Mismatch of Persistence and Occupancy Patterns in Natural
Conditions
We found support for our prediction that persistence and occupancy were
mismatched across a productivity gradient, both when species were
considered individually and together as a community. Each species tended
to occupy a greater proportion of sites as productivity increased (Fig.
1, bottom row); these increases were strongest for Bromus , a
species that was largely absent from sites of low to intermediate
productivity (𝛽1= 1.04 ± 0.30; Table S2), and weakest forPlantago (𝛽1= 0.26 ± 0.26; Table S2, bottom row of Fig. 1). By
contrast, we observed strong mismatches between persistence (i.e.,λ \(\geq\)1) and occupancy. Under conditions with neighbors, two
species (Micropus , Festuca ) were significantly more likely
to persist in more productive environments (Table S3), mirroring
occupancy, whereas for the two others (Plantago , Bromus ),
less productive sites were more conducive to persistence (Table S3; Fig.
1 red lines). Note that Micropus was not predicted to persist in
any location (λ << 1). Surprisingly, for all
species, occupancy patterns more closely reflect persistence in the
abiotic treatment (Fig. 1, blue) compared to the biotic treatment (red).
When scaling from species to the community, persistence significantly
decreased with productivity (slope = -0.25 [-0.40, -0.096], brackets
denote 95% CIs), whereas occurrence responded oppositely, increasing
with productivity (slope = 0.57 [0.42, 0.72]; i.e., significant
interaction between productivity and data type (i.e., persistence data
vs. occupancy data); χ2 = 84.94, df = 2, P< 0.001; Fig. 2). As a result, in unproductive environments,
fewer species occurred than could persist. In contrast, in productive
environments, most species could occur but relatively few could persist
at their current population size (i.e. λ <1).