Primary productivity does not depend upon

Options

A. Plant species
B. environmental factors
C. herbivore species
D. availability of nutrients .

Answer

To solve the question regarding what primary productivity does not depend upon, we can analyze each option provided:

1. **Understanding Primary Productivity**:
- Primary productivity refers to the amount of biomass produced by autotrophs (primarily plants) in a given area over a specific time period. It is a measure of the energy captured by photosynthesis.

2. **Evaluating Each Option**:
- **Option 1: Plant Species**:
- Primary productivity is directly influenced by the types of plant species present, as different species have varying efficiencies in photosynthesis and biomass production. Therefore, it does depend on plant species.

- **Option 2: Environmental Factors**:
- Environmental factors such as light, temperature, and carbon dioxide levels significantly affect photosynthesis and, consequently, primary productivity. Thus, it does depend on environmental factors.

- **Option 3: Herbivore Species**:
- Herbivores consume plants but do not contribute to the production of biomass. In fact, they can reduce the amount of biomass available by eating plants. Therefore, primary productivity does not depend on herbivore species.

- **Option 4: Availability of Nutrients**:
- Nutrients are essential for plant growth and biomass production. The availability of nutrients directly influences the amount of biomass produced. Hence, it does depend on the availability of nutrients.

3. **Conclusion**:
- After evaluating all options, the correct answer is **Option 3: Herbivore Species**, as primary productivity does not depend on herbivores.

**Final Answer**: Primary productivity does not depend on herbivore species (Option 3).