ISSN 1062-3590, Biology Bulletin, 2017, Vol. 44, No. 10, pp. 1208–1214. © Pleiades Publishing, Inc., 2017.
Original Russian Text © S.A. Senator, 2016, published in Povolzhskii Ekologicheskii Zhurnal, 2016, No. 1, pp. 94–105.
Flora Diversity of Physical-Geographical Regions
and a Scheme of Floristic Zoning of Middle Povolzh’e
S. A. Senator
Institute of Ecology of the Volga River Basin, Russian Academy of Sciences, Tolyatti, 445003 Russia
Received January 19, 2015
Abstract—This work presents the first schematic map of floristic zoning of Middle Povolzh’e based on anal-
ysis of the available data, distribution pattern of plants with respect to physical-geographical regions, and flo-
ristic similarity of the regions. The floristic regions are described briefly, and the species of vascular plants,
which determine their specificity, are given.
Keywords: vascular plants, floristic zoning, Middle Povolzh’e
The flora of Middle Povolzh’e (within the Samara
and Ul’yanovsk oblasts) has been studied comprehen-
sively (Saksonov and Senator, 2012; Rakov et al., 2014).
The flora of the investigated area includes no fewer than
1990 species (490 alien species) assigned to 695 genera
and 138 families (Senator, 2014). Nevertheless, a uni-
fied base for botanical–geographical and ecological
data is absent. The floristic zoning of Ul’yanovsk oblast
(Pchelkin et al., 2002) is not detailed and follows the
geomorphologic regions specified by A.P. Dedkov
(1978). There is absolutely no floristic zonation of
Samara oblast, and the scheme of physical-geographi-
cal regions of Middle Povolzh’e is used by experts in
place of it (Fiziko-geograficheskoe…, 1964).
In this work, we present the data on the diversity of
flora of physical-geographic regions of Middle Povo-
lzh’e and an operational scheme of floristic zoning of
MATERIALS AND METHODS
We generalized and analyzed the data of field
investigations performed by employees of the Labora-
tory of Problems of Phytodiversity of the Institute of
Ecology of the Volga River Basin, Russian Academy of
Sciences, in 2007–2014. We studied the samples of
vascular plants taken in the region and kept in herbaria
of the Komarov Botanical Institute, Russian Academy
of Sciences (LE), Moscow State University (MW),
and the Institute of Ecology of the Volga River Basin,
Russian Academy of Sciences (PVB).
The floristic lists of physical-geographical regions
were compared with the use of the Jaccard community
coefficient. Alien and apomictic (of the genera Alche-
milla, Pilosella, and Taraxacum) species were excluded
from the calculation of the coefficient.
The floristic regions were distinguished on the
basis of the lists of species used for the comparison.
Species that determine the specific features of each
floristic region and are indicative of its ecological con-
ditions, characterizing botanical-geographical fea-
tures of its flora were revealed. Landscape conditions
(lithology, features of topography, vegetation, and soil
types) were also taken into consideration in elabora-
tion of the scheme. The existing schemes of physical-
geographical (in particular landscape), botanical-geo-
graphical, and floristic zoning of Middle Povolzh’e
were also analyzed (Senator, 2015).
RESULTS AND DISCUSSION
The data reflect the floristic diversity of the physi-
cal-geographical regions of Middle Povolzh’e shown
on the scheme by A.P. Stupishin (Fiziko-geografich-
eskoe…, 1964) (Table 1).
The use of the Jaccard community coefficient was
based on the following arguments. “It is clear that any
attempt at objective comparison of species lists from
stands (however useful it may be for comparison of
flora of different regions) is based on so many
unproved assumptions that it is scarcely worth
attempting. Especially is this so in view of the crudity
and imprecision of species lists as criteria in character-
izing stands” (Greig-Smith, 1967). In the opinion of
V.I. Vasilevich, the problem of qualitative and quanti-
tative assessment of the similarity of objects is very
important for any science (Vasilevich, 1969, cited by: