PARELAPHOSTRONGYLUS TENUIS IN TERRESTRIAL GASTROPODS FROM WHITE-TAILED DEER WINTER AND SUMMER RANGE IN NORTHERN NEW BRUNSWICK

The prevalence of Parelaphostrongylus tenuis infection was compared in terrestrial gastropods from white-tailed deer ( Odocoileus virginianus) summer range and wintering yards in northern New Brunswick during summer, 1995. Of 10,343 snails and slugs examined, only 4 were infected with 1 to 3 P. tenuis third-stage larvae (0.04%); all of these (the snail Discus cronkhitei and the slugs Deroceras laeve and Arion sp.) were collected from the deer yard. The effective frequency of infection in the wintering yard was 0.09%  and zero (undetectable) on summer range. Mean gastropod densities on summer and winter range did not differ (8.3/m2 and 6.2/m2, respectively). We suggest that the higher frequency of infection in the winter yard results from seasonally increased deer usage of these habitat types, and that moose (Alces alees) using such yards during snow-free periods will have increased risk of infection with P. tenuis. The relatively low prevalence of infection observed in gastropod intermediate hosts may reflect the effect of an unseasonably dry spring and summer on the transmission of P. tenuis

SPATIAL AND TEMPORAL HETEROGENEITY IN THERMAL CONDITIONS FOR WILDLIFE

Temperature is an important component of climatic conditions that drive animal evolution, niche space, and life history traits. We used field-deployed temperature sensors and generalized linear mixed-effects models to quantify the spatiotemporal variation of ambient temperatures in three study areas of western Montana, in support of concurrent studies of moose ecology and population dynamics. We found substantial potential for thermal refuge for moose; temperature ranges observed simultaneously among sites within study areas averaged 7.0°C during summer and 6.1°C during winter. We considered 6 site variables hypothesized to affect local temperatures (elevation, topographic position, aspect, land cover type, forest canopy cover, and the interaction of land cover and solar radiation), and all contributed to model performance. However, the direction and magnitude of effects varied in a cyclic fashion during the 24-hour diel cycle, and in many cases, exhibited reversed effects between day and night. Although spatial heterogeneity in temperature during summer was only slightly higher than during winter, our ability to explain such pattern was much better during summer (average R2 = 0.51–0.56) than during winter (average R2 = 0.09–0.23). We encourage researchers and managers to explore field collection and spatiotemporal modeling of temperature sensor data for cost-effect description of thermal environments for wildlife in local settings

A REVIEW OF METHODS TO ESTIMATE AND MONITOR MOOSE DENSITY AND ABUNDANCE

Acquiring accurate and precise population parameters is fundamental to the ecological understanding and management and conservation of moose (Alces alces). Moose density is challenging to measure and often estimated using winter aerial surveys; however, numerous alternative approaches exist including harvest analysis, public observation, unpiloted aerial system (UAS) surveys, and camera trapping. Given recent developments in a number of field and analytical techniques, there is value in reviewing and synthesizing the strengths and limitations of monitoring methods to best evaluate their respective tradeoffs in management scenarios. We reviewed 89 studies that included 131 estimates or indices of moose density. As expected, aerial surveys were the most common method of obtaining a moose density estimate (58%) followed by use of public data (e.g., harvest records = 27%); more recent studies employed novel methods including UAS. Most estimates (64%) failed to account for imperfect detection of moose (i.e., “sightability”) and this tendency has not improved over time. Density estimates ranged from <0.1 to 10.6 moose/km2 (average = 0.7) and population precision, as measured by the 90% confidence interval, ranged from 6.5 to 120.0% of the density estimate (average = 37.4%). Correlations among estimates obtained for the same populations varied widely, with R2 values ranging from 0.02 to 0.99 (average = 0.58). Our review indicates that: 1) methods to estimate moose density have been dominated by aerial surveys but are diversifying, 2) precision of density estimates has been highly variable and on average lower than broadly accepted target benchmarks, and 3) many methods did not account for sightability and presumably underestimated moose density. We reflect on these trends and discuss how emerging methods, including camera trapping, UAS surveys, and integrated population modeling (IPM) can complement and improve traditional approaches. We suggest that no single “best” method exists, but rather the best method is one that accounts for sightability bias and yields target precision at reasonable cost, which vary by jurisdiction and goal

EXTENDING BODY CONDITION SCORING BEYOND MEASUREABLE RUMP FAT TO ESTIMATE FULL RANGE OF NUTRITIONAL CONDITION FOR MOOSE

Moose (Alces alces) populations along the southern extent of their range are largely declining, and there is growing evidence that nutritional condition — which influences several vital rates – is a contributing factor. Moose body condition can presently be estimated only when there is measurable subcutaneous rump fat, which equates to animals with >6% ingesta-free body fat (IFBFat). There is need for a technique to allow body fat estimation of animals in poorer body condition (i.e., <6% body fat). We advance current methods for moose, following those used and validated with other ungulate species, by establishing a moose-specific body condition score (BCS) that can be used to estimate IFBFat in the lower range of condition. Our modified BCS was related strongly (r2 = 0.89) to IFBFat estimates based on measurable rump fat. By extending the predicted relationship to individuals without measurable fat, the BCS equated severe emaciation with 0.67% IFBFat, supporting the accuracy of the method. The lower end of nutritional condition is important for identifying relationships involving life-history characteristics because most state-dependent changes occur at lower levels of condition. Therefore, until the BCS can be validated with moose carcasses, we believe our method to estimate body fat across the full range of condition should yield better understanding of the drivers underlying declining moose populations

SALIVARY CORTISOL RESPONSE TO FLIES BY MOOSE CALVES

Young animals are particularly vulnerable to environmental stressors that can impair growth and compromise survival. We used salivary cortisol, a glucocorticosteroid hormone, to measure possible stress response of moose calves in Alaska to the abundance of biting and non-biting flies relative to calf age, time of day, and ambient air temperature. We measured salivary cortisol in 5 captive calves up to 4 times daily on 25 days in June-August with corresponding on-host fly collections. We simultaneously collected 2,618 flies, of which 68% were moose flies (Haematobosca alcis), 13% coprophagous flies, 9% mosquitoes (Culicidae), 5% horse and deer flies (Tabanidae), and 2% black flies (Simuliidae). The proportion of moose flies increased steadily, representing nearly all flies by study end. Salivary cortisol levels were minimal and similar (<0.2 μg·dL-1) from 25 to 89 days of age at ambient temperatures ranging from 13 to 34ºC, and did not increase with relative fly abundance. The lack of cortisol response is consistent with observations of minimal reaction to most flies by moose. The dense and fuzzy characteristics of calf pelage may provide a unique, protective barrier to minimize fly bites and exposure to pathogens sometimes associated with wounds or bites. Although a cortisol response to flies was not detected, vector borne pathogens are predicted to increase in a warming climate and warrant surveillance as part of proactive moose management

DEMOGRAPHY AND SUSTAINABLE HARVEST RATES OF LOW-DENSITY MOOSE IN NORTHERN BRITISH COLUMBIA

Numerous moose (Alces alces) populations throughout Alaska, Yukon, and the Northwest Territories occur at low-density, a condition that often persists for decades and is referred to as a low-density equilibrium (LDE). The demographic conditions for these populations include low-density (≤ 0.4 moose/km2), low annual recruitment of calves (~ 0.25 calves/cow), and static population growth (λ ~ 1.00). I used data from aerial surveys and hunter harvest surveys to assess if these conditions applied to 4 moose populations in northern British Columbia, Canada over a 20-year period from 1996/97–2015/16. All populations exhibited low-density, low recruitment, and static growth suggesting that moose in this part of the province exist within a LDE state. Harvest and moose densities were positively related. Harvest rates from survey data ranged from 2.4–3.2% of the total population and 6.1–10.5% of the bull population. A stochastic model was used to estimate sustainable harvest rates defined as rates where the harvest risk was ≤ 10% probability that the post-hunt bull:cow ratio dropped below a given adult sex ratio threshold after 50 years of harvest. Sustainable harvest rates averaged ≤ 2.4% of the total population or ≤ 8.4% of the bull population with 0.50 bulls/cow as the threshold, ≤ 3.2% of the population or ≤ 13.0% of bulls with 0.40 bulls/cow as the threshold, and ≤ 4.1% of the population or ≤ 20.4% of bulls with 0.30 bulls/cow as the threshold. Modelling indicated that even small changes in harvest rates could greatly affect the probability of bull:cow ratios dropping below adult sex ratio thresholds. Research focussed on specific factors contributing to low moose density and increased population survey effort should improve estimates of sustainable harvest rates and management of moose in northern British Columbia

AQUATIC AREAS PROVIDE HIGH NITROGEN FORAGE FOR MOOSE (ALCES ALCES) IN ISLE ROYALE NATIONAL PARK, MICHIGAN, USA

The distribution of ungulates reflects spatial and temporal heterogeneity in forage quality and quantity across the landscape. Aquatic habitats have a patchy spatial distribution and are readily used by moose (Alces alces) and other ecotone specialists. However, the importance of aquatic feeding to moose has largely been attributed to acquisition of sodium, with little consideration given to the relative and comparative quality of aquatic and terrestrial forage types. We show differences in forage quality as measured by crude protein content and carbon:nitrogen (C:N) ratios between aquatic and terrestrial summer forage in Isle Royale National Park, Michigan, USA. Aquatic macrophytes had higher crude protein content and lower C:N ratio than preferred terrestrial plant species of moose. Consequently, measurable consumption of aquatic forage may provide high quality forage in less than optimal habitats. Because the distribution of aquatic habitats on Isle Royale exhibits strong spatial trends, the benefits of aquatic feeding may have spatial influence on the population dynamics of Isle Royale moose

BIRTH RATES AND NEONATE SURVIVAL IN A PARASITE RICH MOOSE POPULATION IN VERMONT, USA

Moose (Alces alces) populations are declining across much of their southern geographic range in North America. In Vermont and other northeastern states, measurable declines are attributed to low calf survival and reduced productivity associated with persistent winter tick (Dermacentor albipictus) parasitism. In 2017–2020, we studied 75 radio-collared female moose (38 calves and 37 adults) in Vermont to examine physiological, spatial, and temporal parameters relative to calf survival and adult productivity. Physiological measures included concentration of fecal glucocorticoid metabolites (fGCM) which reflects stress, and urea nitrogen:creatinine ratios in urine (UN:C) which proxy nutritional state. The pregnancy rate at capture across years was 0.67 (95% CI = 0.50 – 0.80), and was negatively related to presence of lungworm (Dictyocaulus spp.). The birth rate calculated as the average number of offspring delivered per adult female was <1.0 overall (2017–2020, LCI = 0.22, UCI = 0.86), similar across years, but increased with age. Logistic exposure models indicated that daily calf survival to 60 d increased as Julian birth date and days since birth increased (log odds = 0.0819, SE = 0.0215). The per capita independence rate, or rate that adult females add independent calves to the population, was negatively related to UN:C ratios and positively with fGCM. Further, this rate was related to autumnal habitat use of adult females; it was greater in home ranges characterized by large amounts of mature (canopy) evergreen forests and wetland habitats, and small amounts of mixed forests and elevation than in ranges with abundant levels of mixed forest at high elevation. We conclude that winter ticks can negatively affect moose fecundity, and efforts to reduce host (moose) density through harvest or parasite (host) abundance through habitat manipulation may improve productivity and recruitment in local moose populations