Sorex Cinereus Research Articles

Differentiation of two groups of the masked shrew Sorex caecutiens Lax.

The composition of two samples of the masked shrew Sorex caecutiens Lax. from the middle taiga zone of the European part of Russia is analyzed with consideration of morphometric data. Analysis of individual variability of shrews revealed special distinctions of subspecies organization within the climatic zone.

Managing for Habitat Heterogeneity in Grassland Agro-Ecosystems Influences the Abundance of Masked Shrews (Sorex cinereus)

ABSTRACT Many agri-environment programs prescribe modified farming practices and provision of heterogeneous habitat types, such as fallow field edges and shelterbelts. The conservation benefit of these actions to biodiversity has been well described. However, the response of insectivorous small mammals to habitat heterogeneity in agro-ecosystems has received little empirical attention. We compared the abundance of the masked shrew (Sorex cinereus) between hayfields and adjacent mesic old-fields in Nova Scotia, Canada. Masked shrews were almost twice as abundant in old-field habitat and were linked closely to abundance of Aranea (spiders), Coleoptera (beetles), and Malacostraca (slugs). This implies that mesic old-field habitat is beneficial to masked shrews and is a likely population source for shrews that occur in hayfields. Because masked shrews consume large quantities of invertebrate prey (that are often considered agricultural pests), we suggest that old-fields are an important habitat to include in agro-ecosystems that should benefit both wildlife and agricultural producers.

Phylogenetically Distinct Hantaviruses in the Masked Shrew (Sorex cinereus) and Dusky Shrew (Sorex monticolus) in the United States

A limited search for hantaviruses in lung and liver tissues of Sorex shrews (family Soricidae, subfamily Soricinae) revealed phylogenetically distinct hantaviruses in the masked shrew (Sorex cinereus) from Minnesota and in the dusky shrew (Sorex monticolus) from New Mexico and Colorado. The discovery of these shrew-borne hantaviruses, named Ash River virus and Jemez Springs virus, respectively, challenges the long-held dogma that rodents are the sole reservoir hosts and forces a re-examination of their co-evolutionary history. Also, studies now underway are aimed at clarifying the epizootiology and pathogenicity of these new members of the genus Hantavirus.

Gastrointestinal Helminths of the Masked Shrew, Sorex cinereus, from Pennsylvania

Abstract Eight helminth species (6 cestodes, 2 nematodes) were recovered from 30 masked shrews, Sorex cinereus (Mammalia: Soricidae), collected from the Pennsylvania State University Experimental Forest, Centre County, Pennsylvania, U.S.A. All hosts were infected with at least 1 helminth, and species richness ranged from 1 to 6 (mean 3.6). All 8 helminths were new geographic records for Pennsylvania, and 3 tapeworms (Lineolepis lineola, Staphylocystoides serrula, Soricinia pulchra) were new host records for S. cinereus. There appears to be little evidence of host specificity among tapeworms within Sorex spp. in North America, although no species are shared with Blarina spp.

Extreme Male-biased Infections of Masked Shrews by Bladder Nematodes

Intensity of parasitic infection (number of parasites per host) can vary by date, and with host age and sex. We tested whether variation in bladder nematode (Liniscus [¼ Capillaria] maseri) intensity in Nova Scotian masked shrews (Sorex cinereus) was related to these variables. We collected a total of 117 shrews on 8 different sampling occasions between mid-May and mid-August. Univariate relationships suggested that intensities declined between May and August, and were higher in male shrews. In analyses simultaneously testing for relationships between intensity and date, age, and sex, the most compelling pattern was strongly male-biased parasitism.

Prevalence of Cryptosporidium species in wildlife populations within a watershed landscape in southeastern New York State

A cross-sectional study was conducted to determine the prevalence of Cryptosporidium in wildlife in the New York City (NYC) Watershed in southeastern New York State. A total of 6227 fecal samples were collected and evaluated from 5892 mammals (38 species), 263 birds (14 species), 2 reptiles (2 species), 8 amphibians (4 species), and 62 fish (15 species). Cryptosporidium was detected in 30 species. Of the species found positive for Cryptosporidium, 16 represented new records for this parasite— Alosa pseudoharengus, Larus delawarensis, Blarina brevicauda, Sorex cinereus, Parascalops breweri, Myotis lucifugus, Peromyscus maniculatus, Microtus pennsylvanicus, Clethrionomys gapperi, Tamiasciurus hudsonicus, Marmota monax, Erethizon dorsatum, Canis latrans, Mustela erminea, Mustela vison, and Lynx rufus. Factors such as age, sex, season, and land use were evaluated to determine if there was any association with infection by this parasite. Animals were more likely to be positive for Cryptosporidium during spring and in agricultural land use.

Sorex rohweri sp. nov. (Mammalia, Soricidae) from northwestern North America

Sorex rohweri sp. nov. is described on the basis of a series of specimens from the Olympic Peninsula and adjacent western regions of Washington State, USA, and southwestern British Columbia, Canada. It has been misidentified as Sorex cinereus Kerr, 1792, which occurs in the Cascade Range in west-central Washington, in coastal British Columbia, and regions farther to the northeast. The new species is distinguished from S. cinereus by numerous morphological characters: differences in craniodental dimensions; different location and form of the medial tines of the upper incisors; presence of patent postmandibular foramina; different intensity and distribution of dental pigmentation; and different form of the glans penis, along with other details. The combination of characters also separates it from sympatric species of Sorex. Phylogenetic inference of cytochrome b sequences from two specimens of the proposed new species shows them to be distinct from Sorex cinereus and from five sympatric Sorex species, supporting their designation as members of a new species.

Effects of Prebaiting on Small Mammal Trapping Success in a Morrow's Honeysuckle‐Dominated Area

Abstract:Researchers have obtained mixed results in studies that use prebaiting to enhance small mammal trapping success. In 2004–2005 we tested the effects of prebaiting on small mammal trapping success in an exotic and invasive shrub community, Morrow's honeysuckle (Lonicera morrowii), using 4 80 × 120‐m live trapping grids at Fort Necessity National Battlefield in Fayette County, Pennsylvania, USA. We randomly assigned traps to 1 of 3 trapping methods: we prebaited one‐third of the traps 2 nights (n= 3,508 trap‐nights), one‐third one night (n= 3,492 trap‐nights), and one‐third had no prebaiting (n= 3,509 trap‐nights). We compared small mammal richness, diversity, and relative abundance (no. captures/100 trap‐nights) of white‐footed mice (Peromyscus leucopus; n= 462 captures), meadow voles (Microtus pennsylvanicus; n= 89 captures), meadow jumping mice (Zapus hudsonius; n= 221 captures), masked shrews (Sorex cinereus; n= 87 captures), and shorttail shrews (Blarina brevicauda; n= 78 captures) among prebaited traps and non‐prebaited traps. On the first day of trapping, as well as all 4 days combined, richness, diversity, and relative abundance for all species were similar among traps that we had prebaited for 2 nights, one night, and zero nights (P= 0.856). Moreover, total number of captures was similar among prebaiting treatments (P= 0.197). These results suggest that prebaiting does not enhance trapping success for small mammals in a landscape dominated by a dense, exotic shrub. We recommend that managers do not employ prebaiting in areas with similar small mammal species composition in an attempt to increase trapping success, as we did not record a difference in trapping success in prebaited traps compared to non‐prebaited traps.

Nearctic Shrews, Sorex spp., as Paratenic Hosts of Soboliphyme baturini (Nematoda: Soboliphymidae)

Third-stage larvae (L3) of Soboliphyme baturini were discovered for the first time in shrews, Sorex cinereus and Sorex tundrensis from Alaska and the Nearctic. Shrews were found to be infected with L3 at Suloia Lake, south- eastern Alaska, Togiak National Wildlife Refuge, southwestern Alaska, and at the Yukon-Charley Rivers National Preserve near the Yukon-Alaska border. Larvae in shrews from Alaska were morphologically indistinguishable from those known in both insectivores and arvicoline rodents from Russia. The occurrence of S. baturini in Alaskan insectivores further establishes shrews as important hosts in the transmission of S. baturini among mustelids and other carnivores and indi- cates for the first time the basis for a paratenic cycle in the Nearctic.

A synopsis of the fleas (Insecta: Siphonaptera) parasitizing New World species of Soricidae (Mammalia: Insectivora)

A synopsis of the 57 species and 24 genera of New World fleas parasitizing species of Soricidae is provided, with synonymical lists, and distributional and host data. Species analyzed belong to the families Ceratophyllidae (10 genera), Ctenophthalmidae (10 genera), Hystrichopsyllidae (two genera), and Leptopsyllidae (two genera). Three subspecies are elevated to species: Corrodopsylla lira, C. obtusata, and Nearctopsylla hygini. Soricid hosts include 17 species of Sorex, four species of Cryptotis, two species of Blarina, and one species of Crocidura. The species hosting the highest number of flea species is Blarina brevicauda (19 flea species), followed by Sorex cinereus (16), S. pacificus (9), S. trowbridgii (8), S. fumeus (7), S. palustris (7), and Cryptotis parva (7). Most of the flea species analyzed are polyxenous, and belong mainly to genera associated to small rodents and marginally present on Soricidae. The association with Soricidae seems to be more evident in species of Corrodopsylla, Corypsylla, Ctenophthalmus, Doratopsylla, Hystrichopsylla,and Nearctopsylla. Only Corrodopsylla lira, C. barrerai, Ctenophthalmus cryptotis, C. expansus, C. myodosus, Hystrichopsylla cryptotis, H. guatemalensis, Nearctopsylla georgiana, N. pfitzeri, and N. princei are apparently stenoxenous or monoxenous. Taxa analyzed belong to the Nearctic biotic element and are specially diversified in the Mexican Transition Zone.

Structure of forests used by small mammals in the industrially damaged landscape of Sudbury, Ontario, Canada

We studied forest cover and use by small mammals in the fall of 2001 and 2002 in patches of the industrially damaged landscape of Sudbury, Ontario, Canada (46°30′N, 81°00′W). Three common forest patch types in the region were surveyed: semi-barren terrain, a protected arboretum, and a 30-year-old conifer plantation. Each year, four sites per treatment were selected in a 10 km 2 area in the vicinity of the Laurentian University campus. At each site, plant cover (percent low-shrub-herbaceous layer (0–1 m); percent shrub layer (1–3 m); and stand height was surveyed in four 5-m radius plots while number of trees were tallied using a Basal Area Factor 2 prism. Small mammal plots (10 m × 10 m) were set on site with mouse- and squirrel-size live traps for 3 days during 4 weeks in early fall. A total of 398 mammals of 9 species (deer mouse ( Peromyscus maniculatus); short-tailed shrew ( Blarina brevicauda); masked shrew ( Sorex cinereus), eastern chipmunk ( Tamias striatus), red squirrel ( Tamiasciurus hudsonicus), northern flying squirrel ( Glaucomys sabrinus); Gapper's red-backed vole ( Clethrionomys gapperi); meadow vole ( Microtus pennsylvanicus), house mouse ( Mus musculus)) were captured in 1265 trap-nights and 938 trap-days (for diurnal species). There were significant differences in the structural habitat variables among treatments, though corresponding trends in abundance, activity and diversity of mammals were not significant. At a smaller scale we found: (a) a significant positive relationship between site-specific stand height, tree basal area, mammal richness, diversity, short-tailed shrew abundance and flying squirrel activity; (b) a positive effect of percent shrub cover on red squirrel activity; and (c) a negative effect of shrub cover on deer mouse abundance. Our data provides evidence that habitat selection processes occurred at a small scale within the landscape; mammal diversity increased with forest cover recovery, though both positive and negative specific responses to patch structure were detected. We suggest that these small-scale effects may be meaningful for the recovery of fragmented landscapes where suitable (i.e. structured) forest patches are small, within a low quality habitat matrix.

Aggregations of masked shrews ( Sorex cinereus ): density-related mating behavior? / Agrégation de musaraignes masquées ( Sorex cinereus ): accouplement relatif à la densité de la population?

AbstractLarge aggregations of shrews have been reported and various explanations offered for this seemingly rare behavior; however, there has been little evidence to support any particular interpretation. We observed two small aggregations of highly active vocalizing Sorex cinereus while performing wildlife surveys in forested habitats in central Massachusetts, USA. These observations, in conjunction with a review of other reports, including genetic analyses, strongly suggest that such aggregations of adult Sorex are associated with mating behavior, more readily observed during periods of high population density. Published accounts of such behavior may be rare because primarily large aggregations have been reported; however, smaller breeding aggregations may be common.

Aggregations of masked shrews ( Sorex cinereus ): density-related mating behavior? / Agrégation de musaraignes masquées ( Sorex cinereus ): accouplement relatif à la densité de la population?

AbstractLarge aggregations of shrews have been reported and various explanations offered for this seemingly rare behavior; however, there has been little evidence to support any particular interpretation. We observed two small aggregations of highly active vocalizing Sorex cinereus while performing wildlife surveys in forested habitats in central Massachusetts, USA. These observations, in conjunction with a review of other reports, including genetic analyses, strongly suggest that such aggregations of adult Sorex are associated with mating behavior, more readily observed during periods of high population density. Published accounts of such behavior may be rare because primarily large aggregations have been reported; however, smaller breeding aggregations may be common.

Global warming, Bergmann's rule and body size in the masked shrew Sorex cinereus Kerr in Alaska

Summary 1. It was recently shown that body size of Palearctic shrews decreases with increasing latitude, thus contradicting Bergmann’s rule, and this trend was explained by food shortage during the cold northern winter. In Alaska, global warming has resulted in milder winters that may improve food supply. In this study we tested the hypothesis that body size of Alaskan shrews increased during the second half of the twentieth century, in response to global warming. 2. Data on body weight and length of body, tail, hind foot and ear of museum specimens of the masked shrew Sorex cinereus Kerr from Alaska were used in order to examine the effects of latitude, longitude, mean ambient temperature in January and July, and year of collection, on these parameters. 3. We found that variation in body size of the masked shrew in Alaska appears to contradict to the prediction of Bergmann’s rule, decreasing in high latitudes and in areas cold January temperature. 4. Body size of shrews in Alaska increased significantly during the second half of the twentieth century, apparently due to the higher food availability in winter as a result of improved weather conditions for its prey.

The discovery of the masked shrew ( Sorex caecutiens Laxmann, 1788) in southern Norway provides a further suggestion for the post-glacial colonisation of Scandinavia

The discovery of the masked shrew ( Sorex caecutiens Laxmann, 1788) in southern Norway provides a further suggestion for the post-glacial colonisation of Scandinavia

OCCURRENCE AND DISTRIBUTION OF SMALL MAMMALS ON THE GOODNEWS RIVER, SOUTHWESTERN ALASKA

A paucity of data exists on the occurrence, distribution, and abundance of small mammal communities in southwestern Alaska. To add to the understanding of these communities we conducted a comprehensive small mammal survey in southwestern Alaska. We trapped small mammals along the Goodnews River in Togiak National Wildlife Refuge from 26 June to 5 September 1996. Objectives of our study were to determine what small mammal species occur in the Goodnews River area, to determine species distribution in 4 representative habitats during 3 time periods, and to determine ideal time periods to trap small mammals in order to maximize the diversity of species encountered and the number of specimens captured. In 3600 trap-nights we captured 468 specimens including masked shrew (Sorex cinereus), pygmy shrew (S. hoyi), Alaska tiny shrew (S. yukonicus), tundra shrew (S. tundrensis), tundra vole (Microtus oeconomus), red-backed vole (Clethrionomys rutilus), Greenland collared lemming (Dicrostonyx groenlandicus), and brown lemming (Lemmus trimucronatus). The pygmy shrew, Alaska tiny shrew, Greenland collared lemming, and brown lemming are the 1st representatives of these species from the region to be placed in a museum collection. The willow habitat supported the greatest number of specimens captured (n = 170), while the wet tundra habitat yielded the greatest number of species captured (n = 4). The fall trap period (26 August to 5 September) yielded the greatest number of specimens captured (n = 229), while the spring (26 June to 6 July) and summer trap periods (26 July to 5 August) yielded greatest species diversity. Findings of rare and uncommon species illustrate the need to conduct additional surveys in the region.

Attempted isolation ofBlastomyces dermatitidisfrom native shrews in northern Wisconsin, USA

The precise ecological niche of Blastomyces dermatitidis is unknown. The related dimorphic fungus, Paracoccidioides brasiliensis, has been isolated from South American ground-dwelling insectivorous armadillos. We attempted to isolate Blastomyces from shrews, North American ground-dwelling insectivores that have been shown to harbor Histoplasma capsulatum in endemic areas. Forty-seven masked shrews (Sorex cinereus) and 13 northern short-tailed shrews (Blarina brevicauda) were collected in endemic areas of northern Wisconsin and Michigan using pitfall traps. Specimens were collected between 1998 and summer 2002, stored frozen, then necropsied. Cultures of nasopharynx, lungs, liver, spleen and large and small bowel were placed on yeast extract phosphate agar with one or two drops of ammonium hydroxide. Cultures for Blastomyces were negative from all 60 shrews and two deer mice (Peromyscus maniculatus) and three southern red-backed voles (Clethrionomys gapperi), which were trapped inadvertently. Histological examination of 36 of these specimens revealed no Blastomyces yeast forms. Northern Wisconsin shrews do not appear to be carriers of B. dermatitidis.

Soricid Response to Canopy Gaps Created by Wind Disturbance in the Southern Appalachians

We used drift fences with pitfall traps to compare soricid abundance, richness, and demographic parameters among intact multiple-tree windthrow gaps, salvaged gaps, and mature forest in a xeric southern Appalachian forest type during 1997–1999. We also tested whether capture rates were correlated with rainfall, and whether similar-sized species did not co-occur as predicted by multi-species assemblage rules. We captured six species: Blarina brevicauda (Say) (northern short-tailed shrew), Cryptotis parva (Say) (least shrew), Sorex cinereus Kerr (masked shrew), S. fumeus G.M. Miller (smoky shrew), S. hoyi Baird (pygmy shrew), and S. longirostris Bachman (southeastern shrew). Tree basal area, forest structural features, and arthropod abundance differed among treatments, but species richness and abundance of most shrews did not. Captures during June–October were higher in 1998 than in 1997, although 1998 summer rainfall was low. Rainfall was correlated with shrew activity, but explained little of the variability in capture rates (r2 = 0.05). The sex ratio within each species was similar among gap treatments and controls, but differed from 1:1 for S. hoyi, S. longirostris, and S. fumeus. The soricid assemblage did not conform to multi-species assemblage rules; three small-bodied species co-occurred in similar numbers at all study sites. Our results suggest that forest management that mimics conditions created by multiple windthrows in xeric forest of the southern Appalachians is unlikely to affect shrew communities adversely, at least in the short-term.

Long-term effects of precommercial thinning on small mammals in northern Maine

Precommercial thinning (PCT) is being practiced increasingly throughout the Acadian forest of eastern North America to meet silvicultural objectives; however, effects of this practice on wildlife, both immediately and several years post-treatment are not well understood. Forest dependent small mammals have ecological roles as prey for numerous avian and mammalian predators, dispersers of seeds, fruit, and spores, and contribute to nutrient cycling. Researchers in the northwestern USA have suggested that thinning of young, regenerating clearcuts may increase the abundance and diversity of some forest-dependent small mammals by increasing rates of forest development and enhancing the ecological representation of mid-successional stands across managed landscapes. We examined the effects of PCT within conifer-dominated forest stands 1-, 6-, 11-, and 16-years post-treatment, on abundances of mice, voles, and shrews, and on within-stand structure in the commercially managed, Acadian forests of northern Maine. We live-trapped small mammals on 24 herbicide-treated clearcuts treated with PCT and on 13 similar, unthinned stands during summers of 2000 and 2001. Thinning of mid-successional conifer stands resulted in increased abundances, (red-backed voles, Clethrionomys gapperi, P = 0.008; masked shrews, Sorex cinereus, P < 0.001) or had no detectable effect on (deer mice, Peromyscus maniculatus, P = 0.544; short-tailed shrews, Blarina brevicauda, P = 0.517) the 4 most common species of Muridae and Soricidae in northern Maine. In general, abundance of deer mice responded more positively to increasing development class and to the number of years since thinning than other species of small mammals. Several within-stand habitat characteristics associated with stand maturity, such as larger stem diameters and a partially open canopy, occurred in thinned stands. Thus, PCT may accelerate the development of habitat attributes typical of mid-successional conifer stands in intensively managed stands within the Acadian Forest. PCT may increase abundances of small mammal species associated with mid-seral forest conditions at the scale of the forest stand.

PHYLOGEOGRAPHY OF MASKED (SOREX CINEREUS) AND SMOKY SHREWS (SOREX FUMEUS) IN THE SOUTHERN APPALACHIANS

Sorex cinereus (masked shrew) and Sorex fumeus (smoky shrew) are syntopic species co-occurring in relict fragments of spruce–fir habitat on southern Appalachian mountaintops. We conducted phylogenetic and population genetic analyses of 20 high-elevation Sorex populations in 8 distinct boreal islands. Partial mitochondrial DNA sequences (cytochrome b and D-loop) were compared with amplified fragment length polymorphism markers obtained by restriction of whole genomic DNA. The 2 species, though similar in morphology and ecological niche, have dissimilar phylogeographic patterns. S. cinereus, despite its more limited present-day southern Appalachian range, exhibits markedly less population structure than S. fumeus. What structure is present among masked shrew populations is randomized geographically, in contrast to a distinct association between genetic partitioning and geographic location among smoky shrew populations. Disparity in post-Pleistocene population densities of these species might be implicated in the discrepant patterns of phylogeographic structuring evident in their genomes as a result of historical vicariance. Although the metapopulations of both species exhibit genetic signatures consistent with continuous historical expansion, we believe that a localized catastrophic event induced a severe genetic bottleneck in Sorex populations at Whitetop Mountain, Virginia. This study contributes to a better understanding of the repercussions of boreal habitat fragmentation on the population dynamics and genetic diversity of associated vertebrate species.