If the federal government were to exercise this power with respect to, say, the caribou, here's the specific case I have in mind. Caribou behaviour is influenced by things that happen apparently hundreds of miles away.
For example, according to Dr. David Schindler, the caribou are disturbed by SAGD mining activities in the oil sands on provincial land leases. How does the federal government deal with that issue? The caribou could be on federal crown land, yet they're being affected by industrial activity on provincial crown land that is 300 miles away.
If you were to invoke federal authority, which, as you said, flows from a number of sources, how would you use federal authority to solve this problem?