Seed and leaf fall, regulating community assembly and nutrient cycling, are critical components in forests ecosystems. Understanding the interannual variation in seed and leaf fall is key to predicting dynamics of terrestrial ecosystems in response to climate change. El Niño–Southern Oscillation (ENSO) is considered as a powerful predictor for seed and leaf fall, it is one of the most prominent large-scale climate patterns.
Variation of sea temperature and intensity of rainfall related to ENSO lead to widespread changes in atmosphere circulation outside the tropical Pacific and affecting ecosystems worldwide. Under the context of increasing frequency and intensity of ENSO events induced by global warming, it is necessary to explore the ENSO effects on forests ecosystems.
To reveal how ENSO affects the temporal variation of species-level seed and leaf fall, researchers from the Institute of Applied Ecology of the Chinese Academy of Sciences have estimated the relationships among ENSO, local climate, and litterfall, using a 12-year data set of seed and leaf fall in a temperate forest of northeast China, with corresponding local climatic data (relative humidity and precipitation) and two ENSO indices (ENSO12 and ENSO34).
According to the researchers, the effects of ENSO on seed and leaf fall were all significant, but varied with species. Acer pseudo-sieboldianum had the most strongly response to ENSO among the seven studied species, whose seed and leaf was explained 40% and 34% by ENSO indices, respectively.
Interestingly, the researchers found the community synchrony of leaf fall in response to ENSO cycles for the first time. Differently, seed fall was only showed synchrony patterns at seasonal scales, but the signals of synchrony were stronger when ENSO occurred than in normal years. Local climate factors mediating the ENSO effects on the litterfall production, that is rainfall and relative humidity significantly correlated with seed fall of Fraxinus mandshurica and Tilla amurensis at ENSO scales, respectively.
This study systematically elucidates the effects of ENSO on temperate forests’ seed and leaf fall and provided new evidence that ENSO affects terrestrial ecosystems worldwide by atmospheric teleconnections.
This study was published in Science of the Total Environment an it was supported by the National Natural Science Foundation of China and the Strategic Priority Research Program of CAS.
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