Alces (A Journal Devoted to the Biology and Management of Moose)
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POPULATION GENETIC STRUCTURE OF MOOSE (ALCES ALCES) OF SOUTH-CENTRAL ALASKA
Get PDFThe location of a population can influence its genetic structure and diversity by impacting the degree of isolation and connectivity to other populations. Populations at range margins are often thought to have less genetic variation and increased genetic structure, and a reduction in genetic diversity can have negative impacts on the health of a population. We explored the genetic diversity and connectivity between 3 peripheral populations of moose (Alces alces) with differing potential for connectivity to other areas within interior Alaska. Populations on the Kenai Peninsula and from the Anchorage region were found to be significantly differentiated (FST = 0.071, P < 0.0001) with lower levels of genetic diversity observed within the Kenai population. Bayesian analyses employing assignment methodologies uncovered little evidence of contemporary gene flow between Anchorage and Kenai, suggesting regional isolation. Although gene flow outside the peninsula is restricted, high levels of gene flow were detected within the Kenai that is explained by male-biased dispersal. Furthermore, gene flow estimates differed across time scales on the Kenai Peninsula which may have been influenced by demographic fluctuations correlated, at least in part, with habitat change.
VARIATION IN FINE-SCALE MOVEMENTS OF MOOSE IN THE UPPER KOYUKUK RIVER DRAINAGE, NORTHCENTRAL ALASKA
Get PDFFine-scale movements form the foundation of local habitat selection by animals. In northern interior Alaska, the Dalton Highway Corridor Management Area and other parts of Game Management Unit 24 are accessible to moose hunters from the Dalton Highway. Concern that these areas may be a population sink for moose (Alces alces) inhabiting the Gates of the Arctic National Park and Preserve and the Kanuti National Wildlife Refuge prompted this study of movements. We found that migratory bulls and cows traveled about the same distance over the course of a year as non-migratory moose. Although counterintuitive, this may reflect the selective foraging behavior of a low density (∼0.1 moose/km2) moose population in habitat with abundant forage. Maximum movement rates by bulls occurred at the onset of rut at the end of the hunting season. This spike in movement may have given local residents the impression that local moose were migratory and vulnerable to hunting from non-residents. Movement rates were lowest in winter for both bulls and cows, and declined with increasing winter severity, but not temperature specifically. Reduced movement rates by cows during the calving season were not readily evident and annual fidelity to calving sites was minimal
ESTIMATING MOOSE ABUNDANCE AND TRENDS IN NORTHEASTERN WASHINGTON STATE: INDEX COUNTS, SIGHTABILITY MODELS, AND REDUCING UNCERTAINTY
Get PDFThe state of Washington was historically considered to be unoccupied by moose (Alces alces) with initial colonization in the 1920s primarily in the northeastern quarter of the state. All evidence indicates a steadily increasing population since, with moose and moose hunting now firmly established. Given the expectation that Washington's moose population will face increasing challenges in the coming decades, our monitoring objective is to move from index-counts to valid estimates of abundance. We documented environmental covariates as an adjunct to simple counts from annual helicopter-based surveys in 2002–2012, and examined the performance of existing moose sightability models on these data. While acknowledging our inability to compare modeled estimates with actual abundance, we reasoned that if existing models converged on similar results, this would suggest that moose sightability is a sufficiently general phenomenon that the cost of developing a specific local model might not be justified. However, despite using similar covariates, the sightability models applied to our data produced widely disparate abundances and estimates with poor precision. Specifically, where coniferous forest cover renders expected detection probability low, sightability models tend to behave erratically. We also used covariate data bearing on sampling variation to refine our estimate of population trend. Multiple regression analyses revised the linear rate of increase associated with the raw counts of the instantaneous rate of growth, r = 0.084 (SE = 0.019) to an adjusted estimate of r = 0.077 (SE = 0.075). While incapable of transforming an index into a population estimate, accounting for variables likely to affect raw counts may be useful to refine estimates of trend. The use of an approach that avoids the autocorrelation inherent in a simple regression of counts on time better reflects true uncertainty
BROWSE REMOVAL, PLANT CONDITION, AND TWINNING RATES BEFORE AND AFTER SHORT-TERM CHANGES IN MOOSE DENSITY
Get PDFWe monitored forage-based indices of intraspecific competition at changing moose (Alces alces) densities to gauge short-term, density-dependent environmental feedback and to ultimately improve management of moose for elevated sustained yield. In 4 areas of interior Alaska where moose density recently changed, we evaluated the magnitude of change among 4 browse indices: proportional offtake of current annual growth biomass (OFTK), proportion of current twigs that were browsed (PTB), mean twig diameter at point of browsing (DPB), and proportion of plants with broomed architecture. In 1 area where moose density increased 100% in 6 years following effective predation control, browse removal increased 138% for OFTK, 20% for PTB, and 16–42% for DPB of primary browse species, with a 44% increase in brooming. We also studied 3 areas where moose density declined 31–41% following elevated antlerless harvests of 2–4 years duration. In these areas (with intervals of 3–12 years between browse surveys) we found declines of 30–40% in OFTK, 26–68% in PTB, and 11–37% in DPB, but changes in plant architecture were inconsistent. The proportion of parturient cows with neonate twins did not change between browse surveys, presumably because of a substantial lag time influenced by life history of the dominant reproductive cohorts and little change in browse nutrient content and digestibility. Of the 4 browse indices studied, proportional OFTK most consistently reflected the direction and magnitude of short-term changes in moose density. Area-specific measures of habitat and animal conditions at high moose density provided an objective means for gauging the capacity of the respective ecosystems to support moose and maintain forage plants. We used these measures of winter forage and moose condition to justify implementing harvest strategies and to ultimately reduce high moose densities below levels of strong negative feedback
ANALYSIS OF AGE, BODY WEIGHT AND ANTLER SPREAD OF BULL MOOSE HARVESTED IN MAINE, 1980-2009
Get PDFAge, field-dressed body weight, and antler spread data collected from 11,566 harvested moose (Alces alces) were analyzed to assess whether temporal change has occurred in the physical characteristics of bull moose from 1980–2009 in Maine. The annual proportion and antler spread of trophy bulls (spread ≥ 137 cm; n = 851) were also analyzed. There was no evidence of a measurable decline in the body weight or antler spread of adult bull moose (≥1.5 years old), similar to findings in Vermont and New Hampshire in a recent >20 year temporal analysis. There was a slight increase in physical characteristics of yearlings that contrasted with the trend in New Hampshire and Vermont where it is speculated that parasitism by winter ticks (Dermacentor albipictus) reduces growth rate and recruitment by yearlings. The proportion of trophy bulls in the harvest declined proportionally ∼26% (9.3 to 6.9%) as harvest increased >2x from 1980–1987 to 2005–2009; however, the mean spread of trophy bulls declined by only 2% (P = 0.002). Additionally, there were no differences (P > 0.05) in the proportion of harvested bulls within each age class between 1980–1987 and 2005–2009, and the relatively stable proportion of mature bulls (>5 years old) in the harvest across time periods (30–44%) does not suggest selective harvest of older, trophy bulls. In the face of the declining regional population, continued monitoring of harvested moose is warranted to best manage the largest and longest harvested population in the northeastern United States
BODY TEMPERATURE OF CAPTIVE MOOSE INFESTED WITH WINTER TICKS
Get PDFEighteen captive moose calves (Alces alces) were divided into 3 groups that represented 3 levels of winter tick (Dermacentor albipictus) infestation (0, 21,000, and 42,000 ticks). A total of 321 body temperatures (Tb) were taken on 19 occasions between late November and mid-April. The mean Tb of individuals was 38.2 ± 0.4 °C, ranging from 38.0–38.3 °C, and was not different among the control and infested groups (P = 0.816), but varied temporally (P < 0.001) with a significant interaction effect between treatment and time (P = 0.041); these temporal differences are unexplained. The Tbs measured in this study are some of the lowest reported for moose and presumably represent the resting Tb of free-ranging moose, more so than those measured after pursuit, restraint, and/or immobilization during capture. This was not a definitive test of the effects of tick infestation on wild moose because the captive moose consumed a high quality diet throughout winter and surprisingly low numbers of ticks remained on the animals in mid-April
THE CHANGING ROLE OF HUNTING IN SWEDEN-FROM SUBSISTENCE TO ECOSYSTEM STEWARDSHIP?
Get PDFAlthough hunting served traditionally to supply game meat, and that is still important in Sweden, recreation is the most common reason for hunting moose (Alces alces) today. Hunting also serves an important management purpose in regulating moose populations to control crop and forest damage. This study used semi-structured interviews with key stakeholders and officials involved in the recently implemented ecosystem-based, adaptive local moose management system where hunters and landowners become environmental stewards responsible for managing moose in context with forest damage, vehicular collisions, large carnivores, and biodiversity. Our study found that participation and collaboration in reaching management objectives was perceived as positive by stakeholders, although their stewardship is jeopardized if specific management responsibilities are not clarified regarding monitoring. Further, it is important to find long-term funding solutions for monitoring activities that are critical for adequate data collection and to support the stakeholder role as steward. The importance of monitoring must be communicated to individual hunters and landowners to achieve an ecosystem-based moose management system that effectively incorporates both social and ecological values
ESTIMATING MOOSE ABUNDANCE IN LINEAR SUBARCTIC HABITATS IN LOW SNOW CONDITIONS WITH DISTANCE SAMPLING AND A KERNEL ESTIMATOR
Get PDFMoose (Alces alces) are colonizing previously unoccupied habitat along the tributaries of the lower Kuskokwim River within the Yukon Delta National Wildlife Refuge (YDNWR) of western Alaska. We delineated a new survey area to encompass these narrow (0.7–4.3 km) riparian corridors that are bounded by open tundra and routinely experience winter conditions that limit snow cover and depth necessary for traditional moose surveys. We tested a line-transect distance sampling approach as an alternative to estimate moose abundance in this region. Additionally, we compared standard semi-parametric detection functions available in the program Distance to a nonparametric kernel-based estimator not previously used for moose distance data. A double-observer technique was used to verify that the probability of detection at the minimum sighting distance was 1.0 (standard assumption). Average moose group size was 2.03 and not correlated with distance from the transect line. The top semi-parametric model in the program Distance was a hazard-rate key function with no expansion terms. This model estimated average probability of detection as 0.70 with an estimated abundance of 352 moose (95% CI = 237–540). The CV for the semi-parametric model was 20% and had an estimated bias of 1.4%. The nonparametric kernel-based model had an average probability of detection of 0.73 and an estimated abundance of 340 (95% CI = 238–472) moose. The CV for the kernel method was 18% and the estimated bias was <0.001%. Line-transect distance sampling with a helicopter worked well in the narrow riparian corridors with low snow conditions, and survey costs were similar to traditional surveys with fixed-wing aircraft. The kernel estimator also performed well compared to the standard semi-parametric models used in program Distance. Our technique provides a viable approach for surveying moose in similar areas that have restrictive conditions for standard aerial surveys
ECHINOCOCCUS GRANULOSUS GENOTYPE G8 IN MAINE MOOSE (ALCES ALCES)
Get PDFDuring a 2012 survey of harvested moose (Alces alces) in Maine (USA), an incidental finding of hydatid cysts was found in 39% (21 of 54) of lung sets examined. Cytology of cyst contents was consistent with Echinococcus granulosus. The G8 genotype was identified based on PCR and DNA sequencing of a 470 base pair region of the NADH dehydrogenase subunit 1 (NAD1) mitochondrial gene. The hydatid cysts were the northern, or cervid genotype and this is the first confirmed report of E. granulosus in Maine moose. The Atlantic regions of the northern USA and Canada were not previously thought to be endemic regions for E. granulosus. It is presumed that either domestic dogs or eastern coyotes (Canis latrans) are the definitive host