Vernal pool vegetation species composition and indundation data in a restored site, Travis Air Force Base, CA. 2000-2012

We studied ecological dynamics of vernal pool plant
communities in California, USA, focusing on: 1) effects of
dispersal limitation, order of colonization, and frequency of
colonization on plant community composition; 2) invasion of
vernal pools by non-native species, and 3) comparison of
restored vernal pools to naturally-occurring pools. We
manipulated the sequence and timing of plant colonization in a
field experiment with 256 constructed vernal pool basins. Our
observations provided evidence for dispersal limitation,
priority effects, and frequency of colonization. Several
features of historical contingence affected the early formation
of vernal pool plant communities, but we also observed reversals
in community trajectories, suggesting that these effects may be
lost within a decade. Pools that received more seeds of native
species were less invaded, providing evidence for biotic
resistance, but this resistance was eventually overcome.
Constructed pools exhibited similar hydrology as reference
pools, and vernal pool species established populations in many
of the pools that were appropriately inundated. Further, seeding
increased native species abundance in constructed pools. In
summary, our research has revealed that colonization events,
pool hydrologic conditions, and biotic interactions all
influence the formation and persistence of vernal pool plant communities.