not quite. the verb used being "making" and not "causing", the correct way is "in there mutate".
"making the fauna in there mutate"
"causing the fauna in there to mutate"
Naturally, large amounts of Mana generated constant mutations in the flora and fauna, making the living creatures in their mutate into Monsters of all kinds, shapes, and sizes.
Demon Queen Rebirth: I Reincarnated as a Living Armor?!