ISSN 1067-4136, Russian Journal of Ecology, 2006, Vol. 37, No. 5, pp. 299–305. © Pleiades Publishing, Inc., 2006.
Original Russian Text © A.V. Ivanova, G.S. Rozenberg, S.V. Saksonov, 2006, published in Ekologiya, 2006, No. 5, pp. 332–339.
The principle of ecological direction in ﬂoristic
research is that the diversity and composition of ﬂora
are analyzed as a reﬂection of ecological conditions. In
general, the term “ﬂora” applies to large areas and is
abstract in the territorial aspect (Malyshev, 1972). From
the structural standpoint, ﬂora represents a continuum
that is nonuniform throughout its extent. Ecological
conditions in individual regions of a certain territory are
often different, and, therefore, the ﬂora may acquire a
more or less speciﬁc composition differing from that in
the territory as a whole.
In such a region (a constituent part of the territory
under study), we deal with the ﬂora of the minimum ter-
ritorial unit in which plant distribution depends only on
conditions in habitats. Thus, such a ﬂora occupies a
limited area and is quite uniform, being differentiated
only ecologically (but not geographically!). To desig-
nate it, Tolmachev (1974) proposed the term “elemen-
tary, or concrete ﬂora.” Within an elementary ﬂora,
plant species form communities that differ depending
only on local factors.
ELEMENTARY FLORA AND ITS AREA
In practice, research by the method of elementary
ﬂoras is reduced to a thorough survey of a relatively
small key plot with more or less uniform natural condi-
tions. As the survey progresses, the number of recorded
species increases nonuniformly. According to Maly-
shev (1969), this was noted by H. Watson as long ago
as 1835. Initially, the number of species increases
sharply (Fig. 1) (see Rozenberg, 1989; Rozenberg et al.,
1999, p. 242); thereafter, this process slows down and
the number of species reaches the level corresponding
to the so-called minimum range (point A). Data on this
range characterize the community quantitatively.
In the course of theoretical development and practi-
cal applications of this method, two concepts of the ele-
mentary ﬂora have been developed (Shmidt, 1976).
Proponents of the ﬁrst concept (B.A. Yurtsev,
L.I. Malyshev, and others) regard elementary ﬂora as
“the ﬂora of a geographic point,” “a sample character-
izing the ﬂoristic situation at a given point on the earth
surface,” or even “a sample of ﬂora,” which is equiva-
lent to the minimum range (Yurtsev, 1975). Data
obtained by analyzing “a sample of ﬂora” provide an
idea of the entire elementary ﬂora (Shmidt, 1976).
Continuing the survey of the key plot, we initially
enter the “dead zone” in which new plant species, sin-
Experience in Quantitative Analysis of Floristic Structure
and Diversity in Samarskaya Luka
A. V. Ivanova, G. S. Rozenberg, and S. V. Saksonov
Institute of the Ecology of the Volga Basin, Russian Academy of Sciences,
ul. Komzina 10, Tolyatti, Samara oblast, 445003 Russia;
Received October 21, 2005
—Quantitative methods have been applied to the study of ﬂoristic structure and diversity in Samar-
skaya Luka. The results show that Samarskaya Luka is a ﬂoristically heterogeneous area in which six elemen-
tary ﬂoras can be distinguished. This area has been assessed as a ﬂoristically autonomous formation, and its
ﬂoristic representativeness was estimated.
: quantitative methods in ﬂoristics, structure and diversity of ﬂora, ﬂoristic representativeness,
Number of species
Diagram of the number of species as a function of
area, with transition to the neighboring elementary ﬂora.