Nº 3 (2025)

Willows (Salix) are widely distributed geographically, participate in the formation of the vegetation cover, and are widely used in various sectors of the national economy. The aim of this work is to study the biological and morphological characteristics of the boreal willow species in the European part of Russia and their distribution. The research was conducted in the center of the European part of Russia, in its most developed regions, including the Moscow, Vladimir, Nizhny Novgorod, and Penza regions. The study region occupies the center of the East European Plain, the northern and western slopes of the Volga Upland, and the transition to the Oka-Don Lowland. The biomorphological features of 16 willow species were described. The field studies used the methods of "marked bushes" and taxonomic transects. Despite the great similarity in morphological structure, the willow species of the European part of Russia have clear distinctive biomorphological features that distinguish them from each other.

The dormouse is a specialized dendrophilous species, favoring broadleaf forests. A large number of dormouse habitats on the East European Plain have been reduced due to intensive economic activity. As a result, the dormouse is listed in the Red Data Books of 13 regions of the Russian Federation. The aim of this study was to identify factors influencing the presence (or absence) of the dormouse in the forests of the Nizhny Novgorod Region at the northern boundary of its range. Using artificial nests, 25 fragments of broadleaf and mixed-coniferous forests in 11 districts of the Nizhny Novgorod Region were surveyed from 2014 to 2024. The analysis showed that dormice are found only in relict old-growth forests 200 years old or more, avoiding oak forests 150-200 years old. Their presence is influenced by factors such as forest type, stand density, and canopy density. The structure of forest layers is also important. A well-developed understory with a high proportion of common hazel, as well as oak and linden, is essential. No correlation was found between forest fragment size and soil type. The obtained results indicate the need to protect fragments of primary old-growth broadleaf forests, which contain a set of specific characteristics that play a key role in maintaining a stable dormouse population on the northern periphery of its range.

For the development of scientifically sound approaches to the sustainable management of water resources, it is necessary to study the structural components of aquatic communities, including mollusks. The aim of this work is to study the malacofauna of the Sura River basin downstream of the city of Penza, with an analysis of the spatial distribution of species depending on the type of water body. Samples of mollusks were collected in various types of water bodies: the channel of the Sura River (11 stations), its tributaries (4), and oxbow lakes (7). The collection was carried out manually from the substrate, vegetation, and using a hydrobiological net, with the geographical coordinates recorded. A total of 38 species from 10 families were identified. The greatest diversity was noted in the families: Lymnaeidae – 8, Planorbidae – 8, Sphaeridae – 6, and Unionidae – 5. Species preferences for specific biotopes were established: rivers, tributaries, or oxbow lakes. The invasive species Ph. acuta was recorded near populated areas. Both eurybiontic and stenotopic species were discovered (e.g., S. saridalensis and Pl. planorbis – stagnant water bodies; R. auricularia – areas with slow water flow). The presence of the invasive species Ph. acuta indicates anthropogenic influence on the river ecosystem.