Abstract
Intraspecific variability (IV) has been proposed as a new track to
explain species coexistence. Previous studies generally assumed that IV
results from intrinsic differences between conspecifics that widen
species’ fundamental niches and blur differences among species, thus
impeding stable coexistence, but also slowing down the rate of
competitive exclusion. Based on a body of evidence, we here argue that
IV does not necessarily imply differences among conspecifics, nor
species niches overlap: conspecifics differ in their measured attributes
mainly due to differences in the micro-environment they thrive in.
Consequently, they respond more similarly to environmental variation
than heterospecifics, thereby concentrating competition within species
– a necessary condition for species coexistence. We call for new
studies exploring observed IV as an outcome of species-specific
responses to high-dimensional environmental variations that can lead to
inversions of species hierarchy in space and time promoting stable
coexistence.