1. General Model Information

Name: Savanna - Landscape and Regional Ecosystem Model

Acronym: SAVANNA

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Abstract:

Savanna is a spatially explicit, process-oriented model of grassland, shrubland, savanna and forested ecosystems. The Savanna model simulates processes at landscape through regional spatial scales over annual to decadal time scales. The model is composed of hydrologic, plant biomass production, plant population dynamics, ungulate herbivory, ungulate spatial distribution, ungulate energy balance, ungulate population dynamics and wolf predation submodels . Since Savanna is process-oriented rather than empirical or rule-based, it aims toward realistic, general and explanatory representations of ecological change as opposed to descriptions of ecological states or prescribed responses.

Every simulation model has a certain level of tradeoff between mechanistic detail and model simplicity. While highly aggregated or simplified models are easier to use, they are less realistic, less generalizable, and less explanatory. On the other hand, highly mechanistic models are more difficult to implement and the marginal costs of added complexity are high. Highly resolved models are more computationally demanding, which may prohibit their implementation at large spatial or long temporal scales. Therefore, Savanna treats ecological processes at an intermediate level of resolution. The time step of the Savanna model is a week, which allows simulations over longer time scales and larger spatial scales. This time step allows Savanna to simulate landscapes composed of 100-1000 grid cells over 5-50 year time spans in a reasonable amount of time on the current generation of microprocessors.
Source: Coughenour M.B. (1994). Savanna - Landscape and Regional Ecosystem Model (Model Description)
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Overall structure of Savanna, a spatially explicit, dynamic ecosystem model that was originally developed for studies of African pastoralism. It has also been applied to western U.S. and Canadian national parks as an ecosystem management model. Ungulates and their interactions with plants are a principal concern. Savanna is unique in representing linkages between plant production and population processes as well as between ungulate energy balance and their population processes. Primary production is tied directly to the soil water budget. The model uses geographic information systems for both data input and output.

II. Technical Information

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II.2 Source-code:

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III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References