We humans make machines. Over time with technological advancement, we have made increasingly complex machines. But those machines are still nothing in comparison to the complexity of natural machines.
If you think about it, human body is one such unbelievably complex machines. We have been trying to replicate that complexity of brain to produce artificial neural networks (ANN), recreate human emotions and intelligence through machines (Artificial Intelligence, AI) but the technology is still far from any resemblance to human brain or intelligence. Even genome of humans (or any living being) is incredibly complex and still largely a mistery.
An ecosystem is another type of complex machine. The interactions and interdependence of the living and non living nature is so complex that scientists have only started trying to understand the expanse of it.
In any complex machine, careless handling without proper knowledge can be dangerous. Like all such machines, ecosystem also should be handled with utmost care, so that we don't cause any irreversible damage.