What are niches and what do they have to do with the taiga
A niche is a full range of physical and biological conditions in which organisms live and the way organisms use their conditions. It is kind of like a role the organism has to take. The way you tell a organisms niche is by where they live and their habitat.
For example the niche of a Grizzly Bear is the way they distribute berries. When they eat the berries the seeds go through their system. Then in a different location their waste spreads the berries. Without this distribution of seeds the berries would be scarce and then the bears would have no berries to eat.