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Introduction
Canada lynx (Lynx canadensis) populations of northern Washington State were listed as a threatened
species in 1993 and officially recognized under the Federal Endangered Species Act (U.S. Fish and Wildlife
Service) in 2000. Prior to 1991 the lynx was considered problem wildlife with a $5 bounty for hunters
and trappers throughout North America (Stinson D 2001) and did not benefit from any protection.
The two major historical collapses of lynx populations in the 50s and 80s throughout Washington State
was suggested to be largely due to over-trapping and clear-cut forest harvesting (Yan et al. 2013). They
found that currently, a rise in northern hemispheric temperature (NHT), as a result of climate change,
plays a substantial role in affecting lynx populations directly through change in snow condition and
indirectly via impacts to their primary prey species. Historical weather analysis alongside fur harvest
records for lynx seem to indicate a strong correlation between NHT impacts on local weather systems and
implications on lynx populations. Delayed density dependence (DD) as a result of natal care and
development time for kittens to mature contribute 2 - 3 years (10 months prenatal care, 2 years to reach
adult size) to the DD fluctuations, furthermore impacting research into lynx population crashes (Yan et al.
2013).
Available habitat and climatic conditions may influence lynx population dynamics. The fragmented state
of the subalpine-boreal forests of south-central British Columbia, and effects of fire suppression, present a
wide variety in habitat quality. Local weather, influenced through global climate change phenomena, has
seen an increase in rainfall and decrease in snow pack retention, as well as reduced the winter season's
duration (Yan et al. 2013). This can limit the competitive advantage snowshoe-like feet provide the lynx.
Extreme weather systems have become more common and winter storms can greatly reduce the amount
of browse available to the snowshoe hare (Lepus americanus), the primary prey species. Lynx
productivity is directly affected by the abundance of snowshoe hare populations and exhibits a 1-year lag
behind hare's 10-year population cycle (Yan et al. 2013, Fuller et al. 2010). Heavy rainfalls reduce the
hare's second-litter survival dramatically and provide other predators more opportunity to compete.
Snowshoe hare decline is further accentuated by the lag-time effect on predator populations causing an
imbalance in the existing predator-prey relationship.
