Simplify the definition?

[Gloria]

Biodiversity, as it is most commonly used, is tied to ecosystems. It's about the relationships between all the life forms in a self-sustaining natural system.

Very good. Three ideas in one simple statement.
And you have introduced purpose (result?).

Thus the recent attemps to bring ecosystem services to the forefront in discussing the importance of biodiversity.

[hazelnut]

Good definition! I think in science it was once the fashion to reduce concepts to their simplest terms, but the science of living things is about complexities and interconnedness---systems within systems. The task of science has become finding ways for us to understand complexities.