1.4 General Properties of an Ecological Assessment
tem pattern-process relations at the coarsest appropriate scale to reduce costs. Often this can be
done by identifying the pattern of interest and moving up one scale in selecting the pattern that will
be described in assessment or monitoring efforts.
For example, if we are interested in the change of
vegetation at the plant association level (e.g., Douglas fir-Idaho fescue or Douglas fir-snowberry),
sampling strategies could be designed to detect
change at the series level (e.g., Douglas fir forests)
as an initial screening mechanism to identify potential areas of plant association change. The spatial area that could be described by this approach,
for the same level of funding, is much larger than
that which could be described continuously at the
plant association level. In this example, areas that
exhibit change at the series level would be prioritized for more detailed study to better understand
plant association pattern relations in an assessment
area. An approach of this sort follows the coarsefilter strategy for biodiversity conservation (Hunter,
1991) and is a practical way of applying pattern
recognition theory (Jensen et aI., 1996).
1.4.3 Analysis of Ecosystem
Pattern-Process Relations
Ecological assessments require the synthesis of information across many disciplines (e.g., biological,
social, economic, and physical sciences). If these
assessments are to assist managers in implementing ecosystem-based strategies for land management, they must address both the biophysical and
human components of ecosystems (Slocombe,
1993; Grumbine, 1994). Aggregation of information up and down scales must be used in combination with integration models to maximize the use
of current information. The value of information
will change through this aggregation process and
should be well documented during the assessment
process.
To facilitate improved ecosystem management,
ecological assessments should provide descriptions
of the following:
1. Current and historical composition, structure,
and function of an ecosystem.
2. Abiotic and biotic events (including human actions) that contributed to the development of the
current ecosystem condition.
3. Probable future scenarios that might exist under
different types of management strategies (e.g.,
current management direction, maintenance of
historical processes and patterns).
25
These basic components of an ecological assessment are briefly described next, following Lessard
et aI. (1999).
The fact that ecosystems are dynamic and evolutionary suggests that the current status of an
ecosystem is a function of its evolutionary and
ecological history. Accordingly, assessments of
ecosystem conditions and management potential
should describe existing and historical ecosystem
composition, structure, and function in the context
of specific biophysical and human processes associated with each time period. A characterization of
existing conditions gives quantitative or qualitative
evidence of current structure and function. Historical characterizations provide insight into the kinds,
magnitudes, and rates of change in ecosystem structure and function. Historical characterizations also
provide insight into possible future ecosystem development pathways by providing evidence of
dominant disturbance types and regimes, typical
environmental constraints, and variability of biotic
patterns and processes (see Chapter 19).
Because there are real limitations to the productive capacities, structure, and functioning that
might be achieved within an ecosystem at any time,
ecological assessments should characterize plausible ranges of potential future ecosystem conditions
with regard to climatic trends, biophysical environmental conditions, historical development, current
structure, organization, and disturbance regimes.
Additionally, recognizing that ecosystem patterns
and processes are not always perfectly predictable,
the accuracy and specificity of planning and management expectations should be in line with such
uncertainty. Accordingly, desired conditions for
planning should reflect desired dynamics, and management prescriptions should describe a quantifiable range of plausible conditions, rather than a single, narrowly defined target.
This range of desired conditions can best be described through scenario planning, a tool used to
inform society about the implications and trade-offs
in ecosystem management (Haynes et aI., 1996).
Scenario planning differs from traditional alternative evaluation methods of land-use planning,
which describe the effects of different methods for
achieving a desired state, because scenarios describe a set of possible futures given different management strategies and then explore their consequences. Scenarios project qualitative social and
biological outcomes over time, allowing us to learn
about the merits, pitfalls, and trade-offs of management choices and providing required information for decision makers. Examples of scenarios
that might be considered in an ecological assess-
tem pattern-process relations at the coarsest appropriate scale to reduce costs. Often this can be
done by identifying the pattern of interest and moving up one scale in selecting the pattern that will
be described in assessment or monitoring efforts.
For example, if we are interested in the change of
vegetation at the plant association level (e.g., Douglas fir-Idaho fescue or Douglas fir-snowberry),
sampling strategies could be designed to detect
change at the series level (e.g., Douglas fir forests)
as an initial screening mechanism to identify potential areas of plant association change. The spatial area that could be described by this approach,
for the same level of funding, is much larger than
that which could be described continuously at the
plant association level. In this example, areas that
exhibit change at the series level would be prioritized for more detailed study to better understand
plant association pattern relations in an assessment
area. An approach of this sort follows the coarsefilter strategy for biodiversity conservation (Hunter,
1991) and is a practical way of applying pattern
recognition theory (Jensen et aI., 1996).
1.4.3 Analysis of Ecosystem
Pattern-Process Relations
Ecological assessments require the synthesis of information across many disciplines (e.g., biological,
social, economic, and physical sciences). If these
assessments are to assist managers in implementing ecosystem-based strategies for land management, they must address both the biophysical and
human components of ecosystems (Slocombe,
1993; Grumbine, 1994). Aggregation of information up and down scales must be used in combination with integration models to maximize the use
of current information. The value of information
will change through this aggregation process and
should be well documented during the assessment
process.
To facilitate improved ecosystem management,
ecological assessments should provide descriptions
of the following:
1. Current and historical composition, structure,
and function of an ecosystem.
2. Abiotic and biotic events (including human actions) that contributed to the development of the
current ecosystem condition.
3. Probable future scenarios that might exist under
different types of management strategies (e.g.,
current management direction, maintenance of
historical processes and patterns).
25
These basic components of an ecological assessment are briefly described next, following Lessard
et aI. (1999).
The fact that ecosystems are dynamic and evolutionary suggests that the current status of an
ecosystem is a function of its evolutionary and
ecological history. Accordingly, assessments of
ecosystem conditions and management potential
should describe existing and historical ecosystem
composition, structure, and function in the context
of specific biophysical and human processes associated with each time period. A characterization of
existing conditions gives quantitative or qualitative
evidence of current structure and function. Historical characterizations provide insight into the kinds,
magnitudes, and rates of change in ecosystem structure and function. Historical characterizations also
provide insight into possible future ecosystem development pathways by providing evidence of
dominant disturbance types and regimes, typical
environmental constraints, and variability of biotic
patterns and processes (see Chapter 19).
Because there are real limitations to the productive capacities, structure, and functioning that
might be achieved within an ecosystem at any time,
ecological assessments should characterize plausible ranges of potential future ecosystem conditions
with regard to climatic trends, biophysical environmental conditions, historical development, current
structure, organization, and disturbance regimes.
Additionally, recognizing that ecosystem patterns
and processes are not always perfectly predictable,
the accuracy and specificity of planning and management expectations should be in line with such
uncertainty. Accordingly, desired conditions for
planning should reflect desired dynamics, and management prescriptions should describe a quantifiable range of plausible conditions, rather than a single, narrowly defined target.
This range of desired conditions can best be described through scenario planning, a tool used to
inform society about the implications and trade-offs
in ecosystem management (Haynes et aI., 1996).
Scenario planning differs from traditional alternative evaluation methods of land-use planning,
which describe the effects of different methods for
achieving a desired state, because scenarios describe a set of possible futures given different management strategies and then explore their consequences. Scenarios project qualitative social and
biological outcomes over time, allowing us to learn
about the merits, pitfalls, and trade-offs of management choices and providing required information for decision makers. Examples of scenarios
that might be considered in an ecological assess-