(1) The population dynamics of eight wild reindeer herds in Norway, including the high arctic, were studied in relation to food abundance and population density. (2) Density-dependent effects were manifested through winter food limitation. (3) With increasing densities, density-independent factors such as severe weather had additional effects on recruitment, with consequences for population stability. (4) The density effect took the form of decreased juvenile survival, while adult survival in the most abundant and reproductive age classes was not affected. (5) At high density, subadult fecundity fell below the threshold body size for maturity. (6) The fecundity of adults was not affected by density. This finding accords with those made for other large nomadic rather than sedentary ungulates. (7) Density-dependent food limitation was most apparent at high population density, which conforms with the predictions of density-dependent life history models for large mammals.

A density-dependent decrement in size for wild reindeer from 12 different Norwegian herds at 16 different densities was shown using lower jawbone-length as the criterion of size. This criterion was tested and found to adequately predict body size of both bucks and does. Lactation in does did not affect jaw length but significantly affected dressed weights.A decrement in the size of does as a result of gross density was found. This size decrement was further analysed in relation to the habitat densities in winter (R =0.85) and in summer (R=0.75) separately, in order to estimate the relative effects of each factor. For herds with adequate food in winter (no signs of overgrazing of lichens) density in relation to summer habitat and mires yielded the highest predictive power in a multiple regression. For herds with adequate summer pastures, densities per winter habitat and lichen volumes showed likewise a highly significant correlation. The inclusion of the lichen volume data in the regression increased its predictive power. The major effect of resource limitation was to delay the time of calving because a maternal carry-over effect allowed the calf a shorter period of growth to be completed during its first summer. Neonate size at birth was highly correlated with maternal size regardless of the mean calving date although the latter was significantly delayed for small-sized does in food resource-limited herds. Likewise the postnatal growth rate of all calves were not significantly different during 50 days postpartum regardless of maternal conditions in winter feeding. The summer growth rates of bucks ≧1 year did not vary significantly between herds. The age of maturity of food resource-limited does was delayed by one year and growth ceased after the initiation of reproduction. This shows that under conditions of limited resources the does with delayed births of calves allocated less energy to body growth simply because they had less time to replenish body reserves once they were freed of the energetic demands of lactation. The overriding effects of such limitation of food resources is thus to produce a time-lag for the completition of all the important life-history events, such as growth, maintenance and reproduction. From a theoretical point of view, i.e. according to the reproductive effort model their only option is to try to overcome this time limitation to reproductive success.

Part 1: Diet selection was studied on free‐ranging reindeer fitted with an esophageal fistula (EF) and by analysis of rumen samples from reindeer shot in the field. Plant density was assessed from quadrats on field plots. Three measures of palatability were used, the nitrogen, fiber, and total non structural carbohydrate (TNC) contents of samples from clipped vegetation. As lichen density decreased the EK reindeer included progressively more vascular litter and pieces of winter dormant species in their diet. Diets with highest TNC and N/F and the lowest fiber, providing the most readily digestible diets, were selected. The combined density‐quality criterion gave the best prediction of their diets. In summer, forbs, and to some extent grasses and dwarf shrubs, were selected. Plants of highest density and in an early growth phase gave the best prediction of summer diets. In winter the variety of vascular plants utilized increased with increasing herd size and decreasing density of lichens in the vegetation. The width of diets was a function of diversity of available plants. It is suggested that dietary selection by reindeer has been a three stage process: evolution of a gastro‐intestinal system capable of digesting lichens containing secondary compounds, behavioural tracking of the plant production pulse, and diet width scaling according to density‐quality of all potential foods. Part 2: Wild reindeer closely followed the wave of vascular plant production in spring and summer with a significant correlation being found between the daily foraging time per habitat type and the highest concentration of green phytomass. Snow‐bed meadows were the most consistently selected vegetation type by the four herds studied, viz. Hardangervidda, Snøhetta, Prudhoe Bay, and Svalbard, during the summer. Habitat niche‐breadths were narrow during the winter, largely due to the limitation of access to the food supply by the snow‐cover, broadened as the landscape became clear of snow, narrowed again with the initiation of plant growth and broadened once more as the wave of plant production reached all habitat types. At high levels of food resources the alpine herd (Hardangervidda) narrowed the feeding niche breadth (or adopted a selective feeding strategy) as the habitat niche breadth increased. The high arctic herd (Svalbard) living in the least productive environment, at the same time of year adopted a generalist feeding strategy as their habitat niche breadth expanded. Part 3: In this part the temporal organization of a low‐alpine herd of reindeer (Hardangervidda) is described, and subsequently compared with those of two arctic herds. Their foraging efficiencies under different degrees of food availability were analysed, in order to test the hypothesis that food intake changes in response to the prevailing state of the food resources. The number of daily feeding bouts increased from 2 to 6 as the diet changed from the winter to the summer pasturage. Strong winds in winter and insect harassment in summer severely depressed the daily...

Effekter av ernaering og simlas kondisjon på vekst og størrelse av foster hos villrein.TERJE SKOGLAND, DVF, Viltforskningen, Tungasletta 2, N-7000 Trondheim, Norway. Abstract: Fetal growth rates and birth weights were studied in four wild reindeer areas in Southern Norway (Hardangervidda, Hallingskarvet, Knutshø, Forelhogna), representing high and low density populations, with a 5-fold difference in mean lichen winter-food availability. Fetal growth was depressed by 42% in the high-densitv Hardangervidda population, and mean birth weights were 3.7 vs. 6.2 kg, with a 10 days difference in mean birth dates. Fetal size was better correlated with maternal weight, than age. Maternal weights increased until 5 yrs. of age and then decreased in the high-density Hardangervidda population (but not so in the low density Knutshø-Forclhogna populations). 55% of the offspring died before weaning in the Hardangervidda herd, but no significant calf losses were found amont the large-sized does in the food-abundant areas. Sammendrag: Fostervekst og fødselsvekter ble undersøkt i fire villreinområder i Sør-Norge (Hardangervidda, Hallingskarvet, Knutshø og Forelhogna) som representerer høg-og lågtetthetsstammer, med en 5-foldig forskjell i gjennomsnittlig lavbeite-tilgang om vinteren. Fosterveksten ble nedsatt med 42% i høgtetthetsstammen på Hardangervidda og fødselsvektene var i gjennomsnitt 3,7 kg, mot 6,2 kg i det beste området, og med en 10 dagers forsinkelse i midlere fødselsdato. Fosterets størrelse var korrelert med morens vekt, som igjen var avhengig av hennes alder. Hos de minste simlene i det dårligste området økte vektene til 5-års alder, for deretter å avta for hvert gjenlevende år. Hos simlene i det beste området økte vektene til 10-års alder, og var da dobbelt så tunge som fra det dårligste området. 55% av avkommet døde før de var avvent med diing hos Hardangervidda-simlene, mens det ikke var noen statistisk målbar dødelighet hos kalvene i Knutshø-Forelhogna. Ybteenveto: Etelå-Norjan neljallå peura-alueella, jotka ovat Hardangervidda, Hallingskarvet, Knutsho ja Forelhogna, tutkittiin porosikion kasvua ja syntymåpainoja. Alueet edustavat ylintå ja alinta tiheyskantaa ja loytyy 5-kertainen eroavaisuus keskimåarin jåkålålaiduntaan talvisaikaan. Sikion kasvu aleni 42% ylemmåsså tiheyskannassa Hardangervidda-alueella ja syntymåpainot olivat keskimåarin 3,7 kg mutta 6,2 kg parhaimmalla alueella, ja 10 påivån myohastyminen keskimååråisesta syntymåpåivayksestå. Sikion suuruus oli vastaavuussuhteessa emon painoon, joka oli taas riippuvainen sen iåstå. Huonoimmalla alueella pieninpien naaraiden painot lisåantyivåt 5-ikåvuoteen asti, vahetåkseen sen jålkeen jokaista jåljellåolevaa elovuotta kohden. Parhaimmalla alueella naaraiden painot lisåantyivåt 10-ikåvuoteen asti, ja oli silloin kaksi kertaa niin raskaita kuin huonoimman alueen naarasporot. 55% jålkelåisistå kuoli ennenkuin ne olivat vierottuneet Hardangervidda-naarasporoista. Sitåvastoin ei ollut mitåån tilastollisesti mitattavissa olevaa Knutsho -Forelhogna-alueiden vasaku...

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 150.135.239.97 on Mon, 05 Oct 2015 16:54:56 UTC All use subject to JSTOR Terms and Conditions OIKOS 51: 238-242. Copenhagen 1988 Tooth wear by food limitation and its life history consequences in wild reindeer Terje Skogland Skogland, T. 1988. Tooth wear by food limitation and its life history consequences in wild reindeer. -Oikos 51: 238-242.Among small-sized, food-limited females tooth wear was twice as rapid as among well-fed, large females. This effect was caused by overgrazing of winter food resources. With increased tooth wear food-limited females had progressively depleted body reserves (weight and fat deposits) during half of their prime reproductive life-span. An important consequence of this was increased offspring losses and lowered reproductive success. Since energy allocation to growth, fattening, survival and reproduction is dependent on both food availability and effective mastication, tooth wear magnifies the effects of food shortage and counteracts the effects of foraging behaviour to enhance fattening and growth during summer. This result does not support the terminal reproductive effort hypothesis.