Colonization of post-mining landscapes by shrews and rodents (Mammalia: Rodentia,Soricomorpha)

The presence and relative abundance of shrews and rodents have been studied in four different former brown coal mining areas in Lower Lusatia between 1995 and 1997 as well as 2001 and 2002. Several sites of undisturbed, i.e. non-mined, areas were included for comparison. Four species of shrews and four species of rodents have been found. Generally only few shrews were recorded in the Lower Lusatian area. Sorex araneus and S. minutus are the most abundant species, while Crocidura leucodon and C. suaveolens are rare. In the brown coal mining area shrews mainly occur in older sites with higher vegetation. The analysis of the distribution of rodent species revealed that Microtus arvalis having a comparably small spread potential, colonizes sites preferably with dense vegetation, while Apodemus sylvaticus was also found in sites with sparse vegetation. The relative abundance of all species is significantly higher in undisturbed sites. The colonization of the dumped openland areas is difficult for small mammals.     

Distribution of cryptic shrew species of the genus Sorex (Mammalia) on the plain between the Don and Kuban rivers as inferred by molecular markers

Microsatellite and mtDNA markers have been used to identify two pairs of cryptic species Sorex araneus L. (Sorex satunini Ogn.) and Sorex minutus L. (S. volnuchini Ogn.). The new data were obtained on the distribution of these species on the plain between the Don and Kuban rivers. The shrew S. volnuchini and Caucasian mole are distributed on the plain areas up to the Eya River. The endemic species of the Caucasus, the shrews S. satunini and S. volnuchini, are widely distributed across the valleys alongside small streams on the steppe plain. Both species are most abundant on thick grasslands, bushy scrub, and deciduous woodlands. They don??t show any clear differences in habitat preferences.     

Analysis of biodiversity parameters of shrew communities of the Altai Mountains

The communities of insectivorous mammals of the Altai Mountains, each consisting of 4–9 species, are quite similar in species composition and principles of organization. The forest belt of mountains is dominated by the common shrew (Sorex araneus), with the Laxmann’s (Sorex caecutiens), lesser (Sorex minutus), and tundra (Sorex tundrensis) (rarely even-toothed (Sorex isodon)) shrews being codominants. With altitude, the dominants change and some species disappear but no significant changes in the dominance structure of the community occur. Positive correlations between abundance rates recorded in different years and on different plots indicate the stability of communities under study. Analysis of informational indices of diversity reveals four basic possible conditions of communities: a) relatively safe, b) slightly disturbed, c) disturbed, and d) high-altitude slightly evened.     

Small mammal responses to moose supplementary winter feeding

Supplementary feeding of wild large herbivores is a widespread practice in North America and Europe. The presence of feeding stations may have ecological consequences through changes to animal distributions, patterns of herbivory and a net nutrient input into the ecosystem. In Fennoscandia, supplementary feeding of moose in winter (Alces alces) is increasing. Although it has been shown to affect bird communities, its effects on small mammal communities were unknown. Here, we studied the effects of moose supplementary feeding stations on plants and on abundance, reproduction, and biomass of small mammals in years with low and high vole abundance. We sampled small mammals with snap traps and conducted surveys of the field layer vegetation, at varying distances from moose supplemental feeding stations. Due to the vegetation changes induced by feeding stations, abundance of common shrews (Sorex araneus) and Microtus voles were positively affected by long-term moose winter feeding, while bank voles (Myodes glareolus) were not affected. Moose feeding stations did not affect reproduction, individual body mass, or the total biomass of small mammals. Moose winter-feeding stations have impacts on nontarget species, providing islands of preferred grass and forb habitat for Microtus spp. and common shrews, allowing them to penetrate into a matrix of less preferred forest habitat.     

The Celtic fringe of Britain: insights from small mammal phylogeography

Recent genetic studies have challenged the traditional view that the ancestors of British Celtic people spread from central Europe during the Iron Age and have suggested a much earlier origin for them as part of the human recolonization of Britain at the end of the last glaciation. Here we propose that small mammals provide an analogue to help resolve this controversy. Previous studies have shown that common shrews (Sorex araneus) with particular chromosomal characteristics and water voles (Arvicola terrestris) of a specific mitochondrial (mt) DNA lineage have peripheral western/northern distributions with striking similarities to that of Celtic people. We show that mtDNA lineages of three other small mammal species (bank vole Myodes glareolus, field vole Microtus agrestis and pygmy shrew Sorex minutus) also form a ‘Celtic fringe’. We argue that these small mammals most reasonably colonized Britain in a two-phase process following the last glacial maximum (LGM), with climatically driven partial replacement of the first colonists by the second colonists, leaving a peripheral geographical distribution for the first colonists. We suggest that these natural Celtic fringes provide insight into the same phenomenon in humans and support its origin in processes following the end of the LGM.     

Long-term responses in population dynamics and diversity of small mammals in riparian and upland habitats within an agricultural landscape

Riparian zones in agricultural landscapes provide linear non-crop habitats for a variety of plant and mammal species, and hence are an important component of biodiversity. To date, variable responses of abundance, species richness, and species diversity of small mammals have been recorded in riparian and upland habitats. To address this variability, we provide a detailed analysis of seasonal changes in abundance and diversity of terrestrial small-mammal communities over a 7-year period within an agricultural landscape in south-central British Columbia, Canada. We tested the hypotheses (H) that abundance, species richness, and species diversity of communities of small mammals (H₁), and demographic parameters of reproduction, recruitment, and survival of the major species: deer mouse (Peromyscus maniculatus) and montane vole (Microtus montanus) (H₂), would be higher in riparian than upland habitats. Mean total abundance of small mammals was higher in summer and winter, and species richness higher in summer, in riparian than hedgerow habitats. Winter population data supported the total and species abundance patterns for small mammals, but species richness was similar, and diversity lower, in riparian than hedgerow sites during winter periods. Deer mice were the dominant species in terms of abundance and reproductive output for pregnancies and recruitment, but not survival, in riparian sites. Montane voles were similar in abundance and demographic parameters in the two habitats. House mice (Mus musculus) preferred hedgerows and wandering shrews (Sorex vagrans) riparian sites. Demographic parameters for deer mice and montane voles indicated that both riparian and hedgerow sites were “source” rather than “sink” habitats, and likely contribute to maintenance of mammal diversity in agricultural landscapes.     

Tick-Borne Zoonotic Bacteria in Wild and Domestic Small Mammals in Northern Spain

The prevalence and diversity of tick-borne zoonotic bacteria (Borrelia spp., Anaplasma phagocytophilum, Coxiella burnetii, and spotted fever group rickettsiae) infecting 253 small mammals captured in the Basque Country (Spain) were assessed using PCR and reverse line blot hybridization. Trapping sites were selected around sheep farms (study 1, 2000 to 2002) and recreational parks (study 2, 2003 to 2005). The majority of the studied mammals (162) were wood mice (Apodemus sylvaticus), but six other different species were also analyzed: yellow-necked mice (Apodemus flavicollis), shrews (Crocidura russula and Sorex coronatus), bank voles (Clethrionomys glareolus), domestic mice (Mus domesticus), and moles (Talpa europaea). The results showed an infection rate ranging from 10.7% to 68.8%, depending on the small mammal species. One C. russula shrew and one A. sylvaticus mouse gave positive reactions for A. phagocytophilum, and C. burnetii was detected in two domestic mice and one A. sylvaticus mouse in a farm. The DNA of Borrelia spp. was detected in 67 animals (26.5%), most of them presenting positive hybridization with the probe for Borrelia sp. strain R57, the new Borrelia species previously detected in small mammals in our region. Furthermore, a second PCR and reverse line blot hybridization specific for B. burgdorferi sensu lato revealed the presence of Borrelia afzelii in 6.3% of C. glareolus voles and 14.3% of S. coronatus shrews. All small mammals were negative for spotted fever group rickettsiae. These results highlight the relevance of small mammals as reservoirs of some zoonotic bacteria.     

Distribution and coexistence of shrews in patchy landscapes: A field test of multiple hypotheses

Despite the important role of shrews (Soricomorpha: Soricidae) in the functioning of ecosystems, as predators and prey, the effects of habitat loss and fragmentation on this guild of mammals are still unclear. We studied the distribution of 5 species (the greater white toothed shrew Crocidura leucodon; the lesser white toothed shrew Crocidura suaveolens; the pigmy shrew Sorex minutus; the Appennine shrew Sorex samniticus and the Etruscan shrew Suncus etruscus) in a fragmented landscape in central Italy.Shrews were trapped with pitfall traps made from plastic water bottles, the number of traps increased with patch size. A total of 170 individuals, of 5 species of shrews were captured. Shrews were widely distributed in our study area, however patch occupancy was determined mainly by vegetation and geometrical characteristics of the patches. Our data supports the hypotheses that patterns of habitat selection and the dynamics of seasonal abundance (habitat and temporal partitioning between similarly sized species) reduce competitive pressure, thus allowing coexistence of shrews in relatively species-rich assemblages, for such small amounts of habitat. The most important outcome of our results is the crucial role played by vegetation structure in determining distribution patterns. These results strongly suggest that measurements of the vegetation structure of habitat patches should always be included as explanatory variables when studying the distribution of shrews in fragmented landscapes.     

Adaptation of Pelage Color and Pigment Variations in Israeli Subterranean Blind Mole Rats,Spalax Ehrenbergi

Background

Concealing coloration in rodents is well established. However, only a few studies examined how soil color, pelage color, hair-melanin content, and genetics (i.e., the causal chain) synergize to configure it. This study investigates the causal chain of dorsal coloration in Israeli subterranean blind mole rats, Spalax ehrenbergi.

Methods

We examined pelage coloration of 128 adult animals from 11 populations belonging to four species of Spalax ehrenbergi superspecies (Spalax galili, Spalax golani, Spalax carmeli, and Spalax judaei) and the corresponding coloration of soil samples from the collection sites using a digital colorimeter. Additionally, we quantified hair-melanin contents of 67 animals using HPLC and sequenced the MC1R gene in 68 individuals from all four mole rat species.

Results

Due to high variability of soil colors, the correlation between soil and pelage color coordinates was weak and significant only between soil hue and pelage lightness. Multiple stepwise forward regression revealed that soil lightness was significantly associated with all pelage color variables. Pelage color lightness among the four species increased with the higher southward aridity in accordance to Gloger''s rule (darker in humid habitats and lighter in arid habitats). Darker and lighter pelage colors are associated with darker basalt and terra rossa, and lighter rendzina soils, respectively. Despite soil lightness varying significantly, pelage lightness and eumelanin converged among populations living in similar soil types. Partial sequencing of the MC1R gene identified three allelic variants, two of which were predominant in northern species (S. galili and S. golani), and the third was exclusive to southern species (S. carmeli and S. judaei), which might have caused the differences found in pheomelanin/eumelanin ratio.

Conclusion/Significance

Darker dorsal pelage in darker basalt and terra rossa soils in the north and lighter pelage in rendzina and loess soils in the south reflect the combined results of crypsis and thermoregulatory function following Gloger''s rule.     

Cream, a new coat-color mutant in the musk shrew

A coat-color mutant was found in the wild musk shrew (Suncus murinus, Insectivora). Five musk shrews with gray pelage, the common coat color of this species, were captured in the village of Tambum near Jakarta, Indonesia. Two males and two females were transported to Japan and mated. Matings between one male and two females segregated several cream-colored offspring, a color that had never been seen before in this species. From the pedigree record and data on mating experiments, it was confirmed that this mutant coat color was expressed in the homozygote by an autosomal recessive gene designated cr, and at least three of the four wild shrews examined were carriers of this gene. The cr gene was associated with failure of normal pigmentation in the pelage and skin. The mutant shrews also showed some behavioral abnormalities.     

The ecology of Ixodes trianguliceps ticks and their role in the natural foci of ixodid tick-borne borrelioses in the Middle Urals

From 1994 to 2011, over 7000 individuals of small mammals were captured and examined for ticks in the natural foci of ixodid tick-borne borrelioses (ITBB) in the Middle Urals (Chusovskoy District of Perm Territory). Alongside with the taiga tick (Ixodes persulcatus), which is the main Borrelia vector, approximately 5700 feeding individuals of Ixodes trianguliceps have been identified. The latter species has been found to be about five times less abundant than the former. I. trianguliceps has been collected from small mammals belonging to 19 species. Its main hosts are common shrews (Sorex araneus), bank voles (Clethrionomys glareolus), and northern red-backed voles (C. rutilus). I. trianguliceps shows two seasonal peaks of abundance, spring-summer, and summer-autumn. Plating in BSK II medium yielded 72 isolates of Borrelia from a total of 1142 individuals of I. trianguliceps; 64 isolates have been identified with PCR and RFLP. The mean values of the Borrelia infestation rate in I. trianguliceps larvae, nymphs, and adults are 2.6, 10.2, and 8.1%, respectively, which is 5–10 times lower than in the taiga tick individuals collected from the same mammals. Borreliae obtained from I. trianguliceps (as well as those from I. persulcatus) have been identified as Borrelia garinii and B. afzelii, the former spirochete species being more frequent (about 90% of isolates from I. trianguliceps). Our results indicate that I. trianguliceps ticks participate in circulation of the ITBB causative agents in the forests of the Middle Urals. Rare occurrence of the tick and low rates of its infestation with borreliae suggest that the species is unlikely to play a significant role in the epizootic development in the natural foci of ITBB.     

Borrelia japonica in Nature: Genotypic Identification of Spirochetes Isolated from Japanese Small Mammals

Spirochetes were isolated from earlobe tissues of shrews (Sorex unguiculatus, Sorex caecutiens, and Crocidura dsinezumi), voles (Clethrionomys rufocanus), and mice (Apodemus argenteus and Apodemus speciosus) captured in various localities in Japan. The isolates were identified as Borrelia japonica by rRNA gene restriction fragment length polymorphism analysis. The data suggest that these small mammals are candidates of reservoir hosts for B. japonica.     

Habitat occurrence and prey distribution of a multi-species community of shrews in the Siberian taiga

The habitat occurrence and invertebrate prey distribution of nine species of shrew in the mid-taiga of central Siberia were investigated. Species richness ranged from 4–9 shrews per habitat. Sorex araneus and S. caecutiens were numerically dominant in all seven habitats (44 and 36% of the total catch, respectively) while Sorex minutus, S. tundrensis, S. isodon , and S. roboratus each constituted 4–6% and Sorex minutissimus, S. daphaenodon , and Neomys fodiens were rare (< 1% each). There was no overall correlation between abundance of shrews and invertebrate prey, but flood-plain habitats supported the greatest abundance and species richness of shrews, and high density and biomass of prey. Oligochaete-eating shrews were twice as numerous here as in other habitats, coincident with high abundance of oligochaetes. The large, earthworm-feeding Sorex roboratus occurred only here. The more acid, typical taiga habitats had lower adundance and species richness of shrews. They had the lowest density and biomass of prey, particularly oligochaetes, and far fewer oligochaete-eating shrews. The relative paucity of shrews in bush-meadow habitats, despite abundant prey, implied that habitat structure influences shrew distribution. Differential numbers of certain species in the presence or absence of larger congeners also suggested that interspecific competitive effects influence habitat selection by shrews. The high species richness of shrews here in the mid-taiga may be accounted for by the heterogeneous nature of the constituent habitats which provide niches for small and large species of shrew with a range of feeding habits.     

Muscle aging and oxidative stress in wild-caught shrews

Red-toothed shrews (Soricidae, subfamily Soricinae) are an intriguing model system to examine the free-radical theory of aging in wild mammals, given their short (< 18 months) lifespan and high mass-specific metabolic rates. As muscle performance underlies both foraging ability and predator avoidance, any age-related decline should be detrimental to fitness and survival. Muscle samples of water shrews (Sorex palustris) and sympatrically distributed short-tailed shrews (Blarina brevicauda) were therefore assessed for oxidative stress markers, protective antioxidant enzymes and apoptosis. Activity levels of catalase and glutathione peroxidase increased with age in both species. Similarly, Cu,Zn-superoxide dismutase isoform content was elevated significantly in older animals of both species (increases of 60% in the water shrew, 25% in the short-tailed shrew). Only one oxidative stress marker (lipid peroxidation) was age-elevated; the others were stable or declined (4-hydroxynonenal adducts and dihydroethidium oxidation). Glutathione peroxidase activity was significantly higher in the short-tailed shrew, while catalase activity was 2× higher in water shrews. Oxidative stress indicators were on average higher in short-tailed shrews. Apoptosis occurred in < 1% of myocytes examined, and did not increase with age. Within the constraints of the sample size we found evidence of protection against elevated oxidative stress in wild-caught shrews.     

Patterns of sequence variation in the mitochondrial D-loop region of shrews

Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews (genus Sorex) for the region between the tRNA(Pro) and the conserved sequence block-F revealed variable numbers of 79-bp tandem repeats. These repeats were found in all 19 individuals sequenced, representing three subspecies and one closely related species of the masked shrew group (Sorex cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an adjacent 76-bp imperfect copy of the tandem repeats. One individual was heteroplasmic for length variants consisting of five and seven copies of the 79-bp tandem repeat. The sequence of the repeats is conducive to the formation of secondary structure. A termination-associated sequence is present in each of the repeats and in a unique sequence region 5' to the tandem array as well. Mean genetic distance between the masked shrew taxa and the pygmy shrew was calculated separately for the unique sequence region, one of the tandem repeats, the imperfect repeat, and these three regions combined. The unique sequence region evolved more rapidly than the tandem repeats or the imperfect repeat. The small genetic distance between pairs of tandem repeats within an individual is consistent with a model of concerted evolution. Repeats are apparently duplicated and lost at a high rate, which tends to homogenize the tandem array. The rate of D- loop sequence divergence between the masked and pygmy shrews is estimated to be 15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid sequence evolution in shrews may be due either to their high metabolic rate and short generation time or to the presence of variable numbers of tandem repeats.      

Reevaluation of several taxa of Chinese lagomorphs (Mammalia: Lagomorpha) described on the basis of pelage phenotype variation

Melanism is a common phenomenon in the animal kingdom. While the occurrence of melanism in lagomorphs has been less studied, this phenomenon has led to systematic confusion among different forms of pikas (Ochotona) and hares (Lepus). Within Ochotona, the Pianma black pika (O. nigritia) was established primarily based on its pelage phenotype variation compared with the sympatric Forrest's pika (O. forresti). The Gaoligong pika (O. gaoligongensis) was also described based on pelage color differences with O. forresti. However, the specific status of these two taxa has been questioned for several years. We conducted a detailed examination of the cranial characters used for the initial diagnosis of each of these forms (O. forresti, O. gaoligongensis and O. nigritia). Insignificant differences were displayed among these species, thus contradicting the classification of O. gaoligongensis and O. nigritia as separate species. Within Lepus, the Manchurian black hare (Lepus melainus) was also initially described based on the melanistic pelage possessed by this form. We conducted a detailed examination of the cranial characteristics of L. melainus and the sympatric Manchurian hare (L. mandshuricus) and confirmed the synonomy of these forms; L. melainus represents melanistic individuals of L. mandshuricus. These taxonomic mistakes probably resulted from underestimating the prevalence of melanism and the potential for adaptative variation of pelage coloration in nature. A more detailed study on the genetic background leading to the occurrence of melanistic lagomorphs is needed.     

Small mammal populations in relation to hedgerow structure in an arable landscape

The population ecology of small mammals in hedgerows in arable farmland in eastern England is described. Features of hedgerows of importance to individual species are examined. Some 97% of the total 3042 mammals captured were wood mouse Apodemus sylvaticus , yellow-necked mouse Apodemus flavicollis , bank vole Clethrionomys glareolus and common shrew Sorex araneus . Small numbers of harvest mice Micromys minutus , field voles Microtus agrestis , pygmy shrews Sorex minutus and water shrews Neomys fodiens were also caught. Wood mouse, the most numerous species, showed a typical pattern of large numbers in autumn and winter, followed by a simultaneous decline over all hedges in early spring. Population changes were less clear in yellow-necked mouse and bank vole but the yellow-necked mouse was more scarce in the second year of study. Common shrews were most numerous in summer and declined rapidly in autumn. Hedgerow coppicing had a marked effect on yellow-necked mouse numbers but not on wood mouse. In an extensive survey of mammal numbers in relation to hedgerow features, ground cover was found to be the single largest factor influencing size of bank vole populations. Hedgerow condition (lack of gaps) was important to yellow-necked mice, which thrived only in well-established hedgerows. Wood mice appeared little influenced by the characteristics of the hedge. Common shrews were more abundant in hedgerows with adjacent permanent water.     

Parasite-host relationship of flies and small mammals in the Omsk region

A generalized analysis of data on a flea fauna, range of their hosts in various natural zones, and features of parasite-host relationships between fleas and small mammals obtained in the Omsk province during long term researches in 1963-1997 is given. 35 flea species are recorded. The most mass species both on animals and in their nest is Ctenophthalmus assimilis; the numerous species are Amalareus penicilliger, Megabothros rectangulatus, M. walkeri, Peromyscopsylla silvatica, Ctenophthalmus unciatus, Palaropsylla sorecis, Doratopsilla birulai, Neopsylla pleskei, Hystrichopsylla talpae; the usual species--Ceratopsyllus garei, M. calcarifer, M. turbidus, Frontopsylla elata, Amphipsylla sibirica, A. kuznetzowi, Peromyscopsylla dasycnema, Radinopsylla integella, Catalagia dacenkoi. Other species are less numerous or infrequent. The general infection rate of the flea populations on rodents and insectivores makes 30.4%. For certain species it reaches 65.1% (on red-backed vole Cletrionomys rutilus), for regular groups--86.9% (on shrews of the genus Sorex). The greatest variety of the flea populations is observed on Microtus arvalis, the least one--on Sorex caecutiens and S. daphaenodon. In the nests of small mammals the variety of fleas is significantly lower. Based on the index of flea species relative "loyalty" to small mammals and their nest we have recognized 6 groups of fleas.     

Factors explaining increased body size in common shrews (Sorex araneus) on Scottish islands

Aim  Island populations of small mammals are often characterized by a larger body size compared with neighbouring mainland or continental populations of the same species. A number of reasons have been put forward to explain this phenomenon. The aim of this study was to test which of these hypotheses can best explain the increase of body size in common shrews ( Sorex araneus ) on islands.
Location  The fieldwork for this study was carried out on the islands of the Inner Hebrides, Clyde Islands and the west coast of Scotland.
Methods  This study compared body sizes of common shrews from mainland and island sites on the west coast of Scotland, based on measurements of hind foot lengths. On 10 of the 13 islands sampled, common shrews were significantly larger than on the mainland. Body size did not vary significantly among mainland populations. We used the directional contrasts method to test the relative contributions of possible factors explaining the large body size observed in the island populations.
Results  We found that body size of common shrews on islands was positively related to distance from mainland, negatively related to average annual temperature, negatively related to island size, and may also be influenced by the presence or absence of pygmy shrews ( Sorex minutus ) on the island.
Main conclusions  Our results suggest a role for founder events, Bergmann's rule and K -selection in determining body size of common shrews on islands.