Effects of subsidy, plant diversity and succession on resource use and retention efficiencies in primary production

Primary production by terrestrial plants is vital for life and human survival. To provide enough food, feed and fibre to humanity within planetary boundaries, managed ecosystems, such as agriculture and forests, need to become more efficient at using and retaining resources, minimizing losses through leaching and emissions, herbivory and climatic stresses. 

Three main ecological conditions affecting efficiencies and managed in primary production ecosystems are:

• Subsidy of resources, e.g. fertilization, irrigation.
• plant diversity
• successional stage, e.g. defined by disturbances and annual and/or perennial planting. 

We identify and define efficiency metrics of Carbon (C), Nitrogen (N) and water. We develop stochiometric process-based ecosystem models describing interlinked green (inorganic N-plant-herbivore-predator) and brown resource channels (labile organic matter-decomposer-predator). 

Using multiple agricultural and grassland long-term field experiment and parameterise models, we reconcile community and ecosystem ecology to theoretically and empirically map synergies and trade-offs among efficiencies for several resources across gradients of subsidy (quality and quantity), plant diversity and succession. We examine impacts of pedoclimatic conditions and climate change on efficiencies and trade-offs. We derive principles for designing efficient primary producing  ecosystems.