Causes and consequences of spatio-temporal life history variation in semi-domesticated reindeer

Density-dependent regulation of mortality in winter, and inf1uences of climatic and habitat quality on fecundity are central processes in the population dynamics of ungulates in northern environments. However, the population level consequences of such ext ernal environmental influences are moulded by state of the individuals within the population, in particular the individuals' previous life histories and their present age. The interface between individual level responses to environmental variability and p opulation demography will be the subject of the present PhD-project using semi-domesticated reindeer in Norway as the study animals. Semi-domesticated reindeers provide a u nique opportunity to obtain large quantities of relevant information on the subjec t matter. Longitudinal data from selected herds for which the fates of a large number of individuals are known for up to 10 years and ~1aughterhouse data gathered at a large geographic scale, will be used to answer the following questions: (i) How does s patio-temporal variability in density, climate, pasture quality and age composition influence different demographic parameters in reindeer? (ii) What are the consequences of early development of reindeer calves on subsequent life history? (i ii) How does age influence females reproductive strategy in different environments? (iv) How does spatio-temporal environmental variability and variation individual life history influence the growth rate and production of herds, and thus the optimal harv esting strat egies for the reindeer herders?