9
rather than highway construction) which started in 2010. Thus for species with more than one
observation, a sighting probability was calculated by calculating two sighting rates: 2003-2011,
and 2011-2016. For Mule deer, since there was only one sighting after 2011, the overall sighting
probability was calculated as the "post-development" sighting rate. A species was considered
sighted if it was definitively identified at least once during a sampling year. River Otter only had
one sighting through the entire pre and post construction period, so a sighting probability was
not calculated for it. See table 2 for results.
Species
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
pre-
develop
ment
post-
develop
ment
overall
Bobcat 1 2 1
Coyote 3 4 6 10 11 2 4 1 1
Marten 6 1 6 1 0.286
Mule
Deer
2 3 0.5
Raccoon 1 1 1 1 2 1 0.667
River
Otter
1
Total
Species
3 1 3 2 4 2 1 1 1 2
Table 2 Detection history by year and sighting probability pre- and post-construction of new ski hill infrastructure in
the Hyak transect vicinity.
Detection probability for marten decreased by 40 % from pre-construction to post construction,
which is by far the strongest decrease for any species. In comparison, detection probability for
coyote and bobcat did not change. The fact that detection probability rates for coyotes and
bobcats did not decrease further suggests that the decline in marten detections may actually be
significant.
It is difficult to determine the significance of these results, because a similar control site where
no construction activities were carried out was not sampled. Possible explanations for the
decrease in sighting probability are construction, poor snowpack, or a combination of the two. It
is worth noting that being the highest elevation transect within the study and having a generally
northern aspect, the Hyak-Silver Fir site has had the most consistent snow coverage of any of
our transects across the entire duration of the study. Others have found that the simplified
forest structure and forest openings modify, and typically reduce the use of these areas by
American marten (Moriarty et al 2015) while ski hill development has been shown to alter small
mammal populations in ways that could be negative for American marten (Hadley 2004). Our
