Eigil Reimers

Relationship between Age and Tooth Cementum Layers in Norwegian Reindeer

A rapid freeze-sectioning technique for demonstrating annuli in tooth cementurn of rein- deer (Rangifer tarandus) is described. The technique has been applied to a reference material of 37 adult known-age animals and to 1,100 jawbones from two reindeer populations. The known-age ma- terial strongly indicates that the annulation is referable to age. The presence of special rut lines in teeth of males from high quality range indicates that rut-line formation might be related to condition. During a 5-year survey (1963-67) of populations of wild reindeer in mountain areas in southern Norway, some 1,100 lower jawbones from hunted animals were col- lected for age determination. This large sample made it necessary to work out a fairly rapid aging procedure. During the preliminary work several methods were at- tempted. All of these were based on the findings that annuli laid down in tooth den- tine or cementum can be used to determine age in different mammalian species (Laws 1952, 1953, Sergeant and Pimlott 1959, Low and Cowan 1963, McEwan 1963, Linhart and Knowlton 1967, and others). We did not succeed in revealing the an- nuli by grinding, and embedding pro- cedures required too much time. However, annuli can also be demonstrated in decalci- fied frozen sections, as mentioned by Mc- Ewan (1963:112). Although apparently not in use by other authors, freeze-section- ing seemed promising, being both rapid and simple. We accordingly worked out a procedure, details of which will be pre- sented together with a reliability test per- formed on specimens of known age. We noted early that the presence of special rut lines in teeth from males seemed 1 We wish to thank the Norwegian State Game Research Institute and the University of Oslo for financial support, and the State Veterinary Labora- tory for Northern Norway, Harstad, for the supply of known-age material. to be restricted to one of the two popula- tions studied. We feel that a discussion of this observation might also throw some light on the formation of stainable growth layers in teeth. MATERIAL AND METHODS The reference material consisted of lower jawbones from: 1. Eight males and 11 females (domestic) of known age supplied by the State Vet- erinary Laboratory for Northern Norway. 2. Sixteen males and 2 females tagged as calves and killed at different times of the year in Ottadalen wild reindeer area. This area is populated with a small number of animals in very good condition, and the quality of the range is considered excep- tionally good. 3. Thirty males and 19 females killed during the hunting season (Sept. 1-25) in Dovre wild reindeer area and determined from tooth development to be approxi- mately 16 months old. Compared with Ottadalen, the Dovre area is considered overgrazed, owing to previous overpopula- tion. During the survey period the animals here seemed to be in poor condition. The rest of the material consisted of mandibles from 139 males and 22 females from the Ottadalen area, and from 343 males and 511 females from the Dovre area, all killed during the hunting season.

CALVING TIME, GROWTH RATE, AND BODY SIZE OF NORWEGIAN REINDEER ON DIFFERENT RANGES

Among three populations of wild reindeer in alpine areas of varying climatic characteristics in southern Norway, growth rates were found to be most rapid, ultimate body size greater, and calving 2 to 3 wk earlier in North Ottadalen than in Rondane and Hardangervidda. The differences in growth rates, body size, and calving time are believed to be related to more favorable foraging conditions during the spring and summer periods in North Ottadalen. Less favorable winter foraging conditions in Hardangervidda than in Rondane or North Ottadalen did not result in different body weight development during winter in the three areas. Body weights of pregnant females decreased moderately from maximum in autumn to April. From April to June, North Ottadalen females suffered the highest weight drop owing to earlier calving time and later plant growth. The data support the hypothesis of summer growth and winter dormancy in reindeer.

Growth rate and body size differences in Rangifer, a study of causes and effects

The paper discusses growth rate- and body size differences in Rangifer; their causes and effects. Growth rates and autumn body weights vary considerably both within and between Rangifer subspecies. The variation measured is within limits found in animals of same genetical stock subjected to different environments. Reproductive age, pregnancy rate, calving time and mortality either are or may be functionally related to autumn body weights. The differences in growth rates and body size among Rangifer in different areas are caused primarily by differences in environmental factors during the summer, including stress. The quality of the winter pastures has a minor effect on the body size in areas where the summer conditions allow the animals to grow at their maximum rate. In areas where maximum growth rates for various reasons are counteracted, severely overgrazed winter pastures will contribute to reduced body size. Stress in the terms of human disturbance, insects and predators and the effect on Rangifer activity pattern and hence on growth rates and body size need to be more thoroughly dealt with. Forskjeller i vekst og storrelse hos Rangifer, en studie over arsaker og virkninger. Abstract in Norwegian / Sammendrag: Arbeidet diskuterer arsaker til og virkninger av vekst- og storrelsesforskjeller hos Rangifer. Vekst og hostvekter varierer betydelig bade innen og mellom de enkelte AEangj/er-underartene. Variasjonene er imidlertid ikke storre enn de som er beskrevet i bestander med samme genetiske utgangspunkt og utsatt for ulike miljoforhold. Alder ved kjonnsmodning, drektighetsfrekvens, kalvingstid og dodelighet er eller synes a vaere relatert til hostvektene. Vekst-og storrelsesforskjeller hos rein og caribou i ulike omrader skyldes i forste rekke forskjeller i miljofaktorene om sommeren, stress inkludert. Kvaliteten av vinterbeitene har liten effekt pa kroppsstorrelse i omrader hvor forholdene sommerstid tillater maksimal veksthastighet. I omrader hvor dette av forskjellige grunner ikke skjer, vil sterkt overbeitede vinterbeiter bidra til reduserte kroppsvekter. Stress i form av menneskelige forstyrrelser, insekter og rovdyr og effekten pa reinens/caribouens aktivitetsbudsjett og derigjennom pa vekst og kroppsvekt har krav pa storre forskningsinteresse. Rangiferin kasvun ja suuruuden eroavaisuuksia. Tutkielma syista ja vaikutuksista. Abstract in Finnish / Yhteenveto: Tyo kasittelee syita ja vaikutuksia Rangiferin kasvu - ja suuruuseroavaisuuksista. Kasvu ja syyspainot vaihtelevat huomattavasti seka yksittaisissa Rangifer - alalajeissa etta lajien kesken. Vaihtelu ei ole kuitenkaan suurempi kuin se mita on kerrottu laumoista, joilla on sama perinnollinen lahtokohta ja jotka ovat joutuneet erilaisten ymparistotekijoiden vaikuttamiksi. Sukukypsyysika, tiinehtyvyystaajuus, vasonta-aika ja kuolleisuus on tai nayttaa olevan suhteessa syyspainoihin. Syy kasvu - ja suuruuseroavaisuuksiin poroilla ja karibulla eri seuduilla nayttaa ensi sijassa olevan ymparistotekijoiden eroavaisuudet kesalla, stressi mukaanluettuna. Talvilaitumien laadulla on pieni vaikutus ruumiin suuruuteen seuduilla, joissa olosuhteet kesaaikaan sallivat enimmaiskasvunopeuden. Seuduilla, joissa tata ei tapahdu - eri syista johtuen, voimakkaasti ylirasitetut talvilaitumet vaikuttavat alentuneisiin ruumiinpainoihin. Stressi, inhimillisten hairioden muodossa, hyonteiset ja petoelaimet ja poron/karibun vaikutus toimintaan seka siten kasvuun ja ruumiinpainoon ovat seikkoja, jotka vaativat suurempaa tutkimuskiinnostusta.

GROWTH IN DOMESTIC AND WILD REINDEER IN NORWAY

Growth is compared between two wild reindeer ( vRangifer tarsndus ) populations and also be- tween these two populations and the now-dispersed Trio domestic herd from which the two aFild popula- tions were derived. The two wild populations are located in North Ottadalen a near-virgin area, and South Ottadalen an area that was partially heavily grazed. Both areas vere utilized by the Trio herd. Intensive herding of the Trio animals is deemed responsible for their 23 to 43 percent losver dressed weights when compared with the South Ottadalen herd. The longer diastema lengths of the North Otta- dalen population,, when compared with both the South Ottadalen and the Trio populations, reflect the dif- ference in range quality between the North and South Ottadalen areas. GROWTH IN DOMESTIC AND WILD REINDEER IN NORWAY EIGIL REIMERS, The Norwegian Stote Game Reseorch Institute, Vollebekk Abstract: Growth is compared between two wild reindeer ( vRangifer tarsndus ) populations and also be- tween these two populations and the now-dispersed Trio domestic herd from which the two aFild popula- tions were derived. The two wild populations are located in North Ottadalen a near-virgin area, and South Ottadalen an area that was partially heavily grazed. Both areas vere utilized by the Trio herd. Intensive herding of the Trio animals is deemed responsible for their 23 to 43 percent losver dressed weights when compared with the South Ottadalen herd. The longer diastema lengths of the North Otta- dalen population,, when compared with both the South Ottadalen and the Trio populations, reflect the dif-

WINTER MORTALITY AND POPULATION TRENDS OF REINDEER ON SVALBARD, NORWAY

During the winter of 1975/76 on Edge0ya, Svalbard, an estimated 23%0 of the reindeer population starved to death. This implies a population net decrease of 16% and a 65% loss of the calves entering the winter in 1975. Animal body weights and fat accumulation in midsummer indicate that the surviving reindeer seemed to recover rapidly. These data support the hypothesis that weather conditions may limit arctic populations of Rangifer without a preceding overgrazing of ranges.

Reindeer and caribou ( Rangifer tarandus ) response towards human activities

We address the question of how human activities and infrastructure influence reindeer/caribou’s ( Rangifer tarandus ) behaviour and habitat use and review studies based on current methodologies. Anthropogenic activities have a direct affect on Rangifer behaviour through the senses hearing, sight and smell, and all of these are important tools for behavioural risk assessment. Short term indirect responses, such as habituation, sensitisation, avoidance, and displacement, develop through neutral, positive or negative associations towards stimulus in terms of Rangifer ’s ability to experience, learn, and remember. Long term behavioural responses develop through interaction with predators and, for reindeer, also domestication. A survey of the literature dealing with behavioural studies reveals that although Rangifer in most cases retreat from anthropogenic activities, comfort distances (i.e. distances beyond which animal behaviour or activity are not influenced) are relatively short. In most cases, energetic implications appear moderate and small compared to other natural, biotic influences such as disturbance (and death) caused by insect and/or predator harassment. Unless obstructing access, physical constructions of various kinds apparently have limited effects on Rangifer behaviour or habitat use. On the other hand, constructions that do obstruct or limit access and recreational or other motorized and non-motorized activities appear to have stronger impacts on avoidance and redistribution of Rangifer . Behavioural effects that might decrease survival and reproduction include retreat from favourable habitat near disturbance sources and reduction of time spent feeding with resulting energy depletion over time. Rangifer habitat use, habitat avoidance, and feeding preferences are governed by a complexity of natural interacting factors. Domestication, habituation and sensitisation are essential in shaping Rangifer ’s adaptability, and should be included in future studies on reindeer and caribou responses towards various anthropogenic activities. Although cumulative effects from human activities are likely, it remains difficult to separate these from natural variations in Rangifer habitat use and demography. Habitat avoidance towards various human infrastructures and activities is reported, but most studies reporting relatively far (4-25 km) avoidance distances relied on measurements of range properties and animal distribution recorded on 1-2 days annually in winter to induce a potential response from the animals and lack important environmental variables and/or alternative hypothesises. This methodology should be improved in order to enable identification of correlation versus causation. Studies relying on animal behaviour measurements can more correctly identify and test responses to various stimuli while also controlling for degree of domestication and other various environmental variables, but only in a limited time and spatial scale. Furthermore, such studies may not necessarily capture potential population consequences from disturbances. Thus, there are important weaknesses in the two leading methodologies (measuring animal behaviour and indirectly mapping regional/population movements and habitat use through measurements of range properties). To best study Rangifer ’s responses towards anthropogenic infrastructure and activities, we propose that the two methodologies be combined and supplied with modern GPS/telemetry. Abstract in Norwegian / Sammendrag: Rein og caribous reaksjon pa forskjellige menneskelige aktiviteter og installasjoner Vi adresserer sporsmalet om hvordan menneskelig aktivitet og infrastruktur pavirker rein/caribous ( Rangifer tarandus ) atferd og omradebruk og gjennomgar publiserte arbeider basert pa aktuelle metoder. Antropogene aktiviteter har direkte effekt pa reinens atferd via horsel, syn og lukt; alle er viktige for deres risikovurdering. Kortsiktige indirekte reaksjonsmonstre, slik som habituering, sensitivisering, unnvikelse og fortrengning utvikles gjennom noytrale, positive eller negative opplevelser av stimuli i henhold til erfaring, laering og hukommelse. Utviklingen av permanente atferdsmonstre skjer ved samvirke med predatorer og for reinens del, ogsa ved domestisering. En litteraturoversikt om atferdsstudier viser at selv om Rangifer i de fleste tilfeller unnviker antropogene virksomheter, sa er de avstander dyrene velger a ha mellom seg og infrastruktur uten at normalatferden endres, relativt korte. De energimessige implikasjonene er ogsa beskjedne sammenlignet med virkningen av naturlige stressfaktorer sa som forstyrrelser (og dod) forarsaket av insekter og predatorer. Fysiske installasjoner av ulik art har ogsa begrenset effekt med mindre de fysisk hindrer Rangifer s omradebruk. Pa den annen side vil fysiske installasjoner, som hindrer eller begrenser bruken av omrader, og trafikk, bade fottrafikk og trafikk med motorkjoretoy, kunne ha sterkere virkning pa unnvikelsesatferd og omradebruk. Atferdsmessige effekter som kan redusere overlevelse og reproduksjon omfatter unnvikelse fra beiteomrader naer forstyrrelseskilder. For Rangifer er det negative resultatet av dette oket aktivitet, redusert beitetid og nedbygging av energireserver. Rangifer s omradebruk, unnvikelsesatferd og naeringspreferanser bestemmes ut fra et kompleks av naturlige og gjensidig pavirkende faktorer. Domestisering, habituering og sensitivisering som er sentrale begrep i utformningen av Rangifer s tilpasningsevne, bor inkluderes i fremtidige studier av rein og caribous reaksjon pa antropogene aktiviteter. Selv om en kumulativ atferdseffekt av menneskelige aktiviteter er mulig, er det vanskelig a skille slike fra naturlige variasjoner som folge av variasjoner i omradebruk og bestandsdynamiske forhold. Habitatunnvikelse som folge av menneskelig pavirkning er rapportert. De fleste studiene som rapporterer relativt lange unnvikelsesavstander (4-25 km) er imidlertid basert pa malinger av beiteslitasje og lokalisering av dyr registrert i lopet av 1-2 dager arlig i lopet av vinteren og mangler viktige miljoparametere og/eller alternative hypoteser. Denne metoden bor forbedres for a kunne skille mellom korrelasjon og kausalitet. Malinger av atferd gjor mulig en mer korrekt testing av Rangifer s reaksjon pa ulike antropogene stimuli samtidig som man kontrollerer for graden av domestisering og forskjellige miljofaktorer. Atferdsstudiene avgrenses imidlertid i bade tid og rom og vil vanligvis ikke fange opp eventuelle bestandsdynamiske konsekvenser av forstyrrelser. Det hefter folgelig svakheter ved begge de to dominerende metodene som i dag anvendes; maling av atferd og bestandsfordeling og indirekte kartlegging av omradebruk ved maling av beiteslitasje. For a oppna en bedre studiedesign for maling av Rangifer s reaksjon pa antropogen infrastruktur og tilknyttede aktiviteter foreslar vi at de to metodene kombineres og suppleres med GPS/telemetri teknologi.

Behavior responses of wild reindeer to direct provocation by a snowmobile or skier

To better understand the effect of winter tourism and public recreation on wild mountain reindeer (Rangifer tarandus tarandus), we compared reindeer response distances after direct provocations by skiers and snowmobiles during 3 winters in Setesdal-Ryfylke, southern Norway. Reindeer being provoked by a snowmobile discovered the observer at longer distances than reindeer being provoked by a skier (370 [skier] vs. 534 [snowmobile] m; P = 0.002), while total flight (756 vs. 570 m; P = 0.037) and total distance moved (970 vs. 660 m; P= 0.008) by reindeer were shorter for snowmobile than skier provocation. The fright (328 [skier] vs. 328 [snowmobile] m), flight (281 vs. 264 m), and escape (543 vs. 486 m) distances due to skier or snowmobile provocation were not different (P > 0.05). For pooled data, fright distances of reindeer were affected by 2 other independent variables. Fright distance was longer when the animals were provoked from below rather than from above (P= 0.046), while their escape distances were longer when the animals were lying rather than when grazing prior to being provoked (P < 0.05). Based on maximum and minimum distance moved for all provocations pooled, daily estimated energy expenditure of reindeer increased between 31 and 590 kJ, representing 0.2 and 2.9% of their estimated total daily energy expenditure. Overall, provocations by skiers or snowmobiles revealed similar behavioral responses. An estimated maximum rate of 3 daily encounters between reindeer and skiers or snowmobiles during winter vacation and Easter would result in moderate energy costs that should be easily compensated for and thus have no demographic consequences. Increasing snowmobile use will, however, significantly expand the area where humans are in contact with reindeer during winter and spring, a period of negative energy balance for reindeer.

Rangifer population ecology: a Scandinavian perspective

Population ecology is concerned with measuring changes in population size and composition, and identifying the causes of these fluctuations. Important driving variables include animal body size and growth rate, and their relationship to reproduction and mortality. Among wild and domestic reindeer (Rangifer tarandus tarandus), reproductive performance, calving time, calf birth weight and neonatal mortality are strongly correlated to maternal weight. Heavy females enjoy higher pregnancy rates, calve earlier, and give birth to heavier calves which have a higher neonatal survival rate than light females. Most studies indicate that both weaning weight of a calf and mature body weight correlate to its birth weight. Calf body weight and composition influence the rate of attainment of sexual maturity. Females which breed as calves suffer reduced growth and give birth to smaller calves, which suffer higher neonatal mortality and lower rates of postnatal growth. A yet unresolved question is whether reindeer body weight, and hence reproductive performance and neonatal mortality, are more strongly influenced by winter than by summer grazing conditions. This paper reviews population ecology studies on wild and domestic reindeer and promotes the view that body size in Rangifer is determined primarily by grazing conditions during the summer.

Summer response distances of Svalbard reindeer Rangifer tarandus platyrhynchus to provocation by humans on foot

The objective of our study was to examine response distances of Svalbard reindeer Rangifer tarandus platyrhynchus to direct provocation by humans on foot during summer in areas subject to combinations of high or low human activity, and hunting or no hunting. We hypothesised that Svalbard reindeer can become habituated to human activity even when hunted. Reindeer sight, fright, flight and running response distances were measured in response to direct provocation by humans on foot in five areas chosen for their degree of human activity and hunting. No differences in sight distance were found among the five areas. Reindeer in the area with the most human activity in summer and no hunting (Adventdalen) had shorter fright, flight and running distances than reindeer in the area with little human activity and no hunting (Reinsdyrflya). Reindeer response distances in the three areas with hunting and moderate human activity were similar and intermediate to areas with high and low human activity and no hunting There were significant negative correlations between the fright, flight and running distances and the amount of human activity in an area, and with the exception of running distance having a borderline significant value, there were no correlations with intensity of hunting. Our findings suggest that Svalbard reindeer become habituated to human activity and that hunting probably has only a weak or even no influence on it. Furthermore, these findings do not lend support to the hypothesis that reindeer that are hunted by humans are less likely to habituate to human activity than those that are not hunted.

Life-history variation of wild reindeer ( Rangifer tarandus ) in the highly productive North Ottadalen region, Norway

Variation in life history is a central key to understanding population dynamics, and density dependence and climate are important factors in shaping life-history variation in ungulates. Early growth is often sensitive to adverse conditions and this may in turn affect juvenile survival and age at first reproduction. We report variation in body weight of 5079 reindeer Rangifer tarandus from North Ottadalen, a very productive reindeer area in Norway, sampled over 14 years in the period 1967–1989. The North Ottadalen reindeer herd was established in 1964 from a winter herd of some 500 semi-domestic reindeer, and allowed to grow to a peak of over 3300 reindeer in 1974, after which increased harvest decreased the population size. The proportion of lactating yearling females varied between 0% and 50%. Lactating females had lower autumn body weights than non-lactating females. A decline in body weight with age, i.e. senescence, was evident in both males and females from around 7 to 9 years of age. Body weights of all age and sex groups as well as the proportion of yearling females lactating decreased over time, and more so in younger than older males, although the population size declined markedly after the population peak in 1974. We found no effect of the North Atlantic Oscillation or local weather on body weight. The possible causes of the marked decline in performance with time in the North Ottadalen reindeer herd are discussed, and it is suggested that this may be related to the transition from being managed as semi-domestic to wild (i.e. hunted).