The structure of beta-diversity explains why the relevance of phytoindication increases under the influence of park reconstruction

Abstract

Urbanization causes the highest local extinction rates and often leads to the loss of the vast majority of native species. Plant communities are sensitive to urban expansion and are therefore indicators of human land use. A city park, part of which has undergone reconstruction, was studied. The study found that the changes in ecological conditions caused by the reconstruction of a city park can be detected using phytoindication. The informativeness of phytoindication scales was shown to increase under conditions of anthropogenic load. The phytoindication scales are a reliable source of information for assessing the state of the vegetation cover of park plantations. The ecological regimes were assessed based on descriptions of the vegetation cover using Didukh's phytoindication scales. The phytoindication approach allows one to identify changes in ecological regimes that occur as a result of park reconstruction and to separate them from ecological regimes of natural origin. The study showed that the reconstruction of the park significantly affects the conditions of the park and the diversity of vegetation. The ratio of useful phytoindicative information compared to information noise in the structure of beta-diversity of the park's plantations increases significantly as a result of the park's reconstruction. The reconstruction of the park has led to changes in the spatial organization of the vegetation cover. The results obtained indicate a decrease in soil moisture as a result of the park's reconstruction. The park’s reconstruction leads to a significant change in the light regime of the park’s plantings, which leads to changes in the park’s vegetation and soils. Reducing the density of plantations as a result of their pruning during the reconstruction process also decreases the amount of fallen leaves that form leaf litter. A significant increase in the variability of the moisture regime under the influence of the park reconstruction was found. The phytoindication revealed a decrease in the acidity of the soil solution as a result of the reconstruction. The changes in soil acidity are accompanied by an increase in phytoindication estimates of carbonate content in the soil. The observed increase in carbonate content estimates may be an artifact when representatives of another ecological group also have related ecological properties that can be misinterpreted as indicators of certain regimes. The phytoindication also revealed trends in the variability of microclimatic conditions in the park as a result of reconstruction. The reconstruction of the park leads not only to a change in the modal levels of ecological regimes, but also to the formation of specific patterns of their spatial distribution. The heterogenization of the ecological space under the influence of reconstruction has been established. This heterogenization is evident in the fact that areas with homogeneous vegetation cover are decreasing. The accuracy of the description of the spatial process was found to have decreased after the park reconstruction procedures. Smooth spatial structures of the park’s vegetation cover without reconstruction are changing into rough spatial structures of the park after reconstruction. The park’s reconstruction obviously disrupts the course of long-term processes that structure the vegetation cover, which leads to temporal and spatial desynchronization of the dynamics of ecological processes. The spatial variation of variables that indicate soil processes can best be described. In contrast, the phytoindication scales that indicate climatic factors are much less spatially structured. The best variogram model to describe the spatial process is also changing under the influence of reconstruction. The significant consequences of the park reconstruction are time variability and spatial heterogeneity of ecological processes.