Relationships Between Shrews (Sorex Spp.) and Downed Wood In the Vancouver Watersheds, BC (original) (raw)
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Abundance of Common Shrew (Sorex Araneus) in Selected Forest Habitats of Moravia (Czech Republic)
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis
Abundance of common shrew (Sorex araneus) was evaluated on selected forest sites in Moravia, Czech Republic. Six types of habitats were assessed: forest clearings and mature forests in lowlands (173-233 m), uplands (360-600 m), and mountains (600-1200 m). Data were collected over five-year-long periods; 2006-2010 (uplands) and 2007-2011 (lowlands and mountains). Small terrestrial mammals were captured using snap traps laid in lines. In total, 200 individuals of common shrew were trapped. Relative abundance among different habitats was statistically evaluated. The highest relative abundance was found in mountain forest clearings (n = 132, rA = 0.719). Lower abundance was in upland forest clearings (n = 15, rA = 0.384), in mature mountain forests (n = 32, rA = 0.355), and in the lowland forest clearings (n = 9 rA = 0.109). The lowest abundance was in mature upland forests (n = 9, rA = 0.031) and in mature lowland forests (n = 3, rA = 0.011). Differences between sites were statistically significant. Among all altitudes, shrew populations in plantations were significantly more numerous than those in mature forests. Mountain forest clearings with dense herb layer proved to be the most suitable habitat while mature lowland forests with less developed herbaceous layer were the least suitable. Forest clearings proved to be an important refuge for the populations of common shrew.
Canadian Field-Naturalist, 2012
The disjunct eastern population of the Arctic Shrew (Sorex arcticus) has recently been recognized as a separate species, the Maritime Shrew (S. maritimensis) (Wilson and Reeder 2005), based on genetic analysis by Stewart el al. (2002). Before the taxonomic division, most information on either species was based on studies conducted in the western population (S. arcticus), and few publications exist on habitat use by the eastern population, now S. maritimensis. Sorex arcticus occurs in meadow environments and wet Tamarack (Larix laricina)-Black Spruce (Picea mariana) forest (Clough 1963; Buckner 1966; Wrigley et al. 1979), whereas S. maritimensis has been characterized as an associate of grass-sedge marshes, lowlying floodplain, wet meadows, and marsh margins (Herman and Scott 1994; Perry et al. 2004; Scott and Hebda 2004; McAlpine et al. in press). The type specimen of Sorex maritimensis was captured in marsh (Smith 1939), and the sampling by Perry et al. (2004) focused on alder (Alnus sp.) in wet areas. A recent study (Dawe and Herman 2005*) working in open wetland habitat concluded that S. maritimensis is associated with open wetlands with abundant graminoids, particularly Calamagrostis canadensis (Bluejoint Reedgrass), and low tree cover. Maritime Shrew specimens were collected during a study of the effects of pre-commercial forest thinning on small mammals in southern New Brunswick. Study Area Our work was conducted in Black Spruce forests of southeastern New Brunswick, a habitat considered atyp ical for S. maritimensis. Maritime Shrews were collected from nine naturally regenerating clear-cuts, ranging in age from 16 to 29 years since harvest. The sites were open coniferous forest on moist substrates with minimal grass. The sites would not be categorized as wet forest or wetlands (Warner and Rubec 1997), and there were no grassy meadows for a distance of at least several kilometres that would be typical of sites where Dawe and Herman (2005*) reported capturing S. maritimensis. Dominant tree species were Black Spruce, Balsam Fir (Abies balsamea), and Eastern White Pine (Pinus strobus), with smaller amounts of Red Maple (Acer rubrum), birches (Betula spp.), and alders (Alnus spp). Four of nine capture sites had been pre-commercially thinned 5 to 10 years prior to the survey. Our study sites are characterized by moist, semiproductive soils on moderate-poorly drained sites and would be classified as Eco-site 2 in the New Brunswick Ecological Land Classification (Zelazny 2007). Methods We surveyed relative abundance of small mammals in 45 sites with 16 Sherman (H. B. Sherman Inc., Talla hassee, Florida) live traps (dimensions 7.6 ¥ 8.9 ¥ 22.9 cm) and 16 pitfall traps (8.9 cm diameter, 10.8 cm depth) per site, spaced at 20-m intervals along a single 300-m transect. Trapping was conducted between June and September 2005 and between May and early October 2006. Traps were set for seven consecutive nights in each site. Shrews were removed from the sites unless captured alive (<5% captured alive). Sorex maritimensis specimens were identified by examining external morphology and dentition (van Zyll
Notes, 2006
We analyzed shrew community data from 398,832 pitfall trapnights at 303 sites across the upper Piedmont, Blue Ridge, northern Ridge and Valley, southern Ridge and Valley, Cumberland Plateau and Allegheny Mountains and Plateau sections of the central and southern Appalachian Mountains from Alabama to Pennsylvania. The objectives of our research were to describe regional species distributions and to identify macro-environmental factors important to shrews at both the community and individual species scales. Our study documented the presence of nine species with a low of three in the southern Ridge and Valley section to a high of eight in the Blue Ridge section where the Appalachian, Austral and Boreomontane fauna elements converge. Region-wide, shrew species richness was related to increasing elevation and was higher in mesic forest types than in xeric types. Conformity to expected distribution of shrew bodysize (small, medium and large) appropriate for the central and southern Appalachian species pool showed no relationship to elevation gradients. However, xeric forest types conformed to a balanced assemblage of size classes less than expected. Among individual species, presence of masked shrew (Jbrex cinere~s) and smoky shrew (SorexJgme~rrs) was associated strongly with increasing elevation and mesic forests, whereas presence of southeastern shrew (Sorex htlgirost7atis) and southern short-tailed shrew (Bhrdna camhensis) showed an opposite trend with elevation and forest type. The strong relationships we documented between presence of these four species with elevation and forest type facilitated reliable predictive habitat modeling. Conversely , the presence of pygmy shrew (Sorex hoyt) and northern short-tailed shrew (BLarina brevica~da) was not linked to forest type and only weakly linked to increasing elevation. Our analyses failed to produce meaningful relationshps about extreme habitat specialists documented by our survey, the rock shrew (Sorex dj)ar) associated with colluvial talus, the water shrew (Sorex palastn's) associated with high-gradient streams, and the least shrew (Cyjtootis pama) associated with oldfields and early sucessional habitats.
Forest Ecology and Management, 2007
As part of the multidisciplinary National Fire and Fire Surrogate study, we used drift fences with pitfall traps from May to September 2003 and 2004 to determine how three fuel reduction techniques affected shrews in the Southern Appalachian Mountains of North Carolina. Grounddwelling macroarthropods also were collected from a subset of pitfall traps to assess relative prey availability among the treatments. Four experimental units, each >14 ha were contained within each of three replicate blocks. Treatments were (1) prescribed burning; (2) mechanical felling of shrubs and small trees; (3) mechanical felling + burning; (4) forested controls. Mechanical understory felling treatments were conducted in winter 2001-2002, and prescribed burning was conducted in March 2003. High-intensity fires and high tree mortality increased canopy openness in mechanical felling + burn treatment compared to the others. Burning reduced leaf litter depth in both the burned treatments (burn only and mechanical felling + burn), whereas mechanical understory felling alone increased leaf litter depth in that treatment. Dry biomass of grounddwelling macroarthropods was similar among the treatments and control. We collected a total of 269 shrews of four species during 2003 and 2004, including northern short-tailed shrews (Blarina brevicauda), smokey shrews (Sorex fumeus), pygmy shrews (S. hoyi), and southeastern shrews (S. longirostris). Relative abundance of all shrews combined and pygmy shrews was lowest in the mechanical felling + burn treatment, but differed significantly only from the mechanical understory felling treatment where the contrast in leaf litter depth was high. Our results indicate that lowintensity fuel reduction treatments, with minimal change to canopy cover or leaf litter depth, have little impact on shrews. However, high-intensity disturbance, such as prescribed burning that kills trees and dramatically reduces shade and leaf litter depth, can reduce the abundance of some shrew species and all shrews combined, at least in the short term. #
Microhabitat and dietary partitioning in three species of shrews at Yellow Bay Montana
1990
McCracken, Karen E., M.A. July 1990 Zoology Microhabitat and Dietary Partitioning In Three Species of Shrews at Yellow Bay, Montana Director; Kerry R. Foresman I analyzed habitat use patterns and food habitats of three species of shrews (Sorex vagrans. Sorex cinereus. and Sorex montlcolus) In a grand fir (Abies grandis)/ queencup beadllly (Cllntonla unlflora) habitat In northwestern Montana. Distribution of the three species differed significantly across meslc and xerlc sites, with Sorex vagrans captures being most numerous on the meslc site, Sorex cinereus captures most numerous on the xerlc site, and Sorex montlcolus. at Is lower elevatlonal range, was Infrequently captured on both plots. Thirty-five live-trapped Sorex vaerans and Sorex clnereus were marked with phos phorescent dust and released at their site of capture. Mapping of Individual's movements revealed no detectable differences between species, but the most conspicuous habitat component used by both was the space b...
Population dynamics of the common shrew (Sorex araneus) in Central European forest clearings
European Journal of Wildlife Research
The population dynamics of shrews (Soricidae) are not well known even though they form an important part of forest ecosystems and represent suitable bioindicators of ecosystem quality. The aim of this study was to evaluate the population dynamics of shrews in mountain and upland forest clearings in four study areas within the Czech Republic and to reveal how climatic factors influenced fluctuations in their abundance for a decade (2007–2017). In total, we trapped 7,538 individuals of 18 small mammal species. From 760 individuals of seven shrew species, the common shrew (Sorex araneus) was significantly dominated in all study areas. We did not observe any significant, regular multi-annual cycles of the common shrew. However, a cross-correlation in density fluctuation of this species was detected in all mountain areas indicating the influence of environmental factors acting on a larger geographical scale. The autumn abundance of shrews was dependent on the subset of climatic variables...
In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, 1 agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. The University of British Columbia Vancouver, Canada Date AMJL 22 2-QO Z DE-6 (2/88) 11 Abstract Downed wood has long been considered an important habitat component for small mammals, although studies to date have generated equivocal results. To examine this relationship in an experimental manner, I removed and added downed wood on areas within two serai stages and two ecosystems, and monitored the population-level response of: a habitat generalist, the deer mouse (Peromyscus maniculatus), early serai specialists (meadow voles, Microtus pennsylvanicus and long-tailed voles, M. longicaudus) and an old serai specialist (southern red-backed vole, Clethrionomys gapperi). I also studied fine-scale habitat associations of red-backed voles on the treatment areas using radio-telemetry to determine how relationships with downed wood and other habitat components changed with the removal of downed wood from an area. This study was part of two multi-disciplinary silvicultural systems research projects in southern British Columbia. The first was the Opax Mountain Silvicultural Systems Project area, located in a Douglas-fir-lodgepole pine forest in a warm and dry ecosystem in the interior of British Columbia. The second was the Sicamous Creek Silvicultural Systems Project area located in a high-elevation cold, wet Engelmann spruce-subalpine fir forest. My study generated several unexpected results that have not been reported in the correlational studies published to date. The relationships of small mammals with downed wood and vegetation varied by species, as well as with ecosystem. At the Opax site, deer mouse populations responded positively to harvesting but not to downed wood manipulations. The highest densities were found on clear-cuts at the Opax site where downed wood had been removed. Within forested areas, higher densities were found in stands with lower canopy cover and higher shrub cover. At Sicamous, deer mice did not respond to harvest treatments nor downed wood manipulations on forested areas. Lower survival rates and higher rates of capture V
Journal of Mammalogy, 2005
We captured, marked, and recaptured southern short-tailed shrews (Blarina carolinensis) during a 30-month livetrapping study in a woodlot in Jackson County, Illinois, to compare aspects of their life history with those of the northern short-tailed shrew (B. brevicauda). A total of 106,496 trap checks (15,782 trap nights) resulted in 3,430 captures of 313 B. carolinensis from February 1996 through August 1998. Trapping mortality was only 18 individuals. Sex ratio did not differ from 1:1. Estimated population density peaked at 57 individuals/ha in late summer and autumn then declined during winter. Recruitment, including birth and immigration, peaked in spring and late summer each year. Individuals entering the population in the spring and early summer had higher survival rates than those entering in the autumn. A weak correlation was found between recruitment and precipitation, and between population density and humidity. Shrew activity (timing of captures) showed significant relationships with light condition and season. During summer, shrews were caught more frequently at night. In the winter, they were captured more frequently during the day. Capture rate was negatively related to precipitation and positively related to humidity. Population dynamics and activity patterns were similar to those of B. brevicauda.
Ecological Distribution of Shrews in the Cumberland Plateau of Alabama
2015
Shrews are small mammals that often occur in sympatry with other species of shrews. This suggests some form of resource partitioning is occurring. I examined eight habitats in Jackson County, Alabama, and detected evidence of habitat partitioning by shrews in pine forests, mixed forests with liana undergrowth, and deciduous riparian zones. Also, I discovered that I was 11 times more likely to capture a shrew on a night with rainfall than on a night with clear skies. Habitat segregation and increased activity on rainy nights should both be considered when researchers attempt to capture shrews in the field.
2012
Dead wood such as stumps and logs found on the forest floor is a key structural element that is used by a broad spectrum of organisms and contributes to soil nutrient cycling. The complexity of the forest floor in the boreal forest is largely dependent on coarse woody debris (CWD), but actual forestry practices may compromise the future recruitment of this resource. The main goal of our study was to determine the effects of CWD on small mammals in stands of varying green-tree retention levels. Since small mammals are associated with microhabitat components at multiple spatial scales, our secondary goal was to assess the effects of scale on small mammal relationship with CWD. Five trapping sessions were conducted in the boreal forest of western Québec, Canada during the summers of 2009 and 2010 in four managed forest blocks. Each block was composed of 12 independent trapping grids equally distributed in three treatments: clearcuts (0% green-tree retention), partial cuts (30% green-tree retention) and controls (undisturbed). We live-trapped small rodents and used pitfall traps for shrews in trapping sub-grids (fine-scale; 50 m) nested in larger grids (stand-scale; 300 m). Southern red-backed vole (Myodes gapperi) and deer mouse (Peromyscus maniculatus) abundances were positively associated with sites with high volumes of well decayed CWD in all treatments, at the fine-scale. Southern bog lemming (Synaptomys cooperi) abundance was positively associated with well decayed CWD, at both scales, but mainly in clearcut areas. Masked shrew (Sorex cinereus) abundance increased with high volumes of well decayed CWD in clearcuts but only at the stand-scale. In contrast, meadow voles were more abundant in sites with high volumes of well decayed CWD in controls than in sites with small volumes at the stand-scale. Patches of partial cuts with high volumes of well decayed CWD were characterized by high abundances of redbacked voles and this clearly indicates that volume and decay of CWD are important drivers that can mitigate the impacts of tree removal. We found different scale-dependent responses of small mammals to volumes of well decayed CWD, which indicates that associations were found at the individual as well as at the population level. We suggest that partial cuts composed of regularly distributed patches of high volumes of CWD (P11.4 m 3 in patches of 0.03 ha) might have a high potential to maintain red-backed voles, a species associated with mature forests.