T
he distribution of organisms
through space and time is
a fundamental interest of
ecology. Early in the 19th century,
Prussian explorer Alexander von
Humboldt, a founding father of
ecology, made detailed studies of
plant geography in Latin America.
Philip Sclater described the global
distribution of bird species, and
Alfred Russel Wallace did the same
for other vertebrates, proposing six
zoogeographic regions that are
largely still in use today.Communities
Early fieldwork concentrated on
the distribution and abundance
of organisms, but later in the 19th
century scientists increasingly
recognized that survey data could
also throw light on interactions
between species. In a sense, thisrepresented the true birth of the
field of ecology. Pioneers included
American naturalist Stephen A.
Forbes, who studied wild fish
populations in the 1880s, and
Danish botanist Johannes
Warming, who examined the
interaction between plants and
their environment and introduced
the idea of plant communities.
The link between climate and
a region’s dominant vegetation
type was set out by German
botanist Andreas Schimper, who
produced a worldwide classification
of vegetation zones in 1898. In the
early years of the 20th century,
ecologists devoted more attention
to the interrelatedness of all
organisms within an ecosystem,
exemplified by Russian scientist
Vladimir Vernadsky’s concept
of the biosphere.While studying the vegetation
growing on sand dunes along the
shore of Lake Michigan in the
1890s, American botanist Henry
Chandler Cowles realized that there
was a succession of plant species,
with “pioneer” plants being
replaced by others, which were in
turn themselves supplanted. Fellow
American Frederic Clements used
the term “climax community”
to describe the endpoint of this
succession. In 1916, he proposed
that global vegetation patterns
could be thought of as “formations,”
or large communities of plants—
and the organisms that depended
on them—which reflected the
regional climate. In relatively wet,
temperate regions, for example,
deciduous forest may dominate,
but grassland tends to dominate
in drier, more temperate areas.INTRODUCTION
1799
Alexander von Humboldt
sets out for Latin America,
on an expedition that lays
the groundwork for modern
plant geography.1880 S
The earliest forms
of ecological survey
are conducted in
studies of wild fish
by Stephen A. Forbes.1898
Andreas Schimper shows
how the link between a
plant’s physiology and
external conditions
is key to plant ecology.1916
Frederic Clements coins
the term “climax
community” for the
process of stabilization
over time in ecological
communities.1895
In showing how plants
are related to their
environments, Johannes
Warming unites the fields of
botany and ecology.1845
Pierre-François
Verhulst formulates an
equation to predict
population growth.1899
The changing vegetation
of sand dunes inspires
Henry Chandler
Cowles’ idea of
primary succession.160
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