Open Collections

Moose habitat selection in relation to forest cutting practices in northcentral British Columbia

University of British Columbia

This thesis is primarily directed at documenting moose (Alces alces andersonii) habitat selection in an area containing a diversity of ages and styles of logging. The habitat occupation patterns of radio collared moose were recorded during the period April 1980 to May 1983 in an area centred 50 km northeast of Prince George B.C. The habitat associations of the radio collared moose were tested against the following alternate hypotheses. For the winter period: (1) Moose are not randomly distributed but select habitats with greater amounts of forage except when snow depth exceeds 90 cm. If snow depth exceeds 90 cm, then moose will select habitats with greater forest cover. (2) Moose are not randomly distributed but select the habitat with the greatest forest cover as protection from cold stress when air temperatures are lower than -20°C. For the summer (nonwinter) period: (1) Moose are not randomly distributed but select habitats with greater amounts of forage. (2) Moose are not randomly distributed but will select habitats with greater forest cover when air temperatures exceed 20°C. Moose followed a general annual pattern that varied according to the conditions prevalent during individual seasons. In spring, moose were found in open habitats. The spring to summer change of season saw moose move into habitat characterized by high forest cover values. In fall, moose were again associated with habitats with closed forest canopies. Early winter produced a dramatic shift of moose locations into open habitats. In midwinter and late winter, moose retreated to habitats with heavy forest cover. Moose were usually nonrandomly distributed with respect to habitat type. However, the alternate hypotheses generally failed to account for the departures from randomness. In spring, habitat associations suggested selection for habitats with greater forage biomass. However, the correlations between moose habitat associations and available forage biomass were not consistently high and one of four spring periods produced a negative correlation between available forage and habitat associations. In summer, moose habitat associations could be explained by moose avoiding heat stress. Fall habitat associations were never explicable by the tested alternate hypotheses. In early winter, habitat associations once again suggested that moose were selecting habitat which produced plentiful forage. During one early winter, however, there was a higher correlation between moose habitat associations and forest cover than between habitat associations and available forage. In one midwinter season moose habitat associations were consistent with the hypothesis that moose seek habitat with heavy forest cover when snow depths exceed 90 cm, but avoidance of cold stress would have produced the same pattern of habitat association. Neither of the tested alternate hypotheses could explain moose habitat associations in the other midwinter season, nor in two late winter seasons. Comparisons of calculated equivalent black body temperatures (T[sub e]) to known upper critical limits confirmed that heat stress is an important factor for moose in summer. Further, T[sub e] estimates revealed that heat stress and not cold, was affecting moose in winter and that the observed pattern of winter habitat associations could be explained by moose avoiding heat stress. There are hypotheses which were not explicitly tested which could explain moose habitat associations unexplained by the alternate hypotheses: moose may not select habitat on the basis of prevailing conditions, but rather (1) may be exhibiting patterns learned from their dams. (2) Moose avoidance of open areas in fall could be caused by their avoidance of human activity. Finally, (3) the large proportion of moose locations in heavy forest covers in all seasons could be a predator avoidance strategy. The hypothesis that moose require forest cover to protect them from heat stress was much more successful at predicting moose habitat associations than was the hypothesis that moose should seek habitat producing large amounts of forage conditional upon snow depth being less than 90 cm. In fact, forage production conditional upon snow depth could not unequivocally explain the pattern of moose habitat association in any season. However, this result should be interpreted as supporting the need for mature trees on moose range, to avoid heat stress, and not to minimize concern for moose forage requirements. In any season, good moose range will contain both forage and mature trees. On the study area, the heterogenous intermediate utilization logging should be conserved as moose habitat, especially where it occurs on moose winter range. Moose habitat can be conserved or improved with 4 ha clearcuts. Where logging economics demand large clearcuts, cover blocks and travel corridors should be provided to conserve moose habitat.

Text

2010-08-07

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

http://hdl.handle.net/2429/27194

Plant Science

University of British Columbia

Graduate