Friday, October 19, 2007

Week 10: Complex human ecological systems & their dynamics


Read the following, ideally in this order:

* (Recommended) Costanza et al. 1995. Modeling complex ecological economic systems. Bioscience 43: 545-549 (stop at “Fractals and chaos”)

*Holling, C.S. 2001. Understanding the Complexity of Economic, Ecological, and Social Systems. Ecosystems 4: 390-405.

*Lansing & Kremer. 1993. Emergent properties of Balinese water temple networks.

* Arquitt et al. 2005. A systems dynamics analysis of boom & bust in the shrimp aquaculture industry


Kruse, J. et al 2004, Liu et al. 2007, and Chapin. 2006. are optional but have some good points, definitions, and figures.

NOTE: You DO NOT need to summarize or comment on Costanza. ALSO, since Kruse was up as "required" for a day and Arquitt was not, you can summarize either for credit. Arquitt will be more useful to you, though.

FINALLY, you can take till Friday at 10am to e-mail us your proposals, and feel free to write compact annotations/comments this week. Just show us your understanding of the ideas and how they interact and any questions or ideas they raise.

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Unit II_ A Systems Perspective in Human Ecology: Complexity, Dynamics, Scaling, and Social Metabolism

This week we start our unit on a systems perspective on human ecology, pioneered by ecologists H.T. Odum and C.S. Holling, among others. A concept diagram for how the unit topics relate to those from this week is:

Systems thinking --> systems theory/science --> complex systems --> complex human ecological systems --> understanding how complex human eco-systems change over time (dynamics)

… modelers of systems usually look for boundaries that minimize the interaction between the system under
study and the rest of the universe in order to make their job easier. The interactions between ecological and economic systems are many and strong. So, splitting the world into separate economic and ecological systems is a poor choice of boundary.
Costanza et al. 1993

Holling, 2001, advocates a particular view of human eco-systems and their dynamics. How does the idea of adaptive cycles differentiate a hierarchy from Holling’s notion of a panarchy? What are examples in human ecological systems? What do you think of this framework for understanding and modeling complex human eco-systems?

…a spontaneous process of self-organization occurred when we allowed water temples to react to changing environmental conditions over time in a simulation model. Lansing & Kremer, 1993

Steve Lansing, an anthropologist at U. Arizona, has worked extensively in Bali on the intricate ecological relationships between people and landscape, focusing on traditional agricultural and water-management systems. Lansing & Kremer, 1993, is a classic case study of a human-environment complex adaptive system. What are some “emergent properties” of the Balinese water temple networks? What’s an appropriate null hypotheses for their question? What role do feedbacks play in their understanding of the water-temple network?

Arquitt et al, 2005, showcases the “systems dynamics” approach. They are interested in modeling the boom and bust pattern of the Thai shrimp fishing industry as a system. In so doing, they aim to identify appropriate points and mechanisms for intervention to promote greater sustainability. Think about pros and cons of this approach. Think also about the similarities and differences between Arqitt’s approach and that of Lansing & Kremer.

Note the central role of adaptation in all three papers and approaches. Adaptation plays a central role in behavioral ecology, the study of behavioral interactions between organisms and their environment. In systems ecology, the system is the equivalent of an organism, and its “behavior” includes how it and its “outputs” change over time.

As we go move through this unit, think about how the idea of a system, as defined in the glossary, relates to a broad definition of metabolism—the acquisition, transformation, and allocation of energy, matter, or information. How can a metabolic perspective inform and enhance a systems perspective? Can we fruitfully extend this idea from organismal biology to human ecology?

Happy musings,

Bill


Glossary:

chaotic – behavior of a system over time whose trajectory is very dependent on initial conditions and that exhibits nonlinearity. Lansing & Kremer, p. 110, give a nice if abstract verbal description of the difference between chaotic and complex behavior of a system.

complex system – a energetically “open” system of parts, often organized hierarchically, that interact via complex feedback loops to produce nonlinear behavior and often emergent patterns. Examples include ecosystems, economies, and the human immune system.

complex adaptive system – a complex system containing adaptive agents, networked so that the environment of each adaptive agent includes others in the system. (Holland & Miller, 1991)

emergent properties / emergence – properties of a system that are unpredictable from just understanding properties and isolated behaviors of its components. For example, simply studying the behavior of individual ants would not enable you to predict the behavior of a large colony; the complex colonial behavior emerges from the collective, relatively simple behaviors of the individual ants that comprise it.

feedback – in a system, the effect of an output on an input. Positive feedback amplifies the output, while negative feedback dampens it. A classic example is the effect of temperature on a thermostat.

model – (n) a representation of a system; models can be verbal, graphical, or mathematical

nonlinear – behavior, as of a system, that is not a simple sum of the behavior of its elements

resilience – in ecology, the ability of a system to remain unchanged or well-functioning when under some type of pressure

robustness – ability to maintain function or effectiveness under different conditions or limitations. For example, a model is considered robust if you can change assumptions and the model still captures what you intended. Robustness usually refers to a system's function, while resilience refers to the system's structure.

stock and flow diagram – in systems dynamics, a flowchart diagram that highlights relationships between entities that accumulate or deplete over time, called stocks, and their rates of change, called flows

system – a group of “interacting, interdependent parts linked together by exchanges of energy, matter, and information.” Costanza et al. 1993

system dynamics – a) changes over time in a system, b) a field that explores how complex systems change over time

systems thinking – a nonreductionist approach to understanding and studying systems that considers the parts, their connections, and their interactions wholistically. Lansing & Kremer and Arquitt et al. are both examples of a systems approach to human ecology.

threshold – the “tipping point” between one state of a system and another. Landmasses on the sides of a geologic fault, for example, change relative positions when the pressure on them exceeds some threshold.

23 comments:

Milton said...

Have you had a chance to look at Thomas Homer-Dixon's new book - The Up Side of Down (available both in a US and a Canadian version). He's a Canadian who has invested time examining social ingenuity and, in this latest book, how the energy patterns of civilizations function as a key driver. He's giving a talk that I'll attend tonight in Calgary but I've used him for a course I taught last year on World Civilizations and it seems to overlap well with where you're course is at. Buzz Holling is also a Canadian. You can see my own ingenuity project at: www.ingenuityarts.com It would be great to be in your course but the communte between Calgary and New Mexico is significant. Are you associated at all with the Sante Fe Institute? I saw it on your links page.

Steven M. said...

Constanza describes System analysis as:

systems analysis is the scientific method applied across many disciplines, scales, resolutions, and system types in an integrative manner.

That seems very close to the description of biogeography that we have been using. Especially the part about applying methods across various disciplines.

Obviously the papers this week show that biogeogaphiers use system analysis in their work.

What other feilds of biology could these techniques be useful in? Maybe in genetics?

dodegard said...
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dodegard said...

How do complex systems handle chance?

Wenyun said...

For Holling's paper, in the adaptive cycle, the author mentioned that the flexibility and high potental cannot exist together in a stable system (eg. K). Is that always true?

Wenyun said...

What can give the great resilience?

Fred Whiteman said...

In regards to Holling 2001:
What is going on here? I understand the concepts he's discussing, but not how they relate to the situations he's discussing. Has this model been tested? What are its applications? What the heck is the point? The author discusses situations that are similar to what he discusses, but this is anecdotal evidence. He discusses applications for human systems, but provides no test of whether his model actually explains observed situations. And how does any of this relate to sustainable development?

tlvandeest said...

Holling states that the panarchical system is stable except in cases of extremely large events which would collapse the whole system through cascading destruction. But that implies that there is ultimate highest level that can be destroyed due to lack of remembering from a higher level. Or can a large event destroy a system from an intermediate level, with destruction both up to slower moving levels and down to the faster ones. If there is an ultimate level, as implied by the ability of humans to create more levels with time and increase potential, then how is the ulitmate level defined and who makes that decision? Also, does the event need to be on the scale of species destruction of 65 million years ago to cause the collapse of a panarchical system?

helen elizabeth said...

In regards to Lansing (1993), it appears that the bulk of their argument is predicated on the distinction between 'mindless selective processes' and human agency. Who determines where one stops and the other starts? Isn't the mind itself is a product of natural selective processes? To these authors it appears that agency occurs when maladaptive behavior begins. Who defined these parameters?

helen elizabeth said...

Is Arquitt referring to environmental mitigation in this paper?

paul said...

I agree with Helen's difficulty with Lansing's treatment of human agency vs. blind processes.

I disagree, also, that “macroscopic effects on the topography of the adaptive landscape… are not apparent from within the horizons of evolutionary ecology”; any game theoretic model makes the payoffs to a particular strategy dependent on what everybody else does. In fact, this seems like a particularly large, detailed coordination game, into which they put agents with simple learning rules, and saw what happened. True, most evolutionary ecologists wouldn’t look at the exact questions they looked at, but I don’t find it a whole world away.

I like what they did though.

paul said...

The fact that Lansing could parameterize his ABM (agent-based model) with the specific landscape of the Balinese valleys is great. I find it difficult to formulate or trust ABMs that are more general, context-less; you've got such a huge parameter space to explore, so many different things than can vary based on the situation, that it's hard to draw out the helpful conclusions.

Seems like you could gain leverage on more general problems by thinking of a very specific scenario in which the behavior evolves, seeing what happens there, then making the situation more generic in increments.

There are some things they seem to assume without investigating whether the particular assumption is important. For example, what happens to the patterns when farmers look around at 6 neighbors, or 10 neighbors, instead of 4? Could the size of coordinating clusters fall out of this, rather than the fact that they maximize yields? What happens when they also have access to memory of past periods' behavior and payoffs, not just what happened this year?

dtinucci said...

In reference to the Balinese irrigation system - how long have archaeologists determined this system to have been in operation?

As far as shrimp aquaculture, shouldnt we be concerned with future development in this industry? It seems that the lessons learned in Thailand should be applied for sustainablity and safe management of the ecosystem in parts of the globe on the verge of making the same commitments.

Steven M. said...
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Michael said...

Holling states that periods of success carry with them the seeds of subsequent downfall because of the accumulated stresses and rigidities. He later states foresight, communication, and technology help to increase the robusticity of the panarchy by introducing healthy variability. This seems a tad contradictory; given the foresight, communications, and technology, shouldn’t human systems be apt at detecting these “seedling” changes, or be able to agree upon a course of action once they are detected, especially in the face of total collapse?

Anonymous said...

In response to Michael, in the face of total collapse is too late a stage to detect what will happen, because according to Hollings cycle it is already in the process of reorganizing so although factors may change the way in which it "collapses" the cycle has to take its course. Now, although this may sound very fatalistic (uh hum, David), it is not in the sense that foresight and consciousness that humans possess can affect the velocity at which certain stages in the hierarchy play out. I am NOT saying, and neither do I think Holling is saying, that a destiny is determined. Rather than change is inevitable, and that certain systems consistently go through various elements of change.
~Myra~

Anonymous said...

Edit: Rather THAT change is inevitable....
~Myra~

Dan said...

Kruse (my middle name!) et al state that there will always be uncertainties when modeling complex systems. You never truely can control for all the variables and future events add even greater unreliability to these models. Would it be beneficial to test the quality of their complex adaptive system model of artic community sustainability by using the various variables of interest and applying them to past environmental conditions and seen how close to the actual conditions the model predicts? sort of like how Lansing and Kremer modeled a condition in the past and predicted how it actually turned out.

tlvandeest said...

IN the Arquitt et al article, the model they create predicts a solution for the sustainability of the shrimp aquacultures and the enforcement of current government regulations. Has their model been implemented? Are other models predicting similar outcomes used in policy making and enforcement, as well as in other issues?

Paul-
I agree with your statement about the model created by Lansing and Kremer. It definitely lends support to their argument that their model took into account the specifics about the situation in Bali, making it more realistic in its predictions.

dodegard said...

Holling sees humans as having abilities that natural systems do not. Is he implying humans are above the natural complex system, is it that we just have more of a responsibility to not mess with the system, or something else entirely?

Fred Whiteman said...

We've seen several examples of modeling of complex systems demonstrating methods for sustainability. Is it possible to produce a more general model to help us improve the sustainability of humanity as a species?

Aaron McCarty said...

Natural selection, though free of intentionality, is not so "blind" as Lansing and Kremer seem to assume. The natural world is a self-organizing system. Natural selection doesn't have to "try everything" at random; it is subject to the results of past changes (e.g. developmental constraints). Still, I concede the greater point--artificial selection by human agency can drive uni-directional change more efficiently than can natural selection. The authors' talk of "average fitness" sounds like group selectionism...What would keep some individuals from cheating the system to obtain extra benefit for themselves? Honest signaling through religious rituals?

Senorita Myra said...

The thing I got from Lansing and Kremer is that communication is the adaptation that allowed for humans to create a consistent cycle of optimum rice output. I think that their discussion about blind evolution vs. conscious evolution that humans can direct is a all a bunch of hooey. They seem to isolate human activity from the environment as if humans are in total control of the outcomes their implemented ideas may result in. Not just that, humans copy nature. By just understanding how to be consistent with a natural process, such increasing pH of soil, does it make them conscious of their evolution if they are unaware of how little modifications can affect their neighbors optimal output? This is little more than a case of good communication and/or a good community structure that allows individuals to share information about successful irrigation tips.

 
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