Others will still be seeding, but once you take it off your program you will not. I fyou remove a torrent, all you need to do to “get it back” (you never really lost it unless you deleted the files- you simply removed from torrent program) is click on the original torrent link and save it to the same file as previously. Your program should check the files for 100% completion and then start seeding again.
I think you may be confusing seeding and leeching, at least as I understand your above post.
Leeching = downloading
Seeding = uploading. Once you are finished downloading, you should automatically start seeding. However, you’ve probably been seeding (uploading) as you were downloading.
Commonly, it is appreciated that you seed as much as you leech, or maintain at least a 1:1 ratio. If you don’t feel like leaving your torrents open forever, at least seed them to 1.00 (ratio) before removing.
Capiche?