while elevation is the most important factor in
another area. Ecoregions are subdivided into different levels with Level I the coarsest scale and
Level IV the finest scale. Map boundary lines
may vary depending on what level is used. The
EPA approach has been applied to a number of
states, including Alaska (Gallant et al. 1995), to
refine the national system. Nowacki et al. (2002)
combined the Bailey and Omernik approach to
ecoregion mapping in Alaska.
In Canada, the Ecoregion Working Group
(1989) developed a map of ecoclimatic regions.
Also, the Commission for Environmental Cooperation (2006) produced a map of North America
by combining systems for Canada (Wiken 1986),
the United States (Omernik 1987), and Mexico.
Similar concepts of ecological regionalization
have evolved in both Canada and the United
States (Bailey et al. 1985).
The Sierra Club (Elder 1994) has created a
“critical ecoregions” program designed to protect
and restore 21 regional ecosystems in the United
States and Canada. They recently targeted ten of
them to create climate-resilient habitats where
plants, animals, and humans are able to survive
on a warmer planet. The basis for the regions is
not specified.
Maps of individual continents have been produced following the WWF system, e.g., the
Interim Biogeographic Regionalization of
Australia (IBRA) (Commonwealth of Australia
2012). The Digital Map of European Ecological
Regions (European Environment Agency 2002)
shows the continent divided into 68 regions. It is
based on knowledge of climatic and both topographic and geobotanical data, as well as the
opinion of a large team of experts from various
European nature-related Institutions and the
WWF.
Recently, Blasi et al. (2010) defined and
mapped the Ecoregions of Italy according to a
divisive, “top down,” approach, from the global
macroclimatic domains and divisions of Bailey
(1989) down to more detailed units based on an
analysis of potential natural vegetation. Where
potential natural vegetation has been altered by
human intervention, a multidiscipline team used
significant variations in physical components of
the environment (e.g., climate, physiography,
soils, and hydrography) to indirectly delineate
ecological boundaries.
A long history of eco-geographic regionalization in China goes back as early as 500 B.C. The
modern regionalization work began in the midtwentieth century and culminated recently with a
map of China’s ecoregions divided into a hierarchy of ecoregions units (Wu et al. 2003a). The
first level unit, temperature zone, is delineated
with the main criteria of temperature. The second
level unit, humidity region, is based on criteria of
water/moisture states. The third level unit, natural
region, is divided according to medium-size
geomorphologic units. Vegetation types and soils
are applied as supplementary criteria. Of the
existing ecoregional systems, Bailey’s systems
for the United States, North America, and the
continents are comparatively close to China’s system in hierarchical units, mapping procedures,
and regions (Wu et al. 2003b). Ecological regionalization is a base for rational management and
sustainable utilization of ecosystems and natural
resources in China (Fu et al. 2004).
An ecoregion map of Japan has been produced
by Chen and Morimoto (2009). The motivation
for the ecoregion mapping project was twofold:
(1) to characterize Japanese watersheds from an
ecoregion perspective so as to provide a framework for nationwide scaled ecosystem management; and (2) to suggest demarcation of new
political and administrative regions of Japan in
an ecological perspective. Of the map’s two
levels, Ecoregion I is macroscale based on climate; and Ecoregion II is mesoscale based on
major landform and geological classes.
Lastly, ecoregions have been addressed
quantitatively. In this approach, the goal of
ecoregion delineation is to create regions that
are internally homogeneous and distinct from
other regions regarding a particular set of
variables. Given numerical input data, homogeneity can be defined statistically; and algorithms
can be applied to sort and divide observations
into statistically homogeneous groups ergo
regions. Clusters are defined as homogenous
Appendix D: Comparison of Ecoregion and Related Approaches
151
another area. Ecoregions are subdivided into different levels with Level I the coarsest scale and
Level IV the finest scale. Map boundary lines
may vary depending on what level is used. The
EPA approach has been applied to a number of
states, including Alaska (Gallant et al. 1995), to
refine the national system. Nowacki et al. (2002)
combined the Bailey and Omernik approach to
ecoregion mapping in Alaska.
In Canada, the Ecoregion Working Group
(1989) developed a map of ecoclimatic regions.
Also, the Commission for Environmental Cooperation (2006) produced a map of North America
by combining systems for Canada (Wiken 1986),
the United States (Omernik 1987), and Mexico.
Similar concepts of ecological regionalization
have evolved in both Canada and the United
States (Bailey et al. 1985).
The Sierra Club (Elder 1994) has created a
“critical ecoregions” program designed to protect
and restore 21 regional ecosystems in the United
States and Canada. They recently targeted ten of
them to create climate-resilient habitats where
plants, animals, and humans are able to survive
on a warmer planet. The basis for the regions is
not specified.
Maps of individual continents have been produced following the WWF system, e.g., the
Interim Biogeographic Regionalization of
Australia (IBRA) (Commonwealth of Australia
2012). The Digital Map of European Ecological
Regions (European Environment Agency 2002)
shows the continent divided into 68 regions. It is
based on knowledge of climatic and both topographic and geobotanical data, as well as the
opinion of a large team of experts from various
European nature-related Institutions and the
WWF.
Recently, Blasi et al. (2010) defined and
mapped the Ecoregions of Italy according to a
divisive, “top down,” approach, from the global
macroclimatic domains and divisions of Bailey
(1989) down to more detailed units based on an
analysis of potential natural vegetation. Where
potential natural vegetation has been altered by
human intervention, a multidiscipline team used
significant variations in physical components of
the environment (e.g., climate, physiography,
soils, and hydrography) to indirectly delineate
ecological boundaries.
A long history of eco-geographic regionalization in China goes back as early as 500 B.C. The
modern regionalization work began in the midtwentieth century and culminated recently with a
map of China’s ecoregions divided into a hierarchy of ecoregions units (Wu et al. 2003a). The
first level unit, temperature zone, is delineated
with the main criteria of temperature. The second
level unit, humidity region, is based on criteria of
water/moisture states. The third level unit, natural
region, is divided according to medium-size
geomorphologic units. Vegetation types and soils
are applied as supplementary criteria. Of the
existing ecoregional systems, Bailey’s systems
for the United States, North America, and the
continents are comparatively close to China’s system in hierarchical units, mapping procedures,
and regions (Wu et al. 2003b). Ecological regionalization is a base for rational management and
sustainable utilization of ecosystems and natural
resources in China (Fu et al. 2004).
An ecoregion map of Japan has been produced
by Chen and Morimoto (2009). The motivation
for the ecoregion mapping project was twofold:
(1) to characterize Japanese watersheds from an
ecoregion perspective so as to provide a framework for nationwide scaled ecosystem management; and (2) to suggest demarcation of new
political and administrative regions of Japan in
an ecological perspective. Of the map’s two
levels, Ecoregion I is macroscale based on climate; and Ecoregion II is mesoscale based on
major landform and geological classes.
Lastly, ecoregions have been addressed
quantitatively. In this approach, the goal of
ecoregion delineation is to create regions that
are internally homogeneous and distinct from
other regions regarding a particular set of
variables. Given numerical input data, homogeneity can be defined statistically; and algorithms
can be applied to sort and divide observations
into statistically homogeneous groups ergo
regions. Clusters are defined as homogenous
Appendix D: Comparison of Ecoregion and Related Approaches
151