Bug ? Can't finish River Valley

Hey, so I was trying the new version on Mobile of Terra Nil and I cannot figure it out why Im unable to finish the first level :

• I finished all objectives (3 biomes, 6 Wildlife, 7 Climate)
• I removed all structures (no red cross left on map)
• My animals are all "happy"

Still cannot have the red button to leave this place... What am i missing ?