State of the rodent community, assessment of their harmfulness at agricultural sites in the foothill zone of the Republic of Dagestan

Background. Annual losses of grain crops in the world from pests amount to one percent of the harvested crop. Many species of rodents have become permanent inhabitants of agrocenoses and significant pests of fields, gardens, and vegetable gardens. The noted problem sets tasks for regular monitoring of numbers, measures to reduce and maintain the number of rodents at a level safe for humans. The purpose of the study is to assess the species composition, number of rodents living in sheepfolds, farms and other agricultural facilities in a number of areas of the foothills of Dagestan. Materials and methods. The material was collected in the summer at agricultural facilities (crop fields, vegetable gardens, sheepfolds, warehouses, hangars) and in natural biotopes of the Kayakent and Sergokalinsky districts of the Republic of Dagestan in 2021–2022. To assess the species diversity of rodents in the considered conditions, the Simpson diversity index was used. All captured animals were measured for body weight and standard body measurements. In addition, the physiological state of the genitals was analyzed during the autopsy: the weight of the testicles, the number of blue spots or embryos in the uterus were determined. To study the species composition, abundance, and structure of the rodent community, quantitative and qualitative methods of rodent counting using Gero crushers were used. Results. The results showed that the species richness of rodents in natural biotopes was higher than in agricultural facilities. In both areas, the yellow-bellied mouse and the social vole dominated. The number of rodents and the density of burrows in agricultural facilities were more than twice as high as in the natural environment. The species diversity index was higher in the natural environment. The body condition and reproduction rates of rodent species were higher in agricultural facilities than in natural environments. Conclusions. Rodent species richness was higher in natural conditions than in agricultural facilities. The species diversity index was higher in natural biotopes than in agricultural facilities. The dominant status (in abundance) was occupied by the yellow-bellied mouse in both conditions. The number of rodents in agricultural facilities was more than twice as high as in the natural environment. Individuals in agricultural facilities were fatter and had higher fertility values than in natural spaces. A threshold of economic damage was revealed.