Why is the field called a natural community?

The whole world is divided into small ecosystems: forests, rivers, seas, separate areas of land. And each individual ecosystem has its own inhabitants. The field is also a separate ecosystem. There are living beings both on the surface of the earth and underground. They coexist with each other, forming food chains or entering into a relationship of symbiosis (beneficial cooperation). For example, animals, birds, insects and plants can live on the field. They are all related to each other. Plants are eaten by herbivores, and predators prey on grass consumers.