Fluctuations of an introduced population of Svalbard reindeer: the effectsof density dependence and climatic variation

The relative contribution of density-dependent and density-independent Fact ors on variation in the population growth rare of an introduced population Svalbard reindeer was studied by time series analysis. No significant effec ts of either direct or delayed density-dependence were found. Annual variat ion in population growth rate was strongly negatively related to amount of precipitation during winter (i.e. high growth rates occurred when winters w ere dry). There was no significant relationship between the NAG-index and t he population growth rate. However, there was an interaction between popula tion density and the climatic variables, i.e. the effect of climate was str onger at high densities. These results support the view that population flu ctuations of arctic ungulates are strongly influenced by stochastic variati on in climate.