EM Variables by Variable Role

One quick way to compare ecological models (EMs) is by comparing their variables. Predictor variables show what kinds of influences a model is able to account for, and what kinds of data it requires. Response variables show what information a model is capable of estimating.

This first comparison shows the names (and units) of each EM’s variables, side-by-side, sorted by variable role. Variable roles in ESML are as follows:

• Predictor Variables
  • Time- or Space-Varying Variables
  • Constants and Parameters
• Intermediate (Computed) Variables
• Response Variables
  • Computed Response Variables
  • Measured Response Variables

EM Variables by Category

A second way to use variables to compare EMs is by focusing on the kind of information each variable represents. The top-level categories in the ESML Variable Classification Hierarchy are as follows:

1. Policy Regarding Use or Management of Ecosystem Resources
2. Land Surface (or Water Body Bed) Cover, Use or Substrate
3. Human Demographic Data
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services
6. Non-monetary Indicators of Human Demand, Use or Benefit of Ecosystem Goods and Services
7. Monetary Values

Besides understanding model similarities, sorting the variables for each EM by these 7 categories makes it easier to see if the compared models can be linked using similar variables. For example, if one model estimates an ecosystem attribute (in Category 5), such as water clarity, as a response variable, and a second model uses a similar attribute (also in Category 5) as a predictor of recreational use, the two models can potentially be used in tandem. This comparison makes it easier to spot potential model linkages.

All EM Descriptors

This selection allows a more detailed comparison of EMs by model characteristics other than their variables. The 50-or-so EM descriptors for each model are presented, side-by-side, in the following categories:

• EM Identity and Description
• EM Modeling Approach
• EM Locations, Environments, Ecology
• EM Ecosystem Goods and Services (EGS) potentially modeled, by classification system

EM Descriptors by Modeling Concepts

This feature guides the user through the use of the following seven concepts for comparing and selecting EMs:

• Conceptual Model
• Modeling Objective
• Modeling Context
• Potential for Model Linkage
• Feasibility of Model Use
• Model Certainty
• Model Structural Information

Though presented separately, these concepts are interdependent, and information presented under one concept may have relevance to other concepts as well.