10%. in food chain from 1st trophic level to 2nd trophic level only 10% of net primary productivity is eaten and digested.

Net Primary Productivity (NPP)
Net Primary Productivity (NPP) refers to the amount of organic matter (biomass) produced by photosynthetic organisms in a given area after accounting for the energy used in respiration. It is a crucial measure of ecosystem productivity.
Herbivore Consumption of NPP
In terrestrial ecosystems, herbivores play a significant role in energy transfer. On average, only a small fraction of NPP is consumed by herbivores.
Key Points on Herbivore Consumption:
- Percentage of NPP Eaten:
Typically, herbivores consume about 10-20% of the total NPP in a terrestrial ecosystem.
- Digestibility and Assimilation:
Out of the consumed NPP, only about 20-50% is digested and assimilated by herbivores, meaning the actual energy available for higher trophic levels is even less.
- Factors Influencing Consumption:
- Plant Type: Different plants have varying levels of palatability and nutritional content.
- Herbivore Species: Different herbivores have unique feeding habits and efficiencies.
- Environmental Conditions: Factors like climate, seasonality, and ecosystem type affect herbivore feeding rates.
Significance of Herbivores in Ecosystems
Herbivores not only consume NPP but also regulate plant populations, enhance nutrient cycling, and serve as a critical food source for carnivores. Their role in the ecosystem underscores the interconnectedness of trophic levels.
Conclusion
Understanding the consumption of NPP by herbivores is essential for grasping the dynamics of energy flow and nutrient cycling within terrestrial ecosystems. This balance influences biodiversity and ecosystem health.