The muskoxen Ovibos moschatus in north and northeast Greenland: population trends and the influence of abiotic parameters on population dynamics

This paper presents the first long term (1960–89) data set on both muskox Ovibos moschatus density and weather parameters in north and northeast Greenland The muskoxen appear to have expenenced a 25 yr favourable period from the early 1960 ‘ies to the mid 1980’ ies, in which density increased and reached a maximum level The population minimum around 1960 probably represents a long term minimum, following a long, generally unfavourable period between 1940–60 Variation in the local population trends from the southern parts of the muskox distribution m northeast Greenland to the northeast parts, can be divided into three geographical areas (72°–75°N, 75°–77°30 ‘N, and north of 79°30’ N), where density dependent and density independent factors affecting muskox populations are apparently different Regional population stability does not increase towards the north Two density independent (abiotic) factors seem to be of prime importance in determining the muskox population density and distribution in northeast Greenland 1) the amount of winter precipitation affects the distribution of muskoxen negatively, inducing local migrations, but does not have a direct negative effect on large scale variation in density,11) ablation (i.e melting of the upper snow layer) and concomitant ice crust formation in winter have a highly negative effect on muskox density in the southern range, but not in the northern range The two abiotic factors, which show a considerable variation from north to south, are statistically independent and seem to be triggered by different weather conditions The predictions that follow from a climatic model both with respect to the direct influence of abiotic factors on muskox density and the indirect influence of climatic fluctuation, are not fully supported by the data presented here