Dispersal underpins mismatches between persistence and occupancy
By exploring (mis)matches between occupancy and persistence across the
productivity gradient, we found that the role of dispersal is contingent
upon environmental conditions (Fig. 4, Table S6). In unproductive
environments, populations were most likely to be well-matched to
conditions they were found in regardless of whether neighbors were
present or absent–species sorting was observed in 65% of species
[51-81] with neighbors, compared to 0.64 [0.51, 0.78] without
neighbors (Fig. 4; gray). By contrast, in productive environments, sink
populations were common, especially in the presence of neighbors,
suggesting that dispersal tended to be excessive, causing populations in
locations that could not maintain a positive growth rate (Table S6).
Growth rates and proportion of sink populations were not dependent on
intraspecific density dependence (Figs. S7, S8). Generally, dispersal
limitation was uncommon regardless of species interactions. Similar
qualitative trends in species sorting, dispersal limitation, and
dispersal excess occurred with neighbors and without neighbors (Table
S6).