Ecological assessment of the variability of the herbaceous cover composition by contrasting elements of the mesorelief at the Forest Experimental Station of the RSAU-MTAA

The present paper analyzes the results of a comparative ecological study of regional typological patterns of spatial variability of the herbaceous cover composition in the conditions of a gently sloping mesorelief at the Forest Experimental Station of the Russian Timiryazev State Agricultural University – the background object of environmental monitoring for the northern part of the Moscow metropolis. Standardized descriptions of the composition and biodiversity assessments of the vegetation cover are presented on five representative sites of the orographic transect, cutting in the direction from northeast to southwest the gently sloping moraine hill dominating in the mesorelief and its opposite slopes of the northeastern and southwestern exposures, including their foots – with a total height difference not more than 15 meters. The greatest variety of herbaceous species from the 20 families represented in the studied plots was found at the foot of slopes with more stable humidification conditions, and its minimum level was at the summit of a moraine hill with pronounced summer desiccation of the topsoil of the zonal sod Podzoluvisols characteristic for the Forest Experimental Station. Other important ecological factors of herbaceous biodiversity are the exposure and shape of the slope, which affect both the temperature regime and the seasonal dynamics of the topsoil moisture – under conditions of relatively insignificant variation in the tree canopy density and pronounced recreational load on the ground vegetation and topsoil. Humus-podzolic soils dominating on the bottom of the slope of the north-eastern exposure with a steadily increased moisture level are characterized by reduced resistance to recreational load, which leads to the maximum severity of the pathway network and relatively reduced biodiversity indices. The analysis of the patterns of spatial variation in the composition of the herbaceous cover allowed one to identify the problematic environmental situations and factors of reducing its biodiversity, that has to be taken into account when further planning the regulation of recreational load at the Forest Experimental Station and similar areas of the forest infrastructure of the northern part of Moscow, as well as when assessing the projected anthropogenic impact in the conditions of the Moscow megalopolis and comparable urban ecosystems of the southern taiga and mixed-forest subzones at the European territory of Russia. Keywords: BIODIVERSITY, URBAN FOREST PARKS, FOREST ECOSYSTEMS, MOSCOW, IMPACT ASSESSMENT, RECREATIONAL LOAD, HERBACEOUS COVER, ENVIRONMENTAL FACTORS, URBAN ECOSYSTEMS