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

65
feeding behaviour for the population (obtained from Fig. 4.3). Means were computed over six
classes of Te «-19.9°e, -19.9 to -15°C, -14.9 to -10°C, -9.9 to -5°C, -4.9 to ooe and >O°C).
We therefore obtained a time spent feeding for each individual and for each class of Tc. We
tested whether time spent feeding differed between sexes and between classes of Tc using
ANOY As. We perfonned multiple comparisons between classes of Tc using post hoc tests.
4.4. Results
Meteorological conditions
The mean Ta (± SE) measured outside dens between 15 December and 15 April was -7.1 ±
0.7°e in 2004 and -7.3 ± 0.6°e in 2005. The mean wind speed (± SE) was 2.35 ± 0.09 mis
and 2.42 ± 0.09 mis respectively in 2004 and 2005. We did not ca\culate the mean net
radiation between 15 December and 15 April because of sampling interruptions both in 2004
and 2005. The mean Ta (± SE) inside the nine dens sampled was --4.6 ± 0.3°e in 2005 (not
measured in 2004). Air temperature remained higher inside th an outside dens as long as the
outside Ta was below -2.4 oC (Fig. 4.\), a condition encountered during most of the winter.
10
5
~ : ..:......._-,.._
..
.a v; 1\ " 1 /V
CIl
...
CI>
a.
E -10
CI>
-...
Ci: -15
..... _~ .. _._ .... _
.._.._
_.~~~
.:._......._...._... \ ~ /
-20
-25
15-Dec 30-Dec 14-Jan 29-Jan 13-Feb 28-Feb 15-Mar 30-Mar 14-Apr
ine) and inside
Figure 4.1 : Mean daily air temperature (oC) measured outside (black solid 1
(grey solid line) nine porcupine dens, Parc National du Bic, Québec, 15 December 2004-14
April 2005. Black dashed line indicates the mean outside temperature (-2.4°C) above which
temperature inside the den became lower than outside temperature.