Spatial, environmental, and functional distances among temporal ponds attenuate synchronization, stabilizing plant richness and biomass dynamics

Synchronized dynamics reduces ecosystem stability, as local variations in
biomass or richness are directly propagated to variations in metacommunity
dynamics. Synchronization of biodiversity dynamics can occur due to
dispersal among communities and similar responses of different communities
to correlated environmental variations, the Moran effect. This congruent
response of different communities to environmental dynamics depends on
their similar functional composition, which is determined by the
similarity in local conditions and the spatial distance between them. In a
metacommunity of 51 temporary ponds that were surveyed for 14 years, we
evaluated the existence of synchronized dynamics in plant richness and
biomass among communities, and their association with temporal stability.
A wide range of dynamics was observed, from asynchronous to synchronous
rhythms. Path analysis based on Mantel tests supported the decoupling of
richness dynamics by the geographic, environmental, and functional
distances between pairs of communities. However, only the functional
distance between communities weakly affected biomass synchrony. Synchrony
in both richness and biomass between communities reduced the stability of
the biomass dynamic. However, while synchrony in richness reduced its
stability, synchrony in biomass enhanced the stability in richness
dynamic. The role of rare species in richness dynamics and of dominant
species in biomass dynamics may explain the observed discrepancies.
Consequently, the size of metacommunities (the spatial extent and number
of local communities), spatial heterogeneity, and functional diversity
promote ecosystem stabilization by the mechanisms evidenced here. Climate
change, environmental homogenization, and landscape fragmentation may
drive the synchronization and destabilization of biodiversity dynamics.