Dynamics of Phytomass Spatial Organization in a Reserved Steppe Landscape: Case Study of Burtynskaya Steppe, Orenburg Reserve

Abstract

The “hot spot analysis” was applied to materials from 51 Landsat satellite images using the example of the “Burtinskaya Steppe” area of the Orenburgsky Nature Reserve, to study the dynamics of areas of positive phytomass anomalies relative to a neighborhood with a radius of 300 m. The purpose of the study was to establish the dependence of the variability of areas of increased phytomass on the landscape structure and hydrothermal conditions. We concluded that the switching of phytocenoses in transition zones from steppe to meadow type of functioning is ensured by varying the ratio of xerophytes and mesophytes depending on fluctuations in hydrothermal conditions. The frequency and area of positive phytomass anomalies in the bottoms of gullies correlates with their area on partially forested slopes, which indicates the positive role of forest vegetation in the stabilization of moisture influx into the bottoms. In deforested catchment areas of the south-facing slopes, the area of positive phytomass anomalies is determined by the supply of snow moisture, and in the catchment areas of north-facing slopes, by warm-period precipitation. The binding factors for the most stable positive anomalies of phytomass are the moisture convergence and the landform concavity rather than the catchment area.