Integrating Ecology and Environmental Ethics: Earth Stewardship in the Southern End of the Americas Page: 229
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Figure 3. Areas of frontier forests (expanses of relatively
undisturbed, predominantly old-growth forests that are
large enough to maintain viable populations of most of
their characteristic native species) as a function of the
main biome type that remained at the end of the twentieth
century. The data are based on the assessment by Bryant
and colleagues (1997, p. 45). Abbreviation: km2, square
(3) Unique biodiversity and extremely high endemism. Topographic
and climatic barriers isolate the austral South American
forest biome from the nearest tropical forests by
1500-2000 kilometers (km) (Armesto et al. 1998). The high
Andes along with the vast dry steppe of Argentina form the
eastern boundary. To the north lies the hyperarid Atacama
Desert. The southern Pacific Ocean bounds the region on
the west and south. This geographic isolation has generated
remarkably high levels of vascular plant endemism: Close
to 90% of the woody species and 33% of the woody genera
are endemic to this austral biome, including 24 monotypic
genera (Arroyo et al. 1996). In addition, about 60% of the
bryophyte species (mosses and liverworts) are endemic to
the temperate forest biome (Villagran et al. 2005), and the
lush forests and moorlands of the sub-Antarctic Magellanic
ecoregion are home to around 5% of the world's bryophyte
species, on less than 0.01% of the Earth's land surface (Rozzi
et al. 2008a). Among the vertebrate fauna, 50% of fish, 80%
of amphibian, 36% of reptile, 30% of land-bird, and 33%
of mammal species are endemic to the forest biome. Such
levels of endemism are similar to those recorded for some
oceanic islands (Armesto et al. 1996).
(4) The largest area of temperate forests in the Southern
Hemisphere. Extending over 26 of latitude (30o-56 S),
South American temperate and sub-Antarctic forests cover
an area of about 13.6 million hectares (ha) in Chile (Neira
et al. 2002) and 2 million ha in southern Argentina (SADSA
2009). The total forest area of 15.6 million ha is the largest
expanse of evergreen and deciduous temperate rain forest
remaining in the Southern Hemisphere, more than twice
as much as that in New Zealand and Tasmania combined.
New Zealand temperate forests extend over 7 of latitude
(40o-47 S) and cover an area of 4.5 million ha, whereas
those of Tasmania growing between 41 S and 44 S cover an
area of 1.4 million ha (Veblen et al. 1996).
(5) The largest temperate wetland area in the Southern
Hemisphere. South American temperate forests at high
latitudes are embedded in a matrix of peatlands, bogs, and
cushion bogs, known as the Magellanic moorland complex
(Godley 1960). Magellanic moorlands in the narrow tip of
southern South America cover 4.4 million ha and represent
the largest wetland area at high latitude in the Southern
Hemisphere (Arroyo et al. 2005). The only other very large
areas of wetlands in the Southern Hemisphere are tropical,
including the Amazon River Basin, the Pantanal, and the
Congo River Basin (Keddy et al. 2009). Under an oceanic
climatic regime and embedded in archipelagic landscapes,
the Magellanic moorlands offer an ideal system for com-
parative subpolar ecological research, particularly for
assessing the drivers and trends of recent climate change.
Austral peatlands also play a major and poorly understood
role in the regulation of regional hydrologic cycles and,
presumably, in determining the global carbon budget (Diaz
et al. 2007).
(6) The world's cleanest rainwater and streams. Because south-
western South America is positioned outside of air streams
carrying industrial pollutants and receives rainstorms that
originated over the southern Pacific Ocean, the austral
forests and associated ecosystems are to a large extent free
of atmospheric pollution (Hedin et al. 1995). Precipitation
chemistry in this region reveals one of the lowest concentra-
tions of nitrate ever recorded (Likens 1991, Weathers et al.
2000). Therefore, the soils and streams in high-latitude
South American ecosystems are uniquely suited for com-
parative biogeochemical studies, especially with chronically
polluted temperate latitudes in Europe and North America
(Galloway et al. 1994), and they provide a unique baseline
to study the linkages between atmosphere and biosphere
under conditions similar to those that prevailed prior to the
industrial revolution (Hedin et al. 1995).
(7) Patagonian ice fields. Southwestern South America con-
tains vast areas of continental ice: 4200 km2 in the Northern
Patagonian Icefield, 13,000 km2 in the Southern Patagonian
Icefield, and 2300 km2 in the extensive glacier systems of
the Darwin Cordillera on Tierra del Fuego and the neigh-
boring archipelagoes (Porter C and Santana 2003). Together,
these glaciers are (a) the largest ice masses in the Southern
Hemisphere, aside from those in Antarctica; (b) immense
reservoirs of freshwater; (c) unique depositories of records
of past climate changes at high southern latitudes; and
(d) more sensitive to global climate change than the Alaskan
glaciers (Rignot et al. 2003).
March 2012 / Vol. 62 No. 3 * BioScience 229
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Rozzi, Ricardo, 1960-; Armesto, Juan J., 1953-; Gutiérrez, Julio R., 1953-; Massardo, Francisca; Likens, Gene E., 1935-; Anderson, Christopher B. et al. Integrating Ecology and Environmental Ethics: Earth Stewardship in the Southern End of the Americas, article, March 2012; [Reston, Virginia]. (digital.library.unt.edu/ark:/67531/metadc130199/m1/4/: accessed February 24, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT College of Arts and Sciences.