Large old tropical trees as keystone biodiversity structures: the Life on Trees program

Association for Tropical Biology and Conservation annual meeting https://www.atbc2025.org Large old tropical trees as keystone biodiversity structures: the Life on Trees program Leponce Maurice1, Basset Yves2, Aristizábal-Botero Ángela1, Albán Castillo Joaquina3, Aguilar Rengifo Guillermo4, Barbut Jérôme5, Buyck Bart5, Butterill Phil6, Calders Kim7, Carrias Jean-François8, Catchpole Damien9, D’hont Barbara7, Delabie Jacques10, Drescher Jochen11, Ertz Damien12, Heughebaert André13, Hofstetter Valérie14, Leroy Céline15, Leveque Antoine16, Macedo Cuenca Victor4, Melki Frédéric17, Michaux Johan18, Ocupa Horna Luis19, Pillaca Huacre Luis3, Poirier Eddy20, Ramage Thibault21, Rougerie Rodolphe5, Rouhan Germinal5, Rufray Vincent15, Salas Guererro Marcos4, Scheu Stefan11, Schmidl Jürgen22, Silva Dávila Diana3, Valenzuela Gamarra Luis23, Vanderpoorten Alain18, Villemant Claire5, Pascal Olivier17 1 Royal Belgian Institute of Natural Sciences, Vautier st. 29, Brussels, 1000, Belgium; 2 Smithsonian Tropical Research Institute, Panama; 3 Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima, Peru; 4 Servicio Nacional de Áreas Naturales Protegidas por el Estado-Ministerio del Ambiante, Peru; 5 Muséum National d'Histoire Naturelle, Paris, France; 6 Czech Academy of Sciences, České Budějovice,Czech Republic; 7 Ghent University, Belgium; 8 Université Clermont-Auvergne, Clermont-Ferrand, France; 9 Independent Consultant, Lima, Peru; 10 Centro de Pesquisas do Cacau – CEPEC, Itabuna, Brasil; 11 Göttingen University, Germany; 12 Meise Botanic Garden, Belgium; 13 Belgian Biodiversity Platform, Brussels, Belgium; 14 AGROSCOPE, Nyon, Switzerland; 15 AMAP (Univ. Montpellier, CIRAD, CNRS, INRAE, IRD), Montpellier, France; 16 PatriNat (OFB-CNRS-MNHN), Paris, France; 17 Fonds de Dotation Biotope Pour La Nature, Mèze, France; 18 Université de Liège, Belgique; 19 Centro de Investigación en Biología Tropical y Conservación, Piura, Perú ; 20 Independent entomologist, Cayenne, Guyane ; 21 Independent entomologist, Concarneau, France ; 22 Universität Erlangen-Nürnberg, Germany. ; 22 Jardín Botánico de Missouri, Peru E-mail: (presenting author): mleponce@naturalsciences.be The aim of the Life on Trees (LOT, www.lifeontrees.org, https://doi.org/10.3389/ffgc.2024.1425492 ) program is to generate baseline knowledge about the number of eukaryotic species a single large aged tropical tree can host and to understand how these communities of organisms are assembled. The program is conducted in the Andes Amazon biodiversity hotspot. Our first project, LOT01 in the Amazon in 2022, located at 400m a.s.l., involved the study of a spectacular Dussia tessmannii tree (Fabaceae), towering at 50 meters in height. Our second project, LOT02 in the Andes in 2023, at 2450m a.s.l., focused on a 32-meter-tall Ficus americana subsp. andicola. The sampling was carried out by professional climbers, guided by experts of the different eukaryotic groups studied (plants, fungi, animals, protists). To better understand the contribution of different tree components (bark, leaves, fruits, flowers, living and dead wood) to overall tree biodiversity, we assigned observations into communities based on height zone or microhabitat and will examine similarities and nestedness in the composition of these communities. Initial findings indicate that significant diversity is harbored by a single tree in both locations (e.g., LOT01 vs LOT02: 42 vs 114 orchid species, 28 vs 28 fern species, 200+ vs 300+ bryophyte species, and 210+ vs 200+ lichen species identified). These figures set world records for their respective elevations. This confirms that large old tropical trees are important pools of biodiversity probably in relation with the variety of local microhabitats and tree age. canopy, eukaryotes, microclimate, LiDAR, trees We obtained world records for the diversity of orchids, ferns, bryophytes, lichens, and a large diversity of other eukaryotes on single large old trees in the Andes-Amazon.