THE IMPORTANCE OF DIVERSITY IN THE DIET OF MOOSE

Abstract

The array of plant species eaten by moose (Alces alces) has been well documented however, whether their dietary diversity reflects a basic feeding strategy or simply a scarcity of preferred species has not been tested. Closely observed moose on Isle Royale in summer consumed a number of species during each period of sustained feeding (X̄ = 56 ± 4.8 min). To determine preferences when preferred species are not limited, captive moose were offered common, preferred browse species ad libitum. While showing distinct preferences, the experimental animals did not select a monotypic diet. Vegetation analysis revealed that, given the availability of quantitative needs (21.6 kg/day) by feeding on one preferred species; however, they selected for more than one species, suggesting that diversity was an objective. Preferred foods of captive and wild moose were not the same, suggesting that previous experience and/or diet may affect preference. Speculations on the relationship between availability of various species and the nutritional implications of selecting a diverse diet are made.