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
Final Report Abstract
Tropical Lowland Cloud Forests (TLCF, <500 m a.s.l.), detected several years ago in tropical lowland forests, show increased biodiversity particularly of moisture-depending epiphytic plants. However, these ecosystems are under great threat of climate change, particularly due to the increasing droughts in the Amazon. The aims of the project were (i) to unveil the spatial extend of fog-low stratus (FLS) driven TLCF in the Amazon by using remote sensing, (ii) to learn about the resistance of TLCF against Amazon droughts, (iii) to develop and use a process-based model to mechanistically understand the impact of droughts on canopy bryophytes and (iv) to provide climate data in appropriate spatio-temporal resolution to force the model. Based on 18 years of MODIS data, a new fog detection scheme was developed and successfully tested. It showed that potential TLCF areas are a widespread, mainly in concave terrain situations. The main challenge here was to detect subpixel fog occurrence, because most river valleys are below MODIS pixel resolution of 1 km. We then asked how these potential TLCF areas are affected by droughts of different intensities by analysing our novel data set for past Amazon droughts to unveil areas with high resistance. We found the highest occurrence and stability of fog-low stratus in steep river valleys. For a mechanistic understanding of the importance of fog water for epiphytic plants, we modelled bryophyte carbon balances using newly gathered physiological response curves and canopy microclimate data from the tropical lowland forest of Yasuni, Ecuador. We also analysed alpha and beta diversity patterns of epiphytic bryophytes there and found no indication of LTCF but strong vertical and weak horizontal structuring. The model identified weather patterns needed to obtain positive diel carbon balances, a prerequisite for the development of rich epiphyte communities. To operate the model for the entire Amazon, sub-daily microclimatic forcing data are needed, but mechanistic microclimatic modelling is hardly possible at such large scales. Another option is to downscale broad-scale re-analysis data (e.g. 9-km ERA-5 land) to the needed 30-100 m resolution. However, fog is generated by mesoscale cold air drainage flows not properly considered in the ERA-5 process model. Therefore, we tested the downscaling tool microclima, which explicitly considers mesoscale breeze dynamics, and showed that for the Amazon region nocturnal cold air inversions were not accurately calculated. Here, future research must provide better tools for generating more exact microclimatic data fields for tropical lowlands applicable for an area-wide forcing of the developed bryophyte model. Beyond scientific knowledge gain, the outcomes are also of high relevance for conservation. The map of resistant FLS areas mark regions with a high potential for hygric climate-change refugia. Those regions should be priority areas for lowland forest conservation.
Publications
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Räumliche Ableitung eines neuen, durch Nebel angetriebenen Ökosystems im tropischen Tiefland. Poster presentation at 38. Jahrestagung des Arbeitskreis Klima, 25. - 27. Oktober 2019, Tagungshotel Jesteburg. (2019)
Pohl, M., Lehnert, L. & Bendix, J.
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Spatial delineation of a fog-driven ecosystem of tropical lowlands. Poster presentation at 8th International Conference on Fog, Fog Collection and Dew (IFDA2019-2), Taipei, Taiwan, 14–19 July 2019.
Pohl, M., Bendix, J. & Lehnert, L.
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A new fog and low stratus retrieval for tropical South America reveals widespread fog in lowland forests. Remote Sensing of Environment, 264, 112620.
Pohl, Marius J.; Lehnert, Lukas; Bader, Maaike Y.; Gradstein, S. Robbert; Viehweger, Jonas & Bendix, Jörg
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High-resolution tropical rain-forest canopy climate data. Oral presentation at One-day Canopy Conference Online (2021, Xishuangbanna)
Berdugo, M.B., L. Heyer, K. Suárez, J. Deleg, J. Bendix & M.Y. Bader
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Overcoming data limitations to model daily carbon assimilation patterns of epiphytic bryophytes in lowland tropical forests. Poster presentation at Annual meeting of the GfÖ special interest group on Plant Population Biology (PopBio, 2021, Prague ~ online)
Berdugo Moreno, M.B., N. Nicolić, L. Guérot, S. Brach, S.R. Gradstein, J. Bendix & M.Y. Bader
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Scales of diversity in Amazonian rainforest bryophytes. Poster presentation at Annual meeting of the GfÖ special interest group on Plant Population Biology (PopBio, 2021, Prague ~ online)
Bader, M.Y., M.B. Berdugo Moreno, L. Guerot & S.R. Gradstein
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The distribution of fog and low stratus clouds in tropical lowland forests derived from remote sensing infrared data. Poster presentation at 39. Jahrestreffen des AK Klima in Passau, 05.11.2021 – 07.11.2021. (2021)
Pohl, M., Lehnert, L., Bader, M., Viehweger, J., Gradstein, S.R. & Bendix, J.
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A research agenda for nonvascular photoautotrophs under climate change. New Phytologist, 237(5), 1495-1504.
Porada, Philipp; Bader, Maaike Y.; Berdugo, Monica B.; Colesie, Claudia; Ellis, Christopher J.; Giordani, Paolo; Herzschuh, Ulrike; Ma, Yunyao; Launiainen, Samuli; Nascimbene, Juri; Petersen, Imke; Raggio, Quílez José; Rodríguez‐Caballero, Emilio; Rousk, Kathrin; Sancho, Leopoldo G.; Scheidegger, Christoph; Seitz, Steffen; Van Stan, John T.; Veste, Maik; ... & Weston, David J.
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Diversity patterns of epiphytic bryophytes across spatial scales: Species‐rich crowns and beta‐diverse trunks. Biotropica, 54(4), 893-905.
Berdugo, Monica B.; Gradstein, S. Robbert; Guérot, Louise; León‐Yánez, Susana; Bendix, Jörg & Bader, Maaike Y.
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Good days, bad days: weather as a driver of bryophyte carbon-exchange dynamics in tropical rainforest canopies. Oral presentation at 58th Annual Meeting of the Association for Tropical Biology and Conservation (ATBC) (2022, Cartagena, Colombia ~ online)
Berdugo, M.B., N. Nikolic, L. Guerot, S. Bach, J. Bendix, G. Zotz & M.Y. Bader
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High-resolution tropical rain-forest canopy climate data. Environmental Data Science, 1(2022).
Berdugo, Monica B.; Heyer, Leander; Suarez, Contento Karen Yuliana; Déleg, Jorge; Bendix, Jörg & Bader, Maaike Y.
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Klimawandel & Trockenheit in den Tropen: Täler im Amazonasbecken als bevorzugte Klimawandel-Refugien für feuchtigkeitsabhängige Organismen. Poster presentation at 40. Jahrestreffen des AK Klima in Ochsenfurt, 28.-30.10.2022. (2022)
Pohl, M., Lehnert, L., Thies, B., Seger, K., Berdugo, M. B., Gradstein, S. R., Bader, M. & Bendix, J.
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Fog-low stratus (FLS) occurrence under increasing Amazon drought conditions supports the formation of climate change refugia in concave terrain. Oral presentation at 9th International Conference on Fog, Fog Collection, and Dew (FOGDEW2023), July 23-28 2023, Fort Collins, Colorado USA
Bendix, J., Pohl, M., Thies, B., Bader, M & Lehnert, L.
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Valleys are a potential refuge for the Amazon lowland forest in the face of increased risk of drought. Communications Earth & Environment, 4(1).
Pohl, Marius J.; Lehnert, Lukas W.; Thies, Boris; Seeger, Konstantin; Berdugo, Mónica B.; Gradstein, S. Robbert; Bader, Maaike Y. & Bendix, Jörg
