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moisture, elements of mineral nutrition, temperature, and many other internal and
external factors. The modeling of the production process takes into account pho-
tosynthesis, respiration, matter motion, transpiration, division of cells, etc. There
are numerous correlations between these factors and production of plants. Lieth
s
formulas are used most often (Lieth 1985). In order to estimate the annual pro-
duction of plants R
p
(g/cm
2
/year) as a function of the mean-annual temperature
T (
'
C) and the mean annual precipitation amount r (mm), the following estimate
can be used:
°
n
o
Þ
1
R
p
¼ 3
;
000 min
ð
1
þ
exp 1
ð
:
315
0
:
119T
Þ
;
ð
1
exp
0
ð
:
000664r
Þ
Þ
Vegetation biomass density P on a given territory is generally modeled by the
balance equation:
dP
=
dt ¼ min
fq
P
;
R
PP
g
M
P
T
P
where
cient of the considered type of vegetation, R
PP
is
the vegetation productivity for B/D-coef
ρ
P
is a maximum B/D-coef
cient values less than
ρ
P
for the present
values of B/D-coef
cient, M
P
and T
P
are parameters of decay and respiration
expenditure per unit time, respectively.
The use of parametric descriptions of productivity in biogeocenotic models is
important as an addition to the monitoring of vegetation communities. Unfortu-
nately, the existing database and the knowledge do not give any synthesized
information about a huge amount of empirical correlations representing depen-
dences of productivity and other functional components of vegetation communities.
Quite special in the numerical bio-geocenology is the problem of model
description of the competition between individual plants. On the whole, the mutual
impact of plants is described by the so-called competition indices (Bogatyrev 1988).
A freely growing plant is a plant whose functioning is independent of resource and
is determined by only species characteristics and external parameters. An interac-
tion between plants starts with their in
uence on the same resource and with the
mutual intrusion on the territories occupied by free growth. Biomes have more
complicated and diverse interrelationships and, as a result, they differentiate niches
and habitats. Mirkin (1986) introduced
fl
five types of strategies for the plants with
regard to their functioning in the environment (K
violents, S
ecotopic patients,
—
—
S
k
—
false or phytocenotic exple-
rents). A systems approach is possible to a model description of competition and
survival. All these strategies are inherent in individual species to different degrees
and, therefore, synthesizing a model of survival is determined by a concrete set of
the plant
phytocenotic patients, R
true explerents, R
k
—
—
is niche is usually an aggre-
gation of the space it occupies, resources it uses, and additional conditions, for
instance, the presence of pollinators, phytofugs, etc.
'
is requirements to niche parameters. A plant
'
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