The dissertation work describes the features of climatopes in forest biogeocenoses within the valley-terrace landscape in the Steppe zone of Ukraine as one of the aspects of forest resistance to environmental factors. Characteristics of climate-forming processes in valley biogeocenoses were described, features of the ecoclimate formation in biogeocenoses of floodplain and arena terrace (pure pine forest, mixed pine forest and mixed oakery) were revealed, and comparative ecoclimatic characteristics of floodplain and arena biogeocenoses were carried out. The environment-forming and environment-transforming effects of valley forest biogeocenoses were assessed, and the results obtained for solving issues of forest biogeocenoses protection and restoration were proposed.
For the first time the work describes the climatopes in forest biogeocenoses within the valley-terrace landscape of the steppe zone of Ukraine taking into account biogeocenotic cover diversity including that at the parcel level, from the riverbed shaft to arena terrace. The difference in climatic values (relative air humidity, air and soil temperature, illumination, wind speed) in the diversity of forest biogeocenoses in the floodplain and arena terraces of Samara river valley was shown. Quantitative characteristics of the pertinence coefficient for biogeocenoses of valley-terrace landscape near Samara river were found. The results were obtained in regards to relationship between climatopes and ecological diversity of floral composition in forest biogeocenoses.
It was found that zonal features of the climate were significantly transformed under the influence of biogeocenotic cover and landscape features of the area, and peculiar forest-growing conditions with a certain degree of ecological compliance of habitats for forest biogeocenoses were formed. It was shown that the state of climatopes is determined not only by external influences, but also by complex interactions between process elements. All this determines climate heterogeneity, caused its variations and types of environment formation.
Within the floodplain, significant climatic contrasts were observed at a short distance, depending on phytocenotic cover variation and proximity of sampling units relative to water bodies. It is necessary to note the close relationship between the studied ecosystems in the formation of an ecoclimate in floodplain habitats that develop a complex of interconnected ecosystems of smaller orders, plant communities, Meadows, water reservoirs, etc.
Under condition of arena terrace, the main reason for climatic variations is due to the different structure of forest stands in arena biogeocenoses and, as a result, the difference in solar radiation receipted by landscape units and underlying surface. Differences in solar energy and radiation intake, heating and cooling of atmosphere, wind braking, slowing down turbulent exchange cause a formation of following types of eco-climates in the arena terrace: arena semi-dry warm, arena semi-fresh warmish, arena semi-fresh relatively warm and arena fresh relatively cool.
Within the valley forest ecosystems, temperature and moisture processes are developed which have a positive environment-transforming effect on the steppe environment. With comparison of ecoclimatic indicators of biogeocenoses in valley habitats it was found that the greatest environment-transforming effect among all the studied ecosystems is exerted by a following complex of ecosystems: a reservoir – linden-ash oakery of the central floodplain. In the arena, in comparison with the floodplain, the role of zonal factors increases, but ecoclimatic features quite clearly distinguish arena conditions from the habitats of the watershed chernozem steppe.
Forest biogeocenoses in the valley-terrace landscape are considered to be standards of forest resistance to environmental factors, in combination with the environment-transforming role of biota they create a holistic ecological compliance and indisputably need to be preserved and adoption appropriate measures to maintain the existing properties, because it will be possible to prevent the development of negative climatic phenomena that arise including for the research region through the preservation in the natural state of the elements of this system.
