Data from: Seed survival in tropical pioneer trees is unrelated to conspecific distance but linked to fungal infection

Plant demography is heavily influenced by individual survival at local
scales, with host-specific natural enemies potentially reducing the
survival of seeds and seedlings in high-density patches near conspecific
adults, favoring heterospecific recruitment, and ultimately increasing
local plant diversity. Enemy pressure should differ between sites directly
beneath and away from their hosts’ crowns, between sites where their hosts
are abundant versus rare, and among potentially competing plant species.
Assessing the potential pathways by which enemies affect diversity at
local scales requires coupling experimental approaches that track plant
performance with characterization of their enemy communities. We focused
on the fate of individuals at the seed stage, a critical demographic
bottleneck in the plant life cycle. We tested how seed germination is
affected by fungal infection, distance from the adult tree, burial
duration, and host tree identity. We conducted a seed burial experiment on
BCI, Panama, using four pioneer tree species. Seeds were buried beneath
and 30 m away from adult trees and retrieved after 3 and 12 months. We
measured germination, cultured seed-infecting fungi, and evaluated fungal
communities using amplicon sequencing. Germination of all tree species
declined with burial time. Germination of seeds buried below vs. away from
focal trees also did not differ. Fungal isolation frequency and richness
increased after burial but did not change with distance or identity of the
adult tree. Fungal communities in seeds differed markedly among species,
but distance, burial duration, and seed viability status had little effect
on community composition. We found limited evidence that distance from
conspecifics drives seed mortality in the soil. Nonetheless, seed exposure
to the soil increases fungal infections and decreases seed survival,
highlighting the role of fungi in seed demography. We recommend that
future research explore the mechanisms by which host-generalist soilborne
fungi may drive seed mortality in plant communities.