Effects of intensive harvesting on moose reproduction

1. It has been hypothesized that a balanced adult sex ratio is necessary fo r the full participation of ungulate females in reproduction and therefore high productivity. We tested this general hypothesis by combining two compl ementary approaches. 2. First, using telemetry (n = 60) and annual aerial censuses between 1995 and 1998, we compared two moose Alces alces populations in Quebec, Canada, one non-harvested and the other subject to intensive sport harvesting from the end of September to mid-October. We tested the following predictions fo r the harvested population: (i) females increase movements and home ranges during the mating period; (ii) the mating system is modified, with the appe arance of groups of one male and many females; (iii) subadult males partici pate in reproduction; (iv) the mating period extends over two to three oest rus cycles; (v) the calving period extends over several months; and (vi) pr oductivity declines. 3. Daily movements and home range sizes during the mating period did not di ffer between harvested and non-harvested populations. Most groups observed were male-female pairs. Subadult males (1.5-2.5 years old) were only observ ed with females in the harvested population. Mating and calving periods did not differ between populations. The proportion of females that gave birth and the number of calves produced were also comparable in the two populatio ns. 4. Secondly, we also assessed the existence of a relationship between popul ation productivity and percentage of males in various management units of t he province of Quebec that were characterized by a wide range in sex ratios . Contrary to prediction (vi), the number of calves per 100 adult females w as not related to the percentage of adult males in the population. 5. The participation of young adult males (subadults) in reproduction in ou r harvested population may have compensated for the lower percentage of adu lt males, and thus productivity was unaffected. We therefore reject the hyp othesis that intensive harvesting, at least at the level we observed, affec ts reproduction and population productivity. 6. As there are some uncertainties regarding the long-term effects of high hunting pressure, however, managers should favour sex ratios close to level s observed in non-harvested populations.