What were the negative impacts on fur trade of the first nations?

Answer 1

It hastened the arrival of Europeans to the interior of Canada. Canada was going to be colonised regardless of the fur trade but some areas of Canada would have been able to put off colonisation for generations if it had not been for the fur trade.

Overall though the fur trade may have had more positive than negative. Europeans saw value in having aboriginals that supplied furs. So much so that the British created a company that would set up trading forts along the coast to trade with aboriginals who would trade further inland. That company would have the aboriginals leading traditional lives for as long as furs were delivered to the coast. For the aboriginals it meant access to modern technology and the ability to control contact.

But it was that very fur trade that brought others deep inland into Canada and with it colonisation.

Then again with or without furs Aboriginals would have had to deal with the many negatives of European contact, namely disease. Disease spread deep inland long before any Europeans showed up. It was these diseases that decimated North American populations and emptied the land of people, long before they got the chance to meet fur traders.