A textbook by well-known authors defined biodiversity as: the total of all species, populations, communities, genetic pools, and possibly vital processes on the globe. Biodiversity has no clear meaning for researchers or for urban greens. The felt need is there but something else is needed.
The need is not just for the variety of living things as if they were stamps in a collection. The basic value being sought is the ability for the biotic system to maintain itself under impacts, often from us.
A living system has a higher probability of recovering from an impact if it is diverse than if it is composed of fewer kinds of living things – less diverse. That ability to recover after an impact can be called resilience.
Resilience can be measured. It is the probability of recovery after a measured impact. Resilience would be a better measure of the indefinable quantity that biodiversity is trying to represent. Resilience is directly relatable to the complex of processes responsible for self-maintenance of the ecosystem – the primary target of our concern.