Thursday 27 March 2014

How Wolves Change Rivers



When wolves were reintroduced to Yellowstone National Park in the United States after being absent nearly 70 years, the most remarkable “trophic cascade” occurred: by thinning out the population of deer and forcing them to change their eating patterns, valleys experienced less erosion and vegetation regenerated, changing the flow of rivers as a result.

Richard’s comment:

Why is this so surprising? The consequences of removing the wolf and reintroducing the wolf to Yosemite National Park are land management decisions which can be explained using the criteria and indicators of VAST-2 system. We should not be surprised. Of course there were going to be negative impacts on the vegetation structure, species composition and regenerative capacity when the wolf was removed. So too we should not be surprised by the positive effects of reintroducing the wolf as observed /measured in the changes in vegetation structure, species composition and regenerative capacity of the several plant communities.

All this presumes we know what the reference state was when it existed long before the wolf was removed and we know how different it was at the time the wolf was present >70 years ago and that we want to measure it now once the wolf has returned i.e. relative to a reference state.

Watch the video and consider perhaps we need for a similar discussion about the likely positive effects of such decisions on Australia’s plant communities, regarding reintroducing the Dingo into managed landscapes like that found in Yosemite National Park over time  

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