Plantas útiles y su incorporación a los sistemas productivos del departamento del guaviare (amazonia colombiana)

Para conocer las plantas útiles y su incorporación a los sistemas productivos, serealizó un inventario florístico en una zona de transición entre las sabanas naturalesde la altillanura orinocense y la llanura amazónica del departamento del Guaviare,registrando las especies útiles en las áreas de bosque, sabana, rastrojos, arreglosagroforestales, silvopastoriles, jardines y huertos habitacionales, con elacompañamiento de conocedores. Se registraron 301 especies de 199 géneros y 69familias botánicas, las cuales se agrupan en trece categorías de uso. Las familiasmejor representadas son: Mimosaceae (34 especies), Fabaceae (18), Caesalpiniaceae(17) y Burseraceae (14). Del total de especies registradas, 225 son nativas y 76 hansido introducidas a los sistemas productivos de la región. De 65 especies útilesidentificadas en el bosque, 32 fueron registradas en los arreglos silvopastoriles oagroforestales y diez han sido incorporadas a los cultivos. De las 25 especies útilesexistentes en los rastrojos, trece han sido incorporadas a los arreglos

Flora de la estrella fluvial de Inírida (Guainía, Colombia)

We present a list of the vascular plants found in the Inírida fluvial confluence which is part of the Guiana Shield, comprised of flooded and non-flooded heterogeneous forests and white sands with shrubby and herbaceous vegetation known as sabanetas or caatingas. The studied area is considered a high diversity region, classified as an exclusive area in Colombia due to its rare edaphic conditions which support high levels of endemisms. There are 833 species, 402 genera, and 123 families of registered vascular plants. The most represented families are Rubiaceae with 66 species, Melastomataceae with 52, Fabaceae with 36, Euphorbiaceae with 32, Cyperaceae with 31, and Apocynaceae with 24

Utilidad del valor de uso en etnobotánica. estudio en el departamento de putumayo (colombia)

Se presenta una cuantificación y una comparación de los valores de uso de árboles en dos áreas contrastantes del occidente de la Amazonia colombiana y se discute la aplicabilidad y la utilidad de los métodos disponibles en etnobotánica cuantitativa y se proponen nuevas modificaciones para mejorar los métodos en etnobotánica cuantitativa. Se concluye que el Valor de Uso se ve limitado para expresar la realidad de la utilización de las especies y el grado de importancia que tienen para las diferentes comunidades, así como para priorizar especies o áreas para conservación. Por consiguiente, se sugieren algunas estandarizaciones y adaptaciones metodológicas

Flora de la estrella fluvial de Inírida (Guainía, Colombia)

We present a list of the vascular plants found in the Inírida fluvial confluence which is part of the Guiana Shield, comprised of flooded and non-flooded heterogeneous forests and white sands with shrubby and herbaceous vegetation known as sabanetas or caatingas. The studied area is considered a high diversity region, classified as an exclusive area in Colombia due to its rare edaphic conditions which support high levels of endemisms. There are 833 species, 402 genera, and 123 families of registered vascular plants. The most represented families are Rubiaceae with 66 species, Melastomataceae with 52, Fabaceae with 36, Euphorbiaceae with 32, Cyperaceae with 31, and Apocynaceae with 24.Se presenta el listado de especies de plantas vasculares que crecen en la Estrella Fluvial de Inírida, un área que hace parte del Escudo Guayanés, donde la cobertura vegetal incluye bosques heterogéneos no inundables, bosques inundables y zonas cubiertas de arenas blancas con vegetación arbustiva y herbácea, llamadas "sabanetas" o "catingas". El área de estudio es considerada como zona de alta diversidad y se constituye como un área exclusiva en Colombia, con unas condiciones edáficas poco comunes que mantienen altos niveles de endemismo. Se registraron 833 especies de plantas vasculares, correspondientes a 402 géneros y 123 familias, de las cuales las más diversas fueron Rubiaceae con 66 especies, Melastomataceae con 52, Fabaceae con 36, Euphorbiaceae con 32, Cyperaceae con 31 y Apocynaceae con 24

One sixth of Amazonian tree diversity is dependent on river floodplains

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

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, 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 zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

Local hydrological conditions influence tree diversity and composition across the Amazon basin

Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures

Estimating the global conservation status of more than 15,000 Amazonian tree species

Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century