Minecraft doesn't read saves properly

I was building a map on a Bukkit 1.7.9 Server and I wanted to copy it with MCEdit to another save. When I try to open the save with a 1.8 snapshots, the map is messed up. There are missing blocks everywhere, and when I open the save with Minecraft 1.7.9, everything is back to normal. Here's a photo how it looks.