Settlement characteristics of The Emerald Network "Khukhra" and "Riabyna" objects in Sumy region

Abstract

The current state of biotope’s vegetation cover by natural and spontaneous origin of the Khukhra and Riabyna river valleys was researched, which are left-bank tributaries of the Vorskla river, as fragments of the preserved landscape within one of the western spurs of the Central Russian Upland. They are listed as perspective objects of the Emerald Network — Riabyna river valley in Sumy region (UA0000427) and Khukhra river valley in Sumy region (UA0000429). The obtained new data on environmental significance are data for the primary database formation in the monitoring organization of these territorial objects. The researched areas are mainly floodplains, small segments of pine terraces and slope’s fragments of these rivers native banks. The presence numbers of biotopes from Resolution 4 of the Berne Convention (C1.222; C1.223; C1.224, C1.32; C1.33; C1.4; C2.33; C2.34; C3.51; D5.2; E2.2; E5.4; F9.1; G1.11; G1.21; G1.22; G1.A4; G1.A1) are given for both explored objects, in addition, for the valley of the Riabyna river are indicated E1.3; E3.4, and for the Khukhra river — C3.4; E1.2. We have not confirmed the existence of such biotopes as C3.4, E1.3, C1.4 for these objects. Also, the presence of Sarmatian-type pine forests (G3.4232) was noted, which are timed to the elevations of pine terraces. Biotopes with constant excessive moisture are ubiquitous in the waters of low-flow artificial ponds. Eutrophic and mesotrophic vegetation of slow-flowing waters often occurs in shallow water along riverbeds. Biotopes groups of dwarf annual amphibious plants were observed only in fragments. Lowland swamps with sedge thickets without stagnant water are widespread in the floodplain, although they occupy small areas. Biotopes flooded pasture and hay meadows are a variety of options coenotic (herbaceous and cereal, wet and moist high-grass meadows). Biotopes of riparian shrubs, willow and willow-poplar floodplain forests are distributed in small fragments in the riverbed of floodplains. Mixed riparian floodplain and gallery forests occur in low-lying areas at the transition from the floodplain to the pine terrace. In general, shrub and forest vegetation on the terraces of these rivers are currently quite limited and fragmentary. Due to the reduction in the use of hayfields, in the floodplain the presence of indigenous forest remnants is quite relevant, which should be a source for their restoration in large areas. Important environmental object in these areas, as part of the Emerald Network is the local population of Ostericum palustre, and in the valley of the Khukhra river discovered a large population.