Alces (A Journal Devoted to the Biology and Management of Moose)
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PHENOTYPIC VARIATION IN MOOSE: THE ISLAND RULE AND THE MOOSE OF ISLE ROYALE
Get PDFThere is strong empirical support for the island rule, whereby body size in insular populations of animals tends toward gigantism in small-bodied species and dwarfism in large-bodied species (>10 kg). For large-bodied species, underlying reasons for dwarfism in insular populations include lack of predation and resource limitation. We found that metatarsal length of moose (Alces alces) from Isle Royale National Park in Lake Superior (N. America) was significantly shorter than that of mainland moose in Minnesota and Michigan (which were similar in size). On Isle Royale, moose body size was inversely related to moose density at the time of birth, illustrating the resource limitation that is influential where average moose density is 5-10 times higher than on the mainland. Reduced body size probably developed in Isle Royale moose within a half century of their establishment, prior to the arrival of wolves, and subsequently body size should be shaped by the countervailing influences of resource limitation and predation by wolves (Canis lupus). Bones provide an excellent basis for spatio-temporal comparisons of body size among moose populations. With additional data on metatarsus length from moose in Alaska and Sweden, we illustrate important considerations such as sample size, sex differences, and biases arising from source of bone collections
EFFECTS OF ESSENTIAL OILS ON THE FEEDING CHOICE BY MOOSE
Get PDFMoose (Alces alces) browse on coniferous tree species to different extents during winter; for example, Norway spruce (Picea abies) is avoided, Scots pine (Pinus sylvestris) is preferred, with juniper (Juniperus communis) of intermediate use. Conifers contain essential oils that may act as feeding deterrents, thereby reducing food intake by herbivores. Because essential oils are volatile, our objectives were to determine if 1) odour plays a role in the food choice by moose, 2) whether single monoterpenes act as feeding deterrents, and 3) if this might be a mechanism used to discriminate against unpalatable plants. The essential oils of Norway spruce and juniper and 2 monoterpenes (limonene and camphene) predominant in the essential oil of Norway spruce were tested for their potential as deterrents in feeding trials. Deterrence was assessed in food choice experiments by measuring the time spent feeding on food treated with the different odours associated with these compounds. There was no statistical evidence that food treated with the essential oils of spruce and juniper and single monoterpenes from Norway spruce were avoided by moose. However, our data indicate that the essential oil of Norway spruce probably has a negative effect on moose foraging because of the large absolute difference in feeding time between treatments and that overall, odour had a significant effect on feeding time. Because our experimental design may have influenced the results, we suggest research approaches to better measure deterrence effects
DISTINGUISHED MOOSE BIOLOGIST - PAST RECIPIENTS
Get PDFDISTINGUISHED MOOSE BIOLOGIST - PAST RECIPIENT
VISIBILITY OF MOOSE IN A TEMPERATE RAINFOREST
Get PDFAerial surveys are the principal methods used to estimate populations of moose (Alces alces gigas) in Alaska. Accounting for missed animals during aerial surveys is problematical, especially in forested habitats; incorporation of a visibility correction factor to account for the proportion of animals missed is known to improve accuracy of population estimates. Our purpose was to study factors affecting visibility of radio-collared moose during aerial surveys in a temperate rainforest on the Yakutat Foreland, Alaska, USA. Wildlife managers in the area typically assume they observe only 50% of moose during surveys regardless of widely varying conditions. We used logistic regression to examine factors that influenced visibility including vegetation, light conditions, snow cover, and sex, age, and group size of moose. We then used logistic regression to develop a simpler model that only contained variables easily measured during aerial surveys: forest cover, snow cover, light, open versus vegetated habitat, and group size. We used that model to estimate a visibility correction factor. The mean correction factor was 1.304, ranging from1.005-2.138, yielding a population estimate of 699 (90% CI = 671-724) moose from a survey count of 595 animals. Our correction factor was within the range reported for other populations of moose, and lower than the correction factor (2.0) currently used in this area. We conclude that application of site and time-specific visibility models is critical when estimating populations of large ungulates, especially in forested habitats
SEASONAL VARIATION OF PHENOLS, NITROGEN, FIBER, AND IN VITRO DIGESTIBILITY IN SWEDISH MOOSE
Get PDFUnderstanding how different components of food are processed and digested within the compartments of the digestive tract of large herbivores has important implications in their foraging behaviour, nutritional ecology, and techniques for measuring diet composition and nutritional quality of forage. Analysis of contents from different compartments of the digestive tract of moose in central Sweden showed that neutral detergent fiber (NDF) and nitrogen (N) content varied throughout the digestive tract and among individual moose (Alces alces). Total phenols (TP) had an inconsistent pattern throughout the digestive tract, possibly reflecting variation in diet composition and phenol patterns. The study moose were divided into 2 groups; the winter group had low N in the digestive tract and high NDF and dry matter content, and the summer group had high levels of N and low NDF and dry matter content. The phenol platyphyllane, indicative of consumption of dormant silver birch (Betula pendula), was detected throughout the contents of the digestive tract in 2 animals in the winter group. The winter moose had higher NDF than summer moose, indicating the seasonal change in diet quality. In vitro organic matter digestibility (IVOMD) was not different between the summer and winter diets. The effect of birch phenols on IVOMD was concentration-dependent; differences between seasons were apparent at only the highest concentration. The 2 groups had marked differences in digestive content of major nutrients, NDF, and ability to digest forage which were consistent with typical variation in seasonal diet quality
USING PELVIS MORPHOLOGY TO IDENTIFY SEX IN MOOSE SKELETAL REMAINS
Get PDFThe only published method for sex determination in even-toed ungulates (i.e., Cervidae) through the use of skeletal remains (excluding the skull) is pelvic suspensory tuberosity presence/absence in white-tailed (Odocoileus virginianus) and black-tailed deer (Odocoileus hemionus columbianus). Tuberosities are not easily distinguishable on moose (Alces alces) pelvises, even when a large number are available for comparison. Unlike in horses (Equus caballus) with similar skeletal structure as moose, pelvic inlets of moose show no distinctive sex characteristics on an individual level. Several linear angular (n = 5) and linear (n = 3) measurements were made on Isle Royale moose pelvises (n = 35). Results showed statistically significant differences between male and female pelvises for all angles, with unambiguous data collected from the angle created by the ischiatic arch (ventral brim of the ischium). As a rule of thumb, males and females exhibit an ischiatic arch angle of <90° and >90°, respectively. Two of the length measurements were also statistically different; however, overlap of these measurements would prevent their practical use. Learning more about sexing techniques will increase our forensic, archeological, and anatomical knowledge of moose anatomy and benefit sex determination in the field when only headless, scavenged, or partial carcasses remain
COMPOSITIONAL ANALYSIS OF MOOSE HABIAT IN NORTHEASTERN MINNESOTA
No full textABSTRACT: It is well accepted that moose often use early successional habitats in the boreal forest. It is not clear, however, whether use of disturbed habitats represents a preference or simply that moose are more detectable. Previous research based on visual observations assumed that moose were equally detectable in all cover types. We evaluated habitat selection of moose in northeastern Minnesota using telemetry locations and LULC cover type information. We calculated second- and third-order habitat selection using composition analysis. The analyses indicated that while the Cutover cover type ranked highest in summer and winter in both second- and third-order selection, its rank was not significantly different from most other cover types during the winter. Third-order analysis indicated that the rank of Cutover was significantly higher than other cover types during the summer. Selection for aquatic habitats during the summer was not evident in our analysis. Cover types that could provide lower operative temperatures from shade ranked higher than aquatic cover types. Inferences from these analyses should be treated with caution because of inherent weaknesses of use-availability analyses