Question

A rocky area, once bare, is now a green forest . The sequence of succession has

• A. Woody mosses,woody shrubs , mosses and lichens
• B. Lichens , mosses ,woody shrubs and annual herbs
• C. Mosses , lichens , annual herbs and woody shrubs
• D. Lichens , mosses , herbs and woody shrubs

Answer 1

The correct option is D Lichens , mosses , herbs and woody shrubs

The process of succession from a bare rock to a green forest is known as Xerarch or Xerosere. It involves a lot of stages, namely:

1. Crustose lichen stage : Crustose are forms an external protective layer on the surface of the rock. Special types of lichens can grow on ,these rocks. The lichens are called crustose lichens. Examples: Licanora, Rhinodina, etc.

2. Foliage lichen stage: Crustose lichens helps in the formation of foliage lichens. THey are leaf like structures which retains water and maintains moisture on the rock. Examples: Parmelia, Dermaticarpo, etc.

3. Moss stage :The soil becomes more porous leading to the growth of mosses.They penetrate more in to the soil and helps for the growth of herbaceous plants. Examples: Polyerichum, Tornda, etc.

4. Herbaceous (plant) stage: Due to the increases water and hummus, herbaceous plants are grown. Evaporation or transpiration starts taking place. Now bacteria, fungi and other animalscan be found here. Examples: perennial herbs and grass.

5. Shrub stage: Soil is now favourable for shrubs. They grow and become dense. Examples: Rhus, etc.

6. Climax stage: Now the soil allows the growth and establishment of woody plants with dense roots. Later, they are changed into woody forests.