This ecological investigation of the beaver (Castor
canadensis canadensis Kuhl) was part of the Eastern Slopes
(Alberta) Watershed Research program conducted during the summers
of 1968 . 1969 . 1970. and 1971 .
A soil particle size analysis indicated that soil heavy
with clay was used by the beaver for construction purposes in
the Porcupine Hills . Examples were given of the beaver
controlling erosion with the construction of dams . and also
causing erosion to occur . However . in general . the beaver slow
down soil erosion and decrease the loss of soil from this region.
The beaver utilized measureable amounts of herbaceous
vegetation . However, the utilization of herbs by the beaver
requires further investigation. A system of ex~sures and
enclosures of herbaceous vegetation plots was used to study the
utilization of sedges , grasses , and forbs .
The beaver indicated stronger species preference for willow
as compared to aspen . The size preference for willow was in the
1.0 to 10.0 centimeters basal diameter classes , while the beaver
utilization of aspen indicated a preference for the largest
trees with basal diameter greater than 20.0 centimeters.
Willow was the most important plant in the low lying areas
with regard to distribution, abundance and to produce sustained
yield. The beaver used this plant for food and construction
throughout the study area. The distribution of aspen was
limited. and this species did not appear to produce more than
one crop in the lifetime of a beaver colony. Nine out of 15
woody plant types were sampled by the beaver in this region.
A plot-intercept transect technique was used for systematic
vegetation sampling of the woody vegetation in six intensively
studied watersheds.
The beaver population of the Porcupine Hills region of
SW-Alberta is believed to depend upon the chinooks. During the
1971 ground census, a total of 60 active beaver colonies were
tallied on the 930 square kilometers large study area. The
beaver of the region were not found to store large food caches
during fall and winter, however, they are believed to collect
feed periodically throughout the winter months. It was observed
that the severe winter in 1968-69, reduced by 27 per cent the
number of active beaver colonies within the study area.
The Porcupine Hills region had 0.07 beaver colony per
square kilometer in 1971, a low density of beaver colonies due
to the rough topography of the area. However, the importance
of the beaver ponds was somewhat clarified as they provide
increased moisture, which lessens the fire damage, and store
water for wildlife and cattle in the area.
Meteorological data was collected by the author in
collaboration with the Department of Transport.
This ecological investigation of the beaver (Castor
canadensis canadensis Kuhl) was part of the Eastern Slopes
(Alberta) Watershed Research program conducted during the summers
of 1968 . 1969 . 1970. and 1971 .
A soil particle size analysis indicated that soil heavy
with clay was used by the beaver for construction purposes in
the Porcupine Hills . Examples were given of the beaver
controlling erosion with the construction of dams . and also
causing erosion to occur . However . in general . the beaver slow
down soil erosion and decrease the loss of soil from this region.
The beaver utilized measureable amounts of herbaceous
vegetation . However, the utilization of herbs by the beaver
requires further investigation. A system of ex~sures and
enclosures of herbaceous vegetation plots was used to study the
utilization of sedges , grasses , and forbs .
The beaver indicated stronger species preference for willow
as compared to aspen . The size preference for willow was in the
1.0 to 10.0 centimeters basal diameter classes , while the beaver
utilization of aspen indicated a preference for the largest
trees with basal diameter greater than 20.0 centimeters.
Willow was the most important plant in the low lying areas
with regard to distribution, abundance and to produce sustained
yield. The beaver used this plant for food and construction
throughout the study area. The distribution of aspen was
limited. and this species did not appear to produce more than
one crop in the lifetime of a beaver colony. Nine out of 15
woody plant types were sampled by the beaver in this region.
A plot-intercept transect technique was used for systematic
vegetation sampling of the woody vegetation in six intensively
studied watersheds.
The beaver population of the Porcupine Hills region of
SW-Alberta is believed to depend upon the chinooks. During the
1971 ground census, a total of 60 active beaver colonies were
tallied on the 930 square kilometers large study area. The
beaver of the region were not found to store large food caches
during fall and winter, however, they are believed to collect
feed periodically throughout the winter months. It was observed
that the severe winter in 1968-69, reduced by 27 per cent the
number of active beaver colonies within the study area.
The Porcupine Hills region had 0.07 beaver colony per
square kilometer in 1971, a low density of beaver colonies due
to the rough topography of the area. However, the importance
of the beaver ponds was somewhat clarified as they provide
increased moisture, which lessens the fire damage, and store
water for wildlife and cattle in the area.
Meteorological data was collected by the author in
collaboration with the Department of Transport.
