Yes, They are much more strong and need more meat to survive. Being able or not to lift a heavy rock can be the difference between an entire colony of marmots wiped or not. With such small populations of gregarious animals, losing 10 or 20 marmots by three bears in a couple of nights is a serious issue. Is close to the number of survivors in the wild before the rewilding projects started.

Black bears must have some effect on marmots. Both species compete for the food, but the effect can be difficult to study (Black bears eat lots of ants for example, and ants eat surprisingly big amounts of plants also). Ecology is so complex that must be managed by trained professionals, able to see the whole picture, not for companies driven toward selling more newspapers (In the same way as computer security, hospitals, or any other issue important to us; that would cause disasters if not addressed sensibly).