and Kratochwil 2011). The Holdridge system has
been reviewed in relation to several ecosystem
mapping schemes, including Bailey, by Lugo
et al. (1999). Harris (1973) commented on the
inadequacy of the system to predict soil patterns
in Costa Rica.
Walter and Box (1976) developed an ecological classification of the world’s climates. It is
based on the climate-diagram patterns of Walter,
in which temperature and precipitation are plotted
on the ratio 1:2 to show periods of aridity and
humidity. Also taken into account are number of
frost-free days and other extremes that influence
vegetation patterns. Their treatment recognizes
nine different major zonobiomes plus modifiers
that can be added to distinguish particularly dry,
cold, or wet conditions. In addition, major variants
within zonobiomes are introduced: pedobiomes
characterized by extreme edaphic conditions that
cause azonal vegetation; orobiomes that involve
mountain ranges with vertical climate zonation
and elevation belts of vegetation. Zonoecotones,
transition zones between individual zonobiomes,
are also distinguished. Climate zones are determined by drawing lines around climate stations
with similar-appearing climate diagrams as
opposed to applying climate formulas.
The boundaries of ecozones developed by
Schultz (1995 et seq.) follow the subdivision of
the earth into climatic zones established by Troll
and Paffen (1964) in their map, Seasonal
Climates of the Earth. Some geographical
regions are difficult to integrate into one
ecozone; these are indicated as transitional
regions. A few of the ecozones are subdivided
into comparatively independent subregions, such
as Polar/Subpolar zone, which is divided into
tundra and frost debris zone, and ice deserts.
The ecozone map elaborated by Schultz has
overlaps to a great extent with the Walter and
Box zonobiome map.
A global map showing the degree of humaninduced modification of ecosystems was developed at Moscow State University (Milanova and
Kushlin 1993). It reflects the degree of transformation of present-day landscapes (ecosystems).
This map was prepared using existing maps also
authored by Moscow State University entitled
“Geographical belts and zonal types of
landscapes of the world” and “Land use types
of the world.” Each map unit is given a letter
indicating degree of alteration—whether it is virtually undisturbed, with moderate interference
(e.g., secondary vegetation), with strong interference (crop cultivation), or with extremely strong
change (e.g., towns). This map is useful in defining the status of ecosystems, which is essential to
their conservation.
Regional and National Ecoregion
Mapping
TNC (Comer et al. 2003) developed a terrestrial
and marine ecoregions map of the United States
that was originally based on boundaries by Bailey (1995). These boundaries have been extensively modified by TNC’s ecoregional planning
teams; written justification for each modification
is available through TNC’s Ecoregional Planning
Office.
Roger Sayre et al. (2009) of the U.S. Geological Survey in cooperation with TNC recently
produced a map of mesoscale terrestrial
ecosystems for the conterminous United States.
The mapping system was recently extended to
Africa (Sayre et al. 2013). Ecosystems were
identified deductively from the top down by
combining data layers for biogeography,
bioclimate, surficial materials, lithology, landsurface forms, and topographic moisture potential. The methodology was first developed from
South America using concept advanced by
Huggett (1995) and Bailey (1996).
The U.S. Environmental Protection Agency
(EPA) has adopted an empirical ecoregion system developed by Omernik (1987). Boundaries
are determined from overlaying maps of ecosystem components: land-surface form, land use,
potential natural vegetation, and soils. Ecoregion
boundaries are located by subjectively determined coincidence of the component map
boundaries. Factors weighted most heavily
depend on location and scale. For example, precipitation may be more important in one area
150
Appendix D: Comparison of Ecoregion and Related Approaches
been reviewed in relation to several ecosystem
mapping schemes, including Bailey, by Lugo
et al. (1999). Harris (1973) commented on the
inadequacy of the system to predict soil patterns
in Costa Rica.
Walter and Box (1976) developed an ecological classification of the world’s climates. It is
based on the climate-diagram patterns of Walter,
in which temperature and precipitation are plotted
on the ratio 1:2 to show periods of aridity and
humidity. Also taken into account are number of
frost-free days and other extremes that influence
vegetation patterns. Their treatment recognizes
nine different major zonobiomes plus modifiers
that can be added to distinguish particularly dry,
cold, or wet conditions. In addition, major variants
within zonobiomes are introduced: pedobiomes
characterized by extreme edaphic conditions that
cause azonal vegetation; orobiomes that involve
mountain ranges with vertical climate zonation
and elevation belts of vegetation. Zonoecotones,
transition zones between individual zonobiomes,
are also distinguished. Climate zones are determined by drawing lines around climate stations
with similar-appearing climate diagrams as
opposed to applying climate formulas.
The boundaries of ecozones developed by
Schultz (1995 et seq.) follow the subdivision of
the earth into climatic zones established by Troll
and Paffen (1964) in their map, Seasonal
Climates of the Earth. Some geographical
regions are difficult to integrate into one
ecozone; these are indicated as transitional
regions. A few of the ecozones are subdivided
into comparatively independent subregions, such
as Polar/Subpolar zone, which is divided into
tundra and frost debris zone, and ice deserts.
The ecozone map elaborated by Schultz has
overlaps to a great extent with the Walter and
Box zonobiome map.
A global map showing the degree of humaninduced modification of ecosystems was developed at Moscow State University (Milanova and
Kushlin 1993). It reflects the degree of transformation of present-day landscapes (ecosystems).
This map was prepared using existing maps also
authored by Moscow State University entitled
“Geographical belts and zonal types of
landscapes of the world” and “Land use types
of the world.” Each map unit is given a letter
indicating degree of alteration—whether it is virtually undisturbed, with moderate interference
(e.g., secondary vegetation), with strong interference (crop cultivation), or with extremely strong
change (e.g., towns). This map is useful in defining the status of ecosystems, which is essential to
their conservation.
Regional and National Ecoregion
Mapping
TNC (Comer et al. 2003) developed a terrestrial
and marine ecoregions map of the United States
that was originally based on boundaries by Bailey (1995). These boundaries have been extensively modified by TNC’s ecoregional planning
teams; written justification for each modification
is available through TNC’s Ecoregional Planning
Office.
Roger Sayre et al. (2009) of the U.S. Geological Survey in cooperation with TNC recently
produced a map of mesoscale terrestrial
ecosystems for the conterminous United States.
The mapping system was recently extended to
Africa (Sayre et al. 2013). Ecosystems were
identified deductively from the top down by
combining data layers for biogeography,
bioclimate, surficial materials, lithology, landsurface forms, and topographic moisture potential. The methodology was first developed from
South America using concept advanced by
Huggett (1995) and Bailey (1996).
The U.S. Environmental Protection Agency
(EPA) has adopted an empirical ecoregion system developed by Omernik (1987). Boundaries
are determined from overlaying maps of ecosystem components: land-surface form, land use,
potential natural vegetation, and soils. Ecoregion
boundaries are located by subjectively determined coincidence of the component map
boundaries. Factors weighted most heavily
depend on location and scale. For example, precipitation may be more important in one area
150
Appendix D: Comparison of Ecoregion and Related Approaches