Question

Which of the following is considered as pioneer community is xerarch?

Answer 1

Explanation:

Xerarch refers to series of developmental stages in an arid area like bare rock. Lichen stage is the first stage in Lithosere (or succession on bare rock). Bare rock is invaded first by crustose lichens, e.g., Graphis, Rhizocarpon. They corrode the rock at places causing foliose lichen, e.g., Parmelia, Dermatocarpon to invade and eliminate crustose lichens and creating conditions for invasion by mosses. In tropics, blue-green algae are pioneers instead of lichens in lithosere.

Answer 2

Answer:

Xerarch refers to series of developmental stages in an arid area like bare rock. Lichen stage is the first stage in Lithosere (or succession on bare rock). Bare rock is invaded first by crustose lichens, e.g., Graphis, Rhizocarpon. They corrode the rock at places causing foliose lichen, e.g., Parmelia, Dermatocarpon to invade and eliminate crustose lichens and creating conditions for invasion by mosses. In tropics, blue-green algae are pioneers instead of lichens in lithosere.