influence du climat et de la prédation sur l'utilisation de l'habitat et la ...

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Thermalmapping
We found no difference in the power necessary to maintain the inner temperature of the
two taxidennic mounts exposed to simi lar thennal environments (Appendix 2, paired t-test, t
= -0.80, df = 45, P = 0.426) so data from both mounts were pooled in analyses. Operative
temperature had a general negative effect on the power consumed by mounts (Appendix 3,
Table 4 .1). ln the full model including the six initial microhabitats, we found that Tc
interacted with the microhabitat to influence the power consumed by the mounts (Table 4 .1
model 1). This means that ranking of microhabitats (from microhabitat of best "thennal
quality" to microhabitat ofworst "thermal quality") was not the same at cold and warm Tc.
Table 4. 1 : Linear mixed effect models for the power consumed by porcupine mounts
exposed to available conditions of operative tel11perature (Tc), Parc National du Bic, Québec,
December to March 2004-2005. We first tested fo r an effect of Tc, microhabitat, and
Tcx microhabitat. We removed non-significant (NS) interactions between Tcx microhabitat
from final models. When testing the effect of microhabitat, we first considered aIl
l11icrohabitats sampled (i .e. "den", "ground open", "ground co vered" , "deciduous", "conifer
open", "conifer coverecf': model 1). Then we grouped certain microhabitats and compared
effects of groups of microhabitats ("den" vs non-den microhabitats: model 2; arboreal vs
terrestrial: model 3; open vs covered: modeI 4). The type and number (n) ofmeasures
considered for analysis are specified
Model Categories of Measures Tc Microhabitat Tcx microhabitat
microhabitat considered
6 : initial Ali F {I,808) = 48.75 F (5,808) = 1.75 F (5 ,808) = 4.29
categories n = 883 p