How is Skarner's New Passive gonna work on Howling Abyss?

The map is too small to have 5, and they only showed it working on Summoner's Rift, what about the other maps like Twisted Treeline, Crystal Scar, Howling Abyss, I mean if it doesn't work they he's straight up useless(more than they already made him), and with no jungle on ARAM I don't see how they're gonna work there at all unless they're right by the inhibs or something, meaning anywhere else on the map, he's completely useless.