The importance of landscape and habitat properties in explaining instantaneous and long-term distributions of large branchiopods in subtropical temporary pans.

1. The notion that the spatial configuration of habitat patches has to be taken into account
to understand the structure and dynamics of ecological communities is the starting
point of metacommunity ecology. One way to assess metacommunity structure is to
investigate the relative importance of environmental heterogeneity and spatial structure in
explaining community patterns over different spatial and temporal scales.
2. We studied metacommunity structure of large branchiopod assemblages characteristic
of subtropical temporary pans in SE Zimbabwe using two community data sets: a
community snapshot and a long-term data set covering 4 years. We assessed the relative
importance of environmental heterogeneity and dispersal (inferred from patch occupancy
patterns) as drivers of community structure. Furthermore, we contrasted metacommunity
patterns in pans that occasionally connect to the river (floodplain pans) and pans that lack
such connections altogether (endorheic pans) using redundancy models.
3. Echoes of species sorting and dispersal limitation emerge from our data set, suggesting
that both local and regional processes contribute to explaining branchiopod assemblages in
this system. Relative importance of local and regional factors depended on the type of data
set considered. Overall, habitat characteristics that vary in time, such as conductivity,
hydroperiod and vegetation cover, best explained the instantaneous species composition
observed during a snapshot sampling while long-term species composition appeared to be
linked to more constant intrinsic habitat properties such as river connectivity and spatial
location.