In plant succession, when climax community is reached, the net productivity

Options

A. Continues to increase
B. Becomes zero
C. Becomes reduced
D. Becomes stable

Answer

### Step-by-Step Solution

1. **Understanding Plant Succession**: Plant succession is the process by which ecosystems change and develop over time. It begins with a bare area that is colonized by pioneer species.

2. **Pioneer Species**: In primary succession, the first organisms to inhabit a barren environment are usually pioneer species, such as lichens. These organisms help in breaking down rocks and initiating soil formation.

3. **Soil Formation**: As lichens secrete acids to dissolve rocks, they contribute to weathering, which leads to the formation of soil. This allows for the growth of more complex plant species.

4. **Progression to Climax Community**: Over time, as soil quality improves, more advanced plant species like bryophytes and eventually larger plants establish themselves. This process continues through several stages until a climax community is formed.

5. **Characteristics of Climax Community**: A climax community is a stable and mature ecosystem that can sustain itself as long as environmental conditions remain unchanged.

6. **Net Productivity**: In the context of the climax community, net productivity refers to the rate at which energy is stored in the form of biomass after accounting for energy lost through respiration.

7. **Stability of Net Productivity**: When the climax community is reached, the net productivity stabilizes. This means that the amount of energy produced and consumed reaches a balance, resulting in a stable ecosystem.

8. **Conclusion**: Therefore, the correct answer to the question is that when the climax community is reached, the net productivity becomes stable (Option D).