Which of the following parameter decreases as succession proceeds?

Options

A. Humus content
B. Species diversity
C. Net community productivity
D. Biomass

Answer

To solve the question "Which of the following parameters decreases as succession proceeds?" we can follow these steps:

### Step-by-Step Solution:

1. **Understand Ecological Succession**:
- Ecological succession is the gradual process by which ecosystems change and develop over time. It involves a series of progressive changes in the species composition and structure of an ecological community.

2. **Identify the Parameters**:
- The question lists several parameters: humus content, species diversity, net community productivity, and biomass. We need to analyze how each of these parameters behaves during succession.

3. **Analyze Each Parameter**:
- **Humus Content**: Typically increases during succession as organic matter accumulates from decaying plants and animals.
- **Species Diversity**: Generally increases as succession progresses, especially in the later stages, as more species establish themselves in the ecosystem.
- **Net Community Productivity**: This can vary, but it often increases during the early stages of succession as new plants grow and photosynthesize.
- **Biomass**: Refers to the total mass of living organisms in a given area. In the context of succession, biomass can initially increase as new species colonize, but overall, it can decrease in certain stages due to competition and resource limitations.

4. **Determine the Correct Answer**:
- Based on the analysis, the parameter that decreases as succession proceeds is **biomass**. While biomass can fluctuate, the overall trend in certain stages of succession is a decrease due to competition and the changing dynamics of the ecosystem.

### Final Answer:
The parameter that decreases as succession proceeds is **biomass**.

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