129 Annales Universitatis Paedagogicae Cracoviensis Studia Naturae, 1: 129–143, 2016, ISSN 2543-8832 Anatoliy A. Khapugin1,2*, Tatyana B. Silaeva2, Yulia N. Utorova2 1 Mordovia State Nature Reserve, Republic of Mordovia, Temnikov district, Pushta, Russia 2 Mordovia State University, Republic of Mordovia, Saransk, Russia, *hapugin88@yandex.ru Three Maples (Acer L., Aceraceae Juss.) in the Republic of Mordovia, Russian Federation Introduction Genus Acer L. (Maple) includes a large number of species distributed worldwide, but especially in the northern hemisphere. Maples are deciduous trees from 12 m to 35 m in height, rarely evergreen or sometimes shrubs (Morselli, 1989). Classical- ly this genus is considered belonging to the Aceraceae Juss. family (Dicotyledoneae) (Takhtajan, 1987; Cronquist, 1988; Cherepanov, 1995). However, in recent time many studies using pollen morphology (Müller, Leenhouts, 1976), biochemistry of plants (Umadevi, Daniel, 1991) and molecular sequence data (Gadek et al., 1996; Savolainen et al., 2000; APG III, 2009; Buerki et al., 2009) con�rm inclusion of this genus into the Sapindaceae s. lato. �ere are up to 148 wild or cultivated Acer species widely distrib- uted throughout North America, Eurasia and North Africa (Olson et al., 1974). Republic of Mordovia is located in Central Russia. Its territory lies on the border of the forest and forest-steppe zones in Central Russia. Eastern part of the Republic of Mordovia covers the north-west of the Volga Upland, and its western part is located on the west of the Oka-Don Lowland. �erefore, high habitats diversity is observed within this area. Coniferous and mixed forests are distributed in the west and north- west Mordovia. Broad-leaved forests are located in the central and eastern parts of the region. Forest-steppe landscapes dominate in the east and south-east of Mordovia (Yamashkin, 1998, 2012). Within Mordovia four maple species are known. A. platanoides L. is widely dis- tributed species which inhabits plant communities of broad-leaved and mixed forests (Silaeva et al., 2010). A. campestre L. (Field maple) is vulnerable maple species which is on the north-eastern border of its range in the Republic of Mordovia (Utorova et al., 2014). It is known in six districts (Insar, Kadoshkino, Kovylkino, Kochkurovo, 130 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va and Ruzaevka district, as well as in neighborhoods of Saransk). A. campestre is in- cluded in the regional Red Data Book (Resolution of the Government…, 2015). A. ta- taricum L. (Tatarian maple) is species distributed in Mordovia sparsely, as well as in adjacent regions. It is known predominantly within �oodplain broad-leaved forests from 13 districts of the Republic of Mordovia. �ere is a lack of data on the favorable environmental conditions for A. tataricum existing. A. negundo L. (Ash-leaved maple) is alien species known in all districts of Mordovia (Silaeva et al., 2010), as well as in all adjacent regions. �is tree species is aggressive invasive plant included in the Black Data Book of Central Russia (Vinogradova et al., 2010). Better knowledge of ecology and biology of A. negundo is an important task in limiting its penetration into natural ecosystems within secondary range. We aimed to investigate three maple species (Acer campestre, A. tataricum, A. ne- gundo) in conditions of Central Russia on example of the Republic of Mordovia due to the lack of data on the ecology of these species in European part of Russia. Material and methods �e �eld investigations were carried out following Aleksandrova (1964) and Khapugin et al. (2014). For A. campestre and A. tataricum, ecological conditions of habitats have been evaluated using the data on the ecological preferences of vascular plant species which grow with maples together. Distribution of plant species of the accompanying �ora on the ecological groups in relation to water has been carried out according to the classi�cation of Shennikov (1950) with separation of main groups (hygrophytes, mes- ophytes, xerophytes) and intermediate groups (hygromesophytes, mesohygrophytes, xeromesophytes, mesoxerophytes). Ecological scale proposed by Tsyganov (1983) has been used in distribution of plant species of the accompanying �ora on the ecological groups in relation to the lighting/shading. �e �eld investigations of A. campestre populations were carried out in three loca- tions of Kadoshkino district of Mordovia: Adashevo (53.925 N, 44.377 E), Latyshovka (53.961 N, 44.384 E) and Insar station (54.060 N, 44.310 E) in years 2013–2015 (Fig. 1). Within all locations, we established square plots (10×10 m) to investigate the ac- companying �ora and determine the forest’s stand formula. Forest’s stand formula has been determined as percent of individuals of forest stand in the canopy layer per 100 m2 (area of one square plot). In Adashevo location and Insar station the total number of A. campestre individuals was counted. In Latyshovka we established close to each other 2 square plots (10×10 m) (Latyshovka 1 and Latyshovka 2) to investigate the number of 1-year-old A. campestre seedlings (seed reproduction). For this purpose, we estab- lished 10 study plots (1×1 m) within each of large (10×10 m) established plots. In Insar station we have counted number of age-bearing A. campestre individuals per 100 m2. 131 �e �eld investigations of A. tataricum populations were carried out in Bolshie Berezniki district of Mordovia (54.176 N, 46.181 E) in years 2014–2015 (Fig. 1). We established four square plots (10×10 m) in di�erent habitats: �oodplain meadow (plot  1), lime-pine forest (plot 2), �oodplain broad-leaved forest (plot 3), and plant community with A. negundo dominance (plot 4). We investigated the number of A. tataricum individuals per established plot, composition of accompanying �ora; forest stand formula was determined for each of studied plant communities. On the basis of the vascular �ora of herb and shrub layers of studied plant communities, we calculated weighted mean (Diekmann, 2003) of environmental indicator values for several ecological factors (light, temperature, continentality, moisture, reaction pH, nutrient) according to Ellenberg et al. (2001). In this calculation, rij is the response of species i in sample plot j, and xi is the indicator value of species i. �en, weighted mean of all values of those plant species presented in the plot was calculated to estimate the environmental indicator values for factors: Weighted mean = �e �eld investigation of A. negundo populations were carried out in Bolshie Berezniki district of Mordovia (54.176 N, 46.181 E) and on wasteland in Saransk (54.164 N, 45.150 E) in years 2014–2015 (Fig. 1). Within each of these localities, we Fig. 1. Allocation of studied localities with Acer species in the Republic of Mordovia. Symbols: rhombs – localities with Acer campestre in Kadoshkino district: 1 – Insar station, 2 – Latyshovka, 3 – Adashevo; 4 (circle) – locality with Acer tataricum and Acer negundo populations in Bolshie Berezniki district; 5 (square) – locality with Acer negundo in Saransk Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation 132 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va established 2 large square plots (5×5 m) to investigate the number of 1-year-old A. negundo seedlings (seed reproduction). For this purpose, we established 10 study plots (1×1 m) within each of large (25 m2) established plots. �e �eld investigations of A. negundo seed reproduction were carried out in established plot No. 4 for A. tataricum study (see above). �e �eld investigations of A. negundo seed reproduction were car- ried out in the abandoned wasteland with ruderal vegetation in Saransk. Statistical analysis was performed in MS Excel and PAST (Hammer et al., 2001). Results and discussion Acer campestre L. – Field maple As the result of investigations, we found that number of A. campestre individuals per 1 plot in Adashevo widely varied from 8 to 115 di�erent-age plants (240 in total). In Insar locality, this parameter was less variable – from 12 to 53 di�erent-age individ- uals (163 in total). Mean values varied from 32.2 to 40 individuals per 1 established plot (Tab. 1). Tab. 1. Number of Acer campestre individuals per 1 established plot Parameter Locality Adashevo Insar station M 40.00 32.20 m 15.80 7.30 min 8.00 12.00 max 115.00 53.00 Note: M – mean value, m – error of the mean, min – minimal value, max – maximal value Investigations of the number of A. campestre 1-year-old individuals in Latyshovka showed that this parameter varied from 8 (Latyshovka 1) to 31 (Latyshovka 2) individ- uals per 1 established plot (Tab. 2). In average the number of A. campestre 1-year-old individuals varied from 12 to 19.4. Tab. 2. Number of 1-year-old individuals of Acer campestre per 1 established plot Parameter Locality Latyshovka 1 Latyshovka 2 M 13.00 19.40 m 2.60 3.30 min 8.00 12.00 max 22.00 31.00 Note: M – mean value, m – error of the mean, min – minimal value, max – maximal value 133 However, seed reproduction is of little importance in maintaining of A. campestre populations in Mordovia since very few individuals of �eld maple reach the generative age (Utorova et al., 2014). �is suggest with our results: only 11.7% (19 of 163) bear- ing-age individuals of A. campestre were found within established plots in the Insar station locality (Tab. 3). Tab. 3. Characteristics of bearing-age individuals in Acer campestre population in the Insar locality Number of plots Number of bearing-age individuals (percentage of total number of individuals [%]) Average tree girth [cm] Average tree diameter on the breast height [cm] 1 2 (5.10) 21.00 5.90 2 4 (10.50) 10.00 4.20 3 4 (33.30) 8.40 3.10 4 7 (13.20) 15.60 8.20 5 2 (9.50) 6.40 2.20 �e lack of generative individuals in A. campestre populations is completely o�set by an active vegetative propagation by root o�springs. As a result, the group arrangement of young individuals of A. campestre is observed around the parent individual (Fig. 2). Ecological conditions of certain habitats with A. campestre could be assessed on the basis of ecological preferences of plant species of �ora accompanying to this spe- cies. Table 4 includes data on the distribution of plant species of accompanying �ora on ecological groups in relation of plants to water. Fig. 2. Spatial arrangement of Acer campestre individuals amongst woody plant species at estab- lished plots 1 and 5. Symbols: – Acer campestre,  – Acer platanoides,  – Fraxinus excelsior L.,  – Tilia cordata Mill., + – Euonymus verrucosa Scop., M – Quercus robur L., T– Lonicera xylosteum L., × – Sorbus aucuparia L., – – Corylus avellana L. Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation 134 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va Table 4 shows that plant community with A. campestre has been formed in condi- tions of su�cient moisture. Such conditions are typical to the deciduous forests in the river valleys. As seen from table 4, mesophytes group includes the highest percentage of species (53.7%). Among them, there are A. platanoides, Lathyrus vernus (L.) Bernh., Stellaria graminea L. and others. Other ecological groups include less number of species. Tab. 4. Ecological groups on the basis of relation of plants to water in plant community with Acer camp- estre Ecological group Number of species Total number of species [%] Mesophytes 36 53.70 Hygrophytes 9 13.40 Xeromesophytes 8 11.90 Mesohygrophytes 7 10.40 Mesoxerophytes 6 8.90 Hygrophytes 1 1.40 Total 67 100.00 Table 5 includes data on the distribution of plant species of the accompanying �ora on the ecological groups in relation of plants to the lighting/shading. As seen in ta- ble 5, the group of shade-tolerant species dominates (65.6%). It includes such species as Vicia sylvatica L., Milium e�usum L., Lonicera xylosteum L. and others. It indicates the signi�cant shading in plant communities with A. campestre. However, group of light-demanding species includes 29.8% plants of the accompanying �ora. Such situ- ation is typical for deciduous forest exposed to anthropogenic pressure (Burova, Fek- listov, 2007). Tab. 5. Ecological groups of plants in relation to the lighting/shading in plant community with Acer campestre Ecological group Number of species Total number of species [%] Shade-tolerant 44 65.60 Light-demanding 20 29.80 Shade-demanding 3 4.40 Total 67 100.00 An ecological-coenotical characteristic of the �ora, which is accompanying A. campestre, is presented in table 6 with distributing of plant species on several ecolog- ical-coenotical groups. 135 Tab. 6. Ecological-coenotical characteristics of the �ora which is accompanying Acer campestre in the investigated plant communities Ecological-coenotical group Number of species Total number of species [%] Forest 43 63.80 Meadow 16 23.70 Weed 6 8.90 Forest swamp 2 2.80 Total 67 100.00 Species of forest group are predominant (63.8% of total species number) in the accompanying �ora of investigated plant community with A. campestre. Among them, there are Asarum europaeum L., Galium odoratum (L.) Scop., Platanthera bifolia (L.) Rich. and others. Group of meadow species is located on the second place with 16 species (23.7%). Among them, there are Campanula patula L., Stellaria graminea, Ranunculus acris L. and others. Presence of meadow species indicates penetration of these plants through forest roads, cuttings, forest edges and clearings. �ey also con- tribute to the penetration weed plants (6 species; 8.9%) into the plant community with A. campestre. As a whole, the plant community with A. campestre is a typical broad- leaved forest, being under anthropogenic in�uence. Acer tataricum L. – Tatarian maple We investigated accompanying �ora of each of 4 established plots in Bolshie Berezniki district. Established plot 1 was �oodplain meadow plant community with high abun- dance of Fragaria viridis L. (19%), Alopecurus pratensis L. (8%), and Carex praecox Schreb. (6%). Established plot was located in lime-pine forest where Urtica dioica L. (5%), Pteridium aquilinum (L.) Kuhn. (4%), Dryopteris carthusiana (Vill.) H.P. Fuchs (3%), Stellaria media L. (3%) are dominant in herb layer; shrub layer was represented by Rosa cinnamomea L., Euonymus verrucosa, Rubus idaeus L., Ribes nigrum L. Estab- lished plot 3 was located in �oodplain lime-oak forest with dominance of Aegopodium podagraria L. (7%), Glechoma hederacea L. (5%) in herb layer. Established plot 4 was located in �oodplain plant community formed by invasive A. negundo representing about 80% of forest stand; Urtica dioica (15%) and Glechoma hederacea (7%) are dom- inant in herb layer; shrub layer is represented by Padus avium Mill. and A. negundo. Vegetation projective cover varied from 35% (lime–oak) to 80% (�oodplain mead- ow) (Tab. 7). However, the number of A. tataricum individuals was not determined by this parameter. �e highest number of tatarian maple individuals was observed in �oodplain lime–oak forest. Perhaps this can be explained by the fact that �oodplain deciduous forest is a typical habitat for A. tataricum. �e lowest number of tatarian ma- ple individuals was found in �oodplain forest with dominance of A. negundo (Tab. 7). Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation 136 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va �is invasive tree species is capable of forming multilevel plant communities with high density of the forest canopy oppressing native species (Kostina et al., 2016). In- vestigated plant community was probably formed in place of well-moistened forest edge or meadow. �is is consistent with presence of meadow and forest edge species (Filipendula vulgaris Moench, Rumex confertus Willd.) and plants of deciduous forests (Glechoma hederacea, Angelica sylvestris L.) in this seminatural plant community. Tab. 7. Characteristics of established plots with Acer tataricum Parameter Plots 1 2 3 4 Projective cover [%] 80.00 35.00 65.00 65.00 Number of Acer tataricum in- dividuals per plot 32.00 28.00 38.00 26.00 Light 7.00 5.10 5.50 6.10 Temperature 5.70 5.30 5.20 5.50 Continentality 4.50 4.40 4.30 3.70 Moisture 5.00 5.70 5.50 6.40 Reaction 6.80 6.10 6.70 7.00 Nutrient 5.20 5.30 5.80 6.60 Forest stand composition [%] – 70Ps20Tc10Qr+Ap 50Qr40Tc10Pt+Ul 80An20At+Ul+Qr Note: An – Acer negundo, Ap – Acer platanoides, At – Acer tataricum, Ps – Pinus sylvestris L., Tc – Tilia cordata, Qr – Quercus robur, Pt – Populus tremula L., Ul – Ulmus laevis Pall �e analysis of the vascular �ora of herb and shrub layers of studied plant com- munities was carried out according to Ellenberg et al. (2001). Detrended correspond- Fig. 3. Detrended correspondence analysis (DCA) ordination diagram of plots established in plant com- munities with Acer tataricum 137 ence analysis of total set of environmental indicator values (Fig. 3) shows that the lowest number of A. tataricum individuals were found in the most moist and shaded plant communities (established plots 2 and 4). �us, the excessive moisture of habitat adversely a�ects the seed reproduction and development of A. tataricum seedlings, despite the fact that tatarian maple is a species of �oodplain broadleaved forests. �e highest number of A. tataricum individuals was found under conditions of su�cient light and moderate moisture (established plot 1). �us, light and moisture are the most signi�cant environmental factors for A. tataricum populations in the Republic of Mordovia. We selected 25 A. tataricum samaras per each established plot to reveal its mor- phological characteristics. As it is seen from Table 8, samara of A. tataricum reached 3.7 cm in length and 0.9 cm in width as a mean. Tab. 8. Characteristics of Acer tataricum samaras Parameter Length of samara [cm] Width of samara [cm] М 3.70 0.90 m 0.30 0.30 min 2.80 0.40 max 4.20 2.00 Note: M – mean value, m – error of the mean, min – minimal value, max – maximal value We analysed ecological preferences of plant species of �ora accompanying to A. tataricum to estimate ecological conditions of habitats with tatarian maple. Table 9 includes data on the distribution of plant species of accompanying �ora of ecological groups in relation of plants to water. �e mesophytes group dominates with 52 species (51.4%) which are typical for habitats with moderate moisture level. Among them, there are Fragaria vesca, Alopecurus pratensis, Quercus robur and others. Xeromeso- phytes (18.8% of total species number) are located on the second place. Most of them were found on the established plot 1 located in meadow habitat. Among them, there are Festuca rubra L., Elymus (=Elytrigia) repens (L.) Gould, Bromus arvensis L. and others. Plants con�ned to habitats with excessive moisture (hygrophytes, hygromes- ophytes) were presented by 14 species in sum. �ey include Urtica dioica, Athyrium �lix-femina (L.) Roth, Lysimachia nummularia L., L. vulgaris L., Filipendula ulmaria (L.) Maxim. and others. Table 10 includes data on the distribution of plant species of the accompanying �ora of the ecological groups in relation of plants to the lighting/shading. As it is seen from table 10, both light-demanding and shade-tolerant groups contain approximate- ly equal number of species. �is is explained by the fact, that A. tataricum is capable to grow both in open, as well as in woodland habitats. Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation 138 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va Tab. 9. Ecological groups on the basis of relation of plants to water in plant community with Acer tatari- cum Ecological group Number of species Total number of species [%] Mesophytes 52 51.40 Xeromesophytes 19 18.80 Mesohygrophytes 10 9.90 Hygrophytes 9 8.90 Hygromesophytes 5 4.90 Mesoxerophytes 5 4.90 Xerophytes 1 0.90 Total 101 100.00 Tab. 10. Ecological groups of plants in relation to the lighting/shading in plant community with Acer tataricum Ecological group Number of species Total number of species [%] Shade-tolerant 46 45.50 Light-demanding 45 44.50 Shade-demanding 10 9.90 Total 101 100.00 Tab. 11. Ecological-coenotical characteristics of the �ora which is accompanying Acer tataricum in the investigated plant communities Ecological-coenotical group Number of species Total number of species [%] Forest 51 50.10 Meadow 24 23.40 Weed 15 14.70 Forest swamp 10 9.70 Steppe 1 0.90 Total 101 100.00 An ecological-coenotical characteristic of the �ora accompanying A. tataricum is presented in table 11 with distribution of plant species on several ecological-coe- notical groups. Forest group contains the highest number of species (50.1%). Among them, there are Asarum europaeum, Galium odoratum, Platanthera bifolia, Rubus saxatilis L., Scrophularia nodosa L. and others. Second place is occupied by group of meadow plants (24 species) that indicates ability of A. tataricum to grow in �oodplain meadows. Among them, there are Betonica o�cinalis L., Carex vulpina L., Agrostis capillaris L. and others. �e presence of weed species (14.7%) in accompanying �ora indicates disturbance of habitats with tatarian maple. Among them, there are Arctium lappa L., Taraxacum o�cinale Wigg. s.l., Polygonum convolvulus L. and others. �us, 139 A. tataricum populations are capable to grow in open, as well as in woodland habitats of �oodplain including under anthropogenic pressure. Acer negundo L. – Ash-leaved maple Seed reproduction of A. negundo was determined within the established plot 4 to study A. tataricum populations (study plots 1, 2), as well as in Saransk at wasteland overgrown by ash-leaved maple (study plots 3, 4). Brief description of established plot in Bolshie Berezniki district of Mordovia was listed above in section about A. tatari- cum. Vegetation cover of wasteland in Saransk is presented by ruderal plant species. Among them, Conyza (=Erigeron) canadensis (L.) Cronquist, Arctium lappa, Lactuca serriola L., Artemisia vulgaris L., Taraxacum o�cinale are dominant. As a result of investigations, we found that seed reproduction of A. negundo was signi�cantly higher in seminatural plant community with dominance of its invasive species. Although there is no shading that inhibits A. negundo juveniles (Kostina et al., 2016), number of 1-year-old individuals of ash-leaved maple in Saransk was less in 1.7–2.6 time in comparison with habitat in Bolshie Berezniki district of Mordovia (Tab. 12). Probably, more dry conditions of wasteland in Saransk decrease the seed germination of A. negundo that is consistent with results of other researchers (Erfmei- er et al., 2011; Lamarque et al., 2013). Tab. 12. Number of 1-year-old individuals of Acer negundo per study plot in Saransk and in Bolshie Berezniki district of Mordovia Parameter Bolshie Berezniki district Saransk 1 2 3 4 М 66.00 71.00 27.00 39.00 m 8.60 12.50 4.80 9.10 min 43.00 36.00 14.00 18.00 max 95.00 108.00 42.00 67.00 Note: M – mean value, m – error of the mean, min – minimal value, max – maximal value Conclusions Acer campestre populations have relatively low level of seed reproduction (13.0–19.4 of 1-year-old individuals per 100 m2). Investigation of the number of generative in- dividuals shows that only 11.7% of plants reach generative age. Active vegetative propagation of A. campestre suggests maintaining the �eld maple population on the north-eastern border of its range. As a result, group arrangement of A. campestre in- dividuals is observed. Analysis of the accompanying �ora indicates that A. campestre is con�ned to �oodplain broadleaved forests and it capable to grow under moderate disturbance of habitats. Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation 140 A na to liy A . K ha pu gi n, T at ya na B . S ila ev a, Y ul ia N . U to ro va A. tataricum is capable to grow both in open (meadows, forest edges, banks of water bodies) and in woodland habitats in �oodplains. Maintenance and development of A. tataricum populations are provided primarily by a su�cient amount of light and moisture. �e shading, appearing under the canopy of some tree plants (e.g. A. ne- gundo forest stand), has depressing e�ect on A. tataricum seedlings development. �e analysis of the accompanying �ora re�ects the ecological-coenotical con�nement of A. tataricum to plant communities of both forests and meadows in �oodplains. Partic- ipation of weed species (14.7%) in accompanying �ora indicates the ability of tatarian maple to develop in seminatural habitats. Signi�cantly smaller number of A. negundo seedlings (in 1.7–2.6 times) in the ur- ban environment can indicate initial stage of ash-leaved maple invading in this hab- itat. In opposition, in seminatural plant community with A. negundo dominance, its seeds reproduction has a large level, probably due to indirect facilitation of the adult trees for the growth of its own seedlings by suppressing of native plants in this habi- tat. �is is consistent with results of investigations of this phenomenon in relation to exactly A. negundo (Saccone et al., 2010), as well as other plant species (e.g. Siemann, Rogers, 2003). Obtained results about interactions of several maple species (A. tataricum and A. negundo) show the relevance of these studies in relation to study of closely related tree species in conditions of their joint existence. References Aleksandrova, V.D. (1964). �e study of changes of vegetation cover. In: E.M. Lavrenko, A.A. Korchagina (eds.), Field geobotany. 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Physical and geographical conditions and landscapes of the Republic Mordovia. Saransk: Publisher of the Mordovia State University. [In Russian] Yamashkin, A.A. (2012). Geographical atlas of Republic of Mordovia. Saransk: Publisher of the Mordovia State University. [In Russian] Abstract Genus Acer in the Republic of Mordovia is presented by four plant species: Acer campestre L., A. negundo L., A. platanoides L. and A. tataricum L. For A. campestre and A. tataricum we investigated accompanying �ora composition and conducted its analysis; characteristics of populations were carried out. Seed reproduction of A. negundo was investigated in seminatural and anthropogenically disturbed habitats. Seed reproduction is of little importance for the maintenance of A. campestre populations on the north-eastern border of its range. �is is o�set by an active vegetative propagation by root o�springs. All in all, very few A. campestre individuals reach the generative age. A. tataricum is capable to grow in open, as well as in woodland habitats in �oodplains. Su�cient light and moderate moisture are the most signi�cant environmental factors for A. tataricum populations. Depressing of tatarian maple is observed under conditions of shading in plant community with A. negundo dominance. Analysis of the accompanying �oras of A. campestre and A. ta- taricum show the coenotical con�nement of these maple species. Seed reproduction of A. negundo was signi�cantly higher in seminatural habitats with dominance of ash-leaved maple than it was in urban en- vironment. Probably, this is a manifestation of indirect facilitation of the adult A. negundo tree canopy for the growth of its own seedlings by oppressing other plants (e.g. A. tataricum seedlings). �us, we showed relevance for investigations of interactions between closely related tree species. Key words: Acer campestre, Acer negundo, Acer platanoides, Acer tataricum, invasive species, population, rare species, Republic of Mordovia Received: [2016.06.23] Accepted: [2016.08.22] Trzy klony (Acer L., Aceraceae Juss.) w Republice Mordowii (Federacja Rosyjska) Streszczenie Rodzaj klon w Republice Mordowii reprezentowany jest przez cztery gatunki: Acer campestre L., A. ne- gundo L., A. platanoides L. i A. tataricum L. Dla gatunków A. campestre i A. tataricum zbadano skład �ory towarzyszącej oraz przeprowadzono charakterystykę populacji. Zbadano również reprodukcję nasion A. negundo w siedliskach półnaturalnych i antropogenicznie zaburzonych. Na północno-wschodniej gra- nicy zasięgu występowania A. campestre reprodukcja nasion ma niewielkie znaczenie dla utrzymania jego populacji. Jest to równoważone przez aktywne rozmnażanie wegetatywne poprzez odrosty korzeniowe. Niewiele osobników A. campestre osiąga wiek generatywny. A. tataricum rozwija się, zarówno w  miej- scach otwartych, jak i w siedliskach leśnych, na obszarach zalewowych. Odpowiednie warunki świetlne i umiarkowana wilgotność są najbardziej istotnymi czynnikami środowiskowymi dla populacji A. tata- ricum. Nieprawidłowo rozwinięte osobniki klonu tatarskiego obserwowano w  warunkach zacienienia, w zbiorowisku roślinnym z dominacją A. negundo. Analiza �ory towarzyszącej A. campestre oraz A. tata- ricum pokazała cenotyczne uzależnienie tych gatunków. Reprodukcja nasion A. negundo była znacząco wyższa w półnaturalnych siedliskach z dominacją jesieniolistnych klonów, niż w środowisku miejskim. 143 Prawdopodobnie jest to przejaw niebezpośredniego ułatwiania wzrostu siewek A. negundo w starszych drzewostanach poprzez zdominowanie innych roślin (np. siewek A. tataricum). W ten sposób wykazano znaczenie interakcji pomiędzy blisko spokrewnionymi gatunkami drzew. Słowa kluczowe: Acer campestre, Acer negundo, Acer platanoides, Acer tataricum, gatunki inwazyjne, populacja, gatunki rzadkie, Republika Mordowii Information on the authors Anatoliy A. Khapugin At present he studies population ecology and biology of rare and endangered plant species in Central Russia. Also, recently he has carried out investigations of pyrogenic successions in forest ecosystems un- der conditions of southern boundary of the taiga zone. �e results of his investigations are dedicated to biology and ecology of several rare and endangered plants. Additionally, he has investigated the biology and ecology of several alien invasive plants species. Tatyana B. Silaeva Her scienti�c studies are dedicated to research of distribution and ecology of rare plant species in Central Russia and adjacent areas. She works in the �eld of nature conservation. She has also investigated invasion and penetrating of aggressive alien plants species in the Republic of Mordovia. Yulia N. Utorova Her scienti�c interests are devoted to investigation of Acer species in the Republic of Mordovia. She is interested in their ecology, biology and natural conditions of habitats. Three M aples (Acer L., A ceraceae Juss.) in the R epublic f M ordovia, R ussian Federation