Ecological and biological properties of lawn coverages of city of Nikopol (Dnepropetrovsk area)

Abstract

The value of lawns shows up completer in all, when they occupy 40 – 90 % of the areas of green plantations. However in industrial cities their part is less, they have the mainly unsatisfactory state, contain the ruderal species.
 Therefore an ecological ground of creation of proof lawn phytocenosis in cities with high technogenic pressure, and also development of research and practice measures of their arrangement in the conditions of certain anthropogenic landscape taking into account the ecologic and biologic features of turf-forming species and terms of the urbanized environment is the scientific issue.
 The aim of our research is: on the basis of ecologo-phytocenotic researches to set the phytocenotic features of lawns and coverage of lawn type of the urbanized ecosystems on the example of Nikopol for development of ecological bases of creation of proof cenosis in municipal habits and decision of questions of optimization of environment.
 The trial areas under study were located among grasses of grass type and ornamental lawns in the city of Nikopol. The administrative and residential areas of the city were covered. In total, thirty test sites of size 1m2 (metrics) were described, divided into 120 areas of size 0,0625 m2. Characteristics were studied on each test area: illumination, species composition, percentage of projective coverage of each species found, percentage of free plant area.
 In the 30 trial sites covered by our research, 44 species of plants belonging to 15 families were identified. Species saturation of investigated test areas (1m2) varied from 10 to 17 species. Among the families, the primacy of the species composition was occupied by Asteraceae and Poaceae.Taking into account the instructions of V.V. Tarasov, the spectrum of the first percentages of the occurrence of families reproduces the composition of the regional flora with the dominance of cereals and herbs. The analysis of herbaceous vegetation was carried out taking into account the prevalence (in the event of a species) and the quantitative role in the formation of grass (projective coverage). This made it possible to find out the potentialities of species in a certain growth area, that is, competing ability.The triumphal triumph in the whole spectrum of the species we found among the grasses are Trifolium repens L. (occurrence of 93%), Polygonum aviculare L. (90 %), Taraxacum officinale Webb. ex Wigg. (83 %), Ambrosia artemisiifolia L. (80 %), Achillea submillefolium Klok. et Krytska (70 %), Convolvulus arvensis L. (70 %) etc. These are representatives of weed vegetation, for the most part – ruderal species, and even those that are quarantine and undesirable for urban lawn phytocoenoses.Of the Poaceae family, Poa angustifolia L. (87%), Elytrigia repens (L.) Nevsky (77%), Lolium perenne L. (70%) have high incidence. The indicated plants are representatives of both steppe flora, and ray and even forest, which speaks of a wide range of ecological conditions of location among studied lawn phytocoenoses. Typical species that are able to form the most decorative grass cover (according to the classification of O. Laptev) are represented by the species Poa angustifolia, Lolium perenne, Poa pratensis L., Festuca valesiaca Gaud. Their prevalence in the herb is quite variable: from the presence on most of the test areas - Poa angustifolia, to those who met quite rarely – Festuca valesiaca.Most of the investigated test areas form a thin-grasshopper and pyrite-grass-mixed grass group, which corresponds to the specific structure of meadow lawns and conventional urban grasslands. The ecological and phytocenotic composition of the investigated vegetation groups of the lawn type reflects the system formed by certain representatives that make up the botanical and ecological basis for the creation of stable long-lived grass coverings in the urban agglomeration of the steppe zone, is an objective benchmark for targeting the corresponding phytocoenic processes in the desired direction.Correlations analysis of projective coatings was performed to find out the relationship between Ambrosia artemisiifolia and other representatives of the lawn flora. The calculation is based on data from the area of ​​0.25m2 (120 sites). The obtained materials allowed to reveal a mutual correlation of quantitative indicators with a high degree of statistical probability. Thus, a probable negative correlation between the parameters of the projective cover of the plants of the family Fabaceae and Ambrosia artemisiifolia was found.