The ecology and management of moose in North America

During the past decade, in North America, many concepts about moose have changed. Fears that they would be extirpated have been replaced with the knowledge that, when in good habitat, they can withstand heavy hunting pressure. Many of the past estimates of moose numbers and population trends have been guesses, or have been based on information of a subjective nature. In general, very little is actually known about previous moose numbers and fluctuations. Aircraft are now being used extensively to census moose. A transect-line survey method is widely used, however, in Ontario, the results obtained by this method are considered to be too variable to be of value. A system of intensive search of 25-square-mile (65-sq.-km.) plots has now been adopted for use in the province. Results of aerial surveys indicate that densities of 1 moose per 1 or 2 square miles (2.6 or 5.2 sq. km.) are not uncommon for large units of range. The results of studies conducted in British Columbia and Newfoundland have shown that the reproductive rate of moose is quite variable. Three aspects of moose reproduction — breeding and pregnancy rates of yearlings, pregnancy rates of adults, and the occurrence of twins — were found to vary from area to area. There are important differences in the winter food and cover of moose on eastern and western ranges. In the East the key browse species are trees, while in the West the most important species are shrubs (Salix spp.) . Moose on eastern range tend to be rather uniformly distributed in winter, while on western range large concentrations are much more common. The possible role of factors that limit moose populations is considered by the use of three examples : moose on optimum range, on islands, and at the southern limit of eastern range. Over most of the area of moose range, food shortage, interacting with winter tick infestations, appears to be the primary limiting factor. The inadequacy of the annual harvest is the most pressing problem in the management of moose. Hunting regulations across the continent vary from completely closed seasons to long open seasons for the hunting of animals of any sex or age. Browsing by moose appears to have the greatest effect on the flora of the secondary succession of the white spruce-balsam fir-white birch associations of the boreal forest formation. White birch is highly palatable to moose at all times of year and under heavy browsing pressure it may be eliminated. Balsam fir is a winter food and is not seriously affected until the carrying capacity of the range is reached. Of the shrubs, Taxus is most heavily utilized and it virtually disappears when heavily browsed.Pimlott Douglas h. The ecology and management of moose in North America. In: La Terre et La Vie, Revue d'Histoire naturelle, tome 15, n°2-3, 1961. pp. 246-265