Vaccinium myrtillus L. in Kirov region (southern taiga subzone): phytocoenotic confinement and ecological preferences

Vaccinium myrtillus L. is an important component for forming phyto-environment in boreal forest ecosystems, in which it develops various consortium connections. Being a mycorrhizal species, V. myrtillus improves nutrition and stimulates the growth of plants of all layers, supporting inter- and intra-specific connections of different layers of forest communities. In order to estimate the environment-forming role of V. myrtillus in ecosystems it is essential to acquire data on quantitative presence of the species in plant communities composition and on ecological-phytocoenotic peculiarities within its range. The aim of the study is to define phytocoenotic parameters and ecological conditions of V. myrtillus habitats within the southern taiga part of its range (Kirov region). We collected the material during the growing seasons of 2009-2015 and made 110 geobotanical descriptions according to common geobotanical methods (Methods of studies…, 2002). Ecological conditions were estimated based on species compositions in communities using 10 ecological scales by Dmitry Tsyganov (1983). The ecological discomfort index was determined for each habitat (Klimenko, 2012). Common methods of soil analyses were used for different biotopes of the studied species (Arinushkina, 1962). Hemeroby was determined by the species composition in plant communities, in which every species has individual human impact tolerance spectre (Frank and Klotz, 1990). V. myrtillus acts as a dominant or codominant of the herbaceous-shrub synfolium of boreal coniferous and mixed forest communities with 30-70% cover. It is accompanied by the following species: Vaccinium vitis-idaea L., Rubus saxatilis L., Juncus filiformis L., Calamagrostis epigeios (L.) Roth., Thelypteris palustris Schot, Melampyrum sylvaticum L., and Majanthemum bifolium (L.) F. Schmidt. The species is found on gley and gleyic podzolic soils, mostly sabulous, rarely-sandy; and on peatygley and sod-podzolic soils (See Table 1). Bilberry is common on high acidity soils with pH varying from 2.54 to 4.93. The concentration of organic carbon in bilberry forest litter varies from 5.71 to 69.2% (See Fig. 1). V. myrtillus is a mesobiont species whose average ecologic valency coefficient reaches 55%. In the investigated coenopopulations, the species achieves 8.15 to 50.10% of its potential capabilities regarding the studied factors. V. myrtillus is a hemieurybiont by climatic factors (0.58 points). It achieves its maximum on ombroclimatic scale (44.5%). According to climatic scales, ecological conditions of the studied habitats occupy the central position of all possible. The generalized spectrum of soil scales shows the species as a mesobiont (It–0.45). This allows widening V. myrtillus soil humidity scale 1.27 point left and soil moisture variability scale 0.80 points right. On other scales, the environmental position of the studied coenopopulations are within the data given by Dmitry Tsyganov for the species (See Table 2 and Fig. 2). The discomfort index is also given to estimate habitat ecological conditions. Based on phytoindication data and according to the discomfort index, we defined that the most favorable conditions of edapho- and climatopes for V. myrtillus are formed in sphagnum phytocoenoses. The least favorable conditions were noted in bilberry pine and bilberrypleurocarpous moss pine-spruce forest types. The study of hemeroby showed that oligo-mesohemerob species (highly sensitive to anthropogenic factors) prevail in all V. myrtillus coenopopulations, i.e. 41%. A-hemerob, a-euhemerob and polyhemerob species were not noted in any of the studied CPs (See Table 3 and Fig. 3). This proves that the species is of low resistance to anthropogenic influence and can survive moderate intensity human impact. The studied plant communities with V. myrtillus are low-hemerobic.