The influence of seed source, habitat and fungi on Cecropia seed survival in two neotropical forests.

Abstract

Abstract Two experiments were conducted at two neotropical sites: Barro Colorado Island, Panama and La Selva Biological Station, Costa Rica, to assess the relative importance of the intrinsic traits of Cecropia species, including provenances and maternal seed sources, the heterogeneity in seed-infecting fungal communities, and environmental conditions on the survival of seeds in the soil. Experiment 1 addressed the question, 'Is seed source or environment a better predictor of seed survival?' and experiment 2 addressed 'How does local dispersal affect seed fate?'. Taken together, the results demonstrated that environmental conditions in the seed bank have potentially greater influence on Cecropia seed survival than maternal sources or intrinsic seed characteristics. Cecropia seeds dispersed away from fruiting crowns and incorporated into the seed bank have higher survival than seeds that are incorporated into soils below conspecific crowns (fruiting or not). Two conditions associated with Cecropia below-crown sites and found that Cecropia litter cover may have greater effect on seed survival than high Cecropia seed bank density. Litter cover can create moist microhabitats and increase saprophytic fungal biomass in general, which may negatively affect the survival of seeds in soil. Results also showed that many fungi associated with live leaf tissue and litter infect Cecropia seeds, suggesting that litter could even provide a direct inoculum source of fungi capable of infecting seeds.