The relationship between moose (Alces alces) browsing utilisation and the occurrence of different forage species in Sweden

The occurrence of forage in Swedish forests and its consumption by moose at the bush and tree levels have been mapped with the help of data from the Swedish National Forest Inventory (NFI) 1969-1972 and 1983-1987. The correlation between forage occurrence and consumption has also been investigated. In total, some 120 000 sample plots form the basis of the study. Birch was by far the most common source of forage in forests and other land-use classes. The occurrence of forage species varied between regions and most of the forage occurred in low coverage classes, making forage consumption largely dependent on the presence of forage. Most of the browsing vegetation (91%) consisted of six species: birch, sallow/willow, pine, juniper, rowan, and aspen in order of foraging preference. Willow and birch were at the top of the consumption List in most regions, whereas the consumption of pine varied from region to region. Regression analysis showed that there was a significant correlation between the consumption of the six most preferred species and the proportion of available forage per species. It has also been established that the proportion of other forage affected the consumption of pine and birch. The most significant correlation, however, was between the occurrence of pine feed and the consumption of pine. No connection could be found between the occurrence of birch feed and the consumption of pine. Consumption was proportional to the share of forage in each coverage class and between the share of forage in forests and other land-use classes. Willow and rowan were among the most utilised forage, at an average of 21 and 19%, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.