You're right in saying that concerns need to be addressed, though I think that most concerns are unfounded and are bred from fear that leads to exaggeration of events and incidents.

Wolves are the biggest concern in the UK and the primary concern when discussing their reintroduction is the threat to livestock . Have a look at this page on wolf conservation. It gives a good example of how the facts can be exaggerated when emotion comes in to play.

That's not to say that concerns with other animals are much more serious, though from a UK perspective there doesn't seem to be much to worry about. Fear of our natural wildlife is more akin to the fear of sharks that you mentioned.

I think most if not all of the negatives are fiction. The lack of understanding is holding back a genuine fix to our biodiversity problems.

There is a desire to find a human fix to environmental issues with complete disregard for nature's ability to regenerate when given the right conditions. What needs to be first understood is the natural relationship between flora and fauna that you have mentioned. We have the power to establish the sort of conditions necessary for natural regeneration which can allow us to take a step back and let the wildlife make it right.