distribution

Short-term fluctuations of the bird number and distribution, exhibiting a reliable relation with microclimatic phenomena (weather features of adjacent seasons, the nested population value in the previous year etc.) are shown.

The paper analyzes prognostic models of the ornithofauna dynamics of the Northern Lower-Volga region, based on our analysis of cause and effect relationships in the dynamics of their distribution, historicofaunistic layers, and ecological groupings. As a result, abundance and distribution fluctuations have been revealed with no clear relation to the dynamics of climatic parameters but subject to certain cyclicity (Locustella fluviatilis, Motacilla citreola).

The habitation of three species of the Cobitidae family (Misgurnus fossilis, Cobitis taenia, and Cobitis melanoleuca) in the reservoirs of the Northern Lower-Volga region is confirmed. That of two species of the family (Cobitis rossomeridionalis and Sabanejewia aurata) in the region is hypothesized.

Six years have passed since, in 2018, an invasive species from Europe – the Ohrid miner Cameraria ohridella (Lepidoptera: Gracillariidae) penetrated into the Lower and Middle Volga region and began to actively populate urban landscapes planted with horse chestnut. Using the example of the regional center of Saratov, the temporary aspects of settlement and damage to horse chestnut trees over the specifi ed period are considered.

Concerning the distribution of Allium caeruleum Pall. and A. regelianum A. K. Becker, recent literary sources provide confl icting information. Based on the data from the doctoral dissertation of A. O. Tarasov, the results of expeditionary research and our own herbarium collections, it is stated that Allium caeruleum is distributed in the Ozinsky (at least in the vicinity of the village of Nepryakin) and in the Aleksandrovo-Gaisky (at least in the vicinity of the village of Kamyshki) districts of the Saratov region. The presence of A.

On the basis of our 1996-2009 field surveys in the Saratov region and adjacent territories, and our analysis of the literature data, the distribution and abundance dynamics of Dendrocopos major, D. syriacus, D. medius, D. leucotos, and D. minor is considered. The present habitation of D. leucotos in the Saratov region has been established to be associated with ripe deciduous woods in the Saratov Right-Volga-bank region; the bird penetrates for nesting up to 51°40* lati­ tude North along the Khopyor and Medveditsa river valleys. D.

Specific  distributions  features  of distribution of 9 species  of martens in the north of the Lower Volga region have been demostratet. Calcu­ lated width of the spatial niches for these predators and their degree of overlap. Widespread spacies  of martens  in this  region are the weasel, stoat and badger. Black  polecat, pine and stone martens occupy  about half of the possible biotopes, but mink  and steppe polecat are found only in a limited number of habitats.

For the fi rst time in the southern part of the Volga Upland, a detailed study of the population distribution and structure of rare and protected species Hedysarum grandifl orum Pall., listed in the Red Books of the Russian Federation (2008) and the Saratov Region (2021), was carried out. The study was conducted in 2007–2021. To identify the distribution, data from routine observations and information from herbarium specimens, literary data and oral reports were used.