Résumé
Tropical America, including the Caribbean, harbours the highest species diversity compared to any other region in the world. However, this remarkable diversity is facing severe threats from climate and land use change. While plot inventory networks have been successful in generating syntheses on biodiversity patterns and ecosystem functioning; cross-biome, plot-based studies in the tropics are rare, preventing the identification of general vs biome-specific responses to global change drivers. To address this knowledge gap, the SynTreeSys project is utilising worldleading expertise in tropical ecology to conduct a comprehensive assessment of tree species diversity patterns and its conservation status across the region. To achieve this, we are constructing a harmonised database to i) identify spatial patterns of tree diversity and dominance and the underlying causes of their variation, ii) detect zones of exceptional species turnover and, iii) to assess tree species conservation status in tropical America. One of the challenges in tropical regions is ensuring the homogeneous representativeness of biodiversity datasets. In areas with limited information or extensive land use transformation, historical data becomes a valuable source. The SynTreeSys-generated database covers a time span of almost 90 years, with approximately 10% of the plot data collected before 2000. The oldest dataset available dates back to 1934, comprising inventory plots documenting the vegetation of Moraballi Creek in Guyana, published by T. A. W. Davis and P. W. Richards, and gathered by the Amazon Tree Diversity Network (ATDN). In SynTreeSys, we emphasise the importance of "old" data, not only for the inherent value it holds but also for the rich narrative of the studies and their ability to provide historical and detailed descriptions of habitats, vegetation structure, soil, and even species interactions.