Biolopcnl ,Journal of the Linnean Society (1987), 32: 5-16
What is Ecology?
Professor Sir A R T H U R TANSLEY, F.R.S.
Chairman of the Xature Conservany and President of the Council for the Promotion of Field
Sludies
(Originally published in 1951 as a pamphlet by the Council for the Promotion
of Field Studies, which became the Field Studies Council)
The word ecology is now appearing in print more and more frequently, even in
some newspapers. But how many people have any clear idea of what it means?
Apart from those who actually work a t the subject, very few indeed! No doubt
the great majority of biologists, with no special interest in ecology, have a
general notion of what it is about, but many of them are far from appreciating
the full scope and potentialities of the subject. One is often asked just what
ecology is, and an attempt to make its nature and aims as clear as possible to all
who are or may be interested is well worth while, for active ecological work of
one kind and another will be of vital importance to the whole human race in
coming decades.
EARLY HISTORY
The word, or rather its German equivalent, was actually invented by Ernst
Haeckel as long ago as 1870. Haeckel was a well-known German professor of
zoology who gained fame, and indeed notoriety, by expounding and defending
the theory of evolution, which was a t that time far from being as widely
accepted as it is to-day, and joining with it a philosophy of atheistic monism. All
that does not concern us at all. The word was very little used during the next 25
years, and it was not till 1895 that Eugenius Warming, Professor of Botany at
Copenhagen, published a book in which the Danish equivalent of the adjective
“
ecological” was used in the title. This may be rendered into English as PlantAggregates: Foundations o f Ecological Plant Geography. In the following year a
German translation was published, and this was widely read in England and
America, most English-speaking professional botanists being able to read
German hut not Danish.
Warming’s book was an excellent and very attractive exposition of one
fundamental aspect of its subject. It opened something like a new world to many
young botanists, and its publication marks the beginning of the general use of
the words “ecology” and “ecological.” Shortly afterwards A. F. W. Schimper in
Germany, and Charles Flahault in France, who had long occupied themselves
with these topics, also wrote on the subject from somewhat different angles,
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0 1951 Field Studies Council
6
A. TANSLEY
Schimper dealing with what was then known of the vegetation of the whole
world in a large and very fully illustrated volume, of which an English
translation appeared a few years later. The publication of Warming’s and
Schimper’s books was a tremendous stimulus to ecological work in America and
England. A good many of the papers published during the first years of the new
century were, however, rather trivial and some of them decidedly slovenly.
Besides stimulating many good biological minds, ecology had a great attraction
for weaker students, because it was so easy to describe particular bits of
vegetation in a superficial way, tending to bring the subject into disrepute.
Notable exceptions to this futility were the works of the great pioneers of
scientific plant ecology in America, H. C. Cowles and F. E. Clements, and their
pupils and followers. I n Britain the pioneer work was done by Robert and
William G. Smith (Robert Smith had been a pupil of Flahault a t Montpellier)
and their pupils and co-workers, first in Scotland and then in England. In 1904
a small body of enthusiastic workers in plant ecology formed the “British
Vegetation Committee,” succeeded in 1913 by the British Ecological Society
with its Journal o f Ecology; the Journal o f Animal Ecology was started by the
Society in 1932. In 1915 the Ecological Society of America was founded, and its
journal, Ecology, began to appear in 1920.
The reader may well complain at this point that he has still not been told
what ecology actually is. The excuse must be that some little historical
background was desirable first. It will already have become apparent that plant
ecology has to do with vegetation and with plant geography. But there is much
more to ecology than that.
THE ESSENCE OF ECOLOGY
The word ecology is derived, like the common English word economy, from
the Greek oikos, a house, abode, dwelling, and this etymology gives the key to the
meaning of the word. I n its most general sense ecology may be defined as the
study of plants and animals as they live in their natural homes, and this implies the
study of all they are and do when they are “at home.” I n the case of mobile
animals “home” must be extended to include all the places they are in when
they are feeding, seeking food, escaping, sheltering, migrating or breeding-in
fact the whole of their behaviour during life. Most plants do not move actively
about, but they also “behave,” in the sense that they grow in various directions,
and, to various extents, make their own food, and reproduce themselves. While
modern ecological work at the end of the last century and the beginning of this
was practically confined to plants, it was soon extended to animals, and animal
ecology is now an actively developing and important subject. In fact anything
like a satisfactory study of the ecology of the populations of living beings
inhabiting a particular area must include both plants and animals because they
are not only constantly affecting one another, but often depend upon one
another for their wellbeing or even their continued existence.
Green plants form the basis of life as it is lived upon the earth because they,
almost alone, are able to make organic matter, i.e., the substances of which all
living organisms consist, out of inorganic materials like water, carbon dioxide
(from the air) and mineral salts (from the soil). Animals depend for their food
on this activity of green plants, directly through eating them (herbivorous
WHAT IS ECOLOGY?
7
animals), or (carnivorous animals) indirectly by eating other animals which
have fed on the plants.
THE PLANT CARPET
And there is another sense in which plants form the basis of life upon the
earth. I n favourable conditions of climate and soil plants form a more or less
continuous carpet on the earth’s surface-woodland,
grassland, heath, moor,
bog, etc.-where
the carpet has not been destroyed by man or by some
catastrophic natural agency. I n very unfavourable climates, where there is
insufficient water, intense cold throughout the year, or constant violent winds,
plants are unable to form a continuous carpet. In subtropical (and other)
deserts the kinds of plants that can live there at all are represented by scattered
individuals with bare ground between them. In the severest conditions of all
(e.g., on icefields or in the immediate neighbourhood of volcanoes) plants may
be absent altogether.
The normal plant carpet not only supplies the food of herbivorous animals on
which the carnivores depend for their food, it also provides the shelter which most
animals need because many of them cannot live, at any rate continuously,
completely exposed to the elements. Others require shelter to hide from their
enemies, or again to conceal themselves from intended prey so as not to frighten
the intended victim away before the pounce can be made. There are thousands
of kinds of small “invertebrate” animals-many
insects and tiny creatures
belonging to other groups-which live in the carpet of vegetation or in the soil
on which it grows, and never leave it. Plants thus perform essential services to
animals by supplying them with food and shelter; herbivorous animals destroy
plants by eating them, but some (mainly insects) also benefit plants by bringing
pollen (essential for reproduction) from flower to flower, and many animals of
all kinds and sizes also help to distribute seeds from place to place.
PLANT COMMUNITIES
The plant carpet differs, of course, very much according to the conditions in
which it grows, in the first place climate and to a large extent also soil. We have
only to think of the luxuriant evergreen tropical rain forests such as we see in
Malaya and neighbouring regions, the deciduous temperate forests of western
and central Europe and eastern North America, the leathery small-leaved scrub
of the Mediterranean region, and the northern and sub-alpine needle-leaved
coniferous forest, to realise the primary importance of climate in determining
the type of forest that can exist in a given region of the world. And to the forests
we must add the great natural grasslands-the American prairies, the south
Russian steppes, the South African veld-determined
by yet another type of
climate, with summer rainfall but drier than the forest climates. T h e subtropical
deserts of North Africa and south-west Asia are much drier still, with constant
deficiency of water and very sparse distinctive vegetation. Then there is the
special vegetation of high mountains. The influence of soil conditions is seen in
the characteristic vegetation of constantly water-logged soils, giving us swamps,
marshes, fens and bogs, each with different kinds of plants, and at the other
extreme the vegetation of very dry sandy soils. I n forest regions, too, different
kinds of tree often live on different types of soil.
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A. ’I‘ANSLEY
The plant carpet of the world falls naturally, in fact, into unils of vegetation,
or, as we call them, plant communities, each with its own kinds or species of plants,
of which the dominant form and structure are distinctive of the community, and
have a dose relation to the climate or soil, or both, in which they occur. It was
these units of vegetation or communities of plants that Warming and Schimper
described and analysed in their epoch-making books. (Many of the great types
of vegetation had, of course, been described much earlier, e.g., by the great
geographer and naturalist, Humboldt.)
INTEGRATION AND ORGANISATION OF COMMUNITIES
M‘e speak of plant communities by analogy with human communities, for
when any set of animals or plants live side by side in a particular habitat they
always tend to form an entity, primarily because they are living under more or
less identical conditions (differing from those of adjacent areas) which have
similar (though not necessarily identical) effects upon them all, and also because
the individual plants affect one another, through competition for living space
and often in other ways too, as we shall see presently. Of course, the bonds
uniting the members of a human community are very much closer than those of
a plant community or of most animal communities- the “integration” is much
greater-because human beings can communicate with one another through
speech and thus are in a position to have profound psychological effects on one
another’s lives-apart from the unpleasant habit of imprisoning, torturing or
killing one another in large numbers. T h e interactions of human beings living
together have led to a high degree of organisation in human communities, and
this has become extremely complex in those which we call civilised.
Considerable organisation is found also in the communities of many gregarious
non-human animals, for example in some herbivores (cattle, deer, antelopes)
and such carnivores as wolves. But it is in certain gregarious insects (e.g., hivebees, termites and ants) that we meet with the most complex community
organisation in non-human animals, with far-reaching structural and functional
differentiation and division of labour between different “castes)’ (workers,
“soldiers,” etc., which are structurally incapable of breeding, besides the
comparatively few sexual individuals) , and a completeness of “integration” of
the whole community which is still (fortunately) not found among human
beings, though it seems to be the ideal of some moderns, and certain approaches
to it have been made from time to time in human history.
From their very nature plants cannot bring about the kinds of organisation
and integration of the community which have just been mentioned. The
members of human and of many animal communities typically belong to a
single kind or species of animal, though there are a certain number in which two
or more species are associated. But plant communities typically consist of several
or many different species living together-in
the most complex, such as the
Malayan rain-forest, several hundred species in one community. Between the
different species of a plant community various relations exist. Some compete
directly with one another for living space, water and light, and the wcakcr
individuals go to the wall. But in complex communities such as forests in which
the vegetation is “stratified,” there is no direct competition between the
different layers or strata of the forest (trees, shrubs and herbs). T h e shrubs do
WHAT IS ECOLOGY?
9
not compete with the trees, nor the herbs of the forest floor with either trees or
shrubs. O n the contrary, many of the herbs of the forest floor could not exist
except in the shade provided by the foliage of the tree canopy which makes the
air relatively quiet and damp inside the forest, and some of them depend on the
humus of the soil formed by the fallen and decaying leaves of the trees. Then,
again, the great trees of a tropical rain forest support a number of woody
climbers (lianes) which climb up the trunks and flower on the forest roof, and
also a number of plants (epiphytes) which are not rooted in the soil a t all but
grow upon the trunks and branches of the trees and draw their food from humus
lodged in crevices of the tree bark and their water partly from this and partly
from the abundant rainwater running down the trunks of the trees. Quite
similar relationships, though on a much less elaborate scale, exist between the
different components of temperate forests. All such relations of dependence of some
members of a plant community upon others build up the unity of the community
as a whole-a unity which is originally based on the fact that it consists of a
particular collection of species growing together in the same general conditions
of climate and soil, but is notably integrated by the establishment of any form of
interdependence between the members.
Practically all plant communities have animals associated with them in
different ways, ranging from species of birds and mammals which live in forest,
or on grassland or heath, to minute invertebrates which are closely tied to the
plants (often to particular species of plant) by the exigencies of their lives.
Sometimes there are small local communities of small vertebrates, such as
rabbits or voles, in our own woodlands or grasslands, or of various invertebrates,
within the general plant community; and these may be very highly integrated in
themselves-ants’ nests in a conifer (or other) wood are a good example. Many
species of the larger animals, mostly birds and mammals, which are highly
mobile, commonly range, however, through many plant communities, and are
not tied to, or in any way dependent upon particular ones. But when you have
scattered individual animals, or communities of animals, which are so tied, the
entire complex of natural plant and animal life (so long as it is not interfered
with by man), together with the physical factors of climate and soil which
permit its existence, forms, when mature, a n integrated and balanced “system”
which may be called an ecosystem, and can sometimes maintain itself, apparently
indefinitely, so long as the conditions which determine it continue.
Such is the subject matter of ecology and it will be realised at once that it is
both extremely wide and extremely complex.
COLLABORAIION IN ECOLOGICAL WORK
To get really satisfactory ecological knowledge of an ecosystem it is necessary
to make a thorough study of both the plants and the animals present and to
determine their relations to one another, as well as the nature of the habitat or
“home” of the community and the relations of the organisms to it.
Unfortunately, in current biological training the student specialises either in
botany or in zoology and has rarely sufficient knowledge of the other subject to
enable him to make a comprehensive study of both plants and animals. I t is true
that animal ecologists are more and more being forced to acquire some
considerable acquaintance with the plant communities on which their animals
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A. TANSLEY
depend, b u t it is still rare for a plant ecologist to have enough zoological
knowledge to make an adequate ecological investigation of the animal elements
in a n ecosystem. Close collaboration between an animal and a plant ecologist,
or by a team of several, is one way out of this difficulty. But such collaboration,
to be really successful, must be genuinelyjoint work in which each partner fully
follows and understands the contributions of the others. Only thus can a unijied
picture of the whole be built up.
It was the fresh emphasis on the natural aggregates that plants form when left
to themselves, and on the dependence of these on the conditions under which
they live, that led to the great modern development of ecology which began
about the turn of the century. Of course the great types of vegetation had been
recognised and given names in common language from the earliest times. It
could not have been otherwise, since they were the most conspicuous and
important parts of primitive man’s environment even after he had begun to
cultivate the soil and to keep his flocks and herds. They continued to be so
through the ages till the enormous growth of great cities eventually separated
the people who lived in them from their original surroundings-a fateful divorce
whose price we are now paying. But recognition and even intimate practical
familiarity with the great types of plant community and the animals they
contain is a very different thing from their use as objects of close scientific study;
and it is the increasing appreciation of their profound interest and value from
the scientific and the practical points of view that has marked the past halfcentury.
AUTECOLOGY AND ANCILLARY STUDIES
Close study of a plant community always leads to questions about the r61e
and behaviour of particular species which are members of it. Investigation of the
ecology of individual species (autecology as it is called), especially of the dominant
(usually, but not always, the tallest) members of a community, is an essential
(and the most time-consuming) part of ecological work. Until the most
important facts about them are learned it is impossible to penetrate at all deeply
into the ecology of the community as a whole, because of course the latter is
made up of the behaviour and interactions of the species comprising it, and the
dominant species (e.g., the trees that form the canopy of a forest, the ling or
heather of a British heath, certain kinds of grass in a meadow, etc.) may have a
controlling influence on the whole community. While the great development of
modern ecology was initiated, as we have seen, by the recognition of the
importance of plant communities, and they have remained a leading subject in
current research, the ecology of single species presents the most fundamental
problems of all. This kind of fundamental ecology involves a knowledge and use
of the most various branches of biology. First of all, we must know our plants
and animals, recognise the named species and varieties to which they belong,
and that is “systematic” botany and zoology, or taxonomy. Then we must
understand the members or organs of their bodies and how they develop in their
life histories, which is morphology. We cannot understand how a plant or animal
works in detail unless we are familiar with the structure of the tissues (cellaggregations) of which it is composed and through which its activities are
carried on (histoloo). T h e study of how an organism does work, both its internal
WHAT IS ECOLOGY?
12
processes and how it acts on its environment, and its environment on it, is
physiology, a science which underlies most ecological phenomena. Again, we must
know something of the modern science of heredity, called genetics, for many of
the forms we meet in the field cannot be understood without knowing or finding
out their genetic status within a species, with which their ability to live in a
particular community may vary.
It is not intended to suggest that every good ecologist must be an expert in all
these branches of biology-nowadays
an impossible demand. Some sound
elementary knowledge of all of them he must have, but that is not so difficult to
acquire. Above all, however, he must have practical experience of field workand the more the better. Ecology is essentially a “field subject”: progress cannot
be made in it without constant observation (and frequently experiment) in the
field, though some of the ecological problems met with in the field have to be
attacked in the experimental garden or the laboratory, or both.
Besides the particular branches of biology referred to there are certain nonbiological subjects of great importance to the ecologist-climatology
and
meteorology, geology, physiography and soil science (pedology). This is because these
subjects deal with climate and soil, which, as we saw, are the main primary
factors determining the distribution of plant communities, and training in them
is very useful to the ecologist. I n default of that he must make himself
acquainted with those parts of them which are clearly important in the
particular work on which he is engaged.
All this may sound very alarming to the beginner who is attracted to
ecological work but is doubtful of his capacity to fit himself for it. There is,
however, a consideration which should be reassuring. While an ideally complete
equipment for ecological work is impossible in the time available to the student,
and indeed beyond the mental capacity of any individual, the field open to
research is so vast and the problems it presents so diverse and of such varying
degrees of difficulty that everyone who wants to work in the field can find
something really useful to do, whatever his natural bent and his training. And
he can pick up a good deal of necessary knowledge as he goes along.
ECOLOGY AND NATURAL HISTORY
In the early years of the century ecology had a hard fight for recognition, at
least in this country-it was more quickly and widely accepted in America. A
good many biologists tended to regard the subject with something like
contempt-an
attitude partly excused by some of the superficial, trivial, or
slovenly observations published under its name. “There is nothing new in all
this,” they would say, “it is only the old natural history masquerading under a
high-sounding name-and not always very good natural history at that!” It has
needed some decades of steady work to change this attitude, and even to-day a
friend of mine, a first-rate biologist in his own line, professes not to know what
ecology means. But there is plenty of evidence now of its wide acceptance in the
schools and universities and of the increased recognition of its scientific and
practical importance.
It is perfectly true that ecology is natural history-it has been aptly called
scientific or systematised natural history-and that a great deal of the excellent
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A. TANSLEY
natural history work done before Warming and Schimper would now be classed
as ecology. The growing popularity of the subject in this century represents a
breakaway from the confinement of serious work in biology to the laboratory,
museum and herbarium, which at one time divorced the study of plants and
animals from their actual life in their natural surroundings. Laboratory,
muscum and herbarium are still, of course, and always will be, absolutely
necessary for the pursuit of biology, not least as adjuncts to the study of ec,ology
itself, but the primary place in which to work at ecology is necessarily the field.
APPLIED ECOLOGY
What has been written up to this point relates to the pure science of ecology,
pursued for the attainment of fundamental knowledge about living nature and
her ways. But, as in most sciences, we have to regard also the applications of’
such knowledge to practical human uses. Just as a fundamental knowledge of
physics and chemistry is necessary for engineering and for modern industrial
processes, and of human anatomy and physiology for surgery and medicine, so a
knowledge of outdoor biology, soil science and climatology, which may be best
integrated and expressed as ecology, is necessary for any industry concerned
with growing plants, such as agriculture and forestry--for all use of land which
contemplates maintenance of the existing natural vegetation or its replacement
by some crop of man’s choosing. For these purposes it is not always necessary to
take account of all the subtleties of pure theoretical ecology, though many of its
concepts turn out to be very useful in applied work.
A thorough understanding of the ecology of natural forest is a very important
preliminary to the work of the forester in dealing with the growth and timber
production of artificial plantations of trees, and neglect of this training has led to
costly mistakes. The same may be said of the ecology of “rough grazings“
consisting entirely of native plants which were not sown but came there by
themselves. In all such cases a thorough knowledge of what nature is doing on a
particular site is the best and often essential preliminary to satisfactory human
exploitation.
An important job in which ecology is highly relevant is the war against p e s k
attacking crop plants, of which various fungal and insect parasites are the most
important. Here, no doubt, mycology (fungi) and entomology (insects) are the
primary subjects necessary, as is now recognised by the appointment of trained
mycologists and entomologists as pest-control officers. But mistakes arc
frequently made through too narrow a view of the work required. We not only
have to understand the structure and life histories of the fungus and insect pests,
but also the ecology of the host plants, the different conditions in which they
flourish and also those in which they are most liable to attack by the parasite. A
comprehensive and penetrating knowledge of the whole background of a pestattack is the soundest basis for devising efficacious measures against it. Again,
serious errors in practice may arise from too narrow a concentration o n
destruction of a pest attacking a natural community, where the means of’
destruction employed may involve the injury or death of other members of the
community that are useful or essential to the wellbeing of the whole, or the
destructive agent is found to have other unexpected and undesired results.
WHAT IS ECOLOGY?
13
THE GENERAL CASE FOR APPLIED ECOLOGY
At the outset it was said that active ecological work of one kind and another
will be of vital importance to the whole human race in coming decades, and the
reader will naturally want to know what are the grounds of such a sweeping
statement.
They may be stated most generally by saying that we cannot control or utilise
nature to the best advantage unless we first understand her, and that ecological
work is the right road to such an understanding so far as it concerns the
vegetation and animal populations of the world. Apart from the most sterile
areas and those occupied by human constructions the land surface of the earth is
covered either by natural vegetation-----muchof it largely modified by men’s
activities-or by planted crops yielding foodstuffs or industrial raw materialtimber, fibres, rubber and so on. Much natural vegetation is annually destroyed
by human agency, intentionally or carelessly, and not replaced, leaving great
areas derelict, or the method of cultivation is ill-judged, or an area is abandoned
after crop failure. Any of these mistreatments may lead to extensive erosion by
rain or wind or to “dust bowl” formation, according to the climate. Such
careless and disastrous exploitation of man’s natural heritage has been ably
dealt with in more than one recent book. Very little ecology is necessary to point
the way to more intelligent treatment of nature in the most flagrant cases of
abuse. But there are many others in which a proper understanding of the
ecology of the vegetation to be dealt with is really necessary before what is
practicable and what is most advantageous can be settled. T h e recent groundnuts fiasco in Tanganyika is a conspicuous case in point. A thorough ecological
investigation of the areas, especially of their climate and soil, of the bush already
growing there, and of the conditions necessary for the good growth and
economical harvesting of ground-nuts themselves should have been carried out
before this vast and ill-fated adventure into unknown ecological territory was
decided upon. And there were, in fact, highly qualified ecologists available for
such a job. Of course, it would have taken time and the promoters of the scheme
were in a hurry. But if you try to “rush” nature she is very apt to avenge herself
to your ultimate detriment. Nature just won’t be rushed.
THE FOOD-POPULAlION PROBLEM
In the not very distant future the human race is faced by dangers at least as
threatening and certainly more inevitable than those of atom bombs, because
they are inherent in the activities of many hundreds of million people, unless
necessary counter measures are taken in good time. Attention has been called to
them by several instructed and responsible writers, but there is little sign that
those responsible for international corporate action have taken heed. The
human race, or rather, some of the largest parts of it, is breeding a t a rate that
will very soon outrun food supplies which are available now or are likely to
become available unless very far reaching and drastic steps are taken at once or
in the near future.
The possible steps seem to be three-fold. The first is evidently reduction of the
birthrate of the more prolific races. This is clearly a problem of very great
difficulty but one that ought to be squarely faced, for example by the Indian
Government. It scarcely concerns the subject of this pamphlet though it is
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A. TANSLEY
doubtless part of what is now often called “human ecology,” which is far too
vast a subject to deal with here. This is certainly the most important of all
counter measures, for unless the present rate of population growth is brought
down to a much lower level it would seem that no increased annual supply of
food which will be at all practicable could possibly feed the future population of
the world.
Vital as reduction of birthrate is, it is also most important to increase the
quantity and improve the quality of the world’s food supply, in the first place by
getting greater and better quality yields from food-producing land that already
exists. This is essentially a job for the scientific agriculturist; scientific agriculture
is certainly applied ecology, but it is clearly ecology of a very special kind,
depending on a profound knowledge of the optimum conditions for cultivation
of a particular crop in the particular district where it is to be grown. Quantity of
yield depends partly, and quality mainly, on breeding the best new strains of
food plant and that is work for the geneticist or plant breeder. The new wheats
bred in England 40 years or so ago are only one of the earliest and most
conspicuous examples of the striking successes which have been reached in this
field. There have been many others since.
A third step is to bring more potentially food-producing land under
cultivation. That this could be done on a large scale in some tropical and
subtropical countries of at least three continents is certain, but in view of the
urgent need of much more and much better food it is necessary for the proposed
sites and proposed crops to be chosen only with the fullest possible knowledge
that can be obtained beforehand and tested by carefully planned field
experiments. The ecology of existing vegetation on possible sites has first to be
thoroughly studied and compared with that of possible food plants, and then a
series of crucial experiments undertaken before any schemes on a large scale are
entered upon. I n this way very considerable successes could no doubt be
obtained and the world’s food supply significantly increased. This is essentially a
job for ecologists and ecologically trained agriculturists, and it is one of the most
important jobs in the world,
Many ancillary tasks would have to be undertaken, of course: improved
methods of cultivation, of harvesting, of transport, marketing and distribution,
and training of natives in suitably adapted modern agricultural practice. If it is
to be done on a sufficient scale the work must probably be to a large extent
mechanised. Hurry is fatal, as we have recently seen, but delay will be equally
fatal, for the danger of widespread starvation is creeping upon the world year by
year. It is not far from India to-day; serious malnutrition and under-nutrition,
already rife there, is increasing, and the importation of food from other countries
is a mere temporary palliative. The existing food resources of the world are
simply not large enough to meet the need.
An ecological approach to these problems is a necessity because they all
ultimately depend on ecology, whatever specialised technical training may be
required in addition. The means of acquiring the ecological outlook are
therefore of prime importance.
’1 WO RECENT ORGANISATIONS
Within the last few years two organisations, both of which have begun to
serve the ends of ecology, have been set up in this country. One is the Nature
WHAT IS ECOLOGY?
15
Conservancy, which is a minor Government Department under the same
committee of the Privy Council as the Agricultural Research Council. The
Conservancy itself, which makes its own policy and conducts its own affairs,
reporting to the Lord President, who is responsible for it to Parliament, every
year, is a body of about 20 people, mainly naturalists. The work of the salaried
scientific staff is very largely ecological. I n the National Nature Reserves set up
by the Conservancy, good samples of the different natural plant communities
are to be preserved, together with typical animal populations, and in the
Reserves ecological surveys and research will be carried out by members of the
staff and other qualified workers. I n this way a body of ecological knowledge
will be amassed which will be at the disposal of Government Departments,
public authorities, and all responsible bodies and individuals who can use it.
Meanwhile British ecology should be notably advanced. While considerable
knowledge of it has been built up during the past half-century there is a great
deal more that we do not yet know about our native vegetation and animals. All
such knowledge will be valuable not only as pure science but often as a guide to
the wisest forms of land utilisation.
The other organisation is the Council for the Promotion of Field Studies,
which is a private body, but of national scope. This has established four
residential “Field Centres” each under the charge of a trained warden and
assistant warden. T o these Centres students come, classes from the upper forms
of schools with their own teachers, university students, and private individual
students, for a week or more at a time, to carry out field work of every sortmuch of it ecological-under the expert guidance and sometimes the personal
tuition of the warden or assistant warden. The four Centres are widely dispersed
in England and Wales: all four are situated in unspoiled rural country of very
different types, so that a considerable variety of plant communities and animal
populations can be studied by visiting two or more in succession.
The work of the Council has been very successful and has aroused a great deal
of enthusiasm among the visiting students. Not only does it provide training in
an attractive subject of vital importance for the future, but by taking the
students into the open air and into unspoiled nature as the primary field of work
it has a unique effect on their minds and bodies. For many it is their first
experience of a new and fascinating realm of mental activity-both
scientific
and delightful. While the objects of the Council are primarily educational, many
schemes of ecological research are in progress or projected at the different
Centres, and this is a vital element in their work.
Unfortunately the Council’s work is still hampered by insufficient means. The
cost of the scientific staffs at the Centres cannot be met from students’ fees, and
Government grants that have enabled the Council to carry on up till now are to
be drastically reduced.
CONCLUSION
Those who have had no actual experience of serious ecological work in the
field, and who want to understand its essential nature, must realise that this lies
in a distinctive point o f view in the approach t o j e l d biology. The ecological approach
comprehends the diverse features of the landscape with their progressive change
or relative stability, the factors of climate and soil, whether these are wholly
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A. TANSLEY
natural, as in virgin vegetation, or more or less profoundly modified by past or
present human activity-and the living organisms themselves, the centre of the
picture, as they are affected by the factors of their environment and by their
interactions with one another. When once grasped this characteristic unifying
point of view is unmistakable. There are some biologists who are real experts in
their own lines of work, but who have never got hold of it at all, though their
own specialised knowledge is essential to progress in ecological research. An
eminent German plant geographer of the last generation once wrote that the
strength of ecology depends upon the enormous wealth of data that pour into it
from every side, and it was this specialised knowledge from the different
branches of biology and from the ancillary sciences that he had i n mind.
But it is the unifying point of view that makes ecology what it is.