don't use iphoto anymore...

I use Lightroom now, used iphoto when I first bought my macbook pro, but have been using & prefer Lightroom. Is the iPhoto library I initially created taking space on my hard drive? Is there a way to delete it w/out deleting my pics?

I don't need to move them to LR, I have all of my pics on the hard drive in folders & organized by year, date, etc. I use LR to to tag my pics, edit, etc.

Also, when I open iphoto it is requesting an upgrade first, which I didn't want to do since I'm not going to use the program!

Thanks for any help you can offer.
Tami