A terrestrial ecosystem is an ecosystem that exists on land rather than in water. This contrasts with aquatic ecosystems, which are based in water.
Major types of terrestrial ecosystems include forests, deserts, shrublands, grasslands and tundra. The largest of these are forests and the combined category deserts and xeric shrublands. The former covers about 32 percent of the earth's land area and the latter cover 19 to 33 percent, with estimates varying according to the definition. Xeric shrublands are a type of shrubland that is often grouped together with deserts because they are extremely dry.