Bank Voles Clethrionomys Glareolus Research Articles

Direct interference or indirect exploitation? An experimental study of fitness costs of interspecific competition in voles

Studies on competing mammalian species in the past have focused mainly on the competitive exclusion of one species from the preferred habitat of the other. Investigations on effects of competition and coexistence on individual fitness are rare. In this study we were able to measure effects of interspecific competition on major fitness components, using a system with two vole species in asymmetric competition. Survival, reproduction and space use of bank vole Clethrionomys glareolus females were monitored in 32 enclosed populations over four replicates of eight parallel run enclosures. Into half of the enclosures we introduced an additional number of field voles Microtus agrestis, a dominant competitor.Survival of bank vole females was lower under competitive conditions. Total number of breeding females was lower in populations coexisting with competitors. Territory size of bank vole females decreased. Females body weight and litter size bank vole litters conceived during the experiment were not affected by interspecific competition. These characteristics should respond to differences in food resources, and territory size should increase if food was scarce, thus we found no indication of direct exploitation competition between the two species. Space use was overlapping between the species, but individuals of both species were never caught together in the same trap, indicating avoidance behaviour.We conclude that adult bank vole females do suffer fitness consequences through interference competition with field voles, probably basing on increased number of aggressive encounters in the presence of the dominant species. Our results suggest, that direct interference rather than indirect exploitation competition may be the cause for observed fitness decrease in bank vole females.

Lack of a distinct gradient in biomarker responses in small mammals collected at different distances from a highway.

This study describes biomarker effects in small mammals exposed to traffic emissions. Animals were collected at 10-50 m (site 1), 150-200 m (site 2), and 5 km (site 3) from a very busy highway (A2). To distinguish between routes of exposure, strictly carnivorous common shrews ( Sorex araneus) and predominantly herbivorous bank voles ( Clethrionomys glareolus) were collected. As a measure of exposure to polycyclic aromatic hydrocarbons (PAHs), aromatic DNA adduct levels were determined by (32)P-postlabeling techniques in tissue from heart, lung, and liver. Lead (Pb), cadmium (Cd), and copper (Cu) levels were analyzed in kidney as a measure of exposure to heavy metals. EROD and PROD activity and retinoid levels were determined in liver as effect biomarkers for exposure to PAHs and polyhalogenated aromatic hydrocarbons (PHAHs). Relatively high Cd levels in S. araneus and in particular elevated DNA adduct levels in C. glareolus indicated that small mammals at site 3 were exposed to more compounds than at sites 1 and 2 (3 > or = 1 > 2). The latter effect is probably due to an incidental and actual input of airborne pollutants that is deposited on plant surfaces. By consumption of above-ground vegetation, voles are chronically exposed to this pollution. Relatively high background input of PAHs probably hinders that the traffic-related gradient of airborne PAH concentrations found in an earlier study is reflected in DNA adduct levels in small mammals in the present study. Moreover, historical biomarkers for exposure to traffic emissions, such as increased kidney Pb levels, increased hepatic EROD activity, and disturbed hepatic vitamin A homeostasis are no longer applicable to indicate differences in exposure. This is a result of the ban on addition of Pb and chlorinated scavengers to gasoline and of cleaner combustion techniques, which were enforced by law over the past decade. Finally, it is advisable to use only juvenile small mammals for in situ monitoring of diffuse pollution because DNA adduct levels increased with age.

Can demographic parameters be estimated from capture-recapture data on small grids? A test with forest rodents

This preliminary study proposes small trapping grids as an alternative to traditional large grids for the simultaneous monitoring of several rodent populations by capture--recapture. Monthly trapping sessions of wood mouse Apodemus sylvaticus (Linnaeus, 1758) and bank vole Clethrionomys glareolus (Schreber, 1780) were carried on over a small area (0.015 ha, 21 traps). The coherence of demographic parameter estimates on such small grids with those obtained on classical large grids was checked by performing two trapping sessions on a larger grid (0.9 ha, 110 traps, 10 m mesh) surrounding the small grid. We compared the two grid designs on the basis of sex ratio upon first capture, trap saturation rate, minimum number alive (MNA), monthly survival, and trappability. These demographic parameters proved to be non-biased by the trapped area, even though the precision was lower on the small grid. Small grids seem therefore to give the same picture of population dynamics as classical large grids except for parameters sensitive to an edge effect (eg density). By decreasing significantly the trapping effort, small grids will be of particular interest whenever the simultaneous operation of several trapping grids is needed (eg to compare different environmental conditions).

Is habitat linearity important for small mammal communities on farmland?

Summary Farmland is readily divisible into linear habitats such as hedges, and non‐linear habitats such as fields and woodlots. In agricultural landscapes, conservationists have generally focused on enhancing linear habitats, but there are few data from which to judge whether or not this is a good strategy for biodiversity. We investigated whether the linear or non‐linear character of habitat patches, mediated by edge effects, has an impact on the abundance, diversity and richness of the small mammal communities that live within and between them. In particular, we hypothesized, first, that edge effects cause narrow linear habitats to be avoided by specialists such as the bank vole Clethrionomys glareolus, but not by generalists such as the wood mouse Apodemus sylvaticus; secondly, that edge effects lead to specialists being present in atypical habitat, through excursions at the interface between two habitats. We tested these hypotheses by live‐trapping small mammals in grids in the centres of three non‐linear farmland habitats (woodlots, set‐aside and crop fields) and in field boundaries consisting of a series of adjoining linear habitats. We compared mammal communities in the non‐linear habitats with the field boundary as a whole, and with the individual linear habitat elements within the boundary. There was no evidence that specialists avoided linear habitats. Indeed, the field boundary was the most species‐rich habitat surveyed, and bank voles were more abundant in linear hedgerow than in non‐linear woodland. Bank voles were present in linear set‐aside and in the crop edge, but never in non‐linear blocks of set‐aside or crop, implying that they diffused out of the hedgerow into the adjacent habitats. There was no evidence of an effect of habitat linearity on field voles Microtus agrestis, wood mice or common shrews Sorex araneus. Our results suggest that on uncropped land such as set‐aside, the linear or non‐linear character of habitats will make little difference to small mammal abundance and diversity. We advocate similar assessments for other taxa so that the effects of farm management and habitat configuration on biodiversity can be understood more fully.

Yellow-necked mouse attacked a dead bank vole

An unique observation was made when an adult yellow-necked mouseApodemus flavicollis (Melchior, 1834) attacked a dead bank voleClethrionomys glareolus (Schreber, 1780).

ADRENOCORTICAL AND BIOENERGETIC RESPONSES TO COLD IN FIVE SPECIES OF MURINE RODENT

Oxygen consumption, rectal temperature, and plasma concentrations of glucocorticoids, free fatty acids, and glucose were studied in 5 species of rodents after cold exposure that exceeded their homeostatic capability (7°C for 15 min). Adrenocortical responses and metabolic responses (oxygen consumption) to cold were large in 3 solitary, terrestrial species, dwarf hamsters (Phodopus sungorus, P. campbelli, and P. roborovskii) and were minimal in a colonial fossorial species, mole voles (Ellobius talpinus). Bank voles (Clethrionomys glareolus) showed intermediate responses. There were no interspecific differences in mobilization of main bioenergetic substrates (glucose and free fatty acids). Results are interpreted in terms of evolutionary changes of stress: reactivity was positively correlated with the rate of social stimuli and negatively correlated with physically stressful stimuli in the natural environment of the species.

Population dynamics ofClethrionomys glareolus andApodemus flavicollis: seasonal components of density dependence and density independence

Using long-term data on two forest rodent species [the bank voleClethrionomys glareolus (Schreber, 1780) and the yellow-necked mouseApodemus flavicollis (Melchior, 1834)] from the Białowieża Primeval Forest (E Poland), we decompose the annual density-dependent and density-independent structures into their seasonal components. For this purpose we adopt a state-space modelling approach explicitly incorporating sampling stochasticity. As density-independent factors we use the North Atlantic Oscillation (NAO) — a proxy variable for the overall climatic condition — and data on annual seed production. We find a weak effect of the NAO in the annual models for both species as well as during the winter in the seasonal model forC. glareolus. The effect of the NAO disappears, however, when seed-crops are incorporated into the models (for both the annual and the seasonal — suggesting that NAO primarily affects seed production). Seed production enters the models with a positive effect during the winter only, suggesting that the among-year variation in rodent density is primarily accounted for by differences in seed-production, particularly oak seeds. ForA. flavicollis, a slightly positive effect of hornbeam also appears in the summer dynamics. The obtained results are discussed on the basis of earlier studies on the same populations, on the same species studied elsewhere as well as on the basis of general ecological insight.

Relationships between the individual growth rate and the population spatial structure and dynamics in rodents.

The effects of the population density on individual animal growth, development, and reproduction has been extensively studied and reported in detail [1]. However, the existing explanations of these phenomena are incomplete and often inconsistent. The population dynamics of small rodents (especially at northern latitudes) exhibits large-amplitude oscillations called population cycles [2]. Their emergence is often attributed to the operation of intrapopulation mechanisms involved in the regulation of the rate of growth and maturation of young animals [3, 5]. In each population cycle, a short period of high abundance, or a peak, is followed by a long low-abundance period (depression), which, in view of the high fertility of small rodents, seems enigmatic [4]. Stress, lack of food and shelter, epizootics, and other factors are known to inhibit population growth [5]. However, the problem of population cycles remains a key problem of population ecology. The purpose of this study was twofold: (1) to clarify the relationship between the growth rate of young animals and the probability of meeting conspecifics; and (2) to develop a mathematical model to describe the obtained ecologic relationship in energy terms. The most common method for studying natural rodent populations that allows researcher to derive a lot of diverse information is the mark‐recapture technique in plots with regularly spaced traps. This technique was used to study a population of the bank vole Clethrionomys glareolus) inhabiting Ural forests. We also analyzed the vole population data from the southern Urals kindly provided by G.V. Olenev. Capture sessions were carried out at intervals of four to seven weeks. Each capture session lasted for three to five days; traps were inspected twice a day. From weight gains of marked animals from session to session, the relative rate of their growth was estimated. The probability of meeting conspecifics was estimated from the area of home range overlap. The configurations of home ranges were estimated by the harmonic mean transformation method from the coordinates of the points where marked animals were caught [6]. This method, along with the kernel one, is generally accepted as that most adequately assessing the patterns of home range use by individual animals [7]. Analysis of the data showed that the specific growth rate of young voles was maximum if the area of overlap of their home ranges with the home ranges of other animals was 5000 to 7000 m 2 . If the overlap area was

Consumption of Bark and Seeds by Voles in Relation to Habitat and Landscape Structure

Voles cause damage in forestry by eating the bark of seedlings and the seeds of conifers. Folivorous field voles ( Microtus agrestis ), restricted to various types of grassland, are mainly responsible for damage to bark, and granivorous bank voles ( Clethrionomys glareolus ), supported by most forest environments, for the consumption of seeds. Densities of bank and field voles, consumption of bark on indigenous and experimental woody plants, and consumption of experimentally supplied seeds were measured during the vole cycle 1997-2000 in relation to three habitat and three landscape variables. Landscape variables explained field vole densities and consumption of bark to a considerable extent, while habitat variables were more adequate for densities of bank vole and consumption of seeds. Field vole populations may demonstrate a ''mass effect'', where the success of early development and dispersal from subpopulations will decide peak numbers over entire landscapes. Numbers of field voles may affect numbers of the inferior bank vole. Thus, predicting the exact location of vole damage is principally difficult.

Haemogregarines of the genus Hepatozoon (Apicomplexa: Adeleina) in rodents from northern Europe.

We studied the prevalence and distribution of Hepatozoon infections in small rodents from Finland and other areas in northern Europe. Hepatozoon infections were more common in voles (Arvicolinae) than mice (Murinae) and more prevalent in voles of the genus Clethrionomys than in voles of the genus Microtus. Transmission electron microscopical examination of Hepatozoon erhardovae Krampitz, 1964 from bank voles Clethrionomys glareolus (Schreber) showed that intracellular lung meronts were located in alveolar septa. Meronts consisted of varying numbers of merozoites packed with amylopectin vacuoles inside electron-lucent parasitophorous vacuole. The size of the meronts was approximately 19 x 14 microm. Monozoic or dizoic cysts were frequent findings in the lung alveoles; the size of cysts was approximately 10 x 6 microm. Gametocytes were found inside eosinophilic granulocytes in the capillaries of lung tissue. Ultrastructurally, micronemes, microtubules, mitochondria, nuclei and lipid droplets were visible.

Movement behaviour of woodland rodents: looking from beyond small trapping grids

Live-trapping of rodents was conducted over a 12-ha plot on unevenly spaced trap lines, with inner lines forming a 3.5-ha grid of closely spaced traps. This design was used to estimate the probability that bank volesClethrionomys glareolus (Schreber, 1780) and yellow-necked miceApodemus flavicollis (Melchior, 1834) trapped in small grids are true residents rather than visitors from the surrounding area. On average, 12% of the voles and 19% of the mice were trapped within and beyond the grid in the same trapping sessions. As these were mainly wide-ranging males moving over the plot, home ranges of males may be underestimated on small grids. In total, 36% of voles and 39% of mice that were marked in spring-summer were trapped at least once in their life beyond the grid. Typically, these were individuals shifting home ranges and migrating to or from the grid. The size of lifetime ranges of rodents was significantly larger than temporary home ranges and may therefore be underestimated on small grids. “Single--capture” individuals were mainly true transients rather than visitors. Only 12% of voles and 15% of mice resided on the plot for longer time than in the grid.

Effects of Decreased Atmospheric Heavy Metal Deposition in South Sweden on Terrestrial Birds and Small Mammals in Natural Populations

In southern Sweden, where exposure to long range distributedheavy metals is about the highest in Scandinavia, depositionsof cadmium (Cd) and lead (Pb) decreased about 20 and 70%,respectively, between mid-1980s and mid-1990s, as estimated bytheir concentrations in moss. Concentrations of Cd and Pb in tissues of the pied flycatcher (Ficedula hypoleuca) and bank vole (Clethrionomys glareolus) were also lower in 1996and 1997 compared to 1981 and 1982. It is concluded that the decreased deposition rate of these elements in southern Sweden had caused decreased exposure, and thus also to decreased potential risk of detrimental effects on insectivorous birds andherbivorous mammals. There was no indication that breeding results of pied flycatcher was influenced by the decreased deposition of toxic metals.

High-resolution magic angle spinning 1H-NMR spectroscopy studies on the renal biochemistry in the bank vole (Clethrionomys glareolus) and the effects of arsenic (As3+) toxicity

1. High-resolution magic angle spinning (MAS) 1H-NMR spectroscopy was used to study renal metabolism and the toxicity of As3+, a common environmental contaminant, in the bank vole (Clethrionomys glareolus), a wild species of rodent. 2. Following a 14-day exposure to an environmentally relevant dose of As2O3 (28 mg kg -1 feed), voles displayed tissue damage at autopsy. MAS 1H spectra indicated abnormal lipid profiles in these samples. 3. Tissue necrosis was also evident from measurements of the apparent diffusion coefficient of water in the intact tissue using MAS 1H diffusion-weighted spectroscopy, its first application to toxicology. 4. Comparison of renal tissue from the wood mouse (Apodemus sylvaticus) exposed to identical exposure levels of As3+ suggested that the bank vole is particularly vulnerable to As3+ toxicity.

"Single-capture" rodents: vagrants or just newly weaned young?

The reliability of the estimation of residency time of the bank vole Clethrionomys glareolus (Schreber, 1780) and the yellow-necked mouse Apodemus flavicollis (Melchior, 1834) in open populations was assessed by halving the 6-week intervals between trapping sessions.

Molecular evolution of puumala hantavirus in Fennoscandia: phylogenetic analysis of strains from two recolonization routes, Karelia and Denmark.

Like other members of the genus HANTAVIRUS: in the family BUNYAVIRIDAE:, Puumala virus (PUUV) is thought to be co-evolving with its natural host, the bank vole Clethrionomys glareolus. To gain insight into the evolutionary history of PUUV in northern Europe during the last post-glacial period, we have studied wild-type PUUV strains originating from areas along two postulated immigration routes of bank voles to Fennoscandia. Full-length sequences of the S RNA segment and partial sequences (nt 2168-2569) of the M segment were recovered by RT-PCR directly from bank vole tissues collected at three locations in Russian Karelia and one location in Denmark. Phylogenetic analysis showed that strains from Karelia and Finland belong to the same genetic lineage, supporting the hypothesis that PUUV spread to present Finland via a Karelian land-bridge. The Danish PUUV strains showed no particularly close relatedness to any of the known PUUV strains and formed a distinct phylogenetic lineage on trees calculated for both S and M segment sequences. Although no direct link between the Danish PUUV strains and those of the southern Scandinavian lineage was found, within the S segment of Danish PUUV strains, two regions with higher similarity to either northern Scandinavian or - to a less extent - southern Scandinavian genetic lineages were revealed, suggesting evolutionary connections of their precursors.

Asymmetrical competition between the bank vole and the wood mouse, a removal experiment

Experimental removal was conducted to test interspecific competition between the wood mouse Apodemus sylvaticus (Linnaeus, 1758) and the bank vole Clethrionomys glareolus (Schreber, 1780) that dominate the rodent communities in the forested biotopes through most of central Europe.

Homing and space activity in bank voles Clethrionomys glareolus

Spatial activity and homing of bank voles Clethrionomys glareolus (Schreber, 1780) have been studied in the 100 years old alder wood (Carici elongatae-Alnetum Koch, 1926) in the Kampinos National Park near Warsaw.

Changes in the food of British Barn Owls (Tyto alba) between 1974 and 1997

ABSTRACTComparison of the results of a 1993–97 Barn Owl Tyto alba pellet survey with those of a similar survey from 1956–74 showed that Barn Owl diet had changed significantly. The primary differences were a widespread decrease in the percentage of Common Shrew Sorex araneus, combined with an increase in Pygmy Shrew Sorex minutus. The percentage of Wood and Yellow‐necked mice Apodemus sylvaticus and A. flavicollis and Bank Vole Clethrionomys glareolus in the diet also increased. Changes in Barn Owl diet since 1974 were independent of land‐class group, but were dependent upon region. This was due primarily to a large increase in the percentage of Apodemus spp. in Eastern England. Whilst the percentage of Pygmy Shrew in Barn Owl diet showed significant regional variation, there was no significant variation between land‐class groups. The diversity of Barn Owl diet increased between 1974 and 1997, although it was still lower in 1997 than earlier in the century. This increase was dependent upon region, but independent of land‐class group. The combined results of both surveys showed significant interland‐class group variation in dietary diversity. Changes in diet are discussed in relation to the intensification of agriculture and other changes in land management since the 1970s. The effects on Barn Owls of these changes in prey abundance are discussed, particularly in relation to the decline in Barn Owl numbers during the twentieth century.

A longitudinal study of an endemic disease in its wildlife reservoir: cowpox and wild rodents

Cowpox is an orthopoxvirus infection endemic in European wild rodents, but with a wide host range including human beings. In this longitudinal study we examined cowpox in two wild rodent species, bank voles Clethrionomys glareolus and wood mice Apodemus sylvaticus, to investigate the dynamics of a virus in its wild reservoir host. Trapping was carried out at 4-weekly intervals over 3 years and each animal caught was uniquely identified, blood sampled and tested for antibodies to cowpox. Antibody prevalence was higher in bank voles than in wood mice and seroconversion varied seasonally, with peaks in autumn. Infection was most common in males of both species but no clear association with age was demonstrated. This study provides a model for studying other zoonotic infections that derive from wild mammals since other approaches, such as one-off samples, will fail to detect the variation in infection and thus, risk to human health, demonstrated here.

Road verges as habitat for small mammals in Britain

ABSTRACTThere are 370 000 kilometres of roads in Great Britain, mostly bordered by a verge that is potential habitat for small mammals. The present study assessed the importance of road verges as small mammal habitat and investigated the influence of some key features on rodent abundance. Five rodent and three shrew species were live‐trapped on 14 road verges in late summer 1994 and nine verges in autumn 1996 in north Cambridgeshire, UK. On average, between three and four species were captured per verge. Bank Voles Clethrionomys glareolus, Wood Mice Apodemus sylvaticus and Field Voles Microtus agrestis were the most abundant species, with mean densities of 45.5, 40.2 and 29.5 animals km–1 in summer and 52.8, 181.9 and 47.2 animals km–1 in autumn. Numbers varied between verges and this was significantly correlated with particular features on the verge. Bank Vole and Field Vole numbers showed a significant positive correlation with the dimensions of hedges and the width of the tall grass area, respectively. Wood Mice were also more numerous on verges with big hedges but the relationship between mouse abundance and verge structure was complex. The number of mice in 1994 was positively and significantly correlated with hedge features and with the width of the short grass sightline, whereas, in autumn 1996, they were only significantly correlated with total verge width (positive association) and ditch width (negative association).