The effect of seasonal and multiannual environmental variability on the abundance and composition of Neotropical pollen rain was investigated using ten years of seasonal aerial pollen samples from Barro Colorado Island (BCI), Panama. Using canonical correspondence analysis, we identified the environmental variables that most account for intra-annual and inter-annual variability in tropical pollen production and found that pollen rain samples effectively captured the strong seasonality and stratification of pollen flow within the forest canopy. Inter-annual variation in pollen rain composition varied most strongly with the preceding year’s precipitation, with a smaller secondary effect of the current year’s temperature and photosynthetically active radiation (PAR). Our results demonstrate the relative stability of the long-term pollen rain as a larger regional signal of flowering response to climatic variability, while also suggesting that paleoecological interpretations of modern pollen assemblages need to adjust for skewed short-term variability in pollen influx from neighboring pollen taxa
