Introduction:
Succession is a process of change in the species composition and structure of an ecological community over time. It is a natural process that occurs in many ecosystems, including forests, grasslands, and wetlands. Succession can result in a decrease in net community productivity or annual yield. This can occur for several reasons, which will be discussed below.

Factors affecting net community productivity:
Net community productivity (NCP) is the difference between the amount of carbon dioxide taken up by photosynthesis and the amount released by respiration. It is a measure of the overall productivity of an ecosystem. Several factors can affect NCP, including:

- Species composition: Different plant species have different photosynthetic rates and respiration rates. If a community undergoes succession and is replaced by species with lower rates of photosynthesis or higher rates of respiration, NCP will decrease.
- Nutrient availability: Nutrients such as nitrogen and phosphorus are essential for plant growth and photosynthesis. If a community undergoes succession and is replaced by species that are less efficient at acquiring or using nutrients, NCP will decrease.
- Disturbance: Disturbances such as fire, storms, or human activities can disrupt the balance between photosynthesis and respiration in an ecosystem. If a community undergoes succession after a disturbance and is replaced by species that are less adapted to the new conditions, NCP will decrease.

Effects of succession on annual yield:
Annual yield is the amount of biomass produced by an ecosystem in a given year. It is another measure of the productivity of an ecosystem. Succession can affect annual yield in several ways, including:

- Changes in species composition: As mentioned above, different plant species have different rates of photosynthesis and growth. If a community undergoes succession and is replaced by species with lower rates of growth or biomass production, annual yield will decrease.
- Soil quality: Succession can affect soil quality by changing the amount and type of organic matter in the soil. If a community undergoes succession and is replaced by species that are less efficient at adding organic matter to the soil, annual yield will decrease.
- Climate: Succession can be influenced by changes in climate, and changes in climate can also affect annual yield. For example, if a community undergoes succession and is replaced by species that are less adapted to the new climate conditions, annual yield will decrease.

Conclusion:
Succession is a natural process that can result in a decrease in net community productivity or annual yield. This can occur due to changes in species composition, nutrient availability, disturbance, soil quality, or climate. Understanding the factors that affect succession and productivity can help us manage and conserve ecosystems more effectively.

During succesion it changes their lifestyle way of living or surviving which may harm other to sustain there therefore, it is decrease in net community or productivity..