Department of Geosciences and Geography, University of Helsinki, Helsinki, 00014, Finland.
Biological Dynamics of Forest Fragment Project, National Institute for Amazonian Research, Manaus, AM, 69067-375, Brazil.
Nat Commun. 2022 Feb 17;13(1):917. doi: 10.1038/s41467-022-28490-7.
Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet and dry seasons in Central Amazonia to show that plant phenology varies strongly across vertical strata in old-growth forests, but is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we find that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests lost plant material. In contrast, the understory greened up with increased light availability driven by the upper canopy loss, alongside increases in solar radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures in forest edges exacerbated the upper canopy losses of large trees throughout the dry season, whereas the understory in these light-rich environments was less dependent on the altered upper canopy structure. Our findings reveal a strong influence of edge effects on phenological controls in wet forests of Central Amazonia.
对亚马逊森林物候的幅度和时间的预测仍然存在很大争议。在这里，我们使用陆地激光雷达每两周进行一次调查，涵盖了亚马逊中部地区的干湿两季，结果表明，植物物候在古老的森林中垂直层次上变化很大，但对森林破碎化引起的干扰很敏感。结合连续的小气候测量，我们发现，当干季后期的最高日温度达到 35°C 时，未受干扰的森林中大树的上层树冠会失去植物材料。相比之下，由于上层树冠的减少，阳光更加充足，下层植被会变绿，同时太阳辐射也会增加，即使在土壤和大气条件较为干燥的时期也是如此。然而，森林边缘持续的高温加剧了大树在整个旱季上层树冠的损失，而在这些光照充足的环境中的下层植被对树冠结构的改变依赖程度较低。我们的研究结果揭示了边缘效应对亚马逊中部湿润森林物候控制的强烈影响。
