Résumé
It is controversial whether communities are saturated with species, or
have vacant niches. The prevalence of vacant niches and the processes
likely to promote their existence are poorly known. We used a
process‐based forest gap‐model to simulate plant community dynamics in 11
sites along a climatic gradient across central Europe. We then used
hypervolume analyses to study the existence of vacant niches (seen as
empty volumes in the trait space of local species pools and communities),
and we tested for the effect of abiotic (environmental filtering) and
biotic (competition) processes on the functional hypervolumes along the
climatic gradient. Last, we performed invasion simulations to assess the
invasibility of detected vacant niches. Our results suggest that
empty volumes in trait space are common, can arise from both abiotic and
biotic processes, and are more likely in cold climates. We also showed
that most vacant niches are invasible.
4. Synthesis: Our work supports the view that niche space is
unsaturated, and that many viable ecological strategies are absent from
these forest communities.