RESEARCHING THE ECOLOGICAL NICHE IN TAXONOMY
The revealing of an ecological niche, its divergence and other changes that are reflected in the species range is no less important for the study of speciation and phylogenetic reconstructions than the study of changes in morphological characters. The aim of this work is to review the modern methods for studying the ecological niche of taxa that can be used in taxonomy. The concept of an ecological niche has become one of the fundamental in ecology and biogeography. The theory of niches has been intensively developed for almost a hundred years, the concept has been repeatedly refined and analyzed by different specialists from a wide variety of positions. As a result, at present, on the one hand, an ecological niche is understood as a set of ecological factors, abiotic and biotic (including the rhythm of their change), necessary for the existence of a population in an ecosystem, and on the other hand, as a place occupied by a species in a biocenosis, including a complex of its biocoenotic connections and requirements for environmental factors. As a consequence, there are several niche concepts, and choosing the right concept when solving various biological problems is very important. Taxonomists, for whom the ecological characteristics of the taxon are of the greatest interest, in their studies prefer the Grennell niche, the concept of which focuses on the complex of ecological conditions necessary for the existence of the species, and is determined over a wide geographical range and with a high level of generalization. To reveal and assess an ecological niche for taxonomy purposes, two main approaches are currently used - using indicator values and digital technologies. Digital technologies obtain a general generalized picture along the entire taxon's range or for its essential part. However, one should not forget about the limitations of the methods, and, in particular, in research it is extremely important to distinguish the variables describing aspects of the environment that are affected by a species (through consumption or other modifications) from variables that themselves can influence the species without the possibility of being consumed or modified by this species (the so-called «scenopoetic» variables). It is also important to understand that the use of various factors will determine which part of the niche will be displayed: if only climatic parameters are used to model the niche, the model will display only the part of the niche that is conditioned by climatic ones and will obviously be narrower than the model obtained with the help of various «scenopoetic» factors (topographic, soil pH, etc.). For clarification, it seems necessary to call such niche as ecologo-climatic niche. Ecological niche models, which are created by combining species distribution data with environmental GIS data layers, are increasingly being used to answer the fundamental questions about niche evolution, speciation, and accumulation of ecological diversity in clades. The issue of conservatism of the ecological niche is the central issue of evolutionary ecology. It is of the great importance for taxonomy. Detailed studies of the ecological niche and area dynamics allow us to understand the mechanisms that promote the evolution of the niche, or, conversely, hinder it. In addition to speciation issues, the conservatism of the ecological niche makes it possible to use niche models for reconstructing probable changes in species ranges in past geological epochs. The currently available set of methods and algorithms, as well as the available databases, allow taxonomists to solve various problems, at different levels and with varying degrees of accuracy. Of course, both the method of ecological scales and modeling using GIS technologies have their limitations, but both methods are in a state of development and are gradually making it possible to better reflect the true picture of the ecological preferences of the species. Their use even within the p