Water vole (Arvicola amphibious) as an object of long-term biomonitoring in a floodplain area (Western Siberia, Russia)

The paper is devoted to the dynamics of the water vole population in the conditions of total deforestation of valley forests and their subsequent restoration. We analyzed the relative population of small mammals in the typical biotopes in the Tom River basin (Western Siberia) on the border of the forest-steppe and taiga zones. From 1978 to 2019, 1,139 water voles Arvicola amphibius (Linnaeus, 1758) (synonym of A. terrestris) were caught with 50-meter trapping grooves; for 788 individuals we assessed the condition of non-metric features (phenes) of the skull. It was found that changes in the population level are non-cyclical, while against the background of a generally low occurrence of the species in the region, the population level increased tenfold in some years. It was shown that such episodic population surges can significantly impact the structure of the community of small mammals. In the valley of the Tom River, the water vole prefers inhabit wet meadows and ecotone areas between the meadow and the dark coniferous taiga forest. During the years of population surges, the water vole intensely occupies new nesting sites due to the dispersal activity of young animals but at the same time retains the original biotopic preferences. Dispersal of the species takes place in waterlogged wetlands. Most of the animals caught during the peak of their numbers were young animals of late broods born from overwintered individuals. The conducted phenetic analysis revealed the heterogeneity of young animals during the population surge, which allowed us to assume the participation of several populations in the formation of the peak. In the final surge year, the surge was characterized by an extremely low percentage of participation in the breeding of young females and the appearance of a large number of weakened animals, which led to crisis in the species population and the disappearance of the water vole from the captures. The research shows that one cannot predict the success of this process at the current stage; therefore, after flooding, it is necessary to continue monitoring.

Nomen “shchur” as the Ukrainian name of mammals from the genus Arvicola: historical and etymological survey

The ancient Ukrainian zoonym “shchur”, which has long been used for various animals, but most often for large burrowing rodents represented in the aboriginal fauna of Ukraine by the genus Arvicola, is considered. At the same time, this name is also used as a synonym for the word “krysa” (= rat), and in this sense is often identified with the genus Rattus (“patsiuk” = rat) to denote various large rodents from distant lands following a principle “ the small = mice, the large = rats”. Therefore, the name “shchur” is often considered ambiguous and thus worth either forgetting or using only for the alien species. Etymological hypotheses are considered, of which the most relevant to zoological specifics is the one that explains the connection with burrows, ground, and night. This set of features determines the general ecomorphological type: large long-tailed underground mouse-like rodents with expressed nocturnal activity, which appearance in human economies is undesirable. The history of use of the name “shchur” in the special literature, mainly in zoological reviews and other zoological studies, in the period from 1874 to 2020 is analysed. The widespread use of the nomen to denote different groups of animals, and especially rodents of the ecomorphological type “large mice”, which are representatives of the genera Arvicola and Rattus, is shown. Analysis of old sources showed that the name “shchur” was originally used as a common “generic” name for all species as well as some intraspecific forms of both genera, with the definition of semantic differences in the species modifier: water, common, ground, nomadic, basement, black, ship, mill, and so on “shchur”. Unambiguous fixation of Ukrai­nian generic names as equivalents to scientific generic names required the typification of all names, which took place in the Ukrainian scientific nomenclature in the late XIX and early XX centuries. As a result, the name “rat” is proposed to be assigned to the genus Arvicola, and for the genus Rattus to be recorded as the Ukrainian equivalent of the nomen “patsiuk” (“rat”). Arguments are presented to recognise the antiquity of the zoonym “shchur” and therefore to recognise its importance for the designation of aboriginal rodent species, and especially of “water shchur” (water vole, Arvicola amphibius) voles of the genus Arvicola in general. The practice of traditional naming of laboratory rats as “shchur”, as well as the use of the name “shchur” with appropriate definitions to refer to other genera, inclu­ding muskrats (“musk shchur” or “musk rat”), nutria (“marsh shchur” or “marsh rat”) and various representatives of distant faunas (bamboo or spiny tree-rats, etc.) in the Ukrainian zoonymics should be abolished.

Species and ecomorphological differentiation of genus Arvicola (Mammalia) in Eastern Europe

The genus Arvicola is represented in the fauna of Eastern Europe by several taxa and ecological races of semi-species and subspecies rank. Morphological data indicate the taxonomic homogeneity of lowland amphibious forms and a high level of differentiation of some mountain fossorial forms. Analysis of variation of morphometric characters shows a substantial hiatus for the Carpathian form of Arvicola, considered as A. scherman, as well as the absence of sufficient differentiation among other forms such as in lowland water voles from different parts of Ukraine or in mountain forms from the Northern Caucasus. Morphological features of the Carpathian taxon (A. scherman gutsulius) are stable compared to other mountain water vole populations from Europe and its substantial differences from the Caucasian form, which is very close to the lowland A. amphibius, do not support the idea of the ‘effect of mountains’ in the formation of small fossorial forms of Arvicola. The Carpathian Arvicola differs from all of the studied lowland forms in both morphometric and craniometric characters, which are important in the taxonomy and diagnostics of water voles (coefficient of divergence in body and skull dimensions reach CD = 4...5 ϭ. The mountain water vole (A. scherman) is characterized by a number of paedomorphic features that should be recognized as an ancestral state (plesiomorpy), whereas the European water vole (A. amphibius) is considered as an evolutionary advanced and gerontomorphic form. These two species are allopatric and the border between their distribution ranges coincide with the geographic limits of lowland and mountain faunal assemblages. Evidence for the recognition of the mountain fossorial form as either a separate species or an ecological race of the lowland species is considered. The fossorial A. scherman can be included to the group chosaricus–mosbachensis, but it remains unclear whether it should be considered an ancestral form in the evolution of the lowland A. amphibius or as an example of recapitulation of characters due to secondary transition to fossorial lifestyle. A comparison of different geographic forms of Arvicola suggests that the formation of the group took place in piedmont–mountainous areas of Europe, whereas the forms distributed further east are probably derived from the European ones.

The genome sequence of the European water vole, Arvicola amphibius Linnaeus 1758

We present a genome assembly from an individual male Arvicola amphibius (the European water vole; Chordata; Mammalia; Rodentia; Cricetidae). The genome sequence is 2.30 gigabases in span. The majority of the assembly is scaffolded into 18 chromosomal pseudomolecules, including the X sex chromosome. Gene annotation of this assembly on Ensembl has identified 21,394 protein coding genes.

Water Vole Field Signs and Habitat Assessment

An essential guide to assist those surveying for water voles, whether as a professional ecological consultant, a researcher or simply an interested amateur. This book provides detailed descriptions of all the habitats used by water voles, including ideal habitats as well as less typical places, with annotated photos to help the surveyor home in on just the right areas to look. It also contains a comprehensive photographic reference guide to assist in the correct identification of water vole field signs, and explains how to distinguish them from those of similar species. Tips on where and how to search for field signs are also provided, along with guidance on how best to record survey data.

Genomic resources for the North American water vole (Microtus richardsoni) and the montane vole (Microtus montanus)

BackgroundVoles of the genus Microtus are important research organisms, yet genomic resources in the genus are lacking. Providing such resources would benefit future studies of immunology, phylogeography, cryptic diversity, and more.FindingsWe sequenced and assembled nuclear genomes from two subspecies of water vole (Microtus richardsoni) and from the montane vole (Microtus montanus). The water vole genomes were sequenced with Illumina and 10X Chromium plus Illumina sequencing, resulting in assemblies with ~1,600,000 and ~30,000 scaffolds respectively. The montane vole was assembled into ~13,000 scaffolds using Illumina sequencing also. In addition to the nuclear assemblies, mitochondrial genome assemblies were also performed for both species. We conducted a structural and functional annotation for the best water vole nuclear genome, which resulted in ~24,500 annotated genes, with 83% of these receiving functional annotations. Finally, we find that assembly quality statistics for our nuclear assemblies fall within the range of genomes previously published in the genus Microtus, making the water vole and montane vole genomes useful additions to currently available genomic resources.