Defining Wetland Resilience

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This forum supports discussion on topics of interest to the Environmental and Energy Special interest Groups of the System Dynamics Society. Everyone who is logged in may post to this forum.
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Sue Roussie
Posts: 2
Joined: Sun Feb 22, 2009 3:55 pm

Defining Wetland Resilience

Post by Sue Roussie » Mon Feb 23, 2009 8:59 am

I am new to system dynamics but with the help of books and journal articles I have created a causal loop diagram trying to explain wetland resiliency in the aftermath of hurricane storm surge. This is supposed to be my dissertation but I am running into a couple of issues. First some background. I am in the geography department with a concentration in Geographic Information Systems. My dissertation in understanding the dynamics of wetlands as buffers during storm surge from hurricanes so policy managers can manage the restoration and protection of wetlands. I thought SD would be perfect for this. Unfortunately there is concern that there is no spatial aspect to this and how exactly does this fit in with geography and so forth as well as does this contribute to new research. I have researched literature and what I did not find any reference to what I have developed so I know that part is ok. My research is supposed to contribute to an overall community resilience index in the recovery after a hurricane. I figure if I could somehow come up with a numerical index of wetland resilience everyone would be happy. I am just not sure how to do this. If anyone would like to see the causal diagram I developed I can send that. Sometimes it is difficult to explain what I am doing in words.

Thanks in advance.

Richard Dudley
Posts: 65
Joined: Sun Jan 11, 2009 1:17 pm
Location: Etna, New York, USA

Re: Defining Wetland Resilience

Post by Richard Dudley » Mon Feb 23, 2009 8:10 pm


I would be happy to look at your model, diagrams etc. Although I have worked with both wetlands and with SD modeling I haven't tried both at the same time. :) I have not worked with spatial modeling but there is a significant number of people who have combined SD and spatial modeling most notably, I believe at U of Illinois (e.g Bruce Hannon, and with the Spatial Modeling Environment ( . But I am sure you are more aware of these links and possibilities than I am. But the examples I am thinking of (with very limited experience) are those where SD models underlie the spatial changes modeled. That is, these are primarily spatial models.

It is not clear from your statement whether you are hoping to work without spatial modeling, which I think is certainly possible, or whether you think that you would like to, or will need to, incorporate spatial modeling as well. On the surface of it, especially if you are in a GIS department, I can see that there will be a lot of pressure to incorporate the spatial component! On the other hand there are policy issues that are probably not spatial at all. Are you planning to model primarily the physical systems or are you also planning to incorporate the policy system, the way decisions are made and the consequences of those decisions?

Hopefully some others will add their, more focused(?), comments.

Added later: It is my own 'feeling' that there is much to be said for generic models of a particular problem. But spatial models tend to be very place based, very specific to a location. They could be generic, of course, and actually even if place specific, could be used as an example for other similar situations.

Michael Schwandt
Posts: 2
Joined: Mon Jan 12, 2009 8:38 am
Location: Pennsylvania, USA

Re: Defining Wetland Resilience

Post by Michael Schwandt » Tue Feb 24, 2009 8:28 am

If you have not already done so, you can refer to the System Dynamics bibliography to track down other SD-focused publications that address GIS-related issues. That should also help to identify some leading SD researchers applying spatial factors.

In addition to the groups that Richard Dudley mentioned, I think that Andy Ford moderated a discussion at the 2005 ISDC that featured papers applying spatial modeling considerations. I found that session to be very helpful to my thoughts.

Travis Franck
Posts: 34
Joined: Sun Jan 11, 2009 7:48 pm

Re: Defining Wetland Resilience

Post by Travis Franck » Wed Feb 25, 2009 10:09 am

SD is can be pretty useful for understanding wetlands and ecosystems dynamics. There has been one recent paper in SDR about ecosystem succession that utilized GIS:

The spatial dynamics of invasive species spread
Todd K. BenDor, Sara S. Metcalf
< ... 1&SRETRY=0>

I have an simple wetland succession model in my dissertation, but I don't have any spatial resolution. The model will be documented and online in a few months.

Also, Stratus Consulting did a study of wetland succession (for EPA?) in New Jersey. They used GIS. I was in their parallel session at a recent conference. Russ Jones presented and their slides are here:
< ... nelT2A.pdf>


Sue Roussie
Posts: 2
Joined: Sun Feb 22, 2009 3:55 pm

Re: Defining Wetland Resilience

Post by Sue Roussie » Wed Feb 25, 2009 2:23 pm

Thanks for all the information. I will be looking into those and I am already in contact with two of the authors mentioned, one is actually on my committee. My model is in the process of being reformulated so I will send that out shortly. Yes, lots of pressure for the spatial aspect.

Leonard Malczynski
Posts: 96
Joined: Fri Jan 16, 2009 11:12 am
Location: Albuquerque, NM USA

Re: Defining Wetland Resilience

Post by Leonard Malczynski » Thu Apr 02, 2009 2:36 pm

Spatial modeling techniques are presented in one of the appendicies to Andy Ford's 'Modeling the Environment'.

If you feel comfortable with arrays and matrix manipulations you can do the same sort of spatial modeling without taking the SME approach or duplicating stocks and flows. The array sizes match the number of spatially disaggregated areas and simple(?) matricies handle the interaction effects.

Since GIS map data is expressed as points, lines, and polygons with attributes, much of the GIS calculation can also be embedded into SD models as attributes or, if necessary, DLLs or other code to do the GIS analysis.

Please let me know if you need more or examples.

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