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AUTHOR(S):
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Richard D. Lauzon
- rlauzon@axys.net
AXYS Environmental Consulting Ltd.
Calgary, AB, Canada
Scott D. Grindal
- sgrindal@axys.net
AXYS Environmental Consulting Ltd.
Calgary, AB, Canada
Garry E. Hornbeck
Wildlife & Company Ltd.
Calgary, AB, Canada
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Ground squirrels are important in the
prairie ecosystem as a prey base for carnivores, as well as providing
potential burrows for other species (e.g., burrowing owls). However, little
is known about the response of ground squirrels to pipeline construction, and
any resulting impacts on the prairie ecosystem. We investigated the effects
of a recently constructed pipeline on the density and distribution of
Richardson’s ground squirrel (Spermophilus richardsoni) burrows in the
dry mixedgrass ecoregion of southeastern Alberta. We predicted that ground squirrels would be
attracted to the ditchline (excavated area) of a
pipeline right-of-way (ROW) because of the reduced soil density, but would
avoid the workspace (area of vehicle traffic) of the ROW because of soil
compaction. Burrow densities, vegetation cover (%), and vascular plant height
were estimated along a recently constructed (1997) pipeline ROW in the late
summers of 1998 and 1999. Fifty sample plots (4 m x 100 m) were established in each of three treatment groups: (1)
native prairie, adjacent to the ROW; (2) ROW workspace; and (3) ROW ditchline. Burrow densities increased during the first ( =
0.54/plot) and second (
= 1.3/plot) years after pipeline construction in the ditchline,
but remained consistently low in the workspace (
= 0.48 and 0.38/plot). These values were approximately 14-47% of expected
densities of burrows in adjacent prairie control sites (
= 2.76 and 2.78/plot). After reclamation, vegetation cover was similar for
all three treatment areas (
= 51.2 – 66.1%), but vascular plant height tended to be greatest on both the ditchline and workspace of the disturbed ROW (
= 41.4 and 37.2 cm, respectively) than in the undisturbed native prairie (
= 18.2 cm). Our results suggested that ground squirrels re-colonized the
pipeline ROW shortly after construction, but areas of compacted (workspace)
soil are less suitable than excavated (ditchline)
areas after two years. However, disturbed areas in general associated with
pipeline ROW were used less than undisturbed native prairie. This preference
for undisturbed sites may be related to differences in both soil compaction
and vegetation cover and height. Although soil compaction may be difficult to
mitigate, successful reclamation of pipeline ROWs
for ground squirrels may be increased by careful management of vegetation,
such that it approximates more closely to native prairie ground cover.
Keywords:
Richardson’s ground squirrel,
Spermophilus richardsoni, pipeline construction, impacts
Ref#: 6-17
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