The modern
definition of nature derives from the development of the science of
ecology and its application to conservation issues. There have been
at least six developmental stages: formative, descriptive,
quantitative, dynamic, interventionist and
moralistic.
Formative phase
Several people stand
out as major influences on ecological thinking long before the
field coalesced into a unified discipline. Charles Lyell, the
father of geology, in his book Principles of Geology (1830)
helped overturn Linnaean concepts of a static nature under strict
divine rule. Lyell was among the first to understand that
geological change occurred gradually over eons, that species
dispersed actively around the world, and that competition was a
driving force in evolution. Lyell was a major influence on Charles
Darwin. In On the Origin of Species (1859), Darwin built
upon Lyell and advanced natural selection as the primary mechanism
of evolution.
Henry David Thoreau
was contemporary with Darwin and one of the first naturalists to
understand succession as a major pattern of change in ecosystems.
Thoreau also was one of the first to glimpse the loss of species
and habitat and its cultural ramifications at the onset of the
Industrial Revolution. Another American, George Perkins Marsh,
contributed a pioneering global account of humanity's role in
reducing the capacity of Earth to support life in Man and
Nature (1864).
Descriptive phase
Ecology in the early
decades of the 20th century was a descriptive, holistic science.
The key themes were the balance of nature and succession toward a
stable, climax state. Plant ecologist Frederick Clements dominated
the field with his idea of natural communities as interdependent
superorganisms evolving collectively.
Quantitative phase
By the time A. G.
Tansley coined the term "ecosystem" in 1935, Clements's views were
falling from favor. Qualitative, descriptive ecology was being
superseded by a more quantitative ecology of energy and nutrient
flows, food chains, and trophic levels. Natural history was
eclipsed by mathematical models.
Dynamic phase
In the 1940s,
Raymond Lindeman developed important theories on energy flows in
ecosystems and G. E. Hutchinson refined the concept of feedback and
constructed some of the first mathematical models of populations.
Later ecologists built on these fundamentals with Eugene Odum
(ecosystem characteristics), Frank Bormann and Gene Likens
(nutrient flows), and Robert MacArthur (population models) making
key contributions. Where in the past scientists (and
environmentalists) characterised ecosystems as orderly and
relatively balanced, these new viewpoints emphasize systems
as dynamic, changing at different space and time scales, and full
of uncertainty. Nature is not always in "balance"; and changes are
difficult, sometimes impossible, to predict.
No longer was the
study of nature just about numbers of species or types of
ecosystems. The new emphasis on non-equilibrium processes
(especially natural disturbances such as fires and floods) resulted
in a comprehensive definition of nature that includes not only the
diversity of all life forms from genes to landscapes, but also the
fundamental patterns and processes of that produce patterns in life
forms over time and in space.
Phase of intervention
Since the late
1970s, as knowledge of the growing influence of human economic
development on natural patterns and processes has accumulated, the
'biodiversity crisis' emerged. A new ecological world view
appeared in which political and economic intervention is directed
to support conservation management. The management of
biodiversity alongside world economic growth is at the heart of
policies of sustainable development.
Phase of moral
evaluation
Whether trees, or
animals, ought to be preserved 'for their own sakes' wrote the
social historian E.M. Trevelyan is an interesting question on which
different opinions might be held. But the argument for the
preservation of natural scenery and the wild life of English fauna
and flora may be based on motives that regard the welfare of human
beings alone, and it is those arguments alone that I wish here to
put forward. To preserve the bird life of the country is required
in the spiritual interests of the human race, more particularly of
the English section of it, who find such joy in seeing and hearing
birds'.
As Trevelyan
implied, it was not for the sake of the creatures themselves, but
for the sake of men, that birds and animals would be protected in
sanctuaries and wild-life parks. In 1969 the United Nations and the
International Union for the Conservation of Nature defined
'conservation' as 'the rational use of the environment to achieve
the highest quality of living for mankind.'
But even in the
early modern period there were some perhaps hypersensitive persons
who were prepared to go further than this. For them it was
increasingly difficult to accept the primacy of human needs when to
do so involved inflicting pain on domestic animals or eliminating
whole species of wild ones. In more recent times these difficulties
have been widely perceived. Today there are writers of books who
refer to the extermination of the wolf as a 'pogrom' or
'holocaust'; and the law journals carry articles on whether trees
have rights.
The early modern
period had thus generated feelings which would make it increasingly
hard for men to come to terms with the uncompromising methods by
which the dominance of their species had been secured. On the one
hand they saw an incalculable increase in the comfort and physical
well-being or welfare of human beings; on the other they perceived
a ruthless exploitation of other forms of animate
life.