Showing papers on "Flying squirrel published in 2007"

Natal habitat-biased dispersal in the Siberian flying squirrel

Abstract: Theoretically, dispersers should target the habitat where prospects for fitness will be highest. Aiming for a habitat similar to the natal area (natal habitat-biased dispersal) has been hypothesized as a probable rule of thumb for dispersers, but has received very little empirical support to date. We investigated similarities between natal and post-dispersal settlement sites with radio-collared Siberian flying squirrels (Pteromys volans L.). Juveniles born in small patches and raised in nests close to patch edge settled in small patches and used nests close to edges after dispersal. In addition, post-dispersal use of dreys (versus cavities) was similar to that observed in natal sites. However, the quality of settlement habitat was unrelated to the quality of the natal site, which suggests that natal experience on average-quality habitats may not lead to ecological traps for flying squirrels. This study provides evidence that habitat selection at the landscape scale is influenced by habitat of natal area.

Microhabitat associations of northern flying squirrels in burned and thinned forest stands of the Sierra Nevada

Abstract: Prescribed burning and mechanical thinning are used to manage fuels within many western North American forest ecosystems, but few studies have examined the relative impacts of these treatments on forest wildlife. We sampled northern flying squirrels (Glaucomys sabrinus) and microhabitat variables in burned, thinned and control stands of mixed-conifer forest of the southern Sierra Nevada at the Teakettle Experimental Forest. We used this information to determine the effects of burning and thinning on the microhabitat associations of flying squirrels. Across pretreatment stands, the probability of flying squirrel capture increased with decreasing distance to a perennial creek and increasing litter depth. The probability of flying squirrel capture also was greater with increased canopy cover in thinned stands and increased litter depth in burned stands. Greater canopy cover may provide protection from predators, thicker litter layers may harbor a greater abundance of truffles, a primary food of northern flying squirrels, and creeks may provide squirrels with food sources, drinking water and nest trees. Results from this study underscore the need for more information on the effects of forest management on northern flying squirrels near the southern extent of the species' geographic range.

A brief history of the new world flying squirrels: phylogeny, biogeography, and conservation genetics

Abstract: I summarize our current understanding of the evolutionary origin and biogeographic history of the New World flying squirrels (Glaucomys). The emerging synthesis of flying squirrel systematics supports a monophyletic origin for the group in the early Miocene followed by a divergence of New World and Eurasian flying squirrels in the late Miocene. Today, the New World flying squirrels consist of 2 recognized species, G. sabrinus and G. volans. These 2 species are closely associated with the northern coniferous and deciduous hardwood forest biomes of North America, respectively, making them especially useful as biogeographic indicator species for these 2 forest types. Molecular systematic studies have revealed the presence of 2 distinct evolutionary lineages within G. sabrinus (a widespread Continental lineage and a more geographically restricted Pacific Coastal lineage). Bacular morphology and data from nuclear loci suggest recent or ongoing gene flow between these 2 lineages where they meet in the Pacific Northwest of North America. Populations of G. volans from eastern North America represent a 3rd distinct lineage within the genus. Mesoamerican flying squirrels (traditionally considered to be southern forms of G. volans) have not been examined with molecular data and may represent 1 or more additional lineages. From a biogeographic perspective, Quaternary climatic fluctuations and associated changes in the location and extent of forest habitats appear to have been important factors in promoting early evolutionary diversification within the genus; structuring of intraspecific patterns of genetic variation; and producing geographically isolated peripheral populations in high-elevation habitats at the southern extremes of each species’ range, several of which are now of conservation concern. These results have broad implications for understanding the Quaternary biogeography of the coniferous and deciduous forest biomes of North America.

Morphology, locomotor behaviour and microhabitat use in North American squirrels

Abstract: The rodent family Sciuridae (squirrels) presents an ideal system for examining the morphological, behavioural and ecological correlates of locomotor novelty. Ancestrally, sciurids were arboreal, a condition retained by modern tree squirrels. Two major transitions from the arboreal condition are hypothesized to have occurred in the sciurid clade: (1) flying squirrels evolved gliding from arboreal leaping (parachuting) and (2) chipmunks and ground squirrels became semiarboreal/terrestrial. This study examines morphology, locomotor behaviour and microhabitat use under controlled laboratory conditions in three North American sciurids: eastern chipmunk Tamias striatus, red squirrel Tamiasciurus hudsonicus and southern flying squirrel Glaucomys volans. Multivariate space was defined using a series of morphological measurements and by continuously sampling individuals moving under identical conditions in a naturalistic enclosure, controlling for the proximate effects of microhabitat structure. Morphospace was characterized by a contrast between proximal and distal limb elements – flying squirrels exhibited elongated forelimbs and shanks and shortened forefeet and hindfeet, while chipmunks exhibited the opposite pattern. Ethospace was characterized by a contrast between aerial locomotion in flying squirrels and ground-based locomotion in chipmunks. In both instances, red squirrels occupied intermediate positions, as predicted on the basis of retention of ancestral features. Despite significant differences among species at morphological and behavioural levels, ecospace was characterized by overlap between flying squirrels and red squirrels in the use of high supports, and between flying squirrels and chipmunks in the use of large-diameter supports. The lack of concordance at the ecological level underscores the difficulty in making predictions based solely upon organismal design.

How to make a flying squirrel: Glaucomys Anatomy in Phylogenetic Perspective

Abstract: Molecular evidence strongly supports the derivation of flying squirrels from tree squirrels, with the sister group being the Holarctic tree squirrels (Sciurus) and their close relatives. We present a rationale for the hypothesis that the transition occurred among small squirrels, and we propose using the northern flying squirrel (Glaucomys sabrinus) and the southern flying squirrel (Glaucomys volans) as models. Thus, we compare their morphologies with similar-sized tree squirrels (the Central American dwarf squirrel [Microsciurus alfari] and the western dwarf squirrel [M. mimulus]). We compare body proportions of Glaucomys with those of Microsciurus, considering differences as potential adaptations for gliding associated with wing loading, aspect ratio, and parasitic drag. We use the following measurements: lengths of the centra of the thoracic, lumbar, sacral, and caudal vertebrae; and lengths of the long bones (humerus, radius, femur, and tibia), metacarpals, metatarsals, and proximal phalanges of the hands and feet. We then compare these proportions of Microsciurus with those of other species of Sciurini, and the proportions of Glaucomys with other species of Pteromyini, to determine if each is representative or derived within its clade. Members of the genus Glaucomys exhibit relative elongation of the lumbar vertebrae and the forearm, relevant to wing loading and aspect ratio, relative lengthening of the midcaudal vertebrae, and relative shortening of the more distal caudal vertebrae, perhaps of importance for stability and control. Members of the genus Glaucomys also have shorter hands and feet, but these appeared to be elongated in Microsciurus, rather than shortened in Glaucomys, leaving the issue of parasitic drag moot. Finally, we speculate on the genetic changes that have produced these morphological modifications and may facilitate the evolution of gliding flight.

Local habitat patch pattern of the Siberian flying squirrel in a managed boreal forest landscape

Abstract: We examined how the structure of a boreal forest landscape is related to the occurrence of the Siberian flying squirrel Pteromys volans in northern Finland. The flying squirrel inhabits mature spruce-dominated (Picea abies ) mixed forests and is categorised as vulnerable species due to habitat loss and change. We classified a landscape of 374.5 km 2 into potential habitat patches, potential dispersal areas, and areas incapable of being inhabited using national forest inventory data, and surveyed all 136 potential habitat patches for the presence of the species. Different landscape variables were defined, and also connections by the shortest distances to neighbouring habitat patches along both straight lines and least-cost distances based on specific movement costs were measured. Occupied patches were larger in size, contained more deciduous trees for food and nesting cavities, and were in closer proximity to the nearest occupied patches. Occupied patches were mainly located below 300 m a.s.l. The occurrence of flying squirrels was correctly predicted for 88% of the habitat patches using landscape variables. This modelling result proved to be rather general. In addition, the configuration of occupied patches was mainly clustered across the landscape, and distant occupied patches seemed to be linked to other patches via forested connections. We suggest that maintaining a clustered arrangement of good quality habitat patches and regenerating new potential habitat as well as dispersal areas between the habitat patches seem to be appropriate goals for long-term forest management planning to sustain populations of the flying squirrel in the landscape.

Gliding ability of the Siberian flying squirrel Pteromys volans orii

Abstract: Forest fragmentation is a threat to flying squirrel population due to dependence on gliding locomotion in forests. Therefore, it is essential to understand their gliding ability. The gliding locomotion of Pteromys volans orii, were observed from July 2003 to June 2005, in Obihiro, Hokkaido, Japan. The horizontal distance and glide ratio obtained from 31 glides were employed as indicators to know their gliding ability. The gliding ability was not affected by weight and sex in the Siberian flying squirrel. Mean horizontal distance and glide ratio were 18.90 m and 1.70 with great variation. Although maximum values were 49.40 m (horizontal distance) and 3.31 (glide ratio), most of the horizontal distance and glide ratio were in the ‘10–20 m’ and ‘1.0–1.5’, respectively. Therefore, to retain the flying squirrel populations, forest gaps should not exceed the distance traversable with a glide ratio of 1.0 (distance between forests/tree height at the forest edg).

Survey for zoonotic rickettsial pathogens in northern flying squirrels, glaucomys sabrinus, in california

Abstract: Epidemic typhus, caused by Rickettsia prowazekii, is maintained in a southern flying squirrel (Glaucomys volans) sylvatic cycle in the southeastern United States. The northern flying squirrel (Glaucomys sabrinus) has not been previously associated with R. prowazekii transmission. A second rickettsial pathogen, Anaplasma phagocytophilum, infects dusky-footed woodrats (Neotoma fuscipes) and tree squirrels in northern California. Because northern flying squirrels or their ectoparasites have not been tested for these rickettsial pathogens, serology and polymerase chain reaction (PCR) were used to test 24 northern flying squirrels for R. prowazekii and A. phagocytophilum infection or antibodies. Although there was no evidence of exposure to R. prowazekii, we provide molecular evidence of A. phagocytophilum infection in one flying squirrel; two flying squirrels also were seropositive for this pathogen. Fleas and ticks removed from the squirrels included Ceratophyllus ciliatus mononis, Opisodasys vesperalis, Ixodes hearlei, Ixodes pacificus, and Dermacentor paramapertus.

Fungi in Summer Diets of Northern Flying Squirrels (Glaucomys sabrinus) within Managed Forests of Western Alberta, Canada

Abstract: Many forms of hypogeous fungi rely on small mammals to consume and disperse their spores. It is well documented in the Pacific Northwest that northern flying squirrels (Glaucomys sabrinus) rely on hypogeous fungi as a food resource. However, in more northern forests the taxonomic constituents of flying squirrel diets are relatively poorly documented. Using live-capture to obtain fecal samples, I examined dietary fungal diversity from the feces of 44 northern flying squirrels inhabiting variable-aged managed forest stands during late summer in the foothills of west-central Alberta, Canada. Fungal material was found in all specimens, and was identified to order, family, or genera via microscopic spore morphological classification. Twenty-six spore morphologies were found; 1 was identified to order, 4 to family, 13 to genus, and 8 remained unidentified. The most frequently consumed fungi were of the hypogeous form of the genera Cortinarius, Gastroboletus, and Hysterangium. Insect material also figured promin...

Contrasting seasonal dynamics in fleas of the Siberian flying squirrel (Pteromys volans) in Finland

Abstract: 1. The seasonal and spatial variation of the adult flea fauna (Siphonaptera) was examined in connection with live-trapping studies of the Siberian flying squirrel (Pteromys volans) in three study areas in southern Finland between 1997 and 2005. 2. The numerically dominant flea species of the Siberian flying squirrel were Tarsopsylla octodecimdentata octodecimdentata and Ceratophyllus (Monopsyllus) indages indages (Ceratophyllidae); the latter being a host specialist of the Siberian flying squirrel. Tarsopsylla octodecimdentata, which also commonly occurs on the red squirrel (Sciurus vulgaris), infected a large proportion of the host population throughout the winter, whereas C. indages occurred predominantly during the summer and autumn, being practically the only flea species in nests during the flying squirrels’ breeding season and on juveniles still inhabiting their natal nest. 3. The use of nest boxes by flying squirrels did not have any positive effects on flea populations, but it may have had a negative impact on T. octodecimdentata. 4. The potentially vulnerable C. i. indages is a predictable, widespread component in the flea fauna of the Siberian flying squirrel at various spatial scales, and it is likely to occur in most of the permanent flying squirrel populations in Finland.

A GENETIC TEST OF RANGE EXPANSION BY THE SOUTHERN FLYING SQUIRREL (Glaucomys volans) AT ITS NORTHERN RANGE BOUNDARY

Abstract: A genetic test of range expansion by the southern flying squirrel (Glaucomys volans) at its northern range boundary