Browsing by Autor "Juan Ernesto Guevara"

Now showing 1 - 6 of 6

Estimating the global conservation status of more than 15,000 Amazonian tree species
(American Association for the Advancement of Science, 2015) Hans ter Steege; Nigel C. A. Pitman; Timothy J. Killeen; Susan G. W. Laurance; Carlos A. Peres; Juan Ernesto Guevara; Rafael P. Salomão; Carolina V. Castilho; Iêda Leão do Amaral; Francisca Dionízia de Almeida Matos
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 that most 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.
Functional composition of the Amazonian tree flora and forests
(Nature Portfolio, 2025) Hans ter Steege; Lourens Poorter; Jesús Aguirre‐Gutiérrez; Claire Fortunel; William E. Magnusson; Oliver L. Phillips; Edwin Pos; Bruno Garcia Luize; Christopher Baraloto; Juan Ernesto Guevara
Hyperdominance in the Amazonian Tree Flora
(American Association for the Advancement of Science, 2013) Hans ter Steege; Nigel C. A. Pitman; Daniel Sabatier; Christopher Baraloto; Rafael P. Salomão; Juan Ernesto Guevara; Oliver L. Phillips; Carolina V. Castilho; William E. Magnusson; Jean‐François Molino
The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community.
<i>Unraveling Amazon tree community assembly using Maximum Information Entropy</i> : a quantitative analysis of tropical forest ecology
(2021) Edwin Pos; Luiz de Souza Coêlho; Diógenes de Andrade Lima Filho; Rafael P. Salomão; Iêda Leão do Amaral; Francisca Dionízia de Almeida Matos; Carolina V. Castilho; Oliver L. Phillips; Juan Ernesto Guevara; Marcelo de Jesus Veiga Carim
Abstract 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.
Mapping density, diversity and species-richness of the Amazon tree flora
(Nature Portfolio, 2023) Hans ter Steege; Nigel C. A. Pitman; Iêda Leão do Amaral; Luiz de Souza Coêlho; Francisca Dionízia de Almeida Matos; Diógenes de Andrade Lima Filho; Rafael P. Salomão; Florian Wittmann; Carolina V. Castilho; Juan Ernesto Guevara
Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology
(Nature Portfolio, 2023) Edwin Pos; Luiz de Souza Coêlho; Diógenes de Andrade Lima Filho; Rafael P. Salomão; Iêda Leão do Amaral; Francisca Dionízia de Almeida Matos; Carolina V. Castilho; Oliver L. Phillips; Juan Ernesto Guevara; Marcelo de Jesus Veiga Carim