What is npp and gpp?

Net Primary Productivity (NPP) and Gross Primary Productivity (GPP) are key concepts in ecology that describe the productivity of plants. GPP is the total amount of organic matter (biomass) produced by photosynthesis in a given area over a specific time period. NPP, on the other hand, is the amount of biomass that remains after accounting for the energy used by plants for respiration; it represents the energy available to herbivores and higher trophic levels. Essentially, NPP = GPP - respiration.