Showing papers on "Flying squirrel published in 2012"

Squirrels of the World

Abstract: "Squirrels of the World", written by scientists with more than 100 years of collective experience studying these popular mammals, is the first comprehensive examination of all 285 species of squirrels worldwide. The authors reveal virtually every detail of the family Sciuridae, which includes ground squirrels, tree squirrels, flying squirrels, prairie dogs, and chipmunks. Each species-from the familiar gray squirrel of American backyards to the exotic and endangered woolly flying squirrel of Pakistan-is described in a detailed account that includes distinguishing characteristics, ecology, natural history, conservation status, and current threats to its existence. "Squirrels of the World" includes: stunning color photographs that document rare and unusual squirrels as well as common varieties; evolution, morphology, ecology, and conservation status; colorful range maps marking species distribution; images of the skull of each genus of squirrel; and extensive references.

Competitive exclusion within the predator community influences the distribution of a threatened prey species.

Abstract: While much effort has been made to quantify how landscape composition influences the distribution of species, the possibility that geographical differences in species interactions might affect species distributions has received less attention. Investigating a predator-prey setting in a boreal forest ecosystem, we empirically show that large-scale differences in the predator community structure and small-scale competitive exclusion among predators affect the local distribution of a threatened forest specialist more than does landscape composition. Consequently, even though the landscape parameters affecting Siberian flying squirrel (Pteromys volans) distribution (prey) did not differ between nest sites of the predators Northern Goshawks (Accipiter gentilis) and Ural Owls (Strix uralensis), flying squirrels were heterospecifically attracted by goshawks in a region where both predator species were present. No such effect was found in another region where Ural Owls were absent. These results provide evidence that differences in species interactions over large spatial scales may be a major force influencing the distribution and abundance patterns of species. On the basis of these findings, we suspect that subtle species interactions might be a central reason why landscape models constructed to predict species distributions often fail when applied to wider geographical scales.

Evolutionary history of tree squirrels (Rodentia, Sciurini) based on multilocus phylogeny reconstruction

Abstract: Pecnerova, P. & Martinkova, N. (2012). Evolutionary history of tree squirrels (Rodentia, Sciurini) based on multilocus phylogeny reconstruction. —Zoologica Scripta, 41, 211–219. Tree squirrels of the tribe Sciurini represent a group with unresolved phylogenetic relationships in gene trees. We used partial sequences of mitochondrial genes for 12S rRNA, 16S rRNA, cytochrome b and d-loop, and nuclear irbp, c-myc exon 2 and 3 and rag1 genes to reconstruct phylogenetic relationships within the tribe, maximizing the number of analysed species. Bayesian inference analysis of the concatenated sequences revealed common trends that were similar to those retrieved with supertree reconstruction. We confirmed congruence between phylogeny and zoogeography. The first group that diverged from a common ancestor was genus Tamiasciurus, followed by Palaearctic Sciurus and Indomalayan Rheithrosciurus macrotis. Nearctic and Neotropical Sciurus species formed a monophyletic group that included Microsciurus and Syntheosciurus. Neotropical Sciurini were monophyletic with a putative exception of Syntheosciurus brochus that was included in a polychotomy with Nearctic Sciurus in supertree analyses. Our data indicate that Sciurini tree squirrels originated in the northern hemisphere and ancestors of contemporary taxa attained their current distribution through overland colonization from the nearest continent rather than through trans-Pacific dispersal.

Metagenomic analysis reveals a functional signature for biomass degradation by cecal microbiota in the leaf-eating flying squirrel (Petaurista alborufus lena)

Abstract: Animals co-evolve with their gut microbiota; the latter can perform complex metabolic reactions that cannot be done independently by the host. Although the importance of gut microbiota has been well demonstrated, there is a paucity of research regarding its role in foliage-foraging mammals with a specialized digestive system. In this study, a 16S rRNA gene survey and metagenomic sequencing were used to characterize genetic diversity and functional capability of cecal microbiota of the folivorous flying squirrel (Petaurista alborufus lena). Phylogenetic compositions of the cecal microbiota derived from 3 flying squirrels were dominated by Firmicutes. Based on end-sequences of fosmid clones from 1 flying squirrel, we inferred that microbial metabolism greatly contributed to intestinal functions, including degradation of carbohydrates, metabolism of proteins, and synthesis of vitamins. Moreover, 33 polysaccharide-degrading enzymes and 2 large genomic fragments containing a series of carbohydrate-associated genes were identified. Cecal microbiota of the leaf-eating flying squirrel have great metabolic potential for converting diverse plant materials into absorbable nutrients. The present study should serve as the basis for future investigations, using metagenomic approaches to elucidate the intricate mechanisms and interactions between host and gut microbiota of the flying squirrel digestive system, as well as other mammals with similar adaptations.

Gliding locomotion of Siberian flying squirrels in low-canopy forests: the role of energy-inefficient short-distance glides

Abstract: Short glides of less than 20 m seem energy inefficient for the Siberian flying squirrel Pteromys volans as with the northern flying squirrel Glaucomys sabrinus. However, Siberian flying squirrels in low-canopy forests frequently use short glides. Therefore, we sought to clarify the gliding patterns of Siberian flying squirrels for energy-efficient gliding transport in low-canopy forests (mean tree height, 15.3 m) in Hokkaido, Japan, based on records of 66 glides and 35 launch and landing trees. Mean launch height, landing height, and horizontal glide distance were 14.4, 2.7, and 21.4 m, respectively. For short distances, horizontal glide distance was strongly correlated with launch heights but not with launch tree height. For glides of more than 20 m, horizontal glide distance was significantly correlated with both launch height and launch tree height. The mean heights of launch and landing trees for short glides were 15.6 and 19.5 m, respectively. For long glides, these heights were 22.7 and 19.2 m. For short glides, mean launch tree height did not differ from overall mean tree height. However, for long glides, the mean launch tree height was greater than the overall mean tree height. Also, for short glides, the height of the landing tree was greater than that of the launch tree. Launch trees used for long glides were as high as the landing trees used in short glides. From these results, we conclude that Siberian flying squirrels in low-canopy forests save energy by gliding initially from a tree with sufficient height to permit a glide to a taller tree. This taller tree then permits long-distance glides that are energetically more efficient.

Home range and activity of the Indian giant flying squirrel (Petaurista philippensis) in Taiwan: influence of diet, temperature, and rainfall

Abstract: Knowledge on home range and activity patterns, along with their responses to environmental fluctuations, is important for the understanding of wildlife ecology and conservation, but related studies on giant flying squirrel species (genus Petaurista) are still limited. We radio-tracked five Indian giant flying squirrels (Petaurista philippensis) in subtropical Taiwan to assess their home range and activity patterns, as well as their behavioral strategy to cope with fluctuations in food quality. Specifically, we assessed the travelling and resting times of P. philippensis in relation to its energy requirements during periods of low food quality in winter. The influence of temperature and rainfall was also investigated. A total of five individuals were radio-tracked for 1–6 months. The home ranges of four individuals averaged 2.8 ± 2.0 ha (± SD), based on the 95 % kernel method. Mean home ranges of two adult males (4.4 ± 1.3 ha) were larger than a female (1.8) and sub-adult male (0.8). P. philippensis was found to be more active around dusk and dawn and less active at midnight. Daily ranging distance and activities were negatively associated with proportion of mature leaves in diet of the only female that we tracked. Rainfall had negative effects on activities of the males, while temperature had no significant influence. The current study suggested an energy conservative strategy of P. philippensis. Home ranges of P. philippensis are smaller than those of smaller flying squirrel species (genus Glaucomys and Pteromys spp.), which may be related to the differences in food habits and gliding efficiency.

Flying Squirrel Demography Varies Between Island Communities with and without Red Squirrels

Abstract: Recent studies in Southeast Alaska suggest the ecology of Glaucomys sabrinus differs from populations in the Pacific Northwest. In Southeast Alaska, densities were the highest reported for the species, populations were not as closely linked to old-forest attributes, and individuals had a more diverse diet that was less dependent on mycophagy. Pacific Northwest communities are comprised of several arboreal rodents; Southeast Alaska has a depauperate mammal fauna. I hypothesized that Southeast Alaska populations had a broader realized niche because of competitive release. The red squirrel (Tamiasciurus hudsonicus) is the only other arboreal squirrel and it is absent from the southern outer islands of Southeast Alaska’s Alexander Archipelago. I compared demography and body mass of G. sabrinus on Prince of Wales Island to a population in sympatry with T. hudsonicus on a separate island (Mitkof). Home ranges were larger and population density, breeding female density, and juvenile recruitment of G. sabrinus were all lower in sympatry with T. hudsonicus. In a companion study, G. sabrinus on Prince of Wales Island used cavities for denning relatively more frequently than in sympatry with T. hudsonicus on Mitkof Island. Female G. sabrinus depend on cavities for natal dens, and breeding female and population densities are positively correlated with large snag or tree density. The presence of T. hudsonicus may influence G. sabrinus populations by limiting availability of cavities. Furthermore, variation in vertebrate assemblages among islands may influence realized niches of resident species, which manifest unique demographic profiles compared to populations of different ecological communities.

New Distribution Information on Woolly Flying Squirrel (Eupetaurus cinereus Thomas, 1888) in Neelum Valley of Azad Jammu and Kashmir, Pakistan

Abstract: Woolly flying squirrel (Eupetaurus cinereus) is among the least recorded mammals of the world. Most records come from Pakistan's northern mountainous regions. Presence of this species has not been reported in Azad Jammu and Kashmir in the existing literature. Present study investigated the presence of this species in Shounthar Valley of district Neelum, Azad Jammu and Kashmir. Local residents, hunters and Salaajeet collectors were consulted to identify the probable habitat of woolly flying squirrel in the study area. After preliminary consultation, nine sites were selected in Shounthar Valley for further field investigation through attempts at direct observation of the animal in its natural habitat as well as indirect evidence. Evidence suggesting the presence of woolly flying squirrel was found in all nine sites; these lay between 3270m and 3660m elevation. A live animal captured from the study area was confirmed by measurements and photographs to be a woolly flying squirrel, and presence at the other sites is provisionally recorded based on calls, collection of hairs, faecal material, etc. Occupied habitat was characterized by steep slopes, difficult to approach cliffs and mixed vegetation including Abies pindrow, Betula utilis, Juniperus macropoda, Pinus wallichiana, Taxus wallichiana, Skimmia laureola, Potentilla eriocarpa, Poa bactriana, Bergenia stracheyi, Artemisia vulgaris and Bistorta affinis. Habitat degradation due to deforestation and livestock grazing may be the major factors adversely affecting the general habitat in the study area and this species might have negative consequences.

Different Nest Site Selection of Two Sympatric Arboreal Rodent Species, Siberian Flying Squirrel and Small Japanese Field Mouse, in Hokkaido, Japan

Abstract: Numerous vertebrates use tree cavities as nest resources. Mammals such as Carnivora (Zalewski 1997; Wilson and Nielsen 2007), rodents (Taulman 1999; Shibata et al. 2004; Holloway and Malcolm 2007), bats (Sedgeley and O’Donnell 1999; Boonman 2000; Willis and Brigham 2007), and marsupials (Lindenmayer et al. 1991; Smith et al. 2007; Crane et al. 2010), as well as birds (Aitken et al. 2002; Martin et al. 2004; Adamik and Kral 2008), use tree cavities for daily rest, reproduction, and/or overwintering. Sympatric cavity-users often partition their nest cavities to avoid interspecific competition (van Balen et al. 1982; Martin et al. 2004; Shafique et al. 2009). In Hokkaido, northern Japan, there are two cavitynesting rodents, the Siberian flying squirrel (Pteromys volans) (Nakama and Yanagawa 2009; Suzuki et al. 2011) and the small Japanese field mouse (Apodemus argenteus) (Nakata et al. 2009). There may be competition between these two rodents for tree cavities, but their favored nest sites have not yet been compared. Do they select tree cavities of different types, and, if so, what characteristics are their selections based on? These rodents have different physical and ecological characteristics. Pteromys volans (weight, 110 to 142 g; head and body length, 130 to 167 mm; Hanski et al. 2000; Asari et al. 2007; Oshida 2009) is 5 to 14 times heavier than A. argenteus (weight, 10 to 20 g; head and body length, 65 to 100 mm; Nakata et al. 2009). In addition, P. volans, which is an aerial and arboreal user, spends most of its time in the canopy and almost never walks on the ground, even when crossing wide fields (Selonen and Hanski 2003, 2004). Apodemus argenteus also uses arboreal space (Imaizumi 1978; Abe et al. 1989; Sekijima 2004), and it is able to climb to a height of 18 m (Ida et al. 2004). However, it more frequently uses foods on and under the ground than above the ground (Abe 1986). These differences in size and habit between the two species may result in different choices of tree cavities. Larger species of cavity-nesting mammals and birds tend to nest in larger cavities with larger entrances (Martin et al. 2004). Larger flying squirrels use larger trees with larger entrances than do smaller flying squirrel species (Shafique et al. 2009). Larger bird species also nest in larger entrance cavities than do smaller species (van Balen et al. 1982). Thus, we hypothesized that P. volans, with a larger body than that of A. argenteus, would nest in trees with greater diameters at breast height and in larger cavities with larger entrances. In addition, we hypothesized that P. volans, which is usually active in the upper layer of trees, would nest in higher cavities than A. argenteus, which commonly lives on and under the ground. We examined these hypotheses by surveys of tree cavities and nest boxes.

Nesting patterns of southern flying squirrels in managed northern hardwoods

Abstract: Southern flying squirrels (Glaucomys volans) use multiple nest trees for foraging and protection, but nest trees can become scarce following harvests of hardwood forests. In northern Wisconsin, the Managed Old-growth Silvicultural Study tested techniques to remediate logging impacts on forest-dependent wildlife. Three types of canopy treatments were applied (multicohort harvest [0.4-ha and 1.2-ha irregular group shelterwoods], medium gaps [18-m- and 24-m-diameter gaps], and small gaps [11-m-diameter gaps]). To evaluate the effects of treatment on nest tree selection by southern flying squirrels, we tracked 33 radiocollared southern flying squirrels once a week for 5 weeks in late summer, locating 82 nest trees (X 5 2.73 nest trees per southern flying squirrel [95% confidence interval: 2.28–3.18 nest trees]). Canopy treatments were important predictors of nest tree switching. Probability of switching differed by canopy treatment (listed from lowest to highest probability): multicohort harvest: 0.29 (0.17–0.42), medium gaps: 0.44 (0.32–0.56), control: 0.57 (0.41–0.73), and small gaps: 0.73 (0.61–0.85). Lower nest tree switching in the multicohort harvest compared to the small gaps likely reflected availability of habitat resources. Spatial arrangement of canopy gaps and associated effects on southern flying squirrels should be considered when planning timber harvests in northern hardwoods.

Habitat and landscape correlates of southern flying squirrel use of red‐cockaded woodpecker clusters

Abstract: Southern flying squirrels (Glaucomys volans) can have significant negative impacts on red-cockaded woodpecker (Picoides borealis) reproductive success and group size. Although direct control of southern flying squirrels may be necessary in small red-cockaded woodpecker populations (<30 groups), creation of high quality habitat through landscape management is the preferred method for managing larger woodpecker populations. Thus, we determined the habitat and landscape factors within 100 m, 400 m, and 800 m of cluster centers that were related to southern flying squirrel use of red-cockaded woodpecker cavities at the Carolina Sandhills National Wildlife Refuge, South Carolina. At all spatial scales, the number of cavities in the cluster was the most influential variable determining use by southern flying squirrels. At the 400-m and 800-m scales, the amount of stream length was also positively associated with the presence of flying squirrels. The proximity and amount of hardwoods surrounding clusters were not related to southern flying squirrel use at any spatial scale; thus, removal or conversion of hardwood stands surrounding red-cockaded woodpeckers may not be necessary for reducing cavity kleptoparasitism by flying squirrels. However, when establishing recruitment clusters, areas with streams should be avoided and addition of artificial cavities to existing clusters should be done judiciously to minimize the number of excess cavities. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Habitat analysis of a disjunct population of the carolina northern flying squirrel ( glaucomys sabrinus coloratus )

Abstract: The northern flying squirrel Glaucomys sabrinus occurs in a variety of forest types over most of North America, with disjunct populations in the southern Appalachians, Black Hills, southern Rocky Mountains, and Sierra Nevada (Wells- Gosling and Heaney, 1984). A subspecies of sabrinus, the Carolina northern flying squirrel, sabrinus coloratus, is a small nocturnal flying squirrel found in the southern Appalachians. One population of Carolina northern flying squirrel occurs within hemlock-northern hardwood forests along the Cherohala Skyway in western North Carolina. This subspecies was listed as federally endangered on July 1, 1985 (U.S. Fish and Wildlife Service, 1990) largely due to declining populations from habitat loss (Loeb et al., 2000). I sought to determine if the larger habitat surrounding the areas of documented squirrel activity is suitable for squirrel persistence, how habitat size and quality compares between sites with squirrel activity and other sites, and what types of foods the squirrels were consuming. Vegetation surveys of sites with documented G. s. coloratus activity, either den sites or capture sites, and paired random sites approximately 70 meters away were conducted. In addition to general habitat knowledge, these surveys provided information for GIS analysis of the larger habitat around the three focal areas. Using ArcGIS v. 9.3.1 (ESRI, Redlands, CA, USA), a model delineating potential Carolina northern flying squirrel habitat based on six parameters: slope, elevation, aspect, spectral signature of den sites, soil types, and tree height data was created. Denaturing gradient gel electrophoresis and sequencing was performed on G. s. coloratus scat samples to determine fungal or bacterial diet composition. Vegetation surveys revealed G. s. coloratus were utilizing habitat from hemlock to northern hardwood forest and habitat patches that were similar to nearby areas along the Cherohala Skyway. The GIS model revealed an area of potential G. s. coloratus habitat to the north (Stratton Bald). Though the distance from Stratton Bald to my three study sites exceeds G. s. coloratus travel distance, the model also revealed an area much closer than Stratton Bald of smaller suitable patches grouped relatively close together. BLAST results of sequenced DGGE bands of squirrel scat revealed similarity to common fungi, including both ascomycetes and basidiomycetes.