As I understand, biodiversity has two benefits:
- Species might be a functional part of the ecosystem, e.g. balancing other species' numbers or beeing part of the foodchain.
- Species with diverse abilities make sure that "life as a whole" can adapt to changing environments.
These hold true for most species currently alive. For species that have only a few thousand or even a few dozen exemplars left, neither function seems to be achievable. Yet there is a wide consens in protecting such species - what's the reasoning?