Ecosystem valuation is when we try to figure out how much it is worth to have an ecosystem like a certain lake, forest or mountain. We look at all of the different parts of the ecosystem and decide how much each of them is worth. We also look at how people use the ecosystem and how important it is for the environment. For example, a lake might provide us with fresh water to drink and a habitat for animals. We also might use the lake to have fun like fishing and swimming. When we value an ecosystem, we add up all of the different parts and decide how much it is worth.