SIMPPLLE: Simulating Patterns and Processes at Landscape Scales

The long term goal is to have the development of a new geographic area accomplished entirely through the systems graphical user interface once "legal values" have been established for the new geographic area (all the landscape component descriptors, the disturbance processes, and the ecological stratification). At this time the involvement of SIMPPLLE's developers is still required. There is the possibility that we may find some feature of ecosystem behavior that will require additional code development or modification of the user interface screens to make sure we can capture all of the interacting landscape components and provide acceptable model behavior.

Development is encouraged to be approached in a "spiral content". We do not have to go through the steps building the most "complete" model for the target ecosystem. Development of an initial, minimal ecosystem representation provides a prototype for testing how well ecosystem behavior has been captured in order to address management issues. Additional "spirals" can be made through the steps increasing the complexity of the system where desired.

To develop, test, and document a new geographic area for SIMPPLLE, successfully capturing the vegetation dynamics with some representation of land and aquatic units as modifiers of vegetation processes can be expected to encompass six months, especially if model developers continue working on other projects. The process could require less time depending on how aggressive an approach is made.

1. Decision on extent of a geographic area.
The geographic extent over which the system knowledge will be consistent, with the understanding that users can make modifications to the system knowledge through the interface in order to "fine tune" the model behavior to a specific area.

2. Decision of the descriptors for the vegetation.
The choice is a combination of what is available from common inventories, what level of descriptors is needed to predict probability of disturbance processes, and what level is needed to make interpretations for management objectives or ecological functioning. Three lifeforms are used for the vegetation - trees, shrubs, grasses. Each lifeform is described by a dominant species, size-class / structure, and density measure.

3. Identify what disturbance processes affecting vegetation need to be included.
The model includes processes for which the system generates a probability for each stand, for each time step. This is usually insects, disease, wildlife grazing, and wildfire. However other processes such as windthrow and drought that may not have a probability determined can be "locked in" to explore different scenarios.

4. Identify what ecological stratification needs to be used.
As we build the system knowledge how does it vary by this stratification? This can be linked to soil surveys, or some combination of soils, elevation, aspect, etc.

5. Identify specific management treatments / land uses need to be included.

6. Decide the extent to which "regional climate changes" should influence process probability and the change as result of disturbance process.

7. Build "succession" pathways.
Successional pathways or the progression of vegetation through size class, structure, and density for each dominant species in the absence of significant disturbance are organized by the ecological stratifications. Any combination of permanent growth plot data, stand level growth models, and expert opinion can be used to provide the logic.

8. Add the "next state" as a result of each applicable disturbance process to the successional pathways.

9. Develop logic for the probability of each disturbance processes occurring.
This can be developed from any combination of established research or expert opinion.

10. Develop "type of fire" and "fire spread logic".
This can be developed from results of fine scale models on sample stands and / or expert opinion.

11. Develop regeneration logic for each species.

12. Decide the extent "land units", "aquatic units", and "man-made units" should be represented in SIMPPLLE and how to describe them.
Although these landscape components may not be dynamic as the vegetation component, they often influence vegetation disturbance processes probabilities and their impact on the vegetation.

13. Decide on specific "reports" and "interpretations" that can be produced "automatically" by SIMPPLLE.
If reports or interpretations are not done within SIMPPLLE, users can derive them through processing future vegetation and disturbance maps in a gis environment or SIMPPLLE output data summarized in customized Excel spreadsheets.

14. Obtain the initial spatial data sets for a test landscape.
If GIS software other than ERSI is used it will be necessary to develop alternative interfaces to provide the spatial relationships needed in SIMPPLLE as well capabilities to map system output.

15. Test the system on the sample landscape. Test against past disturbance events.

16. On site visit with local ecologists to make model simulations and any adjustments in logic to achieve acceptable model behavior.

17. On site training with users focused on creating data sets, making simulations, managing output, processing output with GIS extensions and excel spreadsheets macros, and applying changes to system knowledge through the graphical user interface.

18. Complete documentation of the unique values and system knowledge for the geographic area.

SIMPPLLE: Simulating Patterns and Processes ad Landscape Scales. For more information, please contact us.