Xerarch - Ecology
Successions initiated on bare rock, wind-blown sand, rocky talus slopes, or other situations where there is an extreme deficiency of water are termed xerarch. Here, we shall discuss the example of a bare rock. It is not only deficient in water but also lacks any organic matter, having only minerals in disintegrated, unweathered state.
The pioneers to colonise this primitive substratum are crustose type of lichens, and through a series of successive seral stages, the succession finally terminates into a forest which constitutes the climax community. As in the hydrarch, successive changes take place in both plants as well as animals, but changes in plants are more obvious than animals.