Winston P. Smith

Ecology of Glaucomys sabrinus: Habitat, Demography, and Community Relations

Abstract 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.

Forest Management and Female Black Bear Denning

Abstract: Most habitats available to black bear (Ur,~usamericanus) in the Mississippi Alluvial Valley (M.4V) consist of seasonally flooded commercial forests where lack of suitable dens may limit population growth. \Ve studied interactions between forest management and flooding relative to female black bear denning. Denning behavior differed between commercial and noncommercial forests. Females used tree dens exch~sivelyon nonco~nmercialforests, whereas on commercial forests, most (83%) were ground dens. L7ariationsin ground den elevation resulted in differing inundation probabilities, altering survival prol.)abilities for neonates. On commercial forests, ground dens with similar inundation probabilities as tree dens allowed successful repro-duction to occur. Management practices that enhance suitable cover in areas of nlirlimal inundation probability may mitigate for lack of den trees in flood-prone landscapes. JOURNAL OF WILDLIFE MANAGEMENT 65(1):34-40 Key words: batture, black bear, denning, elevation, flooding, forest management, Misissippi Allu~ialValley, reproduction, topography, Ursus arnericanus.

Estimating Abundance of Sitka Black-Tailed Deer Using DNA From Fecal Pellets

ABSTRACT Densely vegetated environments have hindered collection of basic population parameters on forest-dwelling ungulates. Our objective was to develop a mark—recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black-tailed deer (Odocoileus hemionus sitkensis) in the temperate coastal rainforest of Southeast Alaska. During 2006–2008, we sampled fecal pellets of deer along trail transects in 3 intensively logged watersheds on Prince of Wales Island, Alaska. We extracted DNA from the surface of fecal pellets and used microsatellite markers to identify individual deer. With genotypes of individual deer, we estimated abundance of deer with moderate precision (±20%) using mark—recapture models. Combining all study sites, we identified a 30% (SE = 5.1%) decline in abundance during our 3-year study, which we attributed to 3 consecutive severe winters. We determined that deer densities in managed land logged >30 years ago (7 deer/km2, SE = 1.3) supported fewer deer compared to both managed land logged <30 years ago (10 deer/km2, SE = 1.5) and unmanaged land (12 deer/km2, SE = 1.4). Our study provides the first estimates of abundance (based on individually identified deer) for Sitka black-tailed deer and the first estimates of abundance of an unenclosed ungulate population using DNA from fecal pellets. Our tool enables managers to accurately and precisely estimate the abundance of deer in densely vegetated habitats using a non-invasive approach.

Characteristics and Adaptive Significance of Latrines of Swamp Rabbits (Sylvilagus aquaticus)

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.

DEMOGRAPHY OF THE PRINCE OF WALES FLYING SQUIRREL, AN ENDEMIC OF SOUTHEASTERN ALASKA TEMPERATE RAIN FOREST

Abstract 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 population in upland-OG than in peatland-MC forest. Mean body mass was similar between habitats. Minimum summer survival varied among years and between habitats. Overwinter survival was less varied and similar among years and between habitats. Reproductive females were more abundant in upland-OG than in peatland-MC, but percentage of reproductive females during spring and percentage of juveniles during autumn were similar between habitats. These results support the conclusion that upland-OG forests of southeastern Alaska are primary habitat for northern flying squirrels. Still, squirrel densities in peatland-MC were higher than those reported for several managed and unmanaged forest types in the Pacific Northwest, and some demographic parameters were similar between upland-OG and peatland-MC. In southeastern Alaska, peatland-MC habitat likely contributes to breeding populations of G. sabrinus and reduces risk of viability in managed landscapes.

Influence of Mississippi alluvial valley rivers on black bear movements and dispersal: implications for Louisiana black bear recovery

American black bear (Ursus americanus) populations were significantly reduced throughout their range, particularly in southeastern North America. Currently, populations in this region are very fragmented, resulting in concern over possible barrier effects of rivers to normal bear movements and dispersal. This is particularly true for Mississippi, where black bear dispersal into the state is critical if populations are to be recovered. Thus, we studied the relative effects of rivercourses on bear movements and dispersal patterns in southeastern Arkansas, 1992–1996. We captured, radiocollared, and uniquely tagged 40 bears and used radiotelemetry to determine their movements. The Mississippi River (width ≈1600 m) deflected bear movements, whereas the White River (width ≈200 m) was not a barrier to bear movements or dispersal patterns. Frequency of river crossing differed by gender (P=0.007) and season (P<0.001). Male bears crossed rivers more frequently than females. Rivers were crossed less from December to March compared to other seasons. Rivers acted as a semipermeable barrier to bear movements and dispersal patterns, which may have major implications for conservation of large mammal metapopulations. Males appear to be influenced less by rivers, so female translocations across rivers may be necessary to recover fragmented bear populations. We provide an example describing direct implications of this study to the recovery of the threatened Louisiana black bear (U. a. luteolus).

A meta‐analysis of forest age and structure effects on northern flying squirrel densities

ABSTRACT Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys Sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels, resulting in small sampling sizes (average = 5.2 sites, n = 14) and high variation (CV = 0.59) across studies. We conducted a meta-analysis of relevant studies from North America to determine how forestry practices affect flying squirrel abundance. Mean effect size was -1.18 [P < 0.001; n = 14) for all studies, indicating a strong difference between control stands and those regenerating postclearcut or following partial harvesting. Our results support the association of northern flying squirrels with mature, uncut forest and their suitability as ecological indicators of these vegetation types.

Maximum sustained yield harvest versus trophy management

We examined hypotheses regarding compatibility of managing white-tailed deer (Odocoileus virginianus) populations for trophy males (i.e., ≥8 points) and maximum sustained yield (MSY) harvests. Harvest of white-tailed deer on Oak Ridge Reservation, Tennessee, USA, began in 1985 following 45 years of protection. We examined several harvest characteristics (e.g., age and sex composition, antler and body size of males) under the assumption that the population had attained an equilibrium during this period and hunter bias toward males was constant across years. During 1985, 273 deer were killed by vehicles on the reservation; by 1994, mortality from vehicles declined to 143 deer. During the study period, annual harvest declined from 923 to 470 deer. We suspect that although the population had attained an equilibrium, it was likely below ecological carrying capacity (K) because of substantial vehicle mortality. Because of the absence of predators and other sources of natural mortality, we assumed that deer-vehicle collisions prior to hunting was the primary factor maintaining the population below K. After the initiation of hunting in 1985, several demographic parameters indicated the population was intensively harvested: 98% of the harvest was composed of males <4 years of age, deer-vehicle mortality was reduced by 50%, and modeling indicated that the population had stabilized at 61% of the prehunt population. Average age of trophy males declined following harvest. Body size of 1.5-year-old males increased following the initial hunt but became variable over the remaining period. Proportion of trophy males harvested declined from 36% to 15% throughout the study period. Following the initial harvest, the high proportion of yearling males harvested suggests that the age distribution of males became truncated. Results from our empirical example support the hypothesis that sustained production of trophy males is a consequence of MSY of either-sex harvests when males are considered trophy with ≥8 points, when annual recruitment at MSY consistently approaches unity, and when hunters show no selectivity bias. These constraints are unlikely under current management prescriptions.

Selection of Day-Roosts By Keen's Myotis (Myotis keenii) at Multiple Spatial Scales

Abstract Keens 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 Keens 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 Akaikes 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 Keens 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 Keens 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 Keens myotis in southeastern Alaska.

Home Range Use by Swamp Rabbits (Sylvilagus aquaticus) in a Frequently Inundated Bottomland Forest

Abstract Home range size of six swamp rabbits in south-central Arkansas was estimated by radio-telemetry from February 1991 through March 1992. The average home range size was significantly larger than previously reported estimates. This difference is partly attributable to the large number of observations per rabbit in our study, but may also be explained by our inclusion of numerous locations of swamp rabbits during periods of deep inundation. All of the individual rabbits tracked used different areas when the study site was flooded. These results provide the first quantitative description of the response of swamp rabbits to flooding.