Syntaxonomic diversity of forest meadows at Ob-Inya watershed in the Novosibirsk Region

Abstract

The syntaxonomic diversity of forest meadows at the Ob-Inya watershed was studied within the Novosibirsk Region. The territory is a part of the Sokur elevation, which approaches the Salair ridge in the south-east. Common is the erosion of the landscape reflected in dense network of river valleys and draws. The vegetation is transitional between subtaiga and forest steppe (Reverdatto, 1931; Vandakurova, 1957; Kuminova, 1973; etc.). Forest meadows (the order Carici macrourae–Crepidetalia sibiricae Ermakov et al. 1999 of the class Molinio-Arrhenatheretea R. Tx. 1937) occur on the edges and glades of grassy aspen and birch forests and are an element of vegetation of both forest steppe zone and the subtaiga subzone. Their set of species and syntaxonomic diversity reflect the soil and climatic conditions of the location and may serve as a criteria for defining the zonal and subzonal borderlines. The aim of the study was to reveal and to characterize the syntaxonomic diversity of the forest meadows of the Ob-Inya watershed. The studies were conducted at the territories of the Novosibirsk, Moshkovo, and Bolotnoye districts. 114 reléves served as a basis for the study. Forest meadows are represented by 2 associations, 2 subassociations, 2 variants and 2 communities from 2 suballiances of the alliance Crepidion sibiricae Mirkin ex Ermakov et al. 1999 (Table 1). Communities of the ass. Crepidetum sibiricae Dymina ex Ermakov et al. 1999 are most common, and occur everywhere in the studied area (Table 2). The association is represented by two subassociations differing by the degree of the moisture content in the habitats. Communities of the subass. typicum occur in depressed highly moistered landscapes primarily in the axial part of the Sokur elevation and in the north-eastern regions of the Ob-Inya watershed. A new subass. Crepidetum sibiricae fragarietosum viridis subass. nov. uniting more xerophytic communities which are uniformly dispersed over the territory in well-drained flat and convex parts of the watershed and on the gentle slopes of the draws. Character for these is participation of xeromesophytes from the diagnostic combination of dry forest meadows of the suballiance Aconito barbati–Vicenion unijugaeKorolyuk et al. 2016. The nomenclature type of the subassociation (holotypus): Table 2, rel. 17 (field number Z20-021), Novosibirsk region, Bolotnoye district, near the Kozlovka village, 55.86934° N, 84.15000° E, 31.08.2020, the author E. G. Zibzeev. Under the increased grazing pressure on the communities of the subass. C. s. fragarietosum viridis, pasture meadows of the var. Poa angustifolia, mostly dominating by Poa angustifolia,were formed near the settlements of the south-western part of the Sokur elevation. There are some meadow-forest plants of the alliance Crepidion sibiricae of the order Carici macrourae–Crepidetalia sibiricae in such communities. A new forest meadow ass. Galatello biflorae–Artemisietum macranthae ass. nov. (Table 3) unites dry forest meadows occurring on the upper parts of the convex slopes of the draws of sunlit exposures in the axial part of the Sokur elevation The communities developed under conditions ecologically closed to these of the subass. Crepidetum sibiricaefragarietosum viridis meadows have more xerophytic composition: the tall-forb species are absent; the abundance and continuity of the meadow mesophytes is lower, while the proportion of meadow-steppe elements is higher. The nomenclature type (holotypus): Table 3, rel. 1 (field number mr20-033), Novosibirsk region, Moshkovo district, the area near the Verkh-Balta village, 55.32588° N, 83.76177° E, 30.08.2020, the author M. P. Tishchenko. This association may be considered as subtaiga variant of the dry forest meadows at the Ob-Inya watershed (the right-bank region of the Ob River). For the species composition and environmental occurrence, communities are similar to the these of the ass. Aegopodio podagrariae–Brachypodietum pinnati Tishchenko et al. 2015 from the subtaiga of the left-bank region of the Ob River. Xeromesophytes as well the hygrophilous species growing in the subtaiga forests are common in their coenofloras. The communities of the ass. Galatello biflorae–Brachypodietum pinnati Korolyuk 1998 on the left-bank region of the Ob River and of the ass. Filipendulo vulgaris–Brachypodietum pinnati Makunina et al. 2010 (Korolyuk, Kipriyanova, 1998; Makunina, 2016) in the right-bank region, occur in similar forest-steppe habitats. In the elevated sites of the central part of the Ob-Inya watershed and in the right-bank region of the Inya River, dry forest meadows of community Iris ruthenica are described (Table 4, rel. 1–6). Character for these is participation of Iris ruthenica and Filipendula vulgaris, rare in the studied area. The community Carex praecox (Table 4, rel. 7–10) includes the forest meadows of the driest habitats, where some steppe species are found. The communities occur in the eastern part of the Ob-Inya watershed on the steep southern and south-western slopes into the valley of the Iksa River, the tributary of the Ob River, in their upper part. To summarize, the forest meadows of the region have more mesophytic composition compared to the forest-steppe communities: no xerophytes and many meadow-steppe species (Peucedanum morisonii, Ligularia glauca, Adonis vernalis, Campanula altaica, Dianthus superbus et al.) common in forest meadows in the forest-steppe zone. The Ob-Inya watershed forest meadow syntaxonomy is rather peculiar, compare to the forest-steppe zone.