This is a wildlife feast that features the migratory animals of the Straits of Gibraltar or the Pillars of Hercules (as it was formerly known), the border between Africa and Europe.
Whenever documentary says something "mysteriously disappear", it means humans caused the destruction of the habitat the creature lived in or poached them to death. Its always one or the other these days, nothing more and nothing less.
You're right! Everywhere around the world, no matter in which continent, it is human greed n corruption that make the forest n nature suddenly "disappear". Political leaders, government officials especially corrupted one's n greedy entrepreneurs are the culprits around the globe! Otherwise this world can exist harmoniously!!