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A history of timber harvest in West Virginia has reduced red spruce (Picea rubens) forests to < 10% of their historic range and resulted in considerable habitat fragmentation for wildlife species associated with these forests. The Virginia northern flying squirrel (Glaucomys sabrinus fuscus) has been described as a red spruce obligate subspecies that must traverse this fragmented landscape to disperse among remnant red spruce patches. Food availability in the forest matrix surrounding red spruce may be a limiting factor to successful dispersal of G. s. fuscus. We examined the diet of flying squirrels using stable isotope analysis and used vegetation surveys to determine the availability of diet items in the habitats encountered by G. s. fuscus in the matrix surrounding red spruce fragments. Stable isotope analysis suggested hypogeous fungi, epigeous fungi, and invertebrates contributed the most to the diet of G. s. fuscus, followed by lichen. Tree buds contributed the least in spring, and beechnuts contributed the least in fall. The vegetation surveys revealed that no habitat type had a greater availability of the diet items that contributed most to the assimilated diet of G. s. fuscus, suggesting that stand age and structure may be more important for diet-item availability than habitat type.

Whereas roads that bisect habitat are known to decrease population size through animal-vehicle collisions or interruption of key life history events, it is not always obvious how to reduce such impacts, especially for flying organisms. We needed a quick, cost-efficient and effective way to determine how best to decrease vehicle-caused mortality while maintaining habitat connectivity for the federally listed Oregon silverspot butterfly, Speyeria zerene hippolyta. Therefore, we gathered targeted ecological information that informed selection of a mitigation option prior to implementation. We sampled butterfly behavior and environmental conditions along a highway and conducted a small-scale experiment along a decommissioned road corridor used by these butterflies. Using our findings, we recommended vegetation management and helped managers eliminate options they were considering that would be ineffective such as increasing shade or wind in the road, and installing fencing or hedgerows aimed at directing flight above traffic. This quick and inexpensive approach of using ecological observations and small-scale experiments to evaluate the likely success of each available mitigation option can be used to determine effective, species-specific solutions for reducing traffic impacts on pollinators and other small, flying organisms of conservation concern.

The survival of many species may be dependent on their ability to exist in human-altered landscapes within metapopulations; in turn, metapopulation persistence is dictated by the ability of individuals to move effectively among patches to promote recolonization. The Taylor’s checkerspot butterfly (Euphydryas editha taylori) is a species that does not naturally occur in fragmented landscapes, yet it is now restricted to a handful of small isolated prairie habitats. Current recovery plans aim to establish a stable metapopulation; however, to date little is known about the species’ ability to move across the landscape. In 2010 and 2011, we conducted marking, tracking and boundary surveys to explore the movement dynamics of adults within two sites in Oregon, USA. Over the survey period, we marked 136 male butterflies, tracked 174 individuals and observed the behavior of 1,576 individual butterflies at site boundaries. Our study revealed a significant sex-bias in the movement dynamics of the Taylor’s checkerspot in both suitable habitat and surrounding matrix. Males were highly motile, whereas females appeared sedentary, rarely moving from their natal site. The limited dispersal behavior of females indicates that populations cannot persist naturally in a metapopulation and thus are at high risk of extinction. Based on our findings, we recommend that managers take proactive measures to increase or enable dispersal (including translocation) to existing and/or restored sites.

Advances in the application of stable isotopes have allowed the quantitative evaluation of previously cryptic ecological processes. In particular, researchers have utilized the predictable spatial patterning in natural abundance of isotopes to better understand animal dispersal and migration. However, quantifying dispersal via natural abundance alone has proven to be of limited utility for species exhibiting short- or mid-distance dispersal events, including most mammalian species. In previous experimental work, we demonstrated that consumption of 1 dose of isotopically enriched baits elicited a distinct ‘‘mark’’ in hair of captive martens (Martes spp.). Herein, we report findings from a field test of our isotopic enrichment approach to mark freeranging animals and quantify dispersal of martens across forest stands at sites in southeastern Alaska and northern British Columbia. In the field, we supplemented bait used in single-capture hair traps with the amino acid glycine artificially enriched in 2 H, 13 C, or 15 N. By applying unique combinations of artificially enriched isotopic markers within discrete forest stands, the isotopic signature of collected hair reflected the forest patch where the individual originated. From our isotopic marks, we were able to infer dispersal events between forested stands and, thus, estimate rates and approximate dispersal distances. Our findings demonstrate that isotopic enrichment can be a cost-effective method to mark the hair of midsized mammals for the quantification of dispersal.

We studied den use and den-habitat selection by the Prince of Wales Island flying squirrel (Glaucomys sabrinus griseifrons) at multiple spatial scales in fragmented temperate rain-forest habitats because of the role dens play in the distribution, reproduction, and population density of this endemic subspecies. We observed differences in spatial patterns associated with den use between juveniles and adults: juvenile core denning areas were almost an order of magnitude larger than those of adults, and juveniles used about one-half the number of dens per month as adults. Female juveniles exhibited both the largest mean and maximum movements between consecutive dens among all age and sex classes. At the microhabitat scale of den selection snags were not selected over live trees, but flying squirrels primarily used cavities in snags and live trees. Flying squirrels also selected dens in the largest diameter live trees and snags, in snags with intermediate levels of decay, in live trees with more conks and visible bole entries, and in western hemlock (Tsuga heterophylla). At the broader scale of den selection flying squirrels chose den locations in neighborhoods with higher-volume forests and lower levels of fragmentation, although not lower absolute amounts of edge, than was available across the landscape. Our results suggest that extensive modification of landscapes from clear-cut logging and the creation of an early-seral matrix appeared to influence spatial patterns of den use in flying squirrels and den selection at the broader scale. When compared to patterns in a more-intact landscape, den selection at the microhabitat scale did not relate to differences in landscape context, suggesting additional factors might play an important role in den use across the region.

Where dispersal is energetically expensive, feeding and food availability can influence dispersal success. The endemic Prince of Wales northern flying squirrel (Glaucomys sabrinus griseifrons) inhabits a landscape mosaic of old-growth, 2nd-growth, and clear-cut stands, with the latter 2 representing energetically expensive habitats. We estimated the diet of flying squirrels using stable isotope and fecal analyses, determined whether food availability varies among forest stands, and assessed the likelihood of foraging across a managed landscape given the distribution of foods on Prince of Wales Island (POW), Alaska. Both stable isotope and fecal analyses revealed that conifer seeds, lichens, and fungi were the main dietary items consumed and assimilated by flying squirrels. Similarly, soil macroinvertebrates were consumed by squirrels, whereas berries were not. Nonetheless, although examination of stable isotope data suggested that squirrels assimilated few nutrients from truffles, this food source was among the most frequent diet items in feces, probably because flying squirrels assimilate elements other than nitrogen from fungi. Our surveys showed that conifer seeds, truffles, and lichens were more prevalent in old-growth than 2nd-growth and clear-cut habitats. Thus, our results indicate that diet and availability of food items on POW may influence foraging success and dispersal movements of G. sabrinus across fragmented landscapes because of limited availability of food resources in the managed habitats. DOI: 10.1644/09-MAMM-A-014R.1.

Although dispersal is an important attribute of animal population ecology, knowledge of dispersal rates or distances for many wide-ranging species is lacking. Current methods require capturing and restraining animals, which can be costprohibitive, fail to collect sufficient samples or change animal ranging behaviors. Herein, we describe a novel, cost-effective and non-invasive method, using bait enriched with stable isotopes to mark the hair of American martens Martes americana. Captive martens that consumed isotopically labeled glycine exhibited significant and progressive enrichment in the isotopic signature of 13 C, 15 N and 2 H in both whole blood and hair. A distinct mark in hair, 42 standard deviations above natural abundance, occurred within 14 days of the second dose. The rate of isotopic labeling of hair was higher in spring, possibly because labeled amino acids became diluted among the many hairs growing during the autumn. Because hair and feathers can be collected non-invasively from large geographic areas without capturing animals, this labeling method can be used to mark and study the movement and dispersal rates of animals across landscapes efficiently.

Keen's myotis (Myotis keenii) has one of the most limited geographic distributions of any species of bat in North America. Because there is little knowledge of its roosting ecology, we examined selection of day-roosts in trees by male and female Keen's myotis at 3 spatial scales (tree, tree plot, and landscape) on Prince of Wales Island, southeastern Alaska, from May to September 2006. We selected variables known to influence roost selection by other tree-roosting bats for logistic regression models. We used Akaike's information criterion to rank all models within and between scales according to their ability to differentiate between characteristics of used and available roosts and we determined the effect of each variable with model-averaged coefficient estimates and associated odds ratios. We tracked 13 females and 6 males to 62 and 24 roosts in trees, respectively. Selection of day-roosts by males and females was most strongly influenced by characteristics of trees. The odds a tree was used for roosting by female Keen's myotis increased with the presence of defects, increasing diameter, and decreasing bark; increasing quadratic mean diameter in the tree plot; and decreasing distance to the nearest stream and increasing proportion of old growth in the landscape. Male Keen's myotis exhibited flexibility in types of roosts chosen, but the odds of a tree being used increased with decreasing bark, the presence of defects, and increasing slope-height. The odds a tree was used as a roost by males also increased with the increasing proportion of trees in early to late decay stages in the tree plot. Some habitat features differed between males and females at each spatial scale and differences are likely a reflection of the energetic demands associated with reproduction. We suggest that maintaining structural components characteristic of old-growth rain forest will promote conservation of Keen's myotis in southeastern Alaska.

Successful dispersal in many species may be a function of the distance at which animals can perceive a particular landscape feature (i.e., perceptual range), as well as energetic costs associated with traversing the distance towards that feature. We used a model, relating perceptual range to body size of mammals, to predict the perceptual range of the northern flying squirrel ( Glaucomys sabrinus (Shaw, 1801)) in fragmented forests of Southeast Alaska. We hypothesized that the perceptual range of flying squirrels would be 325.5–356.5 m in clearcuts and 159.7–174.9 m in second-growth stands. The distance advantage in clearcuts may, however, be lost if the cost of transport in that habitat is higher. Our results suggest that as heuristically predicted by the model, the perceptual range of flying squirrels was greater in clearcut habitats than in second-growth stands. Nonetheless, for both habitats the actual perceptual range was significantly shorter than predicted by the model. We found that precipitation, and associated cloud cover and illumination, and wind speed, which affect olfaction capabilities, influenced orientation success. Although squirrels more often oriented towards the forest edge in clearcuts, they paused more often during their movements, which may lead to higher costs of dispersing through this habitat. The application of the mass-based model to nonagricultural landscapes should be done with caution, and variables such as wind and illumination be measured concurrently. Our data illustrate that dispersing squirrels likely will not venture into managed habitats because logging creates clearcuts larger than the perceptual range of these mammals.

A common arboreal rodent of boreal and montane coniferous forests, the northern flying squirrel (Glaucomys sabrinus) has several life-history traits typical of K-selected species. Density varies among forest types, with core areas of use centering on food patches. Density is largely limited by food, and to a lesser extent, suitable natal dens, but also is influenced by potential competitors and predators. Local abundance of G. sabrinus frequently is correlated with density of large trees and snags, shrub and canopy cover, prevalence of old-forest features (e.g., coarse woody debris), and abundance of hypogeous mycorrhizal fungi (truffles). Diet varies seasonally and among habitats, but truffles (spring and autumn) and lichens (winter) are most often reported. In some parts of its geographic range, G. sabrinus has a more diverse diet and lower reliance on truffles in forests with a depauperate arboreal small mammal community. G. sabrinus is a keystone species in the Pacific Northwest, because its diet facilitates an obligate mutualistic relationship between mycorrhizal fungi and some trees and shrubs and because it is essential prey for mesocarnivores and avian predators. G. sabrinus achieves its highest densities in old growth, but also occurs in secondary forests. Disturbance that reduces structural complexity, canopy cover, or the availability of large, decadent trees typically results in smaller populations through effects on food, den sites, or risk of predation. The fundamental niche of G. sabrinus may be broader than suggested by early research in the Pacific Northwest. Sustaining viable and well-distributed populations in heavily modified landscapes will depend on the capability of remaining forest habitat to sustain breeding populations without immigration, or functional connectivity among fragmented populations such that viable metapopulations will persist. Future research should focus on identifying habitat conditions that sustain breeding populations in modified habitats and determining whether G. sabrinus can migrate freely through a matrix of unsuitable habitat.

We assess locomotor performance by northern flying squirrelsGlaucomys sabrinus Shaw, 1801 and test the hypothesis that gliding locomotion is energetically cheaper than quadrupedal locomotion. We measured 168 glides by 82 northern flying squirrels in Alaska. Mean glide distances varied from 12.46 m to 14.39 m, with a maximum observed glide distance of 65 m. Mean glide angles varied from 41.31° to 36.31°, and mean air speed ranged from 6.26 m/s to 8.11 m/s. There were no differences in the performance of male and female flying squirrels. We used models of transport cost to provide an initial assessment of the hypothesis that gliding locomotion is energetically less expensive than quadrupedal locomotion. For glides of average length, cost of gliding was less than cost of quadrupedal locomotion except when the animals climbed to the launch point very slowly or ran quickly. Thus the hypothesis that gliding is less expensive than quadrupedal locomotion is supported.

We studied habitat relations of the Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons), an endemic of the temperate, coniferous rainforest of southeastern Alaska, because of concerns over population viability from extensive clear-cut logging in the region. We used stepwise logistic regression to examine relationships between microhabitat use (i.e., captures among traps spaced at 40-m intervals) and 26 vegetative and structural habitat features measured in plots centered on trap stations. Seasonal (spring, autumn) models were created for two oldgrowth forest types: upland, western hemlock (Tsuga heterophylla)‐Sitka spruce (Picea sitchensis) forests (upland-OG); and peatland-scrub‐mixed-conifer forests (peatland-MC). Density of trees with diameter at breast height (dbh) .74 cm and abundance of Vaccinium were positively correlated with microhabitat use in peatlandMC during both seasons. During spring and autumn, the odds of capturing a flying squirrel increased by factors of 2.7 and 16.9, respectively, with an increase in mean density of 10 large trees/ha. Microhabitat use of uplandOG during autumn was positively correlated with density of snags with a dbh of 50‐74 cm and negatively correlated with percentage cover of understory herbaceous vegetation; microhabitat use during spring was inversely correlated with percentage surface cover of water. At the macrohabitat (13-ha replicate of forest type) scale, large (.74-cm dbh) trees explained 65% of the variation in density between forest types; percent cover of moss and volume of down wood in decay classes I‐IV explained 70% and 63‐77% of the variation, respectively. Our findings corroborate general patterns reported for western coniferous forests, but suggest that G. sabrinus in temperate rainforests of southeastern Alaska differ ecologically from populations in the Pacific Northwest in important ways.

We studied demography of the Keen’s mouse (Peromyscus keenimacrorhinus) and the Wrangell Island red-backed vole (Clethrionomys gapperi wrangeli) in the Alexander Archipelago during 1998–2000 because of concerns over population viability from extensive clear-cut logging of temperate rain forest in the region. We trapped 1-ha grids and assessment lines with live traps during spring and autumn to compare populations among gap-phase oldgrowth, multicohort old-growth, peatland mixed-conifer, and thinned young-growth (23-year-old) forests. Generally, gap-phase old growth and peatland mixed conifer supported the highest and lowest populations of voles, respectively. One notable exception was during autumn 1998, when vole population levels were highest and density was higher (P , 0.02) in young growth than gap-phase old growth. Mean body mass, minimum summer and overwinter survival, age and sex composition, and percentage reproductive females did not differ among habitats. For Keen’s mouse, density was highest in 1998; overall, populations were highest in young growth and lowest in peatland mixed conifer. Mean body mass and minimum summer and overwinter survival did not differ among habitats, but fewer reproductive females were recorded in multicohort than in gap-phase old growth, peatland mixed conifer, or young growth. Our results suggest that C. gapperi populations in southeastern Alaska are not as sensitive to canopy removal as has been indicated elsewhere in western coniferous forests and that P. keeni populations in southeastern Alaska flourish in a variety of habitats. If the results of our study can be generalized across southeastern Alaska, peatland mixed conifer likely contributes little to breeding populations of C. gapperi and thus is unlikely to mitigate any effects of broad-scale clear-cut logging of old-growth forests.

We studied the Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons) in temperate rain forest of southeastern Alaska to provide the 1st quantitative estimates of demography from southeastern Alaska and test predictions of the hypothesis that Sitka spruce (Picea sitchensis)–western hemlock (Tsuga heterophylla) forest is primary habitat for G. sabrinus in southeastern Alaska. We expected that abundance, body condition, productivity, and summer and overwinter survival of G. sabrinus would be higher in spruce–hemlock forest (which typically are the old-growth forests of upland sites [upland-OG]) than in peatland-scrub–mixed-conifer (peatland-MC) forest. Mean values of minimum number of animals known alive and density during autumn were higher in upland-OG than in peatland-MC, and both were about 2 times higher than corresponding spring values. Age and sex composition of the population was similar among years, between seasons, and between habitats. Males comprised a larger portion of the po...

We radiotagged seven female and two male Marbled Murrelets (Brachyramphus marmoratus) of undetermined breeding status and followed their movements through the inner passages of northern southeast Alaska during the breeding season (May–July) in 1998. Six of the nine murrelets were detected inland in the early morning hours from 24 June to 17 July. Inland visits for each individual were consistent to a particular location, but short in duration, which precluded locating nest sites. We recorded 46 locations at sea up to 124 km (x̄ = 78 ± 27 km) from inland sites during the period 19 June to 16 July. We detected murrelets at inland sites and at sea on the same day on 20 occasions with a mean distance between these locations of 75 ± 42 km. The majority of murrelets were located at sea in western Icy Strait, a productive feeding area at the mouth of Glacier Bay, Alaska. This study provides the first direct evidence that Marbled Murrelets in southeast Alaska are consistently traveling considerable distances between potential nesting and foraging areas. These findings have important implications for murrelet conservation and management efforts in southeast Alaska.

Papers in this Special Feature were presented at a symposium on the biology of Glaucomys sabrinus convened at the 86th Annual Meeting of the American Society of Mammalogists in June 2006. Because G. sabrinus is an arboreal species that relies on several attributes of older forests, it is an ideal model organism for studying impacts of broad-scale habitat loss and alteration from logging, clearing, and natural disturbances. The objective of the symposium was to integrate knowledge of mammalogists from multiple disciplines to achieve a more complete biological portrait to gain insights about how forest communities are being impacted by dramatic changes in forest composition and distribution following European settlement of North America, and to identify gaps in knowledge and information needs that can guide future research. The symposium included 5 papers that encompass a diversity of biological information, including the evolutionary origin and systematics of Glaucomys, the anatomy and evolution of G. sabrinus, its biogeography, genetic variation within and among regional populations, its ecology, functional morphology, kinetics, and issues and challenges of conservation.

Three different types of forests (mature, mixed upland, and cut-over) in central Arkansas were surveyed in June and October 1991 and February and May 1992 for latrines of swamp rabbits ( Sylvilagus aquaticus ). Swamp rabbits deposited >91% of their fecal pellets on logs. A greater density of pellets were found in February 1992 compared to other months. Length, height, diameter, decay class, and percent cover of moss on logs used as latrines by swamp rabbits were recorded. Logistic regression was used to predict the likelihood that a log would be used as a latrine. Increasing decay class, percentage cover of moss, and diameter of logs were correlated with latrines of swamp rabbits. Height of logs did not distinguish between used and unused logs, but length and season were significant predictors of use of logs as latrines in forests of mature bottomland hardwood and cut-over bottomland. Spatial clumping of latrines and peak use during breeding were consistent with the hypothesis that latrines on logs serve as territorial markers. An alternative hypothesis that swamp rabbits elevated themselves on logs to increase their field of view and coincidentally deposited pellets on logs was tested experimentally with three obstruction treatments; visual + physical, only physical, and a control. Treatments were placed on 1-m sections of 54 logs that had been used as latrines in at least 2 of the 4 monthly surveys. Surveys conducted for 4 months after the installation of obstructions showed a significant interaction between use of a log as a latrine, treatment type, and month of survey.

We tested the premise that rates of visitation by raccoons ( Procyon lotor ) to scent stations vary directly with population density by manipulating the density of an island population of this carnivore in middle Tennessee. Despite its widespread use, the scent-station index to population size has not been validated. General protocol for scent stations followed previous investigators; radiotelemetry was used to monitor individual behavior of raccoons. We determined minimum population size from the records of known captures and compared them with visits to scent stations recorded twice monthly during an initial period with no manipulation (May 1987–August 1988); similar procedures were used during an experimental period (September 1988–August 1989) when raccoons were removed and held on the mainland for ca. 1 month during each season and then returned to the island. Abundance of raccoons on the island ranged from 32 to 42 when estimated twice each month; computed indices of relative abundance varied from zero to 286. Rates of visitation by raccoons were highest in spring and summer during both the baseline and experimental period. Visits to scent stations were independent of density throughout the study. During the experimental period, both the largest and smallest observed indices of relative abundance occurred when an estimated 25% of the population had been removed and when all known animals ( n = 40) occurred on the island. Local fluctuations of populations may precipitate changes in behavior of raccoons that preclude the use of scent stations to index abundance, particularly in heterogeneous habitats.

Gliding allows mammals to exploit canopy habitats of old-growth forests possibly as a means to save energy. To assess costs of quadrupedal locomotion for a gliding arboreal mammal, we used open-flow respirometry and a variable-speed treadmill to measure oxygen consumption and to calculate cost of transport, excess exercise oxygen consumption, and excess post-exercise oxygen consumption for nine northern flying squirrels (Glaucomys sabrinus) and four fox squirrels (Sciurus niger). Our results indicate that oxygen consumption during exercise by flying squirrels was 1.26-1.65 times higher than predicted based on body mass, and exponentially increased with velocity (from 0.84 ± 0.03 ml O(2) kg(-1) s(-1) at 0.40 m s(-1) to 1.55 ± 0.03 ml O(2) kg(-1) s(-1) at 0.67 m s(-1)). Also, cost of transport in flying squirrels increased with velocity, although excess exercise oxygen consumption and excess post-exercise oxygen consumption did not. In contrast, oxygen consumption during exercise for fox squirrels was similar to predicted, varying from 0.51 (±0.02) ml O(2) kg(-1) s(-1) at 0.63 m s(-1) to 0.54 (±0.03) ml O(2) kg(-1) s(-1) at 1.25 m s(-1). In addition, the cost of transport for fox squirrels decreased with velocity, while excess exercise oxygen consumption and excess post-exercise oxygen consumption did not. Collectively, these observations suggest that unlike fox squirrels, flying squirrels are poorly adapted to prolonged bouts of quadrupedal locomotion. The evolution of skeletal adaptations to climbing, leaping, and landing and the development of a gliding membrane likely has increased the cost of quadrupedal locomotion by >50% while resulting in energy savings during gliding and reduction in travel time between foraging patches.