What are the characteristics of a terrestrial ecosystems?
Terrestrial ecosystems are those found only on land. Terrestrial means of the land.
There are many types of terrestrial ecosystems, the below shows a long list of these. These ecosystems are differentiated based on the weather, how much rainfall they get on average, the average temperature and the range in temperature over the year, and the terrain (mountains versus plains or valleys).
You can read about these categories of ecosystems here: http://www.eoearth.org/view/article/156487/