The asymmetry of the aquatic macrophyte response to temperature increases with global warming and has to be accounted for in phytoindication

Abstract

The study revealed the relationship between geographic and habitat estimates of the optimum of macrophyte species under temperature gradient conditions. How the estimates correlated with the point and habitat scales of the indicators was determined. The results indicate that the abundance of many species decreases sharply under extreme conditions caused by rising temperatures. The Didukh scales, after applying the ideal indicator method, provide a high level of accuracy for temperature estimation. The explanatory power of the Ellenberg scale was somewhat lower, which can be explained by the fact that this scale is "tuned" to optimal values, and under extreme conditions of factor action, the parameters of niche tolerance to which the Didukh scale is "tuned" have a limiting value. In addition, under extreme conditions, species responses to the impact of a factor often or always deviate from a symmetric model that does not take into account traditional Ellenberg scale values. At the landscape level, changes in temperature are associated with changes in oxygen, electrical conductivity and turbidity. Among the morphological characteristics of water bodies, shoreline development has the greatest influence on the temperature regime. The method of the ideal indicator, which takes into account the asymmetric distribution of species responses, has shown a high ability to indicate the temperature regime of water bodies in the Dnipro floodplain.