The ecology of reproduction in reindeer/caribou (rangifer tarandus) - implications for population dynamics

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Determining the patterns and causes of variation in life history strategies is one of the main goals of ecology, as such variations shape both population dynamics and in turn the evolutionary biology of different species. In heavily managed large herbivore populations, evolutionary and ecological constraints are different from natural populations as the sex ratio and age structure is normally manipulated through harvesting. The resulting skews in sex ratio and age structure may have implications for life history strategies and in particular features related to reproduction; such as conception date, synchronization of the rut, conception rate and gestation length - parameters influencing timing and synchrony of birth as well as birth rate and birth weight. My aim is to investigate the role of male percentage and age structure on the ecology of rut in reindeer, and its implication for population dynamics. Specifically, we will examine (a) the influence of male proportion and age structure on the change in body mass of males and females reindeer during rut; (b) the influence of male proportion and male age structure on female activity during rut, and (c) provide insight on how the proportion of males and male age structure influence rutting behaviour and the synchronies of conception and calving in reindeer. The strength of this research resides in its use of an experimental approach by manipulating the composition of the male segment of the population, which is normally difficult to perform especially in large mammals in the wild. Since we address questions that are of interest both for theoretical ecology and management, the results of the study will be of great interest for management of harvested large herbivore populations worldwide. Indeed, given that most ungulate populations are harvested throughout the world and that in most cases, adult males are preferentially harvested, the results of this project may contribute to the development of new and more appropriate management strategies that sustain the long term productivity of the manipulated populations. The project will also contribute to the training of highly qualified personnel in behavioral and evolutionary ecology.