defense of environmental security call for developing a vision, priorities,
and coordinated approaches (Goodman 1996) (see Table 16.5). Again,
models are one of the most useful tools for this type of analysis.
Clearly, resource management models need to be based on hierarchical
and spatially explicit approaches that incorporate key features of concern
and allow for disturbances, land-use changes, socioeconomic pressures, and
other anthropogenic changes. Examples of using models for such research
exist (as described in previous chapters), but access to these models by
resource managers is limited, and few managers are aware of the current
research directions. Thus, improved availability of modeling tools for
resource management is needed.
16.2 Philosophy of Modeling
One of reasons models are so appropriate to today’s resource management
needs is that the philosophy of modeling requires focusing on key issues.
The use of models is based upon the concept that models can synthesize
the best understanding of the situation given current information. This
perspective builds upon a parsimonious approach to modeling. That is,
modelers should strive to include the least amount of information that
adequately explains the phenomena of interest. The term “adequate” is case
specific, for what may be appropriate in one case will not necessarily work
in another situation. A model can thus be considered a set of hypotheses
about the way a system works, given certain assumptions and context.
Models never contain all of the details of a system. In a discourse on science,
Lagrange is reputed to have said “Seek simplicity, but distrust it.” Models
are an expression of this philosophy.
Assumptions are a key part of the modeling process. To clearly communicate the modeling approach to a user, the set of assumptions for a particular modeling exercise should be specified. The assumptions determine
the level of detail needed in a model and situations to which it can be
applied. They typically are concerned with the temporal and spatial scales
of focus, abiotic and biotic processes, organisms and their relevant life stages
(e.g., adults vs juveniles), and environmental factors (e.g., disturbances) that
are held constant or allowed to vary in controlled ways. In general, the more
the assumptions are specific to a particular case of interest, the more meaningful the model results are for that situation. However, this specificity may
make the model unusable outside of that situation, which leads to the need
to understand and to specify how, why, and where a model will be used.
Another aspect of the minimalist approach to modeling is that a new
model does not need to be developed for every situation. Instead, some
categories of models are appropriate to a particular type of ecological or
resource management problem. When a model is applied to a new location
or related issue, the set of driving variables and parameters usually remains
314
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and coordinated approaches (Goodman 1996) (see Table 16.5). Again,
models are one of the most useful tools for this type of analysis.
Clearly, resource management models need to be based on hierarchical
and spatially explicit approaches that incorporate key features of concern
and allow for disturbances, land-use changes, socioeconomic pressures, and
other anthropogenic changes. Examples of using models for such research
exist (as described in previous chapters), but access to these models by
resource managers is limited, and few managers are aware of the current
research directions. Thus, improved availability of modeling tools for
resource management is needed.
16.2 Philosophy of Modeling
One of reasons models are so appropriate to today’s resource management
needs is that the philosophy of modeling requires focusing on key issues.
The use of models is based upon the concept that models can synthesize
the best understanding of the situation given current information. This
perspective builds upon a parsimonious approach to modeling. That is,
modelers should strive to include the least amount of information that
adequately explains the phenomena of interest. The term “adequate” is case
specific, for what may be appropriate in one case will not necessarily work
in another situation. A model can thus be considered a set of hypotheses
about the way a system works, given certain assumptions and context.
Models never contain all of the details of a system. In a discourse on science,
Lagrange is reputed to have said “Seek simplicity, but distrust it.” Models
are an expression of this philosophy.
Assumptions are a key part of the modeling process. To clearly communicate the modeling approach to a user, the set of assumptions for a particular modeling exercise should be specified. The assumptions determine
the level of detail needed in a model and situations to which it can be
applied. They typically are concerned with the temporal and spatial scales
of focus, abiotic and biotic processes, organisms and their relevant life stages
(e.g., adults vs juveniles), and environmental factors (e.g., disturbances) that
are held constant or allowed to vary in controlled ways. In general, the more
the assumptions are specific to a particular case of interest, the more meaningful the model results are for that situation. However, this specificity may
make the model unusable outside of that situation, which leads to the need
to understand and to specify how, why, and where a model will be used.
Another aspect of the minimalist approach to modeling is that a new
model does not need to be developed for every situation. Instead, some
categories of models are appropriate to a particular type of ecological or
resource management problem. When a model is applied to a new location
or related issue, the set of driving variables and parameters usually remains
314
Virginia H. Dale