ABSTRACT. Twenty females from the Rivikre George caribou herd were captured in April 1987 in northern Quebec and were held in a zoo in Quebec City. Until November 1989, they were kept in an enclosure with a male from the same herd and they were fed ad libitum with pelleted concentrates and hay, supplemented with fresh deciduous leaves in summer. Daily food consumption exhibited an annual cycle, peaking at over 100 g-kg-0.75 in summer and decreasing to CU. 70 g-kg-0.75 by late winter. Food consumption decreased at the end of the last summer, due perhaps to lower hay quality. Mean body mass of adult females increased from 90 kg upon arrival at the zoo to = 115 kg in the autumn of 1987, = 125 kg in September 1988, and then decreased to 113 kg in November 1989. Pregnancy rate increased from 65% in 1987 to 82% in 1989 for animals captured in the wild. Two females born in captivity in 1987 became pregnant as yearlings, while 1 of 3 yearling females ovulated in 1989. Mass of calves at birth was higher in 1988 and 1989 than in 1987, while the calving period advanced by two weeks in the last two years. Growth of calves in summer was unrelated to birth mass and was higher in 1987 and 1988 (450-490 g-d-1) than in 1989 (365 g-d-1). Male calves grew at a faster rate than females. Carcass composition, in terms of lipids, protein and water, did not differ much between calves and yearlings born in captivity and free-ranging animals collected in 1983-84. However, the mass of each component was much lower in free-ranging lactating females than in captive ones. All captive females that had ovulated before necropsy, including one yearling, had at least 7.2 kg of stored fat.

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Following a two-stage sampling plan, 44 1-km2 primary units were systematically allocated between 53 and 59 ° latitude throughout northern Québec to estimate the biomass of terrestrial lichens. Lichens were collected in two secondary units (0.25 m2) located in parts of each primary unit where lichens were visible from a helicopter (lichen stratum). Overall, the lichen stratum covered 51% of the study area and lichen biomass averaged 1223 kg/ha (dry weight; SE = 201; n = 44). Almost 85% of the variance of this mean was attributable to variability between primary units. The biomass in the west was greater than in the east; it was the highest in the [Formula: see text]700-mm precipitation zone and the lowest in the 500- to 599-mm zone. Data on percent plant cover indicated mat mosses increased in importance over lichens in the east. There was a clear relationship between lichen biomass in secondary units on one hand and mat thickness and percent lichen ground cover on the other. Cladinia stellaris (Opiz) Brodo was the most common species; Alectoria ochroleuca (Hoffm.) Mass. and Cornicularia divergens Ach. were typical of the north, whereas Cladina mitis (Sandst.) Hustich characterized the south of the study area. The annual consumption of lichens by caribou was probably 0.5-0.9% of the available biomass in 1987. Key words: biomass, caribou, Cladina, lichens, Quebec.

Ground coverage by woody and herbaceous plant species and standing biomass of vegetation susceptible to being grazed upon were estimated in a 156 km2 area where 190 muskoxen were censused during the preceding autumn. Habitat use was estimated with droppings census. Six terrestrial habitat types were delineated on 1:32 000 aerial photographs and randomly sampled: low shrub on xeric sites (LSX; 64 km2), low shrub on mesic sites (LSM; 45 km2), bare ground (BG; 27 km2), forest-tundra (FT; 12 km2), wet meadow (WM; 2 km2) and riparian willows (RW; 1 km2). Dominant plant species varied greatly between habitat types, and only a few such as Betula glandulosa, Salix arctophila, and Polygonum viviparum were common. Tall shrubs were present only in RW where they covered most of the ground, and in FT. Low shrubs were uniformly distributed and covered 18-32% of the ground, with the exception of RW (5%). Ground cover by herbs had a similar range (i.e. 20-37%), except in RW where the mean exceeded 50%. Mosses and lichens occupied about half of the ground everywhere. Phytomass exhibited great variation within and between habitat types; extreme values averaged 892 kg*ha-1 in LSX, and 1965 kg*ha-1 in LSM. However the difference was not significant due to limited sample size and within habitat variance. Nevertheless the mass of herbaceous dicots was greater in RW than in any other habitat type. Total phytomass was 2-20 times greater in northern Québec than in Greenland. Based on droppings density, muskoxen preferred RW over BG and FT, and LSX over BG. Although the density of muskoxen in the study area was high relative to other muskox ranges, habitat quality and quantity should allow continued population growth