“Bioproductivity is the coordinated manifestation of the efficiency with which biological processes operate at various organization scales, from molecular/cellular to the whole organism and population.”
That’s a really big mouthful but it’s essentially the amount and rate of production which occur in a given ecosystem over a given time period. In agriculture, this productivity for example is called yield. Higher yield implies the use of less land to reach the same productivity.
When we talk about some instances of restoration for example, we also talk about rehabilitating the bioproductivity in the ecoystem – whether it’s in water or in land.