Species composition and morpho-ecological groups of aquatic macrophytes in foothill lakes on the eastern slope of the Southern Urals ( Chelyabinsk region , Russia )

The aquatic macrophyte richness in nine lakes situated in the Chelyabinsk region (Russia) was analyzed. These lakes represent the foothill group, located on the eastern slope of the Southern Urals range. A total of 89 species belonging to 49 genera and 35 families were recorded. The species list includes 40 submerged rooted hydrophytes, 23 hygro-helophytes, 13 helophytes, 6 rooted hydrophytes with floating leaves, 4 free submerged hydrophytes and 3 free floating hydrophytes.


INTRODUCTION
The Chelyabinsk region is situated in the South Ural area, to the east of the southern part of the Ural range.This territory has a well developed hydrographic network, consisting of numerous lakes and rivers.There are more than 3,000 lakes in the region, occupying about 87,900 km 2 .
Due to the area's varied topography, the lakes are very different in their morphological, hydrochemical and hydrological characteristics.The region lies in three natural zones -forest, forest-steppe and steppe.There are mountain lakes, foothill lakes and plain lakes.The macrophytes floristic composition and their community variety depend on the typology of the lakes.Until recently, the region has been rather poorly explored.A full species inventory has not been published.
The present study aims to provide an inventory of the aquatic macrophytes in model lakes, representing different types of foothill lakes, located on the eastern slope of the Southern Urals, in the Chelyabinsk region of Russia (Figure 1).
Very little botanical data has been published for these lakes.Some common information is contained in a manuscript (Tauson 1940) and in proceedings (Gornovsky 1961), but this material is incomplete and now outdated.Some lakes in Chelyabinsk were studied in 1978 by the Institute of Limnology (Leningrad, now St. Petersburg).Later, a book was published, containing some of I. A. Petrova's data on aquatic vegetation

LISTS OF SPECIES
to -14°C, minimum dropping below -40°C).The vegetative period (with average temperature more than 10°C) lasts from the beginning of May to the end of September.In summer, the average temperature is near 15-17°C.The average annual precipitation is about 430-440 mm.Most of the precipitation in the summer is rain (around 200 mm) and, from November to March, is snow.

MATERIALS AND METHODS
Nine lakes were included in this study.Lakes having sufficiently complete species lists were selected.Presumably, they reflect the variety of habitats and floristic variety of this group of lakes (Figure 2).Another reason for this choice is that these lakes are in protected natural areas.Big Ishkul, Big Tatkul, Big Miassovo, Baraus, and Argajash lakes are in the territory of the Ilmen State Natural Reserve, while Turgojak, Koshkul and Small Ealnchic lakes are in regional nature sanctuaries.Small Miassovo Lake only partly belongs to the reserve, but it is connected to Big Miassovo as a joint hydrological system.Thus, anthropogenic impact on these lakes is minimal.This mainly concerns Turgojak and the eastern part of Small Miassovo, on the banks of which lie a few villages and small resorts.There is no industrial pollution, and the main anthropogenic factor is recreation pressure.
The study site covers an area of 800 km 2 near the town of Miass (55°03′ N, 060°05′ E).This territory is characterized by complex relief.There are several mountain ranges extending to the south, with altitudes from 300 to 700 m above sea level.The study area belongs to the pine-birch forests subzone of the forest zone in the Southern Urals and adjoins the forest-steppe zone.The climate of the area is continental, characterized by strong differences between summer and winter.Average annual temperature has been about 2.5°C for the last 10 years, the warmest month is July (19-20°C, maximum reaching to 37°C), and the coldest month is January (-13   (Veisberg 1999).Herein, significantly supplemented and corrected material is represented.Zannichellia repens, Potamogeton alpinus and P. filiformis from Big Miassovo were described by Gornovsky (1961).Other species are confirmed by new herbarium specimens.Small Elanchic, Koshkul, Baraus and Small Miassovo were researched from 2008 to 2010.Data on these lakes are new.In total, about 250 specimens were collected.All voucher specimens are deposited in the Herbarium of Ilmen Nature Reserve of the Urals Division of RAS.Data on Turgojak Lake were taken from the literature (Tkachev 1998), except for Isoëtes lacustris L.
The verification of nomenclature and citation of authors of species found was carried out using the list of species of vascular flora of the Chelyabinsk region by Kulikov (2005) and the keys to stoneworts by Gollerbach and Krasavina (1983).For moss determination we used data by Isakova (2009).

RESULTS AND DISCUSSION
Vegetation is well developed in the foothill lakes of the Southern Urals.In big, deep lakes, it occupies the littoral band and shallow bays.In other types of lakes, plants spread almost over the entire area.Generally, macrophytes grow to a depth of 4-5 m.Coverage varies from 20-100%.
In total, 87 aquatic macrophytes specie from 48 genera and 34 families were found in nine different lakes (Table 2).The most representative flora registered were Magnoliophyta.The richest families were Potamogetonaceae, Cyperaceae, and Ranunculaceae.On the other hand, Charophyta, Bryophyta, Equisetophyta, Polypodiophyta and Lycopodiophyta were insignificantly represented.
All species were divided into morpho-ecological groups according to Papchenkov (1985) (Table 2).Following this classification, we agree that hygro-helophytes should be included among the aquatic macrophytes, as they are closely linked to the water environment.
The investigated lakes are not exactly similar in quantity, composition and frequency of macrophytes (Table 2).The majority of the aquatic macrophytes were found in the mesotrophic lake, Big Miassovo (78 species, 89%).This is a result of the wide variety of biotopes in the lake, as well as the complex shape of the lake basin and its rugged coastline.It is characterized by relatively high diversity of Charophyta and the presence of rare species for the region (Chara strigosa, Warnstorfia fluitans, Zannichellia repens, Caulinia flexilis, C. tenuissima).Other, especially small, lakes have less diverse flora.The species numbers were as follows: Small Miassovo, 67; Big Ishkul, 51; Koshkul, 43; Small Ealnchik, 42; Baraus, 40; and Argajash, 43.This can be explained by less diverse habitats and natural processes of eutrophication.Floristically poorest is the shallow eutrophic-hypertrophic Big Tatkul Lake (24 species).The vegetation is welldeveloped in this lake and covers almost the whole water area, but it is very homogeneous.On the other hand, the oligo-mesotrophic Turgojak Lake, also characterized by a small number of species is, however, rather different from the previous one in composition.It is a deep lake with a narrow littoral band (mainly rocky and sandy) and sparse vegetation.Here, the very rare Isoëtes lacustris was found, indicating water purity.Among other rare plants, Najas marina, found in the Baraus Lake should be noted.It is the second record for the Chelyabinsk region (Veisberg, 2011).About 11% of species were common for all lakes and approximately 20% were found in seven or eight lakes.
As for plant communities, about 30 species were main dominants (Table 2).However, only a few of these were common to all lakes.The most common dominants were Phragmites australis, Typha latifolia, Nuphar lutea, Persicaria amphibia, Potamogeton lucens, P. perfoliatus, Myriophyllum sibiricum and Stratiotes aloides.In Turgojak, Big Miassovo and Baraus lakes, some Charophyta species were also common dominants.
Differences in species diversity of macrophytes and their communities between investigated lakes were mostly due to natural factors such as characteristics of underlying rocks and soils, as well as morphological, hydrological and chemical features.

Figure 1 .
Figure 1.Location of foothill lakes in the Southern Urals.

Table 1 .
Characteristics of foothill lakes of the eastern slope of the Southern Urals.* Veisberg | Aquatic macrophytes of foothill lakes, Chelyabinsk region, Southern Urals, Russiaand Baraus).Big Miassovo and Turgojak are the deepest (Table1).Their shorelines are mostly rocky; the littoral zone is narrow, except for shallow bays.The temperature of the surface layer (2 m) varies from 15-25°C in summer.The period of development of aquatic vegetation occurs from late May to late September, reaching a maximum in July to August.From November to April, the lakes are covered with ice.Big Ishkul, Big Miassovo, Big Tatkul and Argajash lakes were investigated in July to August, from 1990 to 2013.A variety of different habitats and plant communities were observed.Results were partially published *According to Andreeva (1973); Drabkova et al. (1978); Tkachev (1998); Rogozin and Tkachev (2000).