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 Qualitative, descriptive ecology was being superseded by a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.
