2014-2015 Scholars' Research:

  • Barry Chernoff, Director, College of the Environment, Professor of Biology and Earth & Environmental Sciences
  • Fred Cohan, Professor of Biology
  • Joseph Smolinski, Menakka and Essel Bailey '66 Distinguished Visiting Scholar in the College of the Environment
  • Jennifer Tucker, Associate Professor of History and Science in Society and Feminist, Gender and Sexuality Studies

Barry Chernoff

Swimming Upstream: Fragility and Resilience of Freshwater Fishes in Human Dominated Aquascapes

Brief Description: To further develop the theoretical and conceptual bases of the terms fragility and resilience as they apply to system structures (e.g., ecological communities, metapopulations). To then examine the fragility and resilience of metapopulations and communities of freshwater fishes to environmental perturbations. This reserarch will have critical consequences for important conservation issues that deal with "recovery" and "restoration".

Description: The Anthropocene has had huge ipacts on freshwater ecosystems and their biota. Depletion of surficial freshwater resources, contamination, severe hydrological modifications to river basis are among the revalent environmental changes affecting aquatic biota. For example, in the United States alone there are more than 2,000,000 dams - their growth and installation has been exponential through time (Poff and Hart, 2002). Furthermore, the dependence of humans on freshwater fishes worldwide for food, recreation and culture has grown with increasing human populations while freshwater fish stocks have declined globally. Sadly, while technological advances in commercial and artisanal fisheries has increased catch in many cases (e.g., Nile Perch i Lake Victoria of Tanzania and Uganda), fish stocks have declined along with the well-being of fisher commuities. Lastly, the effets of global warming and rising sea levels have the potential to change the dynamical relationships between fishes and their ecosystems.

Fragility and resilience are two terms used to describe the results of dynamical relationships in shystems analysis. Resilience is particularly important and has been receiving much recent attention based upon the pioneering works of Holling (1973, 1978). Resilience has two separate meanings that are important to distinguish The first is the engineering concept that only concerns the time with which a system returns to its previous state following perturbation (Holling, 1973). A better perspective is provided by ecological resilience in which a system can exist in multiple states or conditions. Resilience then measures the dynamical resp9onse of a system to perturbation both in terms of the time that a system may return and the distance from the initial condition that a system may be perturbed prior to its reconfiguration (Holling, 1973; Gunderson, 2010). If a perturbation is greater than the ability of the ecosystem to return to its previous condition then the ecosystem migrates towards another potentially stable state. This is very analogous to the peaks and valleys of genetic landscapes.

Gunderso and colleagues have demonstrated that the concept of ecological resilience brings together the descriptions of the resp9onses of both ecological and human communities to perturbations (Gunderson, 2010; Garmestani et al, 2009; Gunderson et al., 2006; Allen et al., 2005). A clear example of eological resilience is that of the shift from coral dominated ecosystems to algal dominated ecosystems following disturbances such as hurricanes, nutrient overloads or elimination of key grazing species (Hughes et al., 2003). Resilience as applied to human communities has often been referred to as community resilience or urban resilience. For example, Vale and Campanella (2006) use a very simple definition based upon engineering resilience that focuses upon "the capacity of a city to rebound from destruciton". Whereas, others (e.g., Wallace and Wallace, 2008) conceive of a landscape of structures, processes and identities through which a human community may organize itself in response to perturbations.

"Fragility" has often been a poorly defined or undefined term in the literature. Fragility is an expectation that a system will not be able to retain its essence or key structures, processes, etc., in the face of a perturbation of some magnitude of intensity or duration. That is, "fragility" is a statment relative to a tipping point beyond which it will evolve rather than reform. Notice that "fragility" is a statement made in relation to the previous state of the system. For example, if the current load of nutrients continue to run off Florida's southern coastline then coral-based communities will disappear in many areas. An implication of such statements is that previous conditions or structures of a system are prefereable to alternatives - in the case of the coral reefs the preference is over algal-dominated communities. As such, "fragility" is a statement of belief, of experience, or even of bias.

Fragility should be a measure of the vulnerability of the stability of the current conditions of a system to perturbations. In this way, fragility differs from resilience in that fragility is about the balance of forces that pull/push a system into different structural domains Resilience concerns the internal components of a system that provide buffers to change (e.g., ecological redundancy; Tilman et al., 2001) and the dynamical forces that return a system towards previous conditions. Fragility is a continuous measure (from zero to absolute) of forces or interacitons that drive a system away from its current domain.

Knowledge of resilience and fragility are key to conservation ecology and to the formation of adaptive management strategies. Notions such as "recovery" or "restoration" require that we first understand the capacity of a system to absorb perturbations or to evolve to a desired state should "restorative" measures be undertaken (e.g., the removal of a dam). Unfortunately, many restoration plans (e.g., the removal of the Zemko dam) do not take into account the dynamic natures of the systems that are to be restored.

I plan to examine carefully the theories of resilience and fragility and focus upon the effects of drivers of the systems for stability and change. To do this I propose to use network analyses superimposed upon system-landscape surfaces (i.e., surfaces with different sized stability domains, akin to genetic fitness landscapes). However, rather than simple approaching the dynamical movements of systems to monotonic or regular functions, I want to analyze the theory in curvilinear fashion and even use chaos theory to explain configurational evolution of ecological communities to predictable and unpredictable perturbations. I will apply this theoretical reworking to community and environmental data sets for freshwater fishes. I wil also exam the role of systems dynamics to the formation of adaptive management plans and restoration ecology of freshwater fish populations. This work will not only result in the scholarly works listed below but will also contribute to my book on conservation of freshwater fishes and their ecosystems.

Outputs: Articles for peer-reviewed journals

1. The theoretical re-working of fragility and resilience
2. How do freshwater fish populations respond to environmental perturbations
3. "Recovery" and "Restoration" of ecosystems and communities; an aquatics perspective

Literature Cited

Allen, C.R., L. Gunderson, and A. Johnson. 2005. The use of discontinuities and functional groups to assess relative resilience in complex systems. Ecosystems 8(8):958-966.

Garmestani, A. S., C. R. Allen and L. Gunderson. 2009. Panarchy: Discontinuities Reveal Similarities in the Dynamic System Structure of Ecological and Social Systems. Ecology and Society 14(1): 12pp.

Gunderson, L. 2010. Ecological and human community resilience response to natural disasters. Ecology and Society 15(2): 11pp.

Gunderson, L. H., S. R. Carpenter, C. Folke, P. Olsson, and G. D. Peterson. 2006. Water RATs (resilience, adaptability, and transformability) in lake and wetland social-ecological systems. Ecology and Society 11(1): 16pp.

Holling, C. S. 1973. Resilience and stability of ecological systems. Annual review of Ecology and Systematics 4:1-24.

Holling, C. S. 1978. Adaptive environmental assessment and management. J. Wiley and Sons, London, UK.

Hughes, T. P., A. H. Baird, D. R. Bellwood, M. Card, S. R. Connolly, C. Folke, R. Grosberg, O. Hoegh-Guldberg, J. B. C. Jackson, J. Kleypas, J. M. Lough, P. Marshall, M. Nystrom, S. R. Palumbi, J. M Pandolfi, B. Rosen, and J. Roughgarden. 2003. Climate change, human impacts, and the resilience of coral reefs. Science 301:929-933.

Tilman, D. P., B. Reich, J.Knops, D. Wedin, T.Mielke, and C. Lehman. 2001. Diversity and productivity in a long-term grassland experiment. Science 294(5543):843-845.

Vale, L. J., and T. Campanella 2005. The resilient city: how modern cities recover from disaster. Oxford University Press, New York, New York, USA.

Wallace, D., and R. Wallace. 2008. Urban systems during disasters: factors for resilience. Ecology and Society 13(1): 18pp.

Fred Cohan

In the COE Think Tank he is exploring the kinds of human-caused environmental changes that are most likely to lead to changes in the geography of infectious disease. He is writing a magazine article and a book on Global Change and Infectious Disease, which he hopes will make his popular course on this subject (Biol 173/Envs 260) accessible to a much larger audience. He is investigating the kinds of environmental changes that organisms can most and least easily adapt to, focusing on bacteria. He is exploring the kinds of adaptations to human-caused environmental change that can be effectively acquired in bacteria by horizontal genetic transfer. He is exploring the likely consequences to communities and ecosystems if certain microbial players should disappear, characterizing possible keystone effects of individual bacterial species. He is writing a couple of invited articles on concepts of bacterial species. He is writing with his research students and collaborators a couple of articles on the ecological dimensions of speciation in Bacillus and Synechococcus. He is contributing a bi-weekly blog on microbial ecology for the Facebook page of Death Valley National Park.

Jennifer Tucker

Our Think Tank for 2014-15 asks: What is the current "big picture" or fragility, extinction, and resilience? My tack on this question takes that question literally: Where, and with what results, do pictures and picturing practices fit into recent scientific investigation of processes such as extinction, adaptation? Are the challenges of communicating about the processes related to extinction (the fragility of environments, and their adaptation and resilience) also problems of art and visual representation? How have ideas about mass extinction, fragility and adaptation been worked through and conveyed over time as different visual modes (photography, drawings, documentary films, art, new media) have arisen, and as climate science and its publics have taken different forms?

My research project is addressed to these types of conversations in my own field of history of science, as well as in emergent fields of visual studies. During my residency in the COE, I will complete research and writing for the first draft of a scholarly monograph about scientific observation and measurement in the nineteenth-century British and American visual imagination. Provisionally titled, "Science and Measurement in the Victorian Visual Imagination," this will be a book about the relations of art, science and technology during the long reign of Queen Victoria, from the last 1830s to 1903. The past two decades has seen the rise of scholarly and popular interest in what geologist and historian Martin Rudwick in the 1980s influentially called the "visual language of science." This research turns the focus in the other direction, exploring the representation of scientific method as a subject in Victorian art, society and culture. Organized around Victorian public controversies, including climatological concerns and the debate over the origins of life and the depths of the oceans, it will provide the first in-depth look at the myriad pictorial representations of scientific observation in action (in scientific lectures, botanic gardens, and museums) that circulated and helped to define the nineteenth century public image and vision of science.

In addition to this book project, other planned projects include an essay, possible with a student, on the geologist and aerial photographer, John Shelton, author of the prize-winning book, Geology Illustrated, whose pioneering aerial photographs of the California landscape are still used to measure historical changes to the western landscape, and whose original lantern slides were recently deposited in Olin's Special Collections and Archives by his family.

Sum: I plan to have a draft of my third monograph ready to submit for peer review by July 2015, and two peer-reviewed articles published or under review by the same date. I also would like to investigate writing a collaborative opinion piece with the other Fellows.