20
Representativeness Assessments
Patrick S. Bourgeron, Hope C. Humphries, and Mark E. Jensen
20.1 Introduction
Conservation scientists, planners, and managers
generally agree that the ultimate goal of conservation planning is the comprehensive protection of all
aspects of biodiversity (Noss and Cooperrider,
1994); consequently maintaining all ecosystem
components over time and over large areas is a primary objective (Noss, 1983). To achieve its goal,
conservation planning requires knowledge of the
linkages among the various components of ecosystems (e.g., species, biogeochemical processes), including human factors (see Chapters 27 and 29),
across gradients of spatial and temporal variability
(see Chapters 2, 3, and 26), and integrated within
the socioeconomic context (see Chapter 9). Therefore, basic characterization of ecological patterns
and processes of interest at all scales relevant to
ecosystems (see Chapters 2, 3, 22, and 23) is
needed. This knowledge should be used to formulate realistic conservation goals and strategies and
to place networks of conservation areas into the
proper ecological and socioeconomic context for
implementation at relevant ecological, social, and
economic scales (see Chapter 35).
Conservation planning has four major components: identification of conservation targets and selection, design, and management of conservation
areas. Biodiversity patterns of interest are identified and mapped. All such patterns or a subset of
the patterns becomes conservation targets. Selected
Patrick S. Bourgeron and Hope C. Humphries wish to
acknowledge partial funding provided by a Science to
Achieve Results grant from the U.S. Environmental Protection Agency ("Multi-scaled Assessment Methods:
Prototype Development within the Interior Columbia
Basin").
292
areas that support the targets are assigned a conservation status (e.g., wilderness, nature reserve).
Finally, the designated conservation areas are managed to ensure the persistence of the patterns of interest. Current broad-scale conservation assessments have been designed largely to ensure that
networks of conservation areas contain all conservation targets (i.e., representation of species or
communities) by identifying areas where these targets are found (e.g., USGS GAP Analysis Program,
or GAP, Scott and Jennings, 1998; World Wildlife
Fund ecoregional conservation assessment, Olson
and Dinerstein, 1998; Ricketts et aI., 1999a). Determination of the processes maintaining the targets
is usually conducted during the site conservation
planning phase (e.g., Poiani et aI., 1998), which is
concerned with the delineation of conservation area
boundaries, identification and involvement of
stakeholders, and development of management
strategies at the landscape level. A landscape approach to conservation is used increasingly often
(e.g., Kim and Weaver, 1994; Naveh, 1994; Steinitz
et aI., 1996; Leser and Nagel, 1998).
Representativeness assessment (RA) is a relatively recently developed process first described by
Austin and Margules (1986), which originated in
Australia as an aid to conservation planning (see
also Mackey et aI., 1988). As formulated by Austin
and Margules (1986), it differs from other conservation strategies in the inclusion of biotic-environmental relationships as part of the definition of
conservation targets and also in the inclusion of the
concept of scale (e.g., ecologically meaningful regions). RA has been widely used in the southern
hemisphere (Lombard et aI., 1995; Haila and Margules, 1996; DeVantier et al., 1998; Freitag et aI.,
1998; Preen, 1998), but RA principles have only
recently been widely applied in North America
Representativeness Assessments
Patrick S. Bourgeron, Hope C. Humphries, and Mark E. Jensen
20.1 Introduction
Conservation scientists, planners, and managers
generally agree that the ultimate goal of conservation planning is the comprehensive protection of all
aspects of biodiversity (Noss and Cooperrider,
1994); consequently maintaining all ecosystem
components over time and over large areas is a primary objective (Noss, 1983). To achieve its goal,
conservation planning requires knowledge of the
linkages among the various components of ecosystems (e.g., species, biogeochemical processes), including human factors (see Chapters 27 and 29),
across gradients of spatial and temporal variability
(see Chapters 2, 3, and 26), and integrated within
the socioeconomic context (see Chapter 9). Therefore, basic characterization of ecological patterns
and processes of interest at all scales relevant to
ecosystems (see Chapters 2, 3, 22, and 23) is
needed. This knowledge should be used to formulate realistic conservation goals and strategies and
to place networks of conservation areas into the
proper ecological and socioeconomic context for
implementation at relevant ecological, social, and
economic scales (see Chapter 35).
Conservation planning has four major components: identification of conservation targets and selection, design, and management of conservation
areas. Biodiversity patterns of interest are identified and mapped. All such patterns or a subset of
the patterns becomes conservation targets. Selected
Patrick S. Bourgeron and Hope C. Humphries wish to
acknowledge partial funding provided by a Science to
Achieve Results grant from the U.S. Environmental Protection Agency ("Multi-scaled Assessment Methods:
Prototype Development within the Interior Columbia
Basin").
292
areas that support the targets are assigned a conservation status (e.g., wilderness, nature reserve).
Finally, the designated conservation areas are managed to ensure the persistence of the patterns of interest. Current broad-scale conservation assessments have been designed largely to ensure that
networks of conservation areas contain all conservation targets (i.e., representation of species or
communities) by identifying areas where these targets are found (e.g., USGS GAP Analysis Program,
or GAP, Scott and Jennings, 1998; World Wildlife
Fund ecoregional conservation assessment, Olson
and Dinerstein, 1998; Ricketts et aI., 1999a). Determination of the processes maintaining the targets
is usually conducted during the site conservation
planning phase (e.g., Poiani et aI., 1998), which is
concerned with the delineation of conservation area
boundaries, identification and involvement of
stakeholders, and development of management
strategies at the landscape level. A landscape approach to conservation is used increasingly often
(e.g., Kim and Weaver, 1994; Naveh, 1994; Steinitz
et aI., 1996; Leser and Nagel, 1998).
Representativeness assessment (RA) is a relatively recently developed process first described by
Austin and Margules (1986), which originated in
Australia as an aid to conservation planning (see
also Mackey et aI., 1988). As formulated by Austin
and Margules (1986), it differs from other conservation strategies in the inclusion of biotic-environmental relationships as part of the definition of
conservation targets and also in the inclusion of the
concept of scale (e.g., ecologically meaningful regions). RA has been widely used in the southern
hemisphere (Lombard et aI., 1995; Haila and Margules, 1996; DeVantier et al., 1998; Freitag et aI.,
1998; Preen, 1998), but RA principles have only
recently been widely applied in North America