Ecosystem services provide benefits from nature, like clean water and air. A research review looked at different ways to calculate the value of these services. They found four main methods: using market prices, estimating indirectly, asking people their preferences, and using models to study ecosystems. Each method has strengths and limitations. Market prices can be used when they exist, while indirect methods estimate value when prices are not available. Asking people about their preferences is useful in hypothetical situations. Models help integrate all the factors affecting ecosystem services. Different methods have been used to value these services, but each has specific conditions where it works best. More research is needed to figure out the best method in different situations.