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Reindeer grazing problems 283Fig. 2. Reindeer herd at calfingtime, in the month of May. Bythe Same artist Nils Nilsson Skum,courtesy of Nordiska museet.mer is eaten by the reindeer. This is an averagefigure for all the 43 "Lap-village" communities inSweden, and it is valid only with the energy standardand other approximations used. During theautumn period the percentage is a little higher,about 6 to 7. The highest value, however, is measuredin winter, when the degree of utilization is20-25 per cent. The maximum winter figures areabout 40 per cent. This figure seems to representthe hardest utilization that can be maintained fora long period within those areas in northernmostSweden where conditions are at their best for thereindeer husbandry. It is important to stress thatin most years packed snow layers and ice sheets onthe ground make a substantial part of the lichengrazing unavailable. Consequently often all lichenthat can be reached in winter by the reindeer iseaten, resulting in overgrazing of large areas.During catastrophic years most of the wintergrazing ground is covered by ice or hardpackedsnow or the surface crust on the snow is too hardfor the reindeer to penetrate, and they may die bythe hundreds. The winter period is obviously thecritical time of the year. In the long run, the grazingavailable during winter determines the extent towhich reindeer can be kept. This is not only truebecause of the mentioned hard utilization and dif-19-652151 APhS 50ficult availability, but also an effect of the almostcomplete absence of protein and the very limitedquantities of minerals in the monotonous lichendiet. Because of the deficiency in protein, the reindeerusually decrease strongly in body weight,breaking down their own muscular tissues.The cirumstances mentioned will give an idea ofthe extent to which the reindeer exert an influenceon vegetation and flora. It is clear that their effectis slight, except locally, during the growth periodbut of considerable magnitude in the winter season.As mentioned the grazing during winter consistsmainly of different species of lichens. Certain areasare frequented each winter by the reindeer. Thetypical plant community in these areas is a pineforest with lichens dominant in the bottom layerand V accinium vitis-idaea as well as Empetrumhermaphroditum in the field layer. The most commonlichen species are Cladonia alpestris, 0. rangiferina,C. silvatica (agg.) and Stereocaulon paschale.Where the grazing intensity is high the lichen layeris kept low. Large patches are almost totally depletedof lichens, nothing or only basal parts ofthe lichen thalli remaining. In certain areas, as inKaresuando (the northernmost parish in Sweden),the dominant is Stereocaulon, covering vast areas.The opinion has been stated that this is an indica-Acta Phytogeog1·. Suec. 50