FEED SELECTION AND RADIOCESIUM INTAKE BY REINDEER, SHEEP AND GOATS GRAZING ALPINE SUMMER HABITATS IN SOUTHERN NORWAY

Radiocaesium concentrations (Cs-137) were measured in extrusa from oes ophageally fistulated sheep, goats and reindeer grazing alpine summer vegetation in Griningsdalen, Southern Norway in the period 1987-1989. The experiments with sheep and goats were conducted in different subal pine areas. The reindeer were, in addition, grazed in three areas in t he low alpine zone. Glazing bouts lasted for 10-20 min and bite select ions were recorded every 15 s through the grazing bout. Reindeer and g oats had the most diverse food selection whereas sheep fed mainly on g rasses, forbs and to some extent, on leaves of willow. The reindeer ex trusa had the highest radiocaesium activity, apparently to a large ext ent caused by intake of lichens in areas where this type of plants wer e present. Depending on the type of vegetation in the grazed areas the transfer of radiocaesium from soil to grazed vegetation (Bq kg(-1) dr y extrusa/Bq m(-2) soil) was estimated to 0.02-0.04 in sheep, 0.02-0.0 5 in goats and 0.02-0.43 in reindeer for 1987.