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 Qualitative, descriptive ecology was being superseded by a more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.
