G.I. Vasechko STABILITY OF TERRESTRIAL ECOSYSTEMS TO PLANT PESTS: AN AXIOMATIC APPROACH.
PART II. SUBSTANTIATION OF THE AXIOMS PROPOSED IN THE PART I
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PART II. SUBSTANTIATION of the AXIOMS
PROPOSED in the PART I
AXIOM 1(1) DRIVING FORCES
BEHIND PLANT PEST ABUNDANCE DYNAMICS
This Axiom is a retelling of the Ch. Darwin’s idea expressed with the following words: "In
looking on Nature, it is most necessary to keep the foregoing considerations always in mind never to forgot that every single organic being may be said to be striving to the utmost to
increase in numbers; that each lives by a struggle at some period of its life; that heavy
destruction inevitably falls either on young or old during each generation or at recurrent
intervals. Lighten any check, mitigate the destruction even so little, and the number of the
species will almost instantaneously increase to any amount" (Darwin, 1872, p. 62).
The idea that every single organic being (or all the living beings) has the capacity to
unrestricted multiplication is a corner-stone in the theory of evolution and now is proposed as the
same in ESPPs. Probably, this is the most important property of the life on the levels of an
organism and the higher systems (populations, ecosystems). Owing to this capacity, there exist
the stuff (abundance of organisms for natural selection) both in the evolutionary process and the
process of population dynamics. The latter is a closest province to the concept of ESPPs.
The Ch. Darwin’s words "...to keep ... in mind - never to forgot..." demonstrates the great
importance attached by him to this property of life. One may see the congeniality of the
Ch. Darwin’s words and the revelation of Old Testament - "Be fruitful and multiply" turned to
all the living beings. The inmost proximity of Old Testament, Ch. Darwin’s mentality and efforts
of contemporary ecologists induces an inspiration that is necessary for solving of great problems
of our time.
This succession suggests that ESPPs has a mission to clear the mystery of centuries. This
mystery is how the main contradiction of organisms and the environment (the contradiction
between their ability to unrestricted multiplication and the limited vital resources) has been
settling in nature. ESPPs is an epicenter of studies in this direction, and it may help in solving the
main problem of mankind - the optimization of its relations with the environment. This solving
this problem is of crucial importance for surviving of mankind. Also, a synthesis of these ideas is
useful not only for solving of scientific problems, but it is valuable as a step in progress of
mentality. It will help to exclude some misunderstandings that breed strife in the human
community.
As to the facts evidencing in favor of the adequacy of the Axiom 1, it should apply to
Ch. Darwin’s works, the diversity of textbooks and analytical books in the theory of evolution.
In particular, the artistic account of this problem can be found in the book by R. Carson (1962).
The cases of outbreaks of animals and epiphytoties of phytopathogens in a result of their
invasions to new territories (continents and islands) are spectacular illustrations of the adequacy.
These facts serve as the best substantiation of the Ch. Darwin’s words "Lighten any check...and
the number of the species will almost instantaneously increase to any amount."
Thus, the Axiom 1 (an ability of living beings to unrestricted multiplication) is a component
both the Darwin’s theory of evolution and the proposing concept. This coincidence is an
important fact with a standpoint of validity of the concept. This is so because to be valid, any
developing system of knowledge should be connected logically with the scientific province,
whose validity is out of doubt. As to the following Axioms of the proposed concept, the ways of
the concept and the theory of evolution are branching off. Darwinism explains the evolution of
living beings, whereas the proposed concept explains the density of living beings - PPs. They are
close processes, but different ones.
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G.I. Vasechko STABILITY OF TERRESTRIAL ECOSYSTEMS TO PLANT PESTS: AN AXIOMATIC APPROACH.
PART II. SUBSTANTIATION OF THE AXIOMS PROPOSED IN THE PART I
The next postulate of Darwinism is the natural selection of organisms with new traits
appearing due to the ability to unrestricted multiplication, the traits, which occurred to be the
most adapted to given environmental conditions. This selection leads to evolving of a new
species.
In ESPPs, selection on the part of environmental conditions (FESPPs in the proposing
concept) takes place also, although, but this selection has another character, as follows:
i)
It survives organisms of PPs having the best physiological state,
ii)
In some situations, at the selection by FESPPs, it appears the organisms of PPs with
new traits, although after several generations of them, the selection becomes of
inverse direction, so that in a population of PPs, it restores participation of the
organisms with previous traits. This is a microevolutionary oscillatory process.
Therefore, the effect of the selection is the phenomenon of population dynamics, rather than
arising of new species.
At developing the Ch. Darwin’s ideas, the words "striving" and "checks" found more
concrete terms - "species potential" and "environment resistance." On the base of a great many
knowledge in this field, it has been formed the provinces of population ecology of animals and
epidemiology of phytopathogens. However, the systemizing of this material in the form of
generalizations leaves much to be desired.
Among the numerous attempts to pose regulations in population ecology of animals - PPs,
consider the concepts of "self-regulation in a population" proposed by A.J. Nicholson (1954) and
"chance control" proposed by H.G. Andrewartha and L.C. Birch (1954) and R.W. Thompson
(1956). These concepts, it seems to be, the most perfect attempts to explain population ecology
of PPs, and they served as a stimulus at preparing of the present study. On the other hand, these
concepts demonstrate clearly typical limitations in mentality of population ecologists.
The concept by A.J. Nicholson (1954) is the closest to the proposing concept. He has
developed "a number of considerations which appear to him to be axiomatic and therefore
provide a solid basis for an understanding of what he calls population dynamics" writes
W.R. Thompson (1956, p. 381). These considerations include seven points (a-f). The first
of them is similar to the Axiom 1 of the present report, namely: "a) All animals have an innate
ability to reproduce and to multiply under favourable conditions" (Nicholson, 1954, p. 59).
In order to make clear the content of subsequent considerations, let us turn to thoughts of
himself A.J. Nicholson (1958, p. 108): "I shell briefly outline the mechanism of self-regulation in
populations. Each species of animals is necessarily limited to those regions in which everything
it requires is supplied in a quantity, and of a quality, not less than the minimum necessary for
continued existence and reproduction at the replacement rate. Outside such regions the inherent
resistance of the environment prevents the continued existence of the species. Inside these
regions the animal tends to increase authomatically inducing additional resistance to
multiplication. This induced resistance is commonly the depletion of one or more requisites...."
This passage might be commented in such a way: there exists the ecological pessimum for a
given species, where "the inherent resistance of the environment prevents the continual existence
of the species", and there exists the ecological optimum for a given species, where " the animal
tends to increase authomatically inducing additional resistance to multiplication.
This induced resistance is "commonly the depletion of one or more requisites..." The
comments demonstrate the difference between the concept by A.J. Nicholson and the proposing
concept. The main task of the latter concept is explaintion, why in the most of cases species of
animals is unable "to increase authomatically" in its ecological optimum in spite of the lack of
any "the depletion of one or more requisites." Although the numberless studies have been
directed to solving this problem, ecologists have not explaned the fact that absolute majority of
PPs species continually are kept on the level of Insignificant density in quite favorable for them
abiotic conditions and available resources.
In context with the concept of ESPPs, it is important to take into account other views as to
factors of PPs population dynamics. Here is the consideration by W.R. Thompson (1956,
pp. 400-401): "My general conclusion, therefore, is that populations are not self-governing
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G.I. Vasechko STABILITY OF TERRESTRIAL ECOSYSTEMS TO PLANT PESTS: AN AXIOMATIC APPROACH.
PART II. SUBSTANTIATION OF THE AXIOMS PROPOSED IN THE PART I
systems ...Climatic and edaphic factors are the basis of the environmental diversity, producing
not only the fragmentation of habitats but constant change in their character and location. This is
the primary extrinsic factors of natural control... Populations, therefore, are not truly regulated
but merely vary...The variation sometimes assumes a cyclical aspect, but this is usually
attributable to change, not to factors producing oscillations according to definite laws."
In spite of the controversy between R.W. Thompson and A.J. Nicholson, their scientific
positions sometimes are close. True, "...near the fringes of distribution, density-governing
reactions must be slight and inconspicious" (Nicholson, 1958, p. 108).
The idea of "fringes" occurred to be not simply one, namely: "...the fringe area of a species
need not consists of a favourable zone, but may consist of numerous, scattered zones, that are
"fringe" in character for divers reasons, and occur inside and outside climatically favourable
areas"(Wilson, 1968, p. 146). Moreover, according to H.C. Chiang (1961), fringes may be of
various kinds, namely: ‘...climatic, topographic, biotic, advancing, and artificial..." (Ibid., p.
146).
This short review demonstrates the confusion that exists in comprehension of factors of PPs
population dynamics. The Ch. Darwin’s words "The causes which check the natural tendency of
each species to increase are most obscure" (Darwin, 1872, p. 63) continue to be true.
It seems, this confusion will be made away if to consider population dynamics of PPs on the
base of an ecosystem. This is so because it is typical for a natural ecosystem the presence of the
factors that are able to keep hundreds species of PPs on the level below threshold of damage for
dominants over unlimited time, and these factors, probably, operate as a system. When study a
system, one may get a prompt as to validity of its suggestion. In a system, all its components are
in a connection. Therefore, a mistake occurs to be apparent.
To get clear this attempt, it should to list the questions, which will be offered to nature in this
report:
i) Why does a typical natural ecosystem is able to exist over unlimited time in spite of
presence in it potentially destructive agents - hundreds species of PPs (herbivores and
phytopathogens), which stay nearly always on the level below threshold of damage for
dominants?
ii) What kinds of factors cause in natural ecosystems an increase of PPs density above
threshold damage for dominants?
iii) Why do man-made ecosystems (articenoses) are more vulnerable to damage due to PPs?
iv) Is it a self-regulation in a population?
v) What kinds of factors determine the spatial distribution of PPs density?
vi) How does to increase ESPPs?
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