Question

Which one of the following is considered a pioneer community in xerarch?
A. Annual herb
B. Perennial herb
C. Scrub stage
D. Forest stage
E. Lichen

Answer 1

Hint: Xerarch succession takes place in dry regions and they develop from xeric to mesic conditions. Ecological succession that starts on a bare place wherein no life has existed or wherein the preceding vegetation and fauna had been absolutely destroyed is referred to as pioneer succession. The species that invade a bare place are referred to as pioneer species.

Complete answer:
Option A: Perennial herbs regrow each spring. These typically have a shorter blooming period.
So, option A is incorrect.
Option B: Plants that develop and die off in a single season are called annual herbs.
So, option B is incorrect.
Option C: Scrubs are small trees that require soil and moisture for their growth.
So, option C is incorrect.
Option D: With the established order of shrubs, increasingly soil is formed and the environment will become more and more humid. This favours the growth of woody trees. Trees display stunted growth and are sparsely arranged.
So, option D is incorrect.
Option E: In primary succession on rocks, there are lichens which are capable of secreting acids to dissolve rock, support in weathering and soil formation. These later pave manners to a few very small plant lives like bryophytes. Hence, it is considered as pioneer community in xerarch
So, option E is correct.

Hence, Option E is correct

Note:
Because of Exposure to sunlight and excessive deficiency of water, the primary pioneers at the bare rock place are some organisms. These are capable of resisting excessive desiccation because of immoderate dryness. During the monsoon, they take in huge portions of water and flourish rapidly. They are, with time, succeeded as larger plants, and after several stages, in the long run, a strong climax forest is formed.