Phylogeography Of Moose (Alces Alces): Genetic Signatures Of Population History

Thesis (Ph.D.) University of Alaska Fairbanks, 2002Through analysis of mitochondrial DNA (mtDNA) sequences, I examined phylogeographic relationships among moose (Alces alces) from Europe, Asia, and North America and inferred historic population trends explaining present-day structure of genetic variance. Diversity of nucleotide composition in cytochrome b was low worldwide, with no variation detected among North American moose. The North American lineage was more closely related to European than to Asian lineages, indicating a recent colonization of North America and refuting the theory of eastern and western races of moose. An analysis of the control region provided greater resolution, which revealed similar yet more detailed patterns, including detectable variation within North America subspecies. Patterns of genetic variation among regional populations identified central Asia as the source of extant lineages of moose. Moreover, a recent coalescence was indicated, with the most recent common ancestor dating to the last ice age. Two historic expansions of moose populations were detected: an initial expansion in Eurasia coincident with an interstade of the last ice age, and a second expansion in eastern Asia; and North America following the end of the last ice age. Data indicate a low effective population size in Eurasia during the peak of the last ice age followed by population and range expansion, likely facilitated by climate change. Haplotypes within North America formed a star phylogeny, indicative of recent expansion. Nucleotide and haplotype diversity were greatest in central North America and least in peripheral populations (Alaska, Colorado, and eastern North America). My data indicate a pattern of colonization consistent with a large central population providing founders for peripheral populations, perhaps resulting from leptokurtic dispersal. Low diversity in Alaska indicated a bottleneck subsequent to colonization and recent population expansion. Establishment of regional populations through small numbers of founders combined with selection pressure for smaller body size likely led to morphological differentiation among regional populations and likely was adequate for rapid development of subspecies. Nucleotide and haplotype diversity were low in southeastern Alaska, but were high in neighboring areas of British Columbia; there was little sharing of haplotypes occurred despite close proximity, indicating recent admixture of separate colonizing populations

REDUCED GENETIC DIVERSITY IN TWO INTRODUCED AND ISOLATED MOOSE POPULATIONS IN ALASKA

I examined indices of genetic diversity in 2 isolated moose (Alces alces) populations in Alaska that were founded by low numbers of individuals to determine effects of founding and infer whether subsequent gene flow has occurred with surrounding moose populations. Kalgin Island is a small, predator-free island in Cook Inlet that was founded by 6 moose (3 females) in the late 1950s; its population has since undergone dramatic fluctuations. Berners Bay is an isolated population along the coast of southeastern Alaska that was founded by 21 calves introduced in 1958-1960. Genetic attributes of those populations were compared to a population in Yukon Flats in central Alaska that served as an outbred control. Indices from 11 microsatellite markers indicated substantial effects of founding and subsequent isolation. Heterozygosity and allelic diversity, both of which are reduced by genetic bottlenecks, were significantly lower in the introduced populations than the Yukon Flats population. Kalgin Island diversity was significantly lower than that for Berners Bay, and was likely due to the smaller founding size and subsequent population fluctuations. Neither introduced population exhibited evidence of gene flow from surrounding populations. Managers should consider the isolation of those populations when assessing risks to population viability and crafting management strategies

Spatio-temporal Analysis of the Genetic Diversity of Arctic Rabies Viruses and Their Reservoir Hosts in Greenland

There has been limited knowledge on spatio-temporal epidemiology of zoonotic arctic fox rabies among countries bordering the Arctic, in particular Greenland. Previous molecular epidemiological studies have suggested the occurrence of one particular arctic rabies virus (RABV) lineage (arctic-3), but have been limited by a low number of available samples preventing in-depth high resolution phylogenetic analysis of RABVs at that time. However, an improved knowledge of the evolution, at a molecular level, of the circulating RABVs and a better understanding of the historical perspective of the disease in Greenland is necessary for better direct control measures on the island. These issues have been addressed by investigating the spatio-temporal genetic diversity of arctic RABVs and their reservoir host, the arctic fox, in Greenland using both full and partial genome sequences. Using a unique set of 79 arctic RABV full genome sequences from Greenland, Canada, USA (Alaska) and Russia obtained between 1977 and 2014, a description of the historic context in relation to the genetic diversity of currently circulating RABV in Greenland and neighboring Canadian Northern territories has been provided. The phylogenetic analysis confirmed delineation into four major arctic RABV lineages (arctic 1-4) with viruses from Greenland exclusively grouping into the circumpolar arctic-3 lineage. High resolution analysis enabled distinction of seven geographically distinct subclades (3.I - 3.VII) with two subclades containing viruses from both Greenland and Canada. By combining analysis of full length RABV genome sequences and host derived sequences encoding mitochondrial proteins obtained simultaneously from brain tissues of 49 arctic foxes, the interaction of viruses and their hosts was explored in detail. Such an approach can serve as a blueprint for analysis of infectious disease dynamics and virus-host interdependencies. The results showed a fine-scale spatial population structure in Greenland arctic foxes based on mitochondrial sequences, but provided no evidence for independent isolated evolutionary development of RABV in different arctic fox lineages. These data are invaluable to support future initiatives for arctic fox rabies control and elimination in Greenland

Food selection and juvenile survival in Nuttall's cottontails in central Oregon

A population of Nuttall's cottontails (Sylvilagus nuttallii) in Deschutes County, Oregon, decreased fromm 166 individuals in August 1978 to 76 individuals in August 1979. Survival rates of four annual litter groups in 1978 were 0.74, 0.35, 0.72, and 0.93; survival rates for the same litter groups, respectively, in 1979 were 0.12, 0.28, 0.07, and 0.18. Population density and juvenile survival decreased between the 2 years possibly because of alterations in forage quality and quantity caused by precipitation. Numbers of cottontails on the study area on 30 August were related significantly (P<0.O1) to initial breeding density and to precipitation falling during the breeding season (February - July). Survival in juvenile cottontails from birth to 30 August was related significantly to precipitation in the first (P<O.05), third (P<O.01), and fourth (p<0.O1) annual litter groups. Vegetative abundance at the end of the growing season (September) decreased by approximately 30% between the 2 years; the decline corresponded with a 45% decrease in crop-year (September - June) precipitation. Succulence of grasses, forbs, and shrubs was greatest in spring, declined in summer, and increased slightly in late summer. Forbs consistently were the most succulent group, except in September when shrubs were most succulent. Grasses exhibited the greatest variation in succulence in response to precipitation; shrubs exhibited the least. A moisture availability index (MAI) indicated that, despite approximately equal estimates of succulence between the 2 years, moisture was more available to cottontails in 1978 because of greater abundance of vegetation. Cottontails seemingly selected forage groups in relation to their relative succulence, within limits. Shrubs were avoided, and succulent juniper (Juniperus occidentalis) foliage was eaten only in dry periods, possibly because of low tolerance in cottontails to plant secondary compounds, particularly terpenoids. Juveniles selected forbs in significantly (P600 g) juveniles did not differ. Breeding females selected forbs in significantly (P<0.05) greater proportions than males, possibly because of moisture demands associated with reproduction and lactation. Other nutrients, especially protein, that are associated with moisture content of plants, possibly were as important as moisture in determining food habits and population fluctuations in Nuttall's cottontails in central Oregon. The relationship between juvenile survival and precipitation possibly was caused by genotypic variation in efficiency in cottontails to utilize moisture and nutrients

GENETICS, EVOLUTION, AND PHYLOGEOGRAPHY OF MOOSE

Early studies of genetic variation in moose (Alces alces) indicated little variation. Recent studies have indicated higher levels of variation in nuclear markers; nonetheless, genetic heterogeneity of moose is relatively low compared with other mammals. Similarly, variation in mitochondrial DNA of moose is limited worldwide, indicating low historic effective population size and a common ancestry for moose within the last 60,000 years. That ancestor most likely lived in central Asia. Moose likely exhibit low levels of heterogeneity because of population bottlenecks in the late Pleistocene caused by latitudinal shifts in habitat from recurrent climate reversals. A northward movement of boreal forest associated with the end of the last ice age facilitated the northward advance of Asian populations and colonization of the New World, which occurred as a single entry by relatively few moose immediately prior to the last flooding of the Bering land bridge. Despite suffering serial population bottlenecks historically, moose have exhibited a notable ability to adapt to a changing environment, indicating that limited neutral genetic variation may not indicate limited adaptive genetic variation. We conclude that morphological variation among moose worldwide occurred within a few thousand years and indicates that moose underwent episodes of rapid and occasionally convergent evolution. Genetic change in moose populations over very short time scales (tens or hundreds of years) is possible under harvest management regimes and those changes may not be beneficial to moose in the long term. Modeling exercises have demonstrated that harvest strategies can have negative consequences on neutral genetic variation as well as alleles underpinning fitness traits. Biologists should consider such outcomes when evaluating management options

CONSIDERATIONS FOR INTENSIVE MANAGEMENT OF MOOSE IN ALASKA

The Alaska Legislature recently passed a law directing the Alaska Board of Game to identify certain game populations that will be managed intensively. This mandate implies management for maximum sustained yield (MSY), yet managing populations for MSY is problematic. Over-harvest at MSY may cause populations to decrease to low levels, and in the presence of predation low density equilibrium can be established. We recommend maintaining intensively managed populations at densities above the actual point of MSY to avoid potential over-harvests caused by stochastic variation in recruitment. Managing intensively will require better information on factors that influence recruitment and corresponding rates of increase in moose populations, including: age at first reproduction; rates of pregnancy, twinning, age-specific survival, dispersal, and predation; as well as population sex ratios. Population modeling indicates that rate of increase is most sensitive to changes in adult survival, but under most circumstances in real moose populations, calf survival is very important. Factors affecting calf survival include habitat quality, weather, and predation, and the effects of these factors can be minimized by maintaining moose densities slightly above those which maximize recruitment. An intensive management strategy for moose populations in Alaska must include the ability to implement cow harvests, predator management, and habitat management. Aggressive monitoring of population parameters, cause-specific mortality rates, trends in habitat quality, and a knowledge of carrying capacity will be essential to selecting appropriate management strategies. Gaining this information will be expensive but the alternative is potential mismanagement and the risk of population declines

SUPPLEMENTAL FEEDING OF MOOSE DURING WINTER: CAN HAY SERVE AS AN EMERGENCY RATION?

When severe winters result in starvation of moose (Alces alces) in the proximity of human development, people often demand emergency feeding programs. In spite of the controversy surrounding such programs, political decisions may dictate that resource agencies feed starving moose. Consequently, we tested the feasibility of using locally grown grass hay as an emergency ration. In two concurrent experiments (trial 1), 16 captive moose were maintained on either hay or a pelleted ration. In a separate experiment (trial 2), 8 moose calves were fed grass hay for the duration of winter and their health and mass dynamics recorded. Over the 1 weeks of trial 1, adults eating the hay lost an average of 53.0 kg, whereas those consuming the pellets gained 36.3 kg. Calves eating hay maintained body mass, whereas those eating pellets gained 29.5 kg. Calf moose in trial 2 showed no adverse physiological effects from the diet and maintained body mass throughout the winter. Mean urinary urea:creatine rations (U:Cr) differed (P = 0.004) between moose fed hay and pellets), but not among periods in trial 1. These results indicate a difference in intake of nitrogen, but consistency among nitrogen balance over time. Phosphorus:Cr (P:Cr) ratios were not different between treatments (P = 0.42) but different among time periods (P = 0.06), corresponding to a decline in dry matter intake which is typical for moose during winter. Cortisol:Cr (C:Cr) ratios did not differ between treatments (P = 0.82) or among periods (P = 0.19), indicating that the level of physiological stress experienced by the moose did not change. We conclude that although the pellets served as a more complete ration for emergency feeding, locally grown grass hay can serve as an emergency food for moose in reasonably good physical condition. We also tested seven new flavors to improve the palatability of our formulated ration. Moose consumed significantly more feed flavoured with milky whay when compared to the standard ration and the other 6 flavors tested. Recommendations concerning emergency feeding are discussed

PREDICTING BODY MASS OF ALASKAN MOOSE (ALCES ALCES GIGAS) USING BODY MEASUREMENTS AND CONDITION ASSESSMENT

The ability to predict body mass (BM) of moose in the field using simple morphometric induced would be useful in assessing numerous aspects of moose biology and management. Previous studies have used length and girth measurements but  generally have ignored estimates of condition as potential predictors. We evaluated the efficacy of adding a subjective condition class (CC) index to mass-length regressions to improve estimates of body mass; we also evaluated the repeatability of standard morphometric measures. Total length (TL) was a significant but poor predictor of BM and exhibited non-constant variance of residuals. Chest girth (CG) was a better predictor of BM, but the best single predictor was TL*CG2. The addition of CC to the regression improved the fit and reduced the standard error of the estimate. Total length of CG of 5 moose measured repeatedly over a 3-week period varied considerably, with coefficients of variation ranging from 1.9-5.5%. This variation is attributed to the difficulties associated with positioning moose for precise measurement in the field. Morphometric models assessed in this study are useful for predicting BM of moose generally but are not precise enough to predict seasonal changes in mass of mature moose

XYLAZINE IMMOBILIZATION OF MOOSE WITH YOHIMBINE OR TOLAZOLINE AS AN ANTAGONIST; A COMPARISON TO CARFENTANIL AND NALTREXONE

When moose (Alces alces) are kept in captivity, it is often necessary to immobilize them for research purposes or animal care. Carfentanil, a very potent narcotic, used in combination with xylazine hydrochloride is the preferred drug mixture when immobilizing moose in the wild. However, carfentanil is both expensive and potentially dangerous to the handler. We evaluated the use of xylazine hydrochloride, an alpha2 adrenergic sedative and analgesic, used alone, or in combination with either carfentanil citrate or ketamine hydrochloride to immobilize moose at the Moose Research Center. Mean downtime for xylazine alone was not different from xylazine:ketamine and carfentanil:xylazine mixtures. Drugged animals could be approached and handled immediately when given carfentanil:xylazine. Xylazine or xylazine:ketamine drugged animals often lay down 8-12 minutes before completely immobilized. The antagonist yohimbine had no apparent effect on reversal of xylazine - immobilized moose, and recovery times averaged 3:38 ± 2:01 hours. The antagonist tolazoline hydrochloride reduced recovery times significantly (P&lt;0.0001), and animals reversed with this drug were standing within 4 to 31 minutes (x̄ = 21 minutes). Animals immobilized with a mixture of carfentanil:xylazine and reversed with naltrexone were usually standing within 7 minutes with a range from 3 to 21 minutes after administration of the antagonist. Comparison of individual drugs, mixtures and antagonists are discussed relative to cost, efficiency, effectiveness, safety, and reliability of a mobilizing moose

EFFECTS OF POPULATION DENSITY AND SELECTIVE HARVEST ON ANTLER PHENOTYPE IN SIMULATED MOOSE POPULATIONS

We simulated moose (Alces alces) populations held either at or below carrying capacity (K) to determine the effect of population density on harvest rate and frequency of alleles favoring antler growth under a system of selective harvest. A stochastic model of density-dependent population growth was created to achieve stable populations at K with no hunting. Rates of mortality not associated with hunting were increased to simulate predation last for a population held below K. the increased nutrition available to this lower-density population was assumed to result in larger age-specific antler size. Each population was subjected to a harvest plan that defined legal bulls as those with either a spike-fork antler as yearlings (small bulls) or with an antler spread of &gt; 50 inches (127 cm) as large bulls. Harvest, population composition, and frequency of alleles favorable to antler growth were monitored throughout the simulations. For the population held at K, the frequency of favorable antler alleles declined slightly from that obtained in the population with no hunting. When the population was reduced below K, harvest decreased and their proportion of small bowls in the harvest increased compared with the population at K. In the population below K, the frequency of favorable alleles declined steadily, likely to fixation for unfavorable alleles. Ratio of bulls:100 cows in the two harvested populations were similar but ratios of small:large bulls were changing, with the population at lower density exhibiting a higher proportion of small bulls prior to harvest. Under the conditions imposed by our model, increases in age-specific antler size associated with increased nutrition resulted in greater selection against alleles favorable for antler growth under a scenario of selective harvest. Changes in density of moose populations and resulting effects of nutrition on the potential for antler growth must be considered when predicting the outcome of antler-based selective harvests