Amazon rainforests face intensifying water stress due to increases in vapour pressure deficit and changing hydrological regimes. Embolism resistance (Ψ50) is a critical metric of tree survival under drought conditions, it is defined as a plant's capacity to resist disruption of xylem water flow due to air bubble formation from water stress. However, measurements of Ψ50 are only available for a limited number of Amazon locations and species. Conversely, data on forest taxonomic composition are abundant across Amazonia, and if Ψ50 is conserved phylogenetically, these data could provide a way to scale-up drought resistance patterns. Here we evaluate Ψ50 measurements across non-flooded Amazonian tree taxa and reveal a moderate phylogenetic signal, with phylogenetic conservatism evident at the family-level. Notably, Fabaceae is amongst the most embolism-resistant tree families in Amazonia. Leveraging the phylogenetic signal we use species composition and tree size data from 448 forest plots across Amazonia to produce a macroecological assessment of Amazonian vulnerability to embolism. The resulting estimate spatial pattern reveals that forests in the Brazilian and Guiana Shield regions, where Fabaceae abundance is high, show strong resistance to embolism. In contrast, tree communities in Western Amazonia appear more vulnerable to embolism, suggesting a reduced capacity to withstand future drought conditions.

Understanding how the traits of lineages are related to diversification is key for elucidating the origin of variation in species richness. Here, we test whether traits are related to species richness among lineages of trees from all major biogeographical settings of the lowland wet tropics. We explore whether variation in mortality rate, breeding system and maximum diameter are related to species richness, either directly or via associations with range size, among 463 genera that contain wet tropical forest trees. For Amazonian genera, we also explore whether traits are related to species richness via variation among genera in mean species-level range size. Lineages with higher mortality rates—faster life-history strategies—have larger ranges in all biogeographic settings and have higher mean species-level range sizes in Amazonia. These lineages also have smaller maximum diameters and, in the Americas, contain dioecious species. In turn, lineages with greater overall range size have higher species richness. Our results show that fast life-history strategies influence species richness in all biogeographic settings because lineages with these ecological strategies have greater range sizes. These links suggest that dispersal has been a key process in the evolution of the tropical forest flora.

Plants cope with the environment by displaying large phenotypic variation. Two spectra of global plant form and function have been identified: a size spectrum from small to tall species with increasing stem tissue density, leaf size, and seed mass; a leaf economics spectrum reflecting slow to fast returns on investments in leaf nutrients and carbon. When species assemble to communities it is assumed that these spectra are filtered by the environment to produce community level functional composition. It is unknown what are the main drivers for community functional composition in a large area such as Amazonia. We use 13 functional traits, including wood density, seed mass, leaf characteristics, breeding system, nectar production, fruit type, and root characteristics of 812 tree genera (5211 species), and find that they describe two main axes found at the global scale. At community level, the first axis captures not only the 'fast-slow spectrum', but also most size-related traits. Climate and disturbance explain a minor part of this variance compared to soil fertility. Forests on poor soils differ largely in terms of trait values from those on rich soils. Trait composition and soil fertility exert a strong influence on forest functioning: biomass and relative biomass production.

Climate change and increasing availability of resources such as carbon dioxide are modifying forest functioning worldwide, but the effects of these changes on forest structure are unclear. As additional resources become available, for example, through CO2 fertilization or nitrogen deposition, large trees, with greater access to light, may be expected to gain further advantages. Conversely, smaller light-suppressed trees might benefit more if their light compensation point changes, while bigger trees may be the most negatively impacted by increasing heat and drought. We assessed recent changes in the structure of Earth's largest tropical forest by analysing 30 years of Amazonian tree records across 188 mature forest plots. We find that, at a stand level, trees have become larger over time, with mean tree basal area increasing by 3.3% per decade (95% CI 2.4; 4.1). Larger trees have increased in both number and size, yet we observed similar rates of relative size gain in large and small trees. This evidence is consistent with a resource-driven boost for larger trees but also a reduction in suppression among smaller trees. These results, especially the persistence and consistency of tree size increases across Amazonian forest plots, communities and regions, indicate that any negative impacts of climate change on forests and large trees here have so far been mitigated by the positive effects of increased resources.

1. Leaf and wood functional traits of trees are related to growth, reproduction, and survival, but the degree of phylogenetic conservatism in these relationships is largely unknown. In this study, we describe the variability of strategies involving leaf, wood and demographic characteristics for tree genera distributed across the Amazon Region, and quantify phylogenetic signal for the characteristics and their relationships. 2. Leaf and wood traits are aligned with demographic variables along two main axes of variation. The first axis represents the coordination of leaf traits describing resource uptake and use, wood density, seed mass, and survival. The second axis represents the coordination between size and growth. Both axes show strong phylogenetic signal, suggesting a constrained evolution influenced by ancestral values, yet the second axis also has an additional, substantial portion of its variation that is driven by functional correlations unrelated to phylogeny, suggesting simultaneously higher evolutionary lability and coordination. 3. Synthesis. Our results suggest that life history strategies of tropical trees are generally phylogenetically conserved, but that tree lineages may have some capability of responding to environmental changes by modulating their growth and size. Overall, we provide the largest-scale synopsis of functional characteristics of Amazonian trees, showing substantial nuance in the evolutionary patterns of individual characteristics and their relationships.

Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.

Ecuador is a multicultural and megadiverse country where nearly 50 species of wild edible macrofungi (WEM), used by 12 indigenous peoples, have been reported. The Kichwa use 29 species of mushrooms, but aspects of their ecology are unknown. The aim of this study was to study the richness, use, substrates and fruiting seasons of WEM consumed by two peri-urban Kichwa communities settled in the piedmont between the Andes and the Amazon. Between May 2019 to April 2020, we conducted 56 interviews with adults and 12 walks in the chagras and forests. People recognized 26 fungal names related to 12 species of mushrooms, 11 basidiomycetes and one ascomycete. Three species were the most culturally important: Favolus tenuiculus, Bresodolia paradoxa and Lentinus concavus, defined by their abundance, economic importance and taste. Six mushroom species were newly reported for the Kichwa group and four species added to the list of species in the country. All the fungi were lignicolous; they were found on the trunks of 16 species of plants in the chagras. The plant-trees: P. discolor, Inga edulis and C. alliodora were the most common substrates. These species are abundant in the chagras and frequently used for their wood. Ecological and traditional knowledge related to WEM is important to enhance management practices in situ and ex situ.

Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1-6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth's 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world's most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.

Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world’s forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.

We describe the geographical variation in tree species composition across Amazonian forests and show how environmental conditions are associated with species turnover. Our analyses are based on 2023 forest inventory plots (1 ha) that provide abundance data for a total of 5188 tree species. Within-plot species composition reflected both local environmental conditions (especially soil nutrients and hydrology) and geographical regions. A broader-scale view of species turnover was obtained by interpolating the relative tree species abundances over Amazonia into 47,441 0.1-degree grid cells. Two main dimensions of spatial change in tree species composition were identified. The first was a gradient between western Amazonia at the Andean forelands (with young geology and relatively nutrient-rich soils) and central-eastern Amazonia associated with the Guiana and Brazilian Shields (with more ancient geology and poor soils). The second gradient was between the wet forests of the northwest and the drier forests in southern Amazonia. Isolines linking cells of similar composition crossed major Amazonian rivers, suggesting that tree species distributions are not limited by rivers. Even though some areas of relatively sharp species turnover were identified, mostly the tree species composition changed gradually over large extents, which does not support delimiting clear discrete biogeographic regions within Amazonia.

The palms Prestoea acuminata and P. schultzeana are found at altitudes between 800 and 2600 m asl. and 200 and 1300 m asl., respectively. Although they are important components in the dynamics of the Andean-Amazon transition forest, and are used by local communities, there is not enough biological information that explain their strategies for reproductive dynamics and its conservation. In order to contribute to the knowledge of the reproductive biology of these species we studied the diversity of flower visitors and pollinators of each one, the differences between the pistillate and staminate phases and the species shared between them. The study was carried out in the Piedmont evergreen forest and the Napo low evergreen forest of Ecuador. We collected 15 inflorescences of P. acuminata and 9 of P. schultzeana. We then divided the flower visitors into morphospecies and counted, photographed and identified them to the best possible taxonomic level. We counted 10,123 flower visitors from 82 morphospecies in P. acuminata and 1192 from 42 morphospecies in P. schultzeana. Based on abundance and frequency of morphospecies, and observations of pollen in the pistillate phase, we found six potential pollinators in P. acuminata, all Coleoptera, and five in P. schultzeana, three Coleoptera and two Diptera, suggesting the cantharophily syndrome of the former and the myophily of the latter. The palm species shared only one morphospecies of Aleocharinae (Coleoptera, Staphylinidae), showing that flower visitors are very specific to each palm and their importance in maintaining insect diversity in these forests.

Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and v & aacute;rzea forest types, the phylogenetic composition varies by geographic region, but the igap & oacute; and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R-2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R-2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions.

In Ecuador, between the foothills of the Andes and the well-drained terra firme forests of the Amazon, there are two useful palm species, Oenocarpus bataua and O. mapora, which differ mainly in size. Both species are negatively affected by deforestation and land conversion for agriculture and cattle ranching, altering the structure and functioning of ecosystems. Management and restoration plans are therefore needed. To contribute with local knowledge of the species, we studied the diversity of flower visitors of both species in 9 sites in Napo Province during the flowering seasons of 2021 and 2022. We collected 16 inflorescences and measured the length, number of rachillae and flowers of each and correlated them with the richness and abundance of their floral visitors. Finally, we calculated a similarity index between species and developed an interaction network to observe associations between their inflorescences and flower visitors. We found 89 morphospecies of flower visitors, 77 in O. bataua and 51 in O. mapora, and 19 morphospecies are potential pollinators because they are active during the staminate and pistillate phases. This is the first report of flower visitors of O. mapora in western Amazonia, and it shared 40

Urospatha sagittifolia is a medicinal plant with antivenom, antihemorrhagic and anti-inflammatory properties commonly used by vulnerable Amazon indigenous communities to tackle venomous snakebites and their life-threatening consequences. Despite its pharmacological potential as a rich source of drug candidates, its metabolomic profile remains unknown. In this context, this study integrated mass spectrometry-based metabolomics, multivariate analysis, and molecular networks to uncover the chemical composition of U. sagittifolia and its dynamic metabolic changes during three plant growth stages (seedling, juvenile and adult). In general, 50 metabolites were identified in U. sagittifolia tubers by LC-MS (43 metabolites) and GC–MS (seven metabolites). Multivariate analysis using LC-MS showed that the relative concentrations of most of the identified metabolites were higher in seedlings or juveniles than in adults. On the other hand, GC–MS analysis showed that methyl palmitate and methyl stearate were the most abundant in the early growth stages, whereas allantoic acid and palmitic acid prevailed as the plant matured. In summary, this is the first metabolomics-centered mining of U. sagittifolia compositional diversity focusing on chemical-level variability. These valuable findings offer a temporal view of metabolic changes during plant growth stages, which is useful for future bioprospecting, biological screening, and purification of metabolite-based therapeutics.

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution.

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoo-chory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser- availability hypothesis) and/or the availability of resources for constructing

Indigenous societies are known to have occupied the Amazon basin for more than 12,000 years, but the scale of their influence on Amazonian forests remains uncertain. We report the discovery, using LIDAR (light detection and ranging) information from across the basin, of 24 previously undetected pre-Columbian earthworks beneath the forest canopy. Modeled distribution and abundance of large-scale archaeological sites across Amazonia suggest that between 10,272 and 23,648 sites remain to be discovered and that most will be found in the southwest. We also identified 53 domesticated tree species significantly associated with earthwork occurrence probability, likely suggesting past management practices. Closed-canopy forests across Amazonia are likely to contain thousands of undiscovered archaeological sites around which pre-Columbian societies actively modified forests, a discovery that opens opportunities for better understanding the magnitude of ancient human influence on Amazonia and its current state.

Globally, nearly two billion people consume approximately 2,111 species of insects, 92% of which are harvested directly from their natural ecosystems. However, intensifying insect harvesting causes ecological alterations and biodiversity loss. In the Ecuadorian Amazon, the Kichwa people are the primary consumers of insects. Thus, this study characterised the diversity of edible insects, host plants, and cultural significance among two peri-urban Kichwa communities. We used photo-elicitation, free-listing, semi-structured interviews, and in situ walk-in-the-woods to identify relevant edible insects. Then, we used species accumulation curves, the Salience Smith Index (SSI), ecological interaction networks, and extinction models to assess insect-host species interactions and cultural significance. We registered 19 edible insect species from three orders and six families. Furthermore, we reported two new species for the world list of edible insects and one for the Ecuadorian list. Ten insect species were associated with 21 host plant species. The interaction between the Rhynchophorus palmarum beetle and the Bactris gasipaes palm tree had the highest cultural significance (SSI>0.18, P <0.05). Furthermore, we found that 30% of the insect species and 52% of the host plant species (of which 90% were palms) were essential for conserving the interaction network structure. Finally, the extinction models suggested that host plant species knowledge was intrinsically related to edible insect knowledge conservation. Our findings provide basic ecological and cultural information for developing edible insect breeding projects and safeguarding traditional knowledge.