20.2 Defining Representativeness Assessment
(e.g., Davis et aI., 1996; Kiester et aI., 1996; White
et aI., 1999), although conservation of representative examples of major U.S. ecosystems was proposed for the continent early in the 20th century by
the Committee on the Preservation of Natural Conditions (Shelford, 1926).
RA includes three components of conservation
planning: identification, selection, and design of
conservation areas. Routine implementation of RA
has been infrequent because it requires not only the
distribution of conservation targets, but also knowledge of the environmental space they occupy.
While this knowledge exists for some elements of
biodiversity (Noss et aI., 1997; Soule and Terborgh,
1999a), it is rarely available for the entire suite of
species and ecosystems found in an area (but see
Cox et aI., 1994, for an unusual example of the
analysis of the environmental relationships of a
large number of conservation targets in Florida).
The scope (Chapters 1 and 35), methods (Chapters
3, 13 through 18, 20, and 21), and data requirements (Chapters 5 and 7) of integrated regional ecological assessments (IREAs) provide the means to
conduct RAs at large scales.
The purpose of this chapter is to present a
framework for using the principles and tools of
IREA, as presented in this book, to perform RAs
to determine the status of biodiversity, as well as
the status of ecosystem conditions relevant to conservation planning at national, regional, state, and
local levels. The following aspects of RAs are discussed: (1) definition and purpose (Section 20.2),
(2) basic components and requirements (Sections
20.3 and 2004), (3) principles and process of RA
(Section 20.5), and (4) practical implementation
strategies (Sections 20.6 and 20.7).
20.2 Defining Representativeness
Assessment
20.2.1 What Is Representativeness
Assessment?
RA is a process for (1) representing all natural features of interest found in a region within a network
of conservation areas (Austin and Margules, 1986;
Pressey et al., 1993) and (2) characterizing the ecological context of the biota found in any area of a
region (Austin and Margules, 1986; Mackey et aI.,
1988; Engelking et aI., 1994; Bourgeron et aI.,
1995a). The primary objective in conducting RA
is to design a network of conservation areas in a
region that includes all aspects of regional biotic
293
variability, all aspects of regional environmental
variability driving biotic responses, and the maintenance over time of patterns and processes within
the network. Although this agenda is very ambitious, it defines the initial conditions under which
specific and realistic objectives can be determined
given particular biological, economic, and social
constraints.
20.2.2 What Are the Requirements for
Representati veness Assessment?
RA includes three main components of conservation planning: (1) clear definition of conservation
goals and hence of conservation targets and their
geographic distributions (generally known as identification), (2) selection of conservation areas to
achieve the conservation goals, and (3) preliminary
evaluation of the design of the network as a whole
and of individual conservation areas. RA requires
the definition of an area for conducting the assessment and analyses, multiscale descriptions and
mapping of biotic and environmental variability,
and quantification of the environmental relations of
the biota (Austin and Margules, 1986; Margules et
aI., 1987; Mackey et aI., 1988, 1989; Margules and
Stein, 1989; McKenzie et aI., 1989). RA can be
conducted at any spatial scale necessary to meet
the objectives of a project, from assessing the
rangewide distribution of a single feature of biodiversity (e.g., distribution of tree, grizzly bear, or
endemic snail species), to assessing the distributions of all biotic or biophysical features within an
area.
RA has four distinct steps: (I) delineation of areas in which to conduct the assessment and analyses, (2) delineation of land units to serve as the
basis for selection of conservation areas, (3) determination of the conservation suitability of all land
units, and (4) a process for the selection of land
units for inclusion in a regional network of conservation areas.
20.2.3 How Does Representativeness
Assessment Differ from and
Integrate with Other Conservation
Criteria and Strategies?
Common approaches to conservation evaluation
and the selection of conservation areas historically
have included multicriteria scoring procedures
(Pressey and Nicholls, 1989a). Areas are ranked in
order of significance or priority according to scores
(e.g., Davis et aI., 1996; Kiester et aI., 1996; White
et aI., 1999), although conservation of representative examples of major U.S. ecosystems was proposed for the continent early in the 20th century by
the Committee on the Preservation of Natural Conditions (Shelford, 1926).
RA includes three components of conservation
planning: identification, selection, and design of
conservation areas. Routine implementation of RA
has been infrequent because it requires not only the
distribution of conservation targets, but also knowledge of the environmental space they occupy.
While this knowledge exists for some elements of
biodiversity (Noss et aI., 1997; Soule and Terborgh,
1999a), it is rarely available for the entire suite of
species and ecosystems found in an area (but see
Cox et aI., 1994, for an unusual example of the
analysis of the environmental relationships of a
large number of conservation targets in Florida).
The scope (Chapters 1 and 35), methods (Chapters
3, 13 through 18, 20, and 21), and data requirements (Chapters 5 and 7) of integrated regional ecological assessments (IREAs) provide the means to
conduct RAs at large scales.
The purpose of this chapter is to present a
framework for using the principles and tools of
IREA, as presented in this book, to perform RAs
to determine the status of biodiversity, as well as
the status of ecosystem conditions relevant to conservation planning at national, regional, state, and
local levels. The following aspects of RAs are discussed: (1) definition and purpose (Section 20.2),
(2) basic components and requirements (Sections
20.3 and 2004), (3) principles and process of RA
(Section 20.5), and (4) practical implementation
strategies (Sections 20.6 and 20.7).
20.2 Defining Representativeness
Assessment
20.2.1 What Is Representativeness
Assessment?
RA is a process for (1) representing all natural features of interest found in a region within a network
of conservation areas (Austin and Margules, 1986;
Pressey et al., 1993) and (2) characterizing the ecological context of the biota found in any area of a
region (Austin and Margules, 1986; Mackey et aI.,
1988; Engelking et aI., 1994; Bourgeron et aI.,
1995a). The primary objective in conducting RA
is to design a network of conservation areas in a
region that includes all aspects of regional biotic
293
variability, all aspects of regional environmental
variability driving biotic responses, and the maintenance over time of patterns and processes within
the network. Although this agenda is very ambitious, it defines the initial conditions under which
specific and realistic objectives can be determined
given particular biological, economic, and social
constraints.
20.2.2 What Are the Requirements for
Representati veness Assessment?
RA includes three main components of conservation planning: (1) clear definition of conservation
goals and hence of conservation targets and their
geographic distributions (generally known as identification), (2) selection of conservation areas to
achieve the conservation goals, and (3) preliminary
evaluation of the design of the network as a whole
and of individual conservation areas. RA requires
the definition of an area for conducting the assessment and analyses, multiscale descriptions and
mapping of biotic and environmental variability,
and quantification of the environmental relations of
the biota (Austin and Margules, 1986; Margules et
aI., 1987; Mackey et aI., 1988, 1989; Margules and
Stein, 1989; McKenzie et aI., 1989). RA can be
conducted at any spatial scale necessary to meet
the objectives of a project, from assessing the
rangewide distribution of a single feature of biodiversity (e.g., distribution of tree, grizzly bear, or
endemic snail species), to assessing the distributions of all biotic or biophysical features within an
area.
RA has four distinct steps: (I) delineation of areas in which to conduct the assessment and analyses, (2) delineation of land units to serve as the
basis for selection of conservation areas, (3) determination of the conservation suitability of all land
units, and (4) a process for the selection of land
units for inclusion in a regional network of conservation areas.
20.2.3 How Does Representativeness
Assessment Differ from and
Integrate with Other Conservation
Criteria and Strategies?
Common approaches to conservation evaluation
and the selection of conservation areas historically
have included multicriteria scoring procedures
(Pressey and Nicholls, 1989a). Areas are ranked in
order of significance or priority according to scores