Here, we have two aims: (1) to develop a new population
unit categorization that explicitly links a population with
the ecosystem service(s) that it provides; and (2) to provide
an extended definition of population diversity that
formalizes its most important dimensions in an ecosystem
context. We present a conceptual framework for exploring
the relationships between population diversity and the
functioning of ecosystems. Investigating these relationships
empirically in even a few systems presents major
challenges, but we hope our discussion stimulates debate
and innovative ideas about empirical investigations of
what we believe is an area of crucial importance. The
terms ‘ecosystem service’ and ‘ecosystem function’ are
largely interchangeable, as used here, although ecosystem
services can be defined as ecological processes that benefit
people [9], whereas ecosystem functions can be considered
as all ecological processes regardless of whether they are
beneficial to humanity