Can management regulate the population size of wild reindeer ( Rangifer tarandus ) through harvest?

• Published in: Canadian Journal of Zoology
• Main Authors: Strand, O., Nilsen, E.B., Solberg, E.J., Linnell, J.C.D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2012
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Norway; Rangifer tarandus
• Online Access: http://dx.doi.org/10.1139/z11-123; http://www.nrcresearchpress.com/doi/full-xml/10.1139/z11-123; http://www.nrcresearchpress.com/doi/pdf/10.1139/z11-123

We analyzed a 51-year time series of harvest data from a small population of wild mountain reindeer ( Rangifer tarandus (L., 1758)) in southern Norway and examined the relative role of biological and management related processes as drivers of its population dynamics. The population is monitored annually to obtain information on population size and structure, and since 1980, managers have attempted to stabilize the population at about 1.1 reindeer/km 2 . The harvest increased at a higher rate than the population size and was thus probably sufficient to not only limit but also regulate population size. Phase plot analyses showed that the population has varied around a density attractor of about 1.0 reindeer/km 2 since 1980 and is therefore close to the targeted population size of 1.1 reindeer/km 2 . However, the annual harvest explained only 49% of the variation in population growth rate (λ) in a linear regression model, despite relatively low variation in population productivity (proportion of calves). Between 1999 and 2006, the population in Forolhogna declined by almost 50% before recovering to its previous size. We suggest that both imprecise population estimates and high harvest effectiveness at reduced population densities contributed to this decline. As such, this study points to some of the obstacles managers are facing when trying to stabilize productive ungulate populations even when they live in closed populations and in stable, predator-free environments.