7. Biodiversity Patterns in Relation to Climate:
The Coastal Temperate Rainforests of
North America
Paul B. Alaback
The west coast of North America presents a rich array of climatic,
geologic, and historical environments in which a relatively rich flora and
fauna have developed. In contrast to South America , the west coast of
North America is part of a large temperate zone and as such shares serveral
species with continental and in particular the montane biota of inland
portions of the continent. Many species are confined to the coastal region,
suggesting an adaptation to the relatively unique , mild marine climate,
especially that of the temperate rainforest region. Subtleties in climatic
differences between North America and other temperate rainforest types
are hypothesized as a critical factor in explaining differences in structure
and composition of vegetation (Alaback , 1991).
Although much work has been done on describing the biogeography of
many parts of this large region, little work has been done on the broad
climatic and biological patterns that occur within the rainforest regions
(Alaback, 1991; Cordes, 1972; Franklin et al. , 1991; Juday , 1976; Pojar,
Klinka, & Meidinger, 1987; Quay, 1982). This broad-scale approach is
particularly appropriate for understanding linkages between history,
evolution, genetics, and contemporary species interactions. These relationships are of key importance in developing realistic predictions of the
effects of global climate change on these ecosystems. Since the temperature and precipitation patterns are consistent across this broad latitudinal gradient , it is a particularly tempting analog for climate change,
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The Coastal Temperate Rainforests of
North America
Paul B. Alaback
The west coast of North America presents a rich array of climatic,
geologic, and historical environments in which a relatively rich flora and
fauna have developed. In contrast to South America , the west coast of
North America is part of a large temperate zone and as such shares serveral
species with continental and in particular the montane biota of inland
portions of the continent. Many species are confined to the coastal region,
suggesting an adaptation to the relatively unique , mild marine climate,
especially that of the temperate rainforest region. Subtleties in climatic
differences between North America and other temperate rainforest types
are hypothesized as a critical factor in explaining differences in structure
and composition of vegetation (Alaback , 1991).
Although much work has been done on describing the biogeography of
many parts of this large region, little work has been done on the broad
climatic and biological patterns that occur within the rainforest regions
(Alaback, 1991; Cordes, 1972; Franklin et al. , 1991; Juday , 1976; Pojar,
Klinka, & Meidinger, 1987; Quay, 1982). This broad-scale approach is
particularly appropriate for understanding linkages between history,
evolution, genetics, and contemporary species interactions. These relationships are of key importance in developing realistic predictions of the
effects of global climate change on these ecosystems. Since the temperature and precipitation patterns are consistent across this broad latitudinal gradient , it is a particularly tempting analog for climate change,
105