This video is called How Wolves Change Rivers.
From the Google cache.
Canada: no wolves? Less trees, songbirds …
Date: 8/1/05 at 2:42PM
From CBC News in Canada:
Banff food web shows sharp differences without wolves
Last Updated Mon, 01 Aug 2005
In the mid-1980s, wolves naturally recolonized the Bow Valley in Banff National Park, except for areas near the town itself.
Mark Hebblewhite of the University of Alberta in Edmonton and his colleagues have found the exclusion of the wolves caused major changes in the area’s food chain, down through its trophic levels.
See also here.
The loss of primary, or “apex” predators is causing an explosion in secondary, or “mesopredators” around the world, a new study concludes. In this image, the extermination of wolves may allow coyote populations to surge, which in turn can suppress feral cat populations, leading to more rodents, etc. These cascading effects are poorly understood but are causing ecosystem disruptions around the world, scientists say: here.
Jan. 9, 2014 — In ecosystems around the world, the decline of large predators such as lions, dingoes, wolves, otters, and bears is changing the face of landscapes from the tropics to the Arctic — but an analysis of 31 carnivore species published today in the journal Science shows for the first time how threats such as habitat loss, persecution by humans and loss of prey combine to create global hotspots of carnivore decline: here.
Predators’ vital roles in ecosystems justify their conservation, scientists say: here.