Ecosystem services are conventionally defined as the human benefits provided by natural ecosystems and include the capacity of those systems to reproduce or replenish themselves. It is useful, however, to distinguish between two types of flows from nature that benefit humans: ecosystem services and throughput.
Ecosystems generate services at a given rate over time and are not physically transformed into the services they provide. Roughly speaking, a given forest can filter a certain amount of water per day or sequester a certain amount of CO2, though amounts change depending on the health and age of the forest, and essentially the same forest remains at the end of the day. There is a growing scientific consensus that ecosystem services are essential to human survival and that the potential to create technological substitutes is very limited. At the same time, human activities increasingly threaten their adequate provision, posing a dangerous paradox.
Joshua Farley, Abdon Schmitt F., Juan P. Alvez, Norton Ribeiro de Freitas Jr., How Valuing Nature Can Transform Agriculture, The Solutions Journal, Volume 2, Issue 6, November 2011, Pages 64-73
How valuing nature can transform agriculture