Do I need to anchor this shed to a fundation?

We just set it up in our backyard on concrete and have NOT anchored it down. We've had it set up for several months now with the lawnmower, a 3-shelf wire shelf and a bunch of other yard supplies. So far there has been no threat to it blowing/knocking over. If you're worried about super strong winds like tornadoes, then you might want to anchor it down. Hope this helps.