Flowering and fruit-set depend of interactions between climate and soil texture in Amazonian understorey herbs

Abstract The persistence of a plant at an area depend on species ability to survive and reproduce under local conditions. Estimating environmental influence on reproduction is difficult because climatic and soil conditions have synergistic effects on flower and fruit production, but are essential to modeling correctely effects of the climate changes on species distributions. Here, we develop a statistical method that allows investigating the environmental influence on reproduction using reproduction observational data only (no individual plants marking required). We surveyed 30 standardized permanent plots on central Amazonia for six families of monocots herbs. The plots were surveyed for twelve consecutive months. Using the newly developed method, we estimated the effect of climatic (temporal) and edaphic (spatial) covariates on flower and fruit production. We demonstrate that plant reproduction can be estimated from observational data only when enough temporal and spatial data are available. By using the proposed statistical method, we show that the conversion of flowers into fruits in Amazonian monocots is highest in sandy soils, and the difference in conversion rates between sandy and clayey soils is more pronounced in wetter months. By comparing the production of flowers and fruits with previously published data on species occurrence, our results suggesting that species distribution is limited primarily by species capacity to produce fruits (e.g. limited pollination) and not by the capacity to produce flowers. Due to the association of fruit production to climatic and edaphic variable, our results point to potential changes in species reproduction and distribution under future climatic regimes.