Causes of marmot population declines are numerous. Over the long term (i.e., periods involving thousands of years), climate changes have caused both increases and declines of open alpine habitat that constitute suitable marmot habitat. Over more recent time scales, population dynamics may have been influenced by short-term weather patterns and systematic changes in the landscape. In particular, forest clearcutting at low elevations likely altered dispersal patterns. Sub-adult marmots typically disperse from the subalpine meadows in which they were born. Dispersal involves traversing lowland conifer forests and valleys to other subalpine meadows. However, clearcutting has provided marmots with new open areas which constitute habitat. Unfortunately, rapid forest regeneration makes such man-made habitats unsuitable over a few years. One study concluded that clearcuts therefore act as a kind of population "sink" in which long-term reproduction and survival rates are reduced to the point of unsustainability One 2005 study concluded the main cause of recent decline to be predation "associated with forestry and altered predator abundance and hunting patterns". Major predators upon Vancouver Island marmots include golden eagles, cougars and wolves.