, soils and plant communities. Our hypothesis is that:

River basins organize through local non-linear interactions (between vegetation, soils and topography) in such a way that identifiable global patterns emerge on the 3-D structure of the river network and on the organization of vegetation.

The above hypothesis suggests a vegetation-modulated erosion in response to stochastic climatic forcing that involves a co-organization of the structure of the river network and the vegetation of the basin. Modeling will be used within the context of data from two different grass dominated sites. The co-evolution of landscape morphology and its vegetation patterns will be studied under stochastic climate forcing, and constant and varying tectonic uplift (or base level drop). The major questions to be addressed are: 1) Are there any large-scale signatures of vegetation organization in river basins? 2) Is there any global strategy in the organization of landscape morphology and its vegetation cover? 3) What is the impact of climate or uplift fluctuations on vegetation self-organization and erosion rates on a complex adaptive topography? 4) What is the effect of disturbances such as fire and grazing on the co-organization?

Intellectual Merits: Validation of the proposed hypothesis would lead to an improved understanding of the local mechanisms leading to the self-organization of vegetation patterns; the role of landscape topography in mediating the stochastic nature of local interactions; and the degree of coupling between ecological and physical landscape processes constrained over a complex terrain. A model will be developed to adaptively evolve landscape topography, and resulting spatial heterogeneities in soil moisture, and vegetation patterns under stochastic climate forcing. It will provide a framework to assess the sensitivity of the dynamic Eco-Hydro-Geomorphic system to fluctuations and changes in the forcing mechanisms (i.e., climate, tectonic processes), natural and anthropogenic landscape disturbances, and short- and long-term land and water management. Modeling results can be used as a guide to design future field and theoretical work.

Broader Impacts: On the educational side, this project will contribute to the formation of "a new generation of scientists with essential cross-disciplinary experience and perspectives" (Newman et al, 2006).

The results will have a broader relevance to an expanding body of work in grasslands and other water limited regions of the US and the world. It will also provide added scientific and operational value to the ongoing ecosystem monitoring efforts in grasslands in the United States. In addition, the potential payoff of this type of research "includes broad social and economic benefits, addressing serious issues related to water supply and quality as well as ecosystem health and diversity in water-limited environments" (Newman et al, 2006).

This is a highly interdisciplinary project that will combine research results from different branches of earth sciences (i.e., ecology, geomorphology, hydrology) under the umbrella of a physically-based numerical framework.

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