Genetic variability of the cold-tolerant Microtus oeconomus subspecies left behind retreating glaciers

Low Genetic Variability of the Tundra Vole in Lithuania

The distribution and spread of the tundra vole (Alexandromys oeconomus) in Lithuania have been documented over the last 70 years, but the genetic diversity of the species has not been studied. In this study, we examined A. oeconomus trapped in three sites in northern and western Lithuania using mtDNA sequence analysis of the cytb and control region. The western and northern sites are separated by anthropogenic landscape barriers. The western site is subject to regular spring flooding. Phylogenetic analyses of the studied individuals placed them in the Central European phylogroup, suggesting that Lithuanian A. oeconomus originated from northeastern Poland. In Lithuania, the genetic diversity of A. oeconomus at both mtDNA loci was relatively low (Hd < 0.6, π < 0.002) compared to that found in other European samples (Hd = 0.833-0.958; π = 0.00402-0.01552). Individuals analyzed in Lithuania were genetically different from samples collected in Poland and Northern Europe (ΦST > 0.15, p < 0.05). The genetic divergence between the western and northern samples of A. oeconomus in Lithuania, together with the low genetic variability among the voles studied, provides new insights into the phylogeography of the species and the influence of barriers on the colonization of the country.

Genetic Structure of the Root Vole Microtus oeconomus: Resistance of the Habitat Specialist to the Natural Fragmentation of Preferred Moist Habitats

Climate-related changes have a severe impact on wetland ecosystems and pose a serious challenge for wetland-dependent animals as their preferred habitats decline, lose spatial continuity, and appear as isolated islands in the landscape. In this paper, we studied the effects of long-term habitat changes (drying out and fragmentation of wet non-forest habitats) on the genetic structure of the population of the root vole Microtus oeconomus, a species preferring moist habitats. We intended to check what barriers and what distances affected its genetic isolation on a local scale. The study was conducted in the area of Kampinoski National Park in central Poland (Europe). DNA variability of 218 root vole individuals was assessed by genotyping nine microsatellite loci. Despite its spatial fragmentation, the studied population did not seem to be highly structured, and isolation through distance was the main differentiating factor. Even a distance of several kilometres of unfavourable natural habitats and unfavourable terrain did not exclude the exchange of genes between subpopulations. Our results suggest that the genetic effects of the fragmentation of wetlands have been considerably compensated (delayed) due to the migratory abilities of this species. Our study does not provide clear results on the impact of anthropogenic barriers but suggests that such barriers may have a much stronger effect than natural barriers.

Communities of ectoparasitic arthropods associated with the root vole Microtus oeconomus in north-eastern Poland

Ectoparasitic arthropods communities associated with root voles Microtus oeconomus (Pallas, 1776) were analysed in north-eastern Poland. The first M. oeconomus parasites recorded in the history were the fleas Palaeopsylla similis Dampf, Ctenophthalmus congerer Rothschild, C. bisoctodentatus Kolenati, and C. solutus Jordan et Rothschild. Ctenophthalmus uncinatus (Wagner) and Doratopsylla dasycnema (Rothschild) fleas and the Ixodes apronophorus Schulze tick were recorded on M. oeconomus in Poland for the first time. These species are relatively rare in Poland and specific to other species of small mammals. The incidence of M. oeconomus infestations with I. apronophorus, D. dasycnema and C. uncinatus ranged from 0.5 to 0.8 %, respectively. There are large differences in the infestation of Dermacentor reticulatus larvae and nymphs between July and August. In July, D. reticulatus may be considered the dominant ectoparasite species, in August, it is partly replaced by I. ricinus and fleas and is subdominant.

Genetic variability and conservation of the endangered Pannonian root vole in fragmented habitats of an agricultural landscape

The distribution of the endangered glacial relict subspecies, the Pannonian root vole Alexandromys oeconomus mehelyi Éhik, 1928, is restricted to scattered localities in south-western Slovakia, which belong to the north-eastern zone of its range. Human-induced changes and fragmentation of the landscape have led to the gradual loss of suitable habitats and threaten its long-term survival. The study area in the Danubian Lowland is characterised by small habitat fragments and temporal fluctuations of the habitat area. Root voles were sampled at nine sites to study the level of genetic variability and structure of local subpopulations by scoring 13 microsatellite loci in 69 individuals. Genetic differentiation varied amongst local populations and we did not find a significant isolation-by-distance pattern. Bayesian clustering analysis suggested that dispersal effectively prevents marked genetic subdivision between studied habitat fragments. Significant pairwise differentiation between some subpopulations, however, may be the result of putatively suppressed gene flow. Low genetic diversity in the recent populations probably reflects the isolated location of the study area in the agricultural landscape, suggesting that long-term survival may not be assured. In order to maintain genetic diversity, it is essential to preserve (or even restore) habitats and ensure the possibility of gene flow; habitat protection is, therefore, recommended. Continuous assessment is necessary for effective conservation management and to predict the long-term survival chances of the Pannonian root vole in the study area.

Biometric Analysis of Cranial and Somatic Features in the Pannonian Root Vole

The Pannonian root vole Alexandromys oeconomus ssp. mehelyi represents a rare glacial relict, whose occurrence is nowadays bound to several areas in Europe. Four somatic and 25 craniological features were analysed, based on 355 measured specimens. Sex is a significant factor affecting the average value of all four somatic features, where all of them achieve higher values in males than in females. While body length and tail length were also affected by seasons, body weight and the length of the hind foot were stable features present across the seasons. In cranial features, the largest variability in the adult population is characterised by neurocranium breadth (LaN), total length of the cranial base (LB), and skull (LCr); whereas the smallest variability of the cranial dimensions is reflected in the values of the greatest palatal breadth (PS) and postorbital breadth (Io). Calculating the weight from cranial remains may be used to estimate the size of the prey and to determine vole biomass consumed by predators, such as raptors, highlighting the utility of studying feeding ecology.

Importance of Wetland Refugia in Agricultural Landscape Provided Based on the Community Characteristics of Small Terrestrial Mammals

Intensification of agriculture has led, among other negative consequences, also to drying out of wetlands. Nevertheless, some of the wetland biotopes were preserved as small spots. This paper discusses the importance of those areas serving as refugia for small terrestrial mammals. Because small terrestrial mammals in the middle of food webs, they serve as an indicator for the presence of food sources (plants and invertebrates) and suggest the potential of the area as a living space for predators. The experiment took place at lowland agricultural landscape with wetland patches in west and west-east Slovakia (Záhorská and Podunajská nížina lowlands) using catch-mark-release method from 2015 to 2017. The importance was assessed according to abundance, biodiversity, persistence of species during seasons and habitat preference of small terrestrial mammals and equitability of the biotopes. Overall 368 individuals belonging to 12 species were recorded. The lowest abundance and diversity were registered at field biotopes where Apodemus sylvaticus was the most abundant. Microtus arvalis, Clethrionomys glareolus and Sorex araneus dominate at wetland biotopes. The higher biodiversity and abundance of small mammals were recorded at the wetland refugia. The results, together with position of small mammals in food webs, lead to conclusion that the wetland refugia are important habitats for the overall preservation of biodiversity and maintaining them is a part of the strategy for sustainable agriculture.