22
Elements of
Ecological Land Classifications
for Ecological Assessments
Patrick S. Bourgeron, Hope C. Humphries, and Mark E. Jensen
22.1 Introduction
An ecological land classification (ELC) is the product of the formal definition of land-based ecosystems and ecosystem complexes (Rowe and Sheard,
1981; Sims et aI., 1996), based on the ecological
and mapping principles of ecosystem characterization (see Chapters 2 and 3). In addition to the specific requirements of ecosystem characterization
(see Chapter 3), constructing an ELC requires making decisions about the classification concepts to
follow and the specific uses of the ELC (Grossman
et aI., 1999). In practice, the classification process
is a balance between science and art (Sims et aI.,
1996).
In the broad fields of environmental management
and planning, ELCs have been used for a variety
of purposes, such as management of natural resources, land-use planning, and delineation of ecological regions, among others (Zonneveld, 1988,
1989; Klijn, 1994; Sims et aI., 1996). As a result
of recent developments in ecosystem management,
sustainable land development, the need to detect
ecosystem responses to global and land-use changes,
and advances in technology (e.g., remote sensing
data, geographic information systems, and databases; see Chapters 8, 10, and 11), there has been
renewed interest in environmental stratification and
therefore in ELCs. Accordingly, there has been a
proliferation of ELC systems constructed to meet
a variety of objectives, using an array of methods
and technologies (Sims et aI., 1996). Furthermore,
there has been increasing recognition that tradiPatrick S. Bourgeron and Hope C. Humphries wish to
ac~owledge 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").
tional planning and management units (e.g., countries, states, National Forests) generally do not match
the ecological boundaries that bound patterns and
processes of interest (Uhlig and Jordan, 1996).
ELCs have been used to delineate these ecological
boundaries and hence provide a flexible means to
analyze specific issues addressed during ecological
assessments (EAs). Most importantly, ELCs have
been used to provide the spatially explicit framework
needed during EAs (see Chapter 13) to address multiple issues and to monitor trends.
The main objective of this chapter is to provide
an overview of the approaches taken in the development and implementation of ELCs in EAs for
various objectives, at a variety of spatial scales.
This overview is intended to allow EA practitioners to decided what type of system(s) may work for
their particular goals. The chapter makes use of and
complements the material covered in Chapters 2,
3, and 19. It is organized into four main sections:
principles and methods of ELCs, general areas of
application of ELCs, overview of the major ELCs
used worldwide, and examples of specific applications and evaluation of ELCs. The chapter is not
intended to be an exhaustive review of all ELC concepts, systems, and implementation. More extensive reviews can be found in KUchler and Zonneveld (1988), Klijn (1994), Sims et aI. (1996), and
Grossman et aI. (1999).
22.2 Overview of the Principles
and Methods of Ecological
Land Classifications in
Ecological Assessments
ELCs have the general properties of any classification (Sokal, 1974); that is, in their simplest form,
they group objects into sets that share particular at321
Elements of
Ecological Land Classifications
for Ecological Assessments
Patrick S. Bourgeron, Hope C. Humphries, and Mark E. Jensen
22.1 Introduction
An ecological land classification (ELC) is the product of the formal definition of land-based ecosystems and ecosystem complexes (Rowe and Sheard,
1981; Sims et aI., 1996), based on the ecological
and mapping principles of ecosystem characterization (see Chapters 2 and 3). In addition to the specific requirements of ecosystem characterization
(see Chapter 3), constructing an ELC requires making decisions about the classification concepts to
follow and the specific uses of the ELC (Grossman
et aI., 1999). In practice, the classification process
is a balance between science and art (Sims et aI.,
1996).
In the broad fields of environmental management
and planning, ELCs have been used for a variety
of purposes, such as management of natural resources, land-use planning, and delineation of ecological regions, among others (Zonneveld, 1988,
1989; Klijn, 1994; Sims et aI., 1996). As a result
of recent developments in ecosystem management,
sustainable land development, the need to detect
ecosystem responses to global and land-use changes,
and advances in technology (e.g., remote sensing
data, geographic information systems, and databases; see Chapters 8, 10, and 11), there has been
renewed interest in environmental stratification and
therefore in ELCs. Accordingly, there has been a
proliferation of ELC systems constructed to meet
a variety of objectives, using an array of methods
and technologies (Sims et aI., 1996). Furthermore,
there has been increasing recognition that tradiPatrick S. Bourgeron and Hope C. Humphries wish to
ac~owledge 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").
tional planning and management units (e.g., countries, states, National Forests) generally do not match
the ecological boundaries that bound patterns and
processes of interest (Uhlig and Jordan, 1996).
ELCs have been used to delineate these ecological
boundaries and hence provide a flexible means to
analyze specific issues addressed during ecological
assessments (EAs). Most importantly, ELCs have
been used to provide the spatially explicit framework
needed during EAs (see Chapter 13) to address multiple issues and to monitor trends.
The main objective of this chapter is to provide
an overview of the approaches taken in the development and implementation of ELCs in EAs for
various objectives, at a variety of spatial scales.
This overview is intended to allow EA practitioners to decided what type of system(s) may work for
their particular goals. The chapter makes use of and
complements the material covered in Chapters 2,
3, and 19. It is organized into four main sections:
principles and methods of ELCs, general areas of
application of ELCs, overview of the major ELCs
used worldwide, and examples of specific applications and evaluation of ELCs. The chapter is not
intended to be an exhaustive review of all ELC concepts, systems, and implementation. More extensive reviews can be found in KUchler and Zonneveld (1988), Klijn (1994), Sims et aI. (1996), and
Grossman et aI. (1999).
22.2 Overview of the Principles
and Methods of Ecological
Land Classifications in
Ecological Assessments
ELCs have the general properties of any classification (Sokal, 1974); that is, in their simplest form,
they group objects into sets that share particular at321