social, economic, or anthropological analyses. This volume will introduce
the reader to a variety of ecological models that have been successfully
applied to environmental planning. Demonstrations of the uses of some of
these models show the benefits that can be obtained from these types of
tools. The remainder of this chapter explores the different types of models
of environmental resources and sets forth the organization of the book.
1.2 Models
Models are tools that represent essential features of a system so that
relationships can be analyzed within established boundary conditions.
Modeling may be used to simulate natural conditions and scenarios of
resource use. Analyses of models can be used to examine potential impacts
of a decision. Ecological models are a tool for environmental managers to
enhance understanding of both the complexities and the uniqueness of a
given situation and its response to management or change. Models allow
managers to summarize information on the environment, determine where
gaps exist, extrapolate across the gaps, and simulate various scenarios to
evaluate outcomes of environmental management decisions.
1.2.1 Types of Models
There are at least three types of models: heuristic, physical, and mathematical (Dale and O’Neill 1998). Heuristic models tend to be relatively
simple but capture key relationships of the system. They can be depicted as
pictures, diagrams, words, or mathematical relationships. Sometimes scientists call these “back of the envelope” models because they can be explained
in a small amount of space. Such models are appealing in that they are relatively easy to understand. However, their simplicity may mean that some
of the important interactions in the system are not fully characterized.
Physical models are scaled-down versions of the real world, typically
constructed in three dimensions, and are sometimes used to show changes
over time (the fourth dimension). Examples are microcosms, wind tunnels
(used to examine aerodynamic properties of airplanes, cars, and seeds), and
aquariums (used in studies of fish population dynamics). One interesting
example is the use of model streams built of fiberglass in which certain
chemicals can be added or the size, shape, and density of substrate
materials controlled. Stream water is circulated in these models, and the
growth or behavior of fish or invertebrates is observed. The model streams
are designed for monitoring their interior at a height of 1 m rather than
ground level of natural streams, which makes the experiments easier to
observe.
Mathematical models describe relationships via numerical formulations.
The chosen equations should appropriately reflect the constraints of the
1. Opportunities for Using Ecological Models for Resource Management
7
the reader to a variety of ecological models that have been successfully
applied to environmental planning. Demonstrations of the uses of some of
these models show the benefits that can be obtained from these types of
tools. The remainder of this chapter explores the different types of models
of environmental resources and sets forth the organization of the book.
1.2 Models
Models are tools that represent essential features of a system so that
relationships can be analyzed within established boundary conditions.
Modeling may be used to simulate natural conditions and scenarios of
resource use. Analyses of models can be used to examine potential impacts
of a decision. Ecological models are a tool for environmental managers to
enhance understanding of both the complexities and the uniqueness of a
given situation and its response to management or change. Models allow
managers to summarize information on the environment, determine where
gaps exist, extrapolate across the gaps, and simulate various scenarios to
evaluate outcomes of environmental management decisions.
1.2.1 Types of Models
There are at least three types of models: heuristic, physical, and mathematical (Dale and O’Neill 1998). Heuristic models tend to be relatively
simple but capture key relationships of the system. They can be depicted as
pictures, diagrams, words, or mathematical relationships. Sometimes scientists call these “back of the envelope” models because they can be explained
in a small amount of space. Such models are appealing in that they are relatively easy to understand. However, their simplicity may mean that some
of the important interactions in the system are not fully characterized.
Physical models are scaled-down versions of the real world, typically
constructed in three dimensions, and are sometimes used to show changes
over time (the fourth dimension). Examples are microcosms, wind tunnels
(used to examine aerodynamic properties of airplanes, cars, and seeds), and
aquariums (used in studies of fish population dynamics). One interesting
example is the use of model streams built of fiberglass in which certain
chemicals can be added or the size, shape, and density of substrate
materials controlled. Stream water is circulated in these models, and the
growth or behavior of fish or invertebrates is observed. The model streams
are designed for monitoring their interior at a height of 1 m rather than
ground level of natural streams, which makes the experiments easier to
observe.
Mathematical models describe relationships via numerical formulations.
The chosen equations should appropriately reflect the constraints of the
1. Opportunities for Using Ecological Models for Resource Management
7