Objective: To determine the independent effects of climatic perturbation on the lifetime productive performance of female reindeer.

Principal Investigator: Dr Nicholas Tyler. Collaboration: Herder M.A.Sara

Reindeer data are collected in a herd of approximately 600 reindeer, owned and managed by Sámi pastoralists, which grazes all year round at a natural mountain pasture in Finnmark.

Life history data, including year of birth, maternity, live body mass (LBM), growth, pregnancy, calving and survival are currently available for >1500 individual reindeer in 12 successive annual cohorts. (That the number of reindeer for which there are data exceeds the number of reindeer in the herd size reflects the turnover of animals). Data have been recorded for each animal three times annually (September, December and April) since 1991. The dataset will be extended by a further four years during the study.

This longitudinal series is designed specifically to allow retrospective analysis of the effects of climate variation on life-history and demographic variables. Records of maternity for over 700 calves permit analysis of maternal effects on variation in life history traits. Complete lifetime records are also available for approximately 100 cases spanning two generations of reindeer. These data permit analysis of the heritability of selected life-history traits.

Weather: Data from Work Package 1. Local population density: data from the Directorate of Reindeer Husbandry. Herders’ knowledge of the types of local weather conditions that influence forage and foraging conditions in ways important for reindeer herding: Data from WP1 & 3. Method: Multivariate statistical analysis using generalised linear models based on logistic regression (e.g. Forchhammer et al. 1998, 2001) to determine the relative contribution of biotic and climate variables on the performance of reindeer.

Other research tasks include an evaluation of the separate effects of variation in density and climate on selected life history parameters; an identification of the temporal relationships (direct, indirect, lagged) between selected driving (meteorological) and response variables (life-history and demographic parameters). Maternity, life-history and weather data to will be used to determine (i) the relative contribution of maternal effects and climate variation on variation in the LBM of reindeer calves at weaning and (ii) the effects of variation in LBM on the survival (males and females) and the onset of reproduction (females) in those calves.

Finally, a research task will be a determination of the consequences of variation in early (4-16 months) development on the lifetime reproductive performance in female reindeer.