Calf Harvest and Reproductive Rate of Reindeer in Finland

Abstract

Despite a 2-fold increase in density and consequent habitat deterioration, reproductive rates of reindeer (Rangifer tarandus tarandus) in Finland have increased even in herds without supplemental feeding. Winter foods are limited, and reindeer dig for food beneath snow the entire winter; calves commonly share feeding sites with their mothers. Using 28 years of data on calves per female for 56 herds, we found that calf removal led to compensatory changes in reproductive rates in 12 northern herds and the strength of the relationship between harvest rates of calves in years t; and calf to female ratio in year t+1, was greater the longer the period of use of snow-covered foods. Calf harvesting appeared to relieve density-dependent suppression of reproductive rate, even at high reindeer densities