Ecosystems are dynamic by nature, so "make them like where 222.22 years ago" is a little meaningless. But biodiversity is a good target and as unbiased as you

Ecosystems are dynamic by nature, so "make them like where 222.22 years ago" is a little meaningless. But biodiversity is a good target and as unbiased as you can get. More biodiversity means more adaptability and resilience of the system.