Популяційна динаміка та розподіл за біотопами хом’яка (Cricetus cricetus) в Медоборах (Поділля)

Abstract

The results of the surveys and data on biotopic distribution of common hamster burrows in the vicinity of the Medobory Nature Reserve were collected and summarised. In order to study the abundance and density of hamsters, two monitoring sites were established. The first is in the fields between the village of Butsyky and the town of Hrymailiv, and the second is on a farming field in the town of Hrymailiv, where since 2013 the number of common hamster burrows have been recorded in the autumn period of the year. Homestead plots and small-scale plantations of agricultural crops were surveyed using the transect method by one or two investigators. During nine years of research, 170 living burrows were found on the first site, which covers an area of about 10 hectares, and only 7 on the second site, which is located on a farm field. The majority of living burrows were recorded on crops of 3 to 4-year-old alfalfa. An increase in the number of burrows was observed in 2015 and 2019. Additional research was carried out in separate gardens with alfalfa in the vicinity of the town of Hrymailiv, the villages of Lezhanivka, Lychkivtsi, Zelene, and Paivka, and in farm fields, where 52 living burrows were recorded. Separate data were obtained from observation cards of reserve workers and by surveying the local population. The largest colony was found in the village of Lychkivtsi in 2021 in a garden with a four-year-old alfalfa plantation of 0.3 ha, and there were 16 settlements there (3 to 5 burrows per settlements). During nine years of observation, live animals were found only twice: in the village of Butsyky in 2013 (two individuals in a field in fodder beet crops) and near Lezhanivka in 2019 (one individual in a disced rapeseed field, during stork foraging). Usually, they are recorded dead: killed by predators or killed by motor vehicle collisions. Taking into account the distribution of burrows by biotopes, it is worth noting that the decline in the number of hamsters is the result of a decrease in agricultural land area suitable for their existence. The exception is the years 2019–2020, when their number began to increase rapidly, the cause of which could be the mass death of foxes that occurred as a result of poisoning by mouse-like rodents in farm fields in 2018, which served as their food base. As for the animals of the dark morph, their share in the population is no more than 10%, and they often become victims too, since their colouration is clearly visible in their living environs.