A global approach to analyze the extent of the newly detected Tropical Lowland Cloud Forest (TLCF) based on a large-scale analysis of fog frequency and epiphyte growth, with a special focus on South America

热带云雾森林具有非凡的生物多样性，特别是附生植物，通常与山区联系在一起，在那里它们被称为热带山地云林。我们以前在圭亚那的工作表明，在热带低地雨林(海拔500米)的盆地和山谷中，通常以显著较低的附生植物丰度和多样性为特征的盆地和山谷中，存在另一种富含附生植物的云雾森林类型，称为热带低地云雾森林(TLCF)。我们假设这种新的森林类型在全球范围内出现在所有天然热带低地森林中，那里有足够的水分供应，允许在地形凹陷中形成夜间冠雾。该项目的主要目的是结合卫星数据、实地测量、气候模型数据和附生植物生长的机械模型来验证这一假设。首先，利用有关地形、天然森林覆盖和雾发生的全球辅助大数据，在空间上圈定潜在的适宜区域。特别是冠层雾的发生，需要用新开发的热带低地亚像素雾探测方案对全球可用的MODIS数据集进行重新处理。通过应用和验证一个新建立的苔藓、地衣和薄膜蕨类(膜叶蕨科)碳交换模型，研究了TLCF中冠层附生植物丰度与雾发生之间的关系。

Tropical cloud forests, with their extraordinary biodiversity particularly of epiphytic plants, are generally associated with mountainous regions, where they are referred to as Tropical Montane Cloud Forests. Our previous work in the Guianas now suggests that in basins and valleys of the Tropical Lowland Rain Forest (at elevations <500 m a.s.l.), which is normally characterized by a significantly lower epiphyte abundance and diversity, another type of epiphyte-rich cloud forest type exists, referred to as Tropical Lowland Cloud Forest (TLCF). We hypothesize that this new forest type occurs globally in all natural tropical lowland forests where a sufficient moisture supply allows the development of nocturnal canopy fog in terrain depressions. The main aim of the project is to test this hypothesis with a combination of satellite data, field measurements, climate model data and mechanistic modeling of epiphyte growth. First, potentially suitable regions are spatially delineated by means of global ancillary big data on topography, natural forest cover and fog occurrence. Particularly canopy fog occurrence requires reprocessing of the globally available MODIS data set with a newly developed subpixel fog detection scheme for tropical lowlands. The relationship between fog occurrence and the high abundance of canopy epiphytes in the TLCF is examined by applying and validating a newly developed carbon-exchange model for mosses, liverworts and filmy ferns (Hymenophyllaceae).