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Funding: Floristic identification in plots in the RAINFOR forest monitoring network have been supported by the Natural Environment Research Council (grants NE/B503384/1, NE/ D01025X/1, NE/I02982X/1, NE/F005806/1, NE/D005590/1 and NE/I028122/1) and the Gordon and Betty Moore Foundation. 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. Publisher PDF

Aim: In Amazonia, 227 of c. 16,000 tree species account for half the individual trees (termed ‘hyperdominant’ species), and a disproportionate number of these species are palms. Our objectives are to show how and whether palm abundance has changed through the Holocene. Here, we reconstruct a detailed fire and vegetation history from north-western Amazonia, with a focus on changes in palm abundances, and compare our results with regional data.Location: Amacayacu, Colombia.Taxon: Amazonian palms.Methods: We performed charcoal and phytolith analysis on soil cores, and obtained ages of past fires using 14C dating. We measured charcoal abundances and the relative abundances of phytoliths (silica-based microfossils) for all samples. We used these data to reconstruct changes in fire and vegetation, and compared these data with the species composition of palms in the modern forest.Results: Seven 14C dates from charcoal in three cores provided fire ages ranging from 1630 to 2450 calibrated years before present. Charcoal was absent from one-third of the cores. Palm phytoliths from genera such as Iriartea, Socratea, and Astrocaryum have increased through time, while genera such as Euterpe, Hyospathe, and Oenocarpus have remained relatively stable and similar to modern levels. Overall, palm abundances were negatively correlated with charcoal measurements. Decorated sphere phytoliths, produced from unknown arboreal taxa were positively correlated with charcoal presence and abundance.Main conclusions: Palms have increased at Amacayacu and other forest plots through time, but the increases are largest in north-western Amazonia. The presence of fire, however, dampens the increase in palms through time. When compared with reconstructions from other Amazon regions, our results suggest that increases in palm abundances in the late Holocene occurred both in the presence and absence of direct pre-Columbian human influence, and that response was strongest in north-western Amazonia when human influence was minimal.

Made available in DSpace on 2021-06-25T10:27:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The forests of Amazonia are among the most biodiverse plant communities on Earth. Given the immediate threats posed by climate and land-use change, an improved understanding of how this extraordinary biodiversity is spatially organized is urgently required to develop effective conservation strategies. Most Amazonian tree species are extremely rare but a few are common across the region. Indeed, just 227 ‘hyperdominant’ species account for >50% of all individuals >10 cm diameter at 1.3 m in height. Yet, the degree to which the phenomenon of hyperdominance is sensitive to tree size, the extent to which the composition of dominant species changes with size class and how evolutionary history constrains tree hyperdominance, all remain unknown. Here, we use a large floristic dataset to show that, while hyperdominance is a universal phenomenon across forest strata, different species dominate the forest understory, midstory and canopy. We further find that, although species belonging to a range of phylogenetically dispersed lineages have become hyperdominant in small size classes, hyperdominants in large size classes are restricted to a few lineages. Our results demonstrate that it is essential to consider all forest strata to understand regional patterns of dominance and composition in Amazonia. More generally, through the lens of 654 hyperdominant species, we outline a tractable pathway for understanding the functioning of half of Amazonian forests across vertical strata and geographical locations. Institute of Environment Department of Biological Sciences Florida International University School of Geography University of Leeds Center for Global Discovery and Conservation Science Arizona State University Instituto Nacional de Pesquisas da Amazônia (INPA) Ecology and Evolutionary Biology University of Michigan Departamento de Ciencias Forestales Universidad Nacional de Colombia Departamento de Biología Universidad Autónoma de Madrid Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM) Universidad Autónoma de Madrid Naturalis Biodiversity Center Systems Ecology Vrije Universiteit Lancaster Environment Centre Lancaster University Environmental Change Institute University of Oxford Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences School of Geosciences University of Edinburgh Missouri Botanical Garden Brazilian Agricultural Research Corporation (Embrapa) Universidad Nacional de San Antonio Abad del Cusco Department of Intergrative Biology University of California Berkeley Department of Biology University of Turku Instituto de Investigaciones de la Amazonía Peruana UNELLEZ-Guanare Programa de Ciencias del Agro y el Mar Herbario Universitario (PORT) Compensation International Progress S. A.—Ciprogress Greenlife AMAP Université de Montpellier CIRAD CNRS INRAE IRD Environmental and Rural Science University of New England INRA UMR EcoFoG AgroParisTech CNRS CIRAD Université des Antilles Université de Guyane CIRAD UMR EcoFoG BIOMAS Universidad de Las Américas Instituto de Ecología Herbario Nacional de Bolivia Departamento de Biologia Universidade Federal de Rondônia Laboratoire Evolution et Diversité Biologique (EDB) CNRS/UPS School of Geography Earth and Environmental Sciences University of Plymouth Department of Ecology and Evolutionary Biology Cornell University Department of Geography University of Exeter Facultad de Ciencias Biológicas Universidad Nacional de la Amazonía Peruana Estación Biológica del Jardín Botánico de Missouri Institut de Ciència i Tecnologia Ambientals Universitat Autònoma de Barcelona School of Geography & Sustainable Development University of St Andrews Department of Environment and Development Federal University of Amapá Centre for Tropical Environmental and Sustainability Science (TESS) and College of Marine and Environmental Sciences James Cook University Department of Environmental Science and Policy George Mason University Inventory and Monitoring Program National Park Service Smithsonian Institution Department of Plant Sciences University of Cambridge Living with Lakes Centre Laurentian University DRGB Instituto Nacional de Innovación Agraria (INIA) Herbarium Amazonense (AMAZ) Universidad Nacional de la Amazonia Peruana Department of Ecology Universidade de São Paulo Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Centro de Estudos da Biodiversidade Universidade Federal de Roraima Museo de Historia Natural Noel Kempff Mercado Universidad Autónoma Gabriel Rene Moreno Faculdade de Ciências Agrárias Biológicas e Sociais Aplicadas Universidad do Estado de Mato Grosso Centro de Biociências Universidade Federal do Rio Grande do Norte Department of Ecology Evolution and Behaviour University of Minnesota Department of Geography University College London Departamento de Ciencias Biológicas Universidad de Los Andes (Colombia) Centro de Ciências Biológicas e da Natureza Universidade Federal do Acre Nicholas School of the Environment Duke University Iwokrama International Centre for Rainforest Conservation and Development Smithsonian’s National Zoo & Conservation Biology Institute Instituto de Ciencias Naturales Universidad Nacional de Colombia Universidade Federal Rural da Amazônia—UFRA/CAPES Museu Paraense Emílio Goeldi Laboratorio de Ecología de Bosques Tropicales y Primatología Fundación Natura Colombia Universidad de Los Andes Facultad de Forestales Universidad Nacional de la Amazonía Peruana Institute of Research for Forestry Development Universidad de los Andes School of Environmental and Forest Sciences (SEFS) University of Washington Universidad Regional Amazónica Ikiam Agteca-Amazonica Universidad Autónoma del Beni Instituto Amazónico de Investigaciones (IMANI) Universidad Nacional de Colombia Broward County Parks and Recreation Biological Sciences Florida Atlantic University-Davie Museu Universitário Universidade Federal do Acre Facultad de Ingeniería Ambiental Universidad Estatal Amazónica Department of Biology Washington University in St Louis National Institute for Space Research (INPE) Geoinformática & Sistemas (GeoIS) School of Earth Sciences and Environmental Sustainability Northern Arizona University Department of Geography and the Environment University of Texas at Austin Instituto de Ciência e Tecnologia São Paulo State University (UNESP) School of Anthropology and Conservation University of Kent Universidade Federal do Amazonas Herbario Alfredo Paredes (QAP) Universidad Central del Ecuador School of Geography Earth and Environmental Sciences University of Birmingham Department of Life Sciences Imperial College London Science and Education The Field Museum Universidad Tecnica del Norte Herbario Nacional del Ecuador Research Institute Alexander von Humboldt Instituto de Ciência e Tecnologia São Paulo State University (UNESP)

1. The extent to which historical dispersal, environmental features and geographical barriers shape the phylogenetic structure and turnover of tree communities in northwestern Amazonia at multiple spatial scales remains poorly understood.2. We used 85 floristically standardized 0.1‐ha plots (DBH ≥ 2.5 cm) distributed in three subregions of northwestern (NW) Amazonia across three main habitat types (floodplain, swamp and terra firme forests) to hypothesize that (a) historical dispersal overcome geographical barriers, which meant low local phylogenetic relatedness and low phylogenetic turnover. (b) Geographical barriers triggered dispersal limitation, causing high local and subregional phylogenetic clustering and high regional phylogenetic turnover. (c) Edaphic properties and flooding were negatively associated with stem size and determined the tree phylogenetic structure and turnover at local and regional scales in Amazon forests.3. We found that the extent to which environmental or evolutionary features shaped the phylogenetic structure and phylogenetic similarity of tree communities in NW Amazonia was scale dependent. Specifically, we show that the relative importance of environmental factors increases as spatial scale and species pool decreases. Furthermore, we find that these results are generally robust for both adult and juvenile trees.4. Synthesis. Our analysis at the regional (NW Amazon) scale lends support to the idea of Amazonian forests as a large meta‐community primarily structured by historical dispersal at large spatial scales with an increasing importance of environmental factors at finer spatial scales. The convergence of ancestral lineages across habitat types may have been due to the relatively recent formation of geographical barriers that promoted local isolation and allopatric speciation.

Aim: Studies that monitor high‐mountain vegetation, such as paramo grasslands in the Andes, lack non‐destructive biomass estimation methods. We aimed to develop and apply allometric models for above‐ground, below‐ground and total biomass of paramo plants.Location: The paramo of southern Colombia between 1°09′N and 077°50′W, at 3,400 and 3,700 m a.s.l. Methods: We established 61 1‐m2 plots at random locations, excluding disturbed, inaccessible and peat bog areas. We measured heights and basal diameters of all vascular plants in these plots and classified them into seven growth forms. Near each plot, we sampled the biomass from plants of abundant genera, after having measured their height and basal diameter. Hence, we measured the biomass of 476 plants (allometric set). For each growth form we applied power‐law functions to develop allometric models of biomass against basal diameter, height, height x basal diameter and height × basal area. The best models were selected using AICc weights. Using the observed and predicted plant biomass of the allometric set we calculated absolute percentage errors using cross‐validation. The biomass of a plot was estimated by summing the predicted biomass of all plants in a plot. Confidence limits around these sums were calculated by bootstrapping.Results: For groups of 15%) errors. Applying groups that resembled the 1‐m2 plots in density and composition, the errors for above‐ground and total biomass estimates were 2 (mean ± SD), respectively. These values were within the range of biomass estimates obtained destructively in the tropical Andes. Conclusions: In new applications, if target vegetation samples are similar regarding growth forms and genera to our allometric set, their biomass might be predicted applying our equations, provided they contain at least 50–100 plants. In other situations, we would recommend gathering additional biomass measurements from local plants to evaluate new regression equations.

We evaluate the role of differences in substrate age and environmental conditions, as represented by different geological units, in determining the phylogenetic structure and distribution of tree communities in the northwest Amazon. We used 412 0.1-ha plots distributed across the three main geological units (craton, tertiary and alluvial) in the Colombian Amazon, to answer the following research questions: i) To what extent do environmental filtering and dispersal limitation determine the phylogenetic composition of tree communities across geological units in the Colombian Amazon? and ii) Are there differences between geological units in the extent to which niche conservatism shapes the phylogenetic structure of indicator species (i.e., strong habitat-specialists) in tree communities? The results of our study give support for both environmental filtering and dispersal being important drivers of the phylogenetic structure and turnover of tree communities. Nonetheless, the extent to which geology explained the phylogenetic turnover of tree communities was surpassed by the geographic distance between plots, which was used to account for effects of dispersal limitation. This finding suggests that most of the lineages have had sufficient time to migrate and establish into adjacent geological units, contradicting claims that geological conditions are the dominant factors determining the distribution of tree communities across northwestern Amazonia. However, in the craton unit, indicator species were more closely related than expected by chance, while in the alluvial and tertiary units, observed relationships were not statistically different from null expectations. These results indicate that environmental filtering is asymmetrical among geological units, with the craton environment being the most restrictive. In contrast, the alluvial unit may be relatively easy to colonize and hence ecological strategies may be more labile through evolutionary history.

The biomass of plant communities in the high mountains of the Andes (páramo) is a key factor controlling the carbon retention and freshwater supply, which are important environmental services for the human population. Using d-sep tests, we examined four causal path models that show how the aboveground biomass of a series of small plots in undisturbed páramo vegetation in southern Colombia was explained by the abiotic environment (elevation, and five soil variables: pH, exchangeable Al, available P, carbon, and bulk density), vascular species composition (as extracted four axes of a Non-Metric Multidimensional Scaling ordination) and trait information related to plant productivity (community weighted means of specific leaf area (SLA) and maximum plant height). Causality could not be rejected for most path models. Nearly 50% of the aboveground plant biomass was explained by path models in which trait information together with soil variables and species composition had a direct influence on aboveground plant biomass. Community weighted means of SLA were negatively related with aboveground biomass and those of maximum plant height positively. Soil acidity and to a lesser degree soil bulk density acted as key soil variables driving the aboveground biomass. Species composition most strongly affected the variation in the aboveground biomass.

Within the tropics, the species richness of tree communities is strongly and positively associated with precipitation. Previous research has suggested that this macroecological pattern is driven by the negative effect of water-stress on the physiological processes of most tree species. This implies that the range limits of taxa are defined by their ability to occur under dry conditions, and thus in terms of species distributions predicts a nested pattern of taxa distribution from wet to dry areas. However, this ‘dry-tolerance’ hypothesis has yet to be adequately tested at large spatial and taxonomic scales. Here, using a dataset of 531 inventory plots of closed canopy forest distributed across the western Neotropics we investigated how precipitation, evaluated both as mean annual precipitation and as the maximum climatological water deficit, influences the distribution of tropical tree species, genera and families. We find that the distributions of tree taxa are indeed nested along precipitation gradients in the western Neotropics. Taxa tolerant to seasonal drought are disproportionally widespread across the precipitation gradient, with most reaching even the wettest climates sampled; however, most taxa analysed are restricted to wet areas. Our results suggest that the ‘dry tolerance' hypothesis has broad applicability in the world's most species-rich forests. In addition, the large number of species restricted to wetter conditions strongly indicates that an increased frequency of drought could severely threaten biodiversity in this region. Overall, this study establishes a baseline for exploring how tropical forest tree composition may change in response to current and future environmental changes in this region. © 2016 The Authors

Made available in DSpace on 2018-12-11T17:17:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Ministério da Ciência, Tecnologia e Inovação Ministério da Educação Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species' area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments. Coordenação de Botânica Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, C.P. 399 Programa de Pós-Graduação em Ciência Ambientais Universidade Federal Do Pará, Rua Augusto Corrêa 01 Biodiversity Dynamics Naturalis Biodiversity Center, PO Box 9517 Marine and Coastal Management, Deltares, Boussinesqweg 1 Coordenação de Biodiversidade Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 EMBRAPA Centro de Pesquisa Agroflorestal de Roraima, BR 174 km 8, Distrito Industrial Herbario Amazónico Colombiano Instituto SINCHI, Calle 20 No 5-44 Department of Integrative Biology University of California Universidad San Francisco de Quito Colegio de Ciencias Biológicas Diego de Robles y Vía Interoceánica Coordenação de Pesquisas em Ecologia Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 School of Geography University of Leeds, Woodhouse Lane Department of Wetland Ecology Institute of Geography and Geoecology Karlsruhe Institute of Technology - KIT, Josefstr 1 Biogeochemistry Max Planck Institute for Chemistry, Hahn-Meitner Weg 1 Departamento de Botânica Instituto de Pesquisas Científicas e Tecnológicas Do Amapá - IEPA Campus Do IEPA da Fazendinha, Rodovia JK Km 10 AMAP IRD Cirad CNRS INRA Université de Montpellier, TA A-51/PS2, Bd. de la Lironde Science and Education Field Museum, 1400 S. Lake Shore Drive Coordenação de Dinâmica Ambiental Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 Jardín Botánico de Missouri Departamento de Ecologia Universidade Estadual Paulista - UNESP Instituto de Biociências - IB, Av. 24 A 1515 Centro de Biociências Departamento de Ecologia Universidade Federal Do Rio Grande Do Norte, Av. Senador Salgado Filho 3000 Divisao de Sensoriamento Remoto - DSR Instituto Nacional de Pesquisas Espaciais - INPE, Av. dos Astronautas 1758 Herbario Vargas Universidad Nacional de San Antonio Abad Del Cusco, Avenida de la Cultura, Nro 733 Departamento de Geografia Universidade Estadual Paulista - UNESP Instituto de Geociências e Ciências Extas - IGCe Departamento de Biologia Universidade Federal de Rondônia, Rodovia BR 364 s/n Km 9.5 Center for Tropical Conservation Duke University Nicholas School of the Environment Programa de Pós-Graduação em Biodiversidade e Biotecnologia - PPG-Bionorte Universidade Federal de Rondônia Campus Porto Velho, Km 9.5 Instituto Boliviano de Investigacion Forestal Santa Cruz, Av. 6 agosto 28 Km 14,Doble via La Guardia Casilla, 6204 Programa de Pós-Graduação em Ecologia e Conservação Universidade Do Estado de Mato Grosso Instituto de Investigaciones de la Amazonía Peruana - IIAP, Av. A. Quiñones km 2.5 Geography College of Life and Environmental Sciences University of Exeter Departamento de Ciencias Forestales Universidad Nacional de Colombia, Calle 64 x Cra 65 Agteca-Amazonica Facultad de Ciencias Agrícolas Universidad Autónoma Gabriel René Moreno Santa Cruz Prédio da Botânica e Ecologia Embrapa Recursos Genéticos Biotecnologia Parque Estação Biológica, Av. W5 Norte Projeto Dinâmica Biológica de Fragmentos Florestais Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 Centre for Tropical Environmental and Sustainability Science College of Science and Engineering James Cook University Laboratório de Ecologia de Doenças Transmissíveis da Amazônia (EDTA) Instituto Leônidas e Maria Deane Fiocruz, Rua Terezina 476 Programa de Pós-graduação em Biodiversidade Saúde Instituto Oswaldo Cruz IOC/FIOCRUZ Pav. Arthur Neiva, Térreo Av. Brasil 4365 Centro de Investigaciones Ecológicas de Guayana Universidad Nacional Experimental de Guayana Calle Chile, urbaniz Chilemex Laboratorio de Ecología de Bosques Tropicales y Primatología Universidad de Los Andes, Carrera 1 # 18a- 10 Programa de Pós-Graduação em Biologia (Botânica) Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 Institute of Biodiversity and Ecosystem Dynamics University of Amsterdam, Sciencepark 904 Programa de Ciencias Del Agro y El Mar Herbario Universitario (PORT) UNELLEZ-Guanare Endangered Species Coalition, 8530 Geren Rd MAUA Working Group Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 Inventory and Monitoring Program National Park Service, 120 Chatham Lane Center for Conservation Education Sustainability Smithsonian Conservation Biology Institute, 1100 Jefferson Dr. SW, Suite 3123 Biologia Vegetal Universidade Estadual de Campinas, Caixa Postal 6109 Institute of Molecular Plant Sciences University of Edinburgh, Mayfield Rd Royal Botanic Garden Edinburgh, 20a Inverleith Row Programa de Pós-Graduação em Ecologia Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo 2936 Forest Ecology and Forest Management Group Wageningen University Wageningen University and Research, Droevendaalsesteeg 3, P.O. Box 47 Natural Capital and Plant Health Royal Botanic Gardens Kew Ecosistemas Biodiversidad y Conservación de Especies Universidad Estatal Amazónica, Km. 2 1/2 vía a Tena (Paso Lateral) Museo de Historia Natural Noel Kempff Mercado Universidad Autónoma Gabriel Rene Moreno Santa Cruz, Avenida Irala 565 Casilla Postal 2489 Centro de Biociências Departamento de Botânica e Zoologia Universidade Federal Do Rio Grande Do Norte Campus Universitário Department of Biology University of Miami Coral Fairchild Tropical Botanic Garden Coral Instituto de Biociências Dept. Ecologia Universidade de Sao Paulo - USP, Rua do Matão, Trav. 14, no. 321 Diretoria de Pesquisas Científicas Instituto de Pesquisas Jardim Botânico Do Rio de Janeiro Escuela de Biología Herbario Alfredo Paredes Universidad Central, Ap. Postal 17.01.2177 International Center for Tropical Botany (ICTB) Department of Biological Sciences Florida International University, 11200 SW 8th Street, OE 243 Grupo de Ecología de Ecosistemas Terrestres Tropicales Universidad Nacional de Colombia Sede Amazonía Institute of Biological and Health Sciences Federal University of Alagoas, Av. Lourival Melo Mota, s/n Museu Universitário Centro de Ciências Biológicas e da Natureza Laboratório de Botânica e Ecologia Vegetal Universidade Federal Do Acre Universidad Regional Amazónica IKIAM, Km 7 via Muyuna Cirad UMR Ecofog AgrosParisTech CNRS INRA Univ Guyane Campus Agronomique Iwokrama International Programme for Rainforest Conservation Department of Biological Sciences Humboldt State University, 1 Harpst Street New York Botanical Garden, 2900 Southern Blvd Servicios de Biodiversidad EIRL, Jr. Independencia 405 Herbario Nacional de Bolivia Universitario UMSA, Casilla 10077 Correo Central Missouri Botanical Garden, P.O. Box 299 School of Environmental Sciences University of East Anglia Laboratoire Evolution et Diversité Biologique CNRS Université Paul Sabatier UMR 5174 EDB Department of Forestry Management Universidad Nacional Agraria la Molina, Avenido La Molina, Apdo. 456 School of Geosciences University of Edinburgh, 201 Crew Building, King's Buildings Biology Department Center for Energy Environment and Sustainability Wake Forest University, 1834 Wake Forest Rd Department of Anthropology University of Texas at Austin, SAC 5.150, 2201 Speedway Stop C3200 Andes to Amazon Biodiversity Program Madre de Dios Fundación Puerto Rastrojo, Cra 10 No. 24-76 Oficina 1201 Colegio de Ciencias Biológicas y Ambientales-COCIBA Galapagos Institute for the Arts and Sciences-GAIAS Universidad San Francisco de Quito-USFQ Department of Wildlife Ecology Conservation University of Florida, 110 Newins-Ziegler Hall Fundación Estación de Biología, Cra 10 No. 24-76 Oficina 1201 Embrapa Amazônia Oriental Trav. Dr. Enéas Pinheiro S/no Instituto de Ciencias Naturales Universidad Nacional de Colombia, Apartado, 7945 Amazon Conservation Team, Doekhieweg Oost #24 Facultad de Ciencias Forestales y Medio Ambiente Universidad Nacional de San Antonio Abad Del Cusco, Jirón San Martín 451 Laboratory of Human Ecology Instituto Venezolano de Investigaciones Científicas - IVIC, Ado 20632 Departement EV Muséum National d'Histoire Naturelle de Paris, 16 rue Buffon Instituto de Ciência Agrárias Universidade Federal Rural da Amazônia, Av. Presidente Tancredo Neves 2501 PROTERRA Instituto de Investigaciones de la Amazonía Peruana (IIAP), Av. A. Quiñones km 2 5 ACEER Foundation, Jirón Cusco No 370 Universidad Autónoma Del Beni José Ballivián Campus Universitario Final, Av. Ejercito Regional Norte Amazónico Centro de Investigación y Promoción Del Campesinado, C/Nicanor Gonzalo Salvatierra No 362 Environmental Change Institute Oxford University Centre for the Environment Dyson Perrins Building, South Parks Road School of Agriculture and Food Sciences ARC Centre of Excellence for Environmental Decisions CEED University of Queensland Instituto de Investigaciones para El Desarrollo Forestal (INDEFOR) Universidad de Los Andes, Conjunto Forestal, C.P. 5101 School of Environmental and Forest Sciences University of Washington University of Nottingham, University Park Geography and the Environment University of Texas at Austin, 305 E. 23rd Street, CLA building Laboratório de Ciências Ambientais Universidade Estadual Do Norte Fluminense, Av. Alberto Lamego 2000 Department of Biology University of Maryland GeoIS, El Día 369 y El Telégrafo, 3o Piso Environmental Science and Policy Northern Arizona University FOMABO Manejo Forestal en Las Tierras Tropicales de Bolivia Escuela de Ciencias Forestales (ESFOR) Universidad Mayor de San Simon (UMSS) Agricultural Services Ministry of Agro-Industry and Food Security Agricultural Services Ministry of Agro-Industry and Food Security Mauritius Herbarium Department of Bioscience Aarhus University, Building 1540 Ny Munkegade Ciencias Biológicas Universidad de Los Andes, Carrera 1 # 18a- 10 Medio Ambiente PLUSPRETOL Center for Conservation Education and Sustainability Smithsonian's National Zoo Conservation Biology Institute, National Zoological Park, 3001 Connecticut Ave Tropenbos International, Lawickse Allee 11 PO Box 232 Instituto de Biodiversidade e Floresta Universidade Federal Do Oeste Do Pará Campus Tapajós, Rua Vera Paz Department of Biology University of Missouri Facultad de Biologia Universidad Nacional de la Amazonia Peruana, Pevas 5ta cdra School of Anthropology and Conservation University of Kent, Marlowe Building Herbario Nacional Del Ecuador Universidad Técnica Del Norte Ecology and Biodiversity Group Utrecht University, Padualaan 8 Systems Ecology Free University, De Boelelaan 1087 Departamento de Ecologia Universidade Estadual Paulista - UNESP Instituto de Biociências - IB, Av. 24 A 1515 Departamento de Geografia Universidade Estadual Paulista - UNESP Instituto de Geociências e Ciências Extas - IGCe CAPES: 407232/2013-3-PVE CNPq: 407232/2013-3-PVE Ministério da Ciência, Tecnologia e Inovação: 407232/2013-3-PVE Ministério da Educação: 407232/2013-3-PVE

Aim Tropical forests store 25% of global carbon and harbour 96% of the world's tree species, but it is not clear whether this high biodiversity matters for carbon storage. Few studies have teased apart the relative importance of forest attributes and environmental drivers for ecosystem functioning, and no such study exists for the tropics. Location Neotropics. Methods We relate aboveground biomass (AGB) to forest attributes (diversity and structure) and environmental drivers (annual rainfall and soil fertility) using data from 144,000 trees, 2050 forest plots and 59 forest sites. The sites span the complete latitudinal and climatic gradients in the lowland Neotropics, with rainfall ranging from 750 to 4350 mm year−1. Relationships were analysed within forest sites at scales of 0.1 and 1 ha and across forest sites along large-scale environmental gradients. We used a structural equation model to test the hypothesis that species richness, forest structural attributes and environmental drivers have independent, positive effects on AGB. Results Across sites, AGB was most strongly driven by rainfall, followed by average tree stem diameter and rarefied species richness, which all had positive effects on AGB. Our indicator of soil fertility (cation exchange capacity) had a negligible effect on AGB, perhaps because we used a global soil database. Taxonomic forest attributes (i.e. species richness, rarefied richness and Shannon diversity) had the strongest relationships with AGB at small spatial scales, where an additional species can still make a difference in terms of niche complementarity, while structural forest attributes (i.e. tree density and tree size) had strong relationships with AGB at all spatial scales. Main conclusions Biodiversity has an independent, positive effect on AGB and ecosystem functioning, not only in relatively simple temperate systems but also in structurally complex hyperdiverse tropical forests. Biodiversity conservation should therefore be a key component of the UN Reducing Emissions from Deforestation and Degradation strategy.

Analyses of forest loss and protected areas suggest that 36 to 57% of Amazonian tree flora may qualify as “globally threatened.”, 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.

Andean streams drain metal-rich bedrock and are subjected to an extreme altitude gradient, which may create highly selective conditions for life. The aim of the present study was to evaluate the combined effects of metals and altitude on benthic macroinvertebrate community composition in Andean streams. Metal-rich sites were characterized by high metal concentrations and low pH, and high-altitude sites were characterized by high ultraviolet-B radiation and low concentrations of dissolved organic matter. Canonical correspondence analysis indicated that the patterns in faunal composition were best explained by metals followed by altitude, with dipterans and collembolans occurring mostly under harsh conditions of high altitude and high metal levels. Interaction between metals and altitude was most evident at metal-rich sites. It is suggested that in Andean streams, metal leaching from igneous rock and altitude may be important factors confining benthic macroinvertebrate communities, reducing their numbers and changing their composition toward specialized taxa.

Mountains are rich in biodiversity and provide ecosystem services for their inhabitants. These regions are currently threatened by land use and land cover changes (LUCC), therefore an efficient monitoring is required to capture such changes. The aim of this study is to test a landscape change analysis in a mountain region to guide landscape management by including: (1) LUCC trends, (2) LUCC trends across the elevation gradient and (3) changes in spatial configuration. This framework was applied to the Peruvian Jalca grasslands (>3000 m a.s.l.), located in the Tropical Andes for the period 1987–2007. We used object-based classification of Landsat TM and patch metrics for each land cover class. Our results show an overall loss of Jalca (−1.5%/yr) and montane forest and shrubland (−2.8%/yr) with higher rates than other Andean regions. Furthermore, fragmentation is observed for the Jalca while montane forest and shrubland class is not fragmenting but the largest patches are vanishing, potentially affecting the connectivity between natural areas. Agriculture has replaced the Jalca, especially in the upper zones of the Andes showing an upward expansion of crops. However tree plantation and mining had increased more dramatically than agriculture (>9%/yr). Upper and less fragmented Jalca areas may be suitable for conservation purposes while agriculture may better expand in already degraded natural areas. Records of changes across the elevation gradient and in spatial patterns result in useful information for decision makers and may improve ecosystem management not only in the Tropical Andes but also in other mountain regions.

Seasonal (semestral) counts of aquatic birds at five Andean lakes in Ecuador (Colta, La Mica, Yambo, Yahuarcocha and San Pablo) were analyzed to detect trends in population size between 2004 and 2011.Trends of four abundant species (Ardea alba, Anas georgica, Fulica ardesiaca and Oxyura jamaicensis) and those of five functional groups (based upon body size and diet) were tested using generalized additive mixed modeling. In total, 19 bird species were consistently recorded over the whole period. The Andean Coot (F. ardesiaca) was found in highest densities (c. 3 birds per ha at Colta and Yambo). No significant trends were detected. However, the counts of functional groups exhibited a seasonal pattern (higher counts in February than in July), possibly due to lower resource availability in the dry season. Piscivorous species were relatively abundant at one lake (Yahuarcocha), which might be related to the introduction of Tilapiine cichlid fishes.

Inventories of past and present land cover changes form the basis of future conservation and landscape management strategies. Modern classification techniques can be applied to more efficiently extract information from traditional remote-sensing sources. Landsat ETM+ images of a mountainous area in Mexico form the input for a combined object-based and pixel-based land cover classification. The land cover categories with the highest individual classification accuracies determined based on these two methods are extracted and merged into combined land cover classifications. In total, seven common land cover categories were recognized and merged into single combined best-classification layers. A comparison of the overall classification accuracies for 1999 and 2006 of the pixel-based (0.74 and 0.81), object-based (0.77 and 0.71) and combined (0.88 and 0.87) classifications shows that the combination method produces the best results. These combined classifications then form the input for a change detection analysis between the two dates by applying post-classification, object-based change analysis using image differencing. It is concluded that the combined classification method together with the object-based change detection analysis leads to an improved classification accuracy and land cover change detection. This approach has the potential to be applied to land cover change analyses in similar mountainous areas using medium-resolution imagery.

Intestinal samples from the one-month-old Siberian mammoth calf ‘Lyuba’ were studied using light microscopy and ancient DNA to reconstruct its palaeo-environment and diet. The palynological record indicates a ‘mammoth steppe’. At least some pollen of arboreal taxa was reworked, and thus the presence of trees on the landscape is uncertain. In addition to visual comparison of 11 microfossil spectra, a PCA analysis contributed to diet reconstruction. This yielded two clusters: one of samples from the small intestine and the other of large-intestine samples, indicating compositional differences in food remains along the intestinal tract, possibly reflecting different episodes of ingestion. Based on observed morphological damage we conclude that the cyperaceous plant remains and some remains of dwarf willows were originally eaten by a mature mammoth, most likely Lyuba’s mother. The mammoth calf probably unintentionally swallowed well-preserved mosses and mineral particles while eating fecal material deposited on a soil surface covered with mosses. Coprophagy may have been a common habit for mammoths, and we therefore propose that fecal material should not be used to infer season of death of mammoths. DNA sequences of trnL and rbcL genes amplified from ancient DNA extracted from intestinal samples confirmed and supplemented plant identifications based on microfossils and macro-remains. Results from different extraction methods and barcoding markers complemented each other and show the value of longer protocols in addition to fast and commercially available extraction kits.

Habitat loss and fragmentation are considered major threats to biodiversity, especially in tropical mountain ecosystems. Most studies focus on the relationships between biodiversity and patch characteristics such as patch size, connectivity or degree of contrast with the surrounding matrix, but leave the rate of change within these variables little explored. We analyzed the importance of changes in patch characteristics over time on species diversity and species composition in the paramo of northern Peru, a tropical grassland ecosystem, locally known as jalca. We obtained land use/cover maps for 1987 and 2007 spanning an area of 6300 km2, and quantified land use change, jalca patch characteristics and their proportional changes over 20 yr. In 2009, 371 vascular plant species were recorded in 92 plots, each plot representative of single patches. Between 1987 and 2007, jalca cover decreased from 47 to 35 percent due to encroaching agriculture. This activity showed an upward shift probably favored by climate change. The number of jalca patches increased, mean patch size decreased, and the patches showed a higher contrast with the surrounding matrix. Multiple linear regression failed to show that species diversity relates to changes in patch characteristics. Canonical correspondence analysis indicated that species composition relates to the degree of contrast between the patch and its surrounding matrix and its changes through time. We concluded that changes in patch characteristics are important only for species composition. This study highlights the importance of considering matrix management with a long term perspective for conservation efforts.

The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small; change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America show a change in biome assignment, but to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucatán peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation reflecting a generally cool and dry environment. Cool grass/shrubland is prevalent in southeast Brazil whereas Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate rain forest indicating that forest was present at some locations at the LGM. Some sites in Central Mexico and lowland Colombia remain unchanged in the biome assignments of warm mixed forest and tropical dry forest respectively, although the affinities that these sites have to different biomes do change between 18 000±1000 14C yr BP and present. The "unresponsive" nature of these sites results from their location and the impact of local edaphic influence.

Modern pollen spectra were studied in forest and páramo vegetation from the Guandera area, northern Ecuador. Pollen representation was estimated by comparing the presence of plant taxa from a recent vegetation survey with the pollen spectra in moss polsters and pollen traps. In total, 73 pollen taxa were identified in the pollen rain. Per relevé, moss polsters and pollen traps contained 21 pollen taxa on average. Redundancy analyses (RDA) of pollen rain spectra against vegetation types yielded similar results for moss polsters and pollen traps. Spectra from forest, páramo, and cultivated field/meadows were well separated along the principal RDA axes, showing the potential to distinguish these vegetation types in pollen records. The modern pollen spectrum from a patch of páramo vegetation located in Andean forest was similar to the spectra of the surrounding forests. Likewise, the pollen spectrum from a forest patch in páramo was similar to spectra from the nearby páramo matrix. The modern pollen spectra from cultivated field/meadows hardly contained pollen taxa typically found in páramo or forest. In both forest and páramo, pollen taxa with wind-dispersed pollination syndromes were overrepresented. Clusia, Ilex, and Weinmannia (only with high percentages) seemed best to infer local presence of forest from pollen records. Puya, Apiaceae, Poaceae (only with high percentages), and Cyperaceae came out as best candidates to infer the presence of páramo vegetation.

SummaryThe Black-breasted Puffleg Eriocnemis nigrivestis is a hummingbird endemic to Ecuador and considered Critically Endangered, given its limited distribution, low population numbers, and ongoing habitat degradation. We investigated habitat use patterns using landscape and microhabitat variables. In addition, we explored a previously postulated competition hypothesis involving the Black-breasted Puffleg and the Gorgeted Sunangel Heliangelus strophianus. Our results suggest that landscape variables may play a role in the habitat selection process; specifically the distance to nearest forest border seems to have a significant effect on our habitat model. We speculate that, as the species is known to perform seasonal movements, the avoidance of forest border might reduce the physiological stress caused by altitudinal migration. At microhabitat level, Black-breasted Puffleg seems not sensitive to forest structure variables. Our findings suggest that ensuring forest tract connectivity, between the altitudinal extremes of the species’ range at the north-western flanks of the Pichincha volcano, might be crucial for survival of the species during its annual cycle. However, non-metric multidimensional scaling (NMDS) indicates that Black-breasted Puffleg and the Gorgeted Sunangel do not overlap spatially, but this finding is not conclusive considering our field observations.

Fossil pollen data from sediment cores may be used as a measure for past plant diversity. According to the theory of probability, palynological richness is positively related to the pollen count. In a low pollen count, only common taxa are detected, whereas rare taxa are only detected by chance. The detection of all pollen taxa requires a very high pollen count, which is time-consuming. In regular palynological investigations, the detected richness in pollen spectra varies with the pollen count. Rarefaction analysis estimates palynological richness in an exactly equal-sum count for all samples, so that comparison between samples is meaningful. However, the over-representation of some taxa suppresses the detection probability of rare taxa; low total pollen abundance in a sample enhances the detection probability of rare taxa and long-distance transported pollen grains. These factors bias the observed palynological richness and distort comparisons. Palynological richness in a pollen count proportional to its pollen influx may be one proxy for reconstructing diversity trends through time. The use of this proxy overcomes most problems encountered in rarefaction analysis, but is constrained by inaccuracy in estimating pollen influx due to the imprecise time control of sediment cores. Estimating palynological richness by mathematical methods may be another way of reconstructing pollen diversity. Pollen data tend to reflect diversity on a regional scale. Sites from small basins have the advantage of recording diversity at both local and regional scales, if the detection of each taxon is independent. By associating one site from a large basin with a series of sites from very small basins (e.g. forest-hollows), information about both regional and local diversity may be obtained. Entomophilous pollen taxa may have to be measured using a different strategy than anemophilous taxa.

The first bryophyte survey results from Colombian Amazonia are presented. Bryophyte species, differentiated into mosses and liverworts, and further into four life-form classes, were sampled in 0.1-ha plots. These plots were distributed over four landscape units in the middle Caquetá area: floodplains, swamps, terra firme forests and white-sand areas. The total numbers of bryophyte species in the units were 50, 45, 45 and 32, respectively. The plots in floodplains and swamps were richer in moss species than the terra firme and white-sand plots, suggesting that coexistence of many moss species is favoured by high humidity. Moss species with fan life-forms preferred floodplains. On the other hand, liverwort species richness was highest in white-sand plots, which suggests that light incidence controls liverwort species-richness, perhaps more than humidity. All plots from the floodplain of the Caquetá River differed remarkably in species composition (of both mosses and liverworts) from the other landscape units. This may be due to the unique properties of this varzea system where, during yearly flooding events, soil, dead logs and stems are covered with a fresh layer of nutrient-rich fine silt, enhancing the surface for colonization and improving the conditions for productive bryophyte growth compared with elsewhere in the middle Caquetá area

The species richness, number of plants, biomass, and species composition of holo- and hemi-epiphytes were recorded in fifty-six 0.04-ha plots, distributed over forest fallows of 2–30 y old and mature forests in lowland Amazonia (Amacayacu National Park, Colombia). A total of 9190 epiphytic plants representing 162 species were recorded on 4277 phorophytes. Seventy species were classified as holo-epiphyte and 85 as hemi-epiphyte. Aroids were most diverse (58 species) and represented 76% of the total recorded biomass. Anemochory was more dominant among holo-epiphytes and zoochory among hemi-epiphytes. The species richness, density and biomass of both holo- and hemi-epiphytes increased significantly from young fallows to old fallows and mature forests. Hemi-epiphytes had greater density and biomass than holo-epiphytes. In canonical ordination, forest age did not relate to the species composition of holo-epiphytes. However, for hemi-epiphytes, the age effect was significant, suggesting that species turnover takes place in the ageing fallows.

In a case-study from Colombian Amazonia, species information from ferns and Melastomataceae was used to explain the compositional patterns of other vascular plant species in 40 widely distributed 0.1-ha plots. Canonical correspondence analysis was applied to regress vascular plant species composition in the forests against information from these two indicator groups (summarized as axes of principal coordinate analyses), together with that from soils, landscape, and the spatial sampling design. In total, 53,941 individuals of 2480 vascular plant species were recorded. Of these, 17,473 individuals and 132 species were from ferns and Melastomataceae. In 19 well-drained upland (tierra firme) plots 19,622 vascular plant individuals and 1716 species were found, with 3793 plants and 91 species from ferns and Melastomataceae. In both the set of all landscapes and the subset of tierra firme forests the principal PCoA axes of the two indicator groups were highly related to the main patterns of forest species composition. In principle, therefore, ferns and Melastomataceae can be used to detect and forecast changes in the forest composition of the study area. However, evidence was not obtained that ferns and Melastomataceae show more potential to predict the main patterns in species composition of forests than soil, landscape, and spatial variables. The partioning of the total variation in forest composition showed that the correlation of ferns and Melastomataceae with other forest plants was quite independent from that of soil, landscape, and space. Direct effects of ferns and Melastomataceae on other plants might be obtained from experimental studies of between-plant interactions, concentrating on the seedling or juvenile stages of trees and lianas, both above-ground as well as in the rooting environment.

Epiphytism in Colombian Amazonia was described by counting vascular epiphytes in thirty 0.025-ha (5 · 50 m) plots, well-distributed over the main landscape units in the middle Caquetaarea of Colombian Amazonia. Each plot was directly adjacent to a 0.1-ha plot at which the species composition of trees and lianas (diameter at breast height (DBH) ‡ 2.5 cm) had been recorded 3 years earlier. The purpose of the study was to explore abundance, diversity, and dis- tribution of epiphytes between the principal landscape units. A total of 6129 individual vascular epiphytes were recorded belonging to 27 families, 73 genera, and 213 species (which included 59 morpho-species). Araceae, Orchidaceae, and Bromeliaceae were the most speciose and abundant families. A total of 2763 phorophytes were registered, 1701 (62%) of which with DBH ‡ 2.5 cm. About 40-60% of the woody plants with DBH ‡ 2.5 cm carried epiphytes, which points at low phorophyte limitation throughout all landscapes. Epiphytism was concentrated on stem bases. Just as trees, epiphyte species assemblages were well associated with the main landscapes. Contrary to trees, however, epiphyte abundance and diversity (species richness, Fisher's alpha index) hardly differed between the landscapes. This calls for caution when explanations for distribution and dynamics of tree species are extrapolated to growth forms with a totally different ecology.

The effect of a pine plantation on a native subparamo system in the Andes of Colombia (3 100 In above sea level) was studied. The vegetation of an 8 year-old plantation with Pinus patula was compared to that of the surrounding native subparamo. 59 plots made in the subparamo vegetation contained 121 vascular plant species. These plots were classified into three subparamo communities and one Andean scrub community. Sixty-four plots made in the pine plantation contained 76 vascular plant species and were subdivided into four classes of pine cover. With increasing pine cover, pine plantation plots tended to become less similar to the subparamo communities. Habitat-specific subp ramo species tended to disappear with increasing pine cover. After controlling for the effects of environmental variables in a partial canonical correspondence analysis, pine cover had a significant impact on plant species patterns. It is concluded that afforestation with Pinus patula resulted in strong negative effects on diversity and composition of the subparamo vegetation at the study site. (C) 2003 Elsevier Ltd. All rights reserved.

The floral composition of the vegetation on the sandstone plateaus near Araracuara (Colombian Amazonas) was studied on the basis of 92 vegetation relevees. We compared the vegetation data with samples of the modern pollen rain in the 18 relevees that had non-barren pollen samples. By using the association index of Davis [Rev. Palaeobot. Palynol. 40 (1984) 295–315] and correspondence analysis, we evaluated to which degree pollen spectra reflect the actual vegetation. Rain forest taxa appeared overrepresented in the pollen rain on the sandstone plateau. Poaceae, Xyris, Cyperaceae, and Melastomataceae showed highest correspondence between pollen rain and measured vegetation cover, whereas Bonnetia, Bromeliaceae, and Ochnaceae showed an intermediate level of accuracy. Pollen analysis of a 25-cm sediment core, reflecting vegetation changes on the Araracuara sandstone plateau during the latest Holocene cm, showed a transition from open Rapateaceae-dominated vegetation to a Bonnetia martiana-dominated scrub. Successional stages in the pollen record were interpreted as discrete vegetation communities in the field, all occurring at present day as part of a mosaic-like vegetation. The pollen record included a substantial number of genera and families in which C4 and CAM physiological pathways are common.

Large-scale patterns of Amazonian biodiversity have until now been obscured by a sparse and scattered inventory record. Here we present the first comprehensive spatial model of tree α-diversity and tree density in Amazonian rainforests, based on the largest-yet compilation of forest inventories and bolstered by a spatial interpolation technique that allows us to estimate diversity and density in areas that have never been inventoried. These data were then compared to continent-wide patterns of rainfall seasonality. We find that dry season length, while only weakly correlated with average tree α-diversity, is a strong predictor of tree density and of maximum tree α-diversity. The most diverse forests for any given DSL are concentrated in a narrow latitudinal band just south of the equator, while the least diverse forests for any given DSL are found in the Guayana Shield and Amazonian Bolivia. Denser forests are more diverse than sparser forests, even when we used a measure of diversity that corrects for sample size. We propose that rainfall seasonality regulates tree α-diversity and tree density by affecting shade tolerance and subsequently the number of different functional types of trees that can persist in an area.

Distribution patterns of vascular plants with diameter at breast height (dbh) ≥ 2.5 cm were studied on the basis of compositional data from 30 small plots located in a rain-forest area in Colombian Amazonia. The research questions were: How are distribution patterns of species in relation to local abundance in plots? Do understorey species (defined as species with individuals that never attained dbh ≥ 10 cm anywhere) show better correlations with soils and environment than canopy species (defined as species with individuals that attained dbh ≥ 10 cm)? Are patterns found in the entire range of landscape units comparable to those found in well-drained uplands alone? Species that occurred in more than one plot showed higher local abundances. This pattern was consistent among environmental generalists and specialists. Locally rare species (with only one individual in a plot) occurred mostly in well-drained uplands. Considering all landscape units, Mantel tests showed substantial correlations between environmental data (soil chemical data, drainage and flooding) and species composition. Canopy species were only slightly less correlated with environmental data than understorey species. Elimination of the spatial component in the data did not reduce these correlations. In well-drained uplands, understorey species were better correlated with soils than canopy species. Here, however, the spatial configuration of the plots became more important in explaining species patterns.

Colombian biomes are reconstructed at 45 sites from the modern period extending to the Last Glacial Maximum (LGM). The basis for our reconstruction is pollen data assigned to plant functional types and biomes at six 3000-yr intervals. A reconstruction of modern biomes is used to check the treatment of the modern pollen data set against a map of potential vegetation. This allows the biomes reconstructed at past periods to be assessed relative to the modern situation. This process also provides a check on the a priori assignment of pollen taxa to plant functional types and biomes. For the majority of the sites, the pollen data accurately reflect the potential vegetation, even though much of the original vegetation has been transformed by agricultural practices. At 18 000 14C yr BP, a generally cool and dry environment is reflected in biome, assignments of cold mixed forests, cool evergreen forests and cool grassland-shrub; the latter extending to lower altitudes than presently recorded. This signal is strongly recorded at 15 000 and 12 000 14C yr BP, the vegetation at these times also reflecting a relatively cool and dry environment. At 9000 14C yr BP there is a shift to biomes thought to result from slightly cooler environmental conditions. This trend is reversed by 6000 14C yr BP; most sites, within a range of different environmental settings, recording a shift to more xeric biome types. There is an expansion of steppe and cool mixed-forest biomes, replacing tropical dry forest and cool grassland-shrub biomes, respectively. These changes in biome assignments from the modern situation can be interpreted as a biotic response to mid-Holocene climatic aridity. At 3000 14C yr BP the shift is mainly to biomes characteristic of slightly more mesic environmental conditions. There are a number of sites that do not change biome assignment relative to the modern reconstruction, although the affinities that these sites have to a specific biome do change. These anomalies are interpreted on a site-by-site basis. Spatially constant, but differential response of the vegetation to climatic shifts are related to changes in moisture sources and the importance of edaphic controls on the vegetation. The Late Quaternary reconstruction of large-scale vegetation dynamics in Colombia allows an understanding of the environmental controls on these to be developed. In particular, shifts in the character of the main climatic systems that influence Colombian vegetation are described

Biomes are reconstructed in Colombia from modern (core-top) pollen data derived from twenty-two sites along an altitudinal gradient (2000 to 4100 m) that encompasses the tree line. The 'biomization' methodology is described in a stepwise manner that details the reconstruction of vegetation along an altitudinal gradient. In the majority of the cases, the results are comparable to site-specific descriptions of the vegetation. At altitudes between 2000 and 3000 m, cool mixed forest and cool evergreen forest biomes are important. Between 3000 and 3700 m the cool grassland / shrub biome is dominant. Above 3700 m, the affinity score to arboreal biomes is low with a concomitant increased affinity to the cool grassland biome that co-dominates along with the cool grassland / shrub biome. Hence, the technique is shown successful at reconstructing modern vegetation, this is particularly so when affinity scores to the range of biomes, rather the single most dominant biome, are used to describe vegetation composition. The results are able to delimit the altitudinally-induced changes in vegetation, from Andean forest associations, open forest and shrub grassland complex through to high altitude grasslands. However, this ability of the modern pollen data to predict the potential vegetation, via the biomization technique, is complicated by several site-specific factors that impact on the vegetation. Of particularly importance localised environmental conditions, particularly moisture regime. An additional area of interest is the impact that human activity has had on the vegetation. By manipulation of the input matrices, which are assigned a priori, and consultation of the range of biome affinity scores, it is possible to identify which sites reflect an anthropogenic signal and how this is manifested within the pollen data. By investigating the range of affinity scores, these factors can be identified and the relatively subtle changes in reconstructed vegetation determined, in particular how the composition and quantity of the arboreal component changes about the tree line. The results are discussed in context of using tree line position, and altitudinally-induced floristic changes, for palaeoclimatic reconstruction.

The assignment of Colombian pollen data to biomes allows the data to be synthesised at 10 ‘time windows’ from the present-day to 6000 radiocarbon years before present (BP). The modern reconstructed biomes are compared to a map of modern potential vegetation to check the applicability of the method and the a priori assignment of pollen taxa to plant functional types and ultimately biomes. The reconstructed modern biomes are successful in describing the composition and distribution of modern vegetation. In particular, altitudinal variations in vegetation within the northern Andean Cordilleras are well described. At 6000 BP the biomes are mainly characteristic of warmer environmental conditions relative to those of the present-day. This trend continues until between 4000 and 3000 BP when there is a shift to more mesic vegetation that is thought to equate to an increase in precipitation levels. The period between 2500 and 1000 BP represents little or no change in biome assignment and is interpreted as a period of environmental stability. The influence attributed to human-induced impact on the vegetation is recorded from 5000 BP, but is particularly important from 2000 BP. The extent of this impact increases over the Late-Holocene period, and is recorded at increasingly high altitudes. Despite these changes, a number of sites do not change their biome assignment throughout the analysis. This asynchronous vegetation response is discussed within the context of site location, non-linear response of vegetation to Late-Holocene environmental change, regionally differential signals, localised human impact and methodological artefacts.

A large number of newly published and unpublished hectare plots in Amazonia and the Guiana Shield area allow an analysis of family composition and testing of hypotheses concerning alpha-diversity in the south American rain forest. Using data from 94 plots the family-level floristic patterns in wet tropical South America are described. To test diversity patterns, 268 plots are used in this large area. Contrary to a widely held belief, western Amazonian plots are not necessarily the most diverse. Several central Amazonian plots have equal or even higher tree diversity. Annual rainfall is not a good estimator for tree diversity in the Amazonia area and Guiana shield. Plots in the Guiana Shield area (and eastern Amazonia) usually have lower diversity than those in central or western Amazonia. It is argued that this is not because of low rainfall or low nutrient status of the soil but because of the small area of the relatively isolated rain forest area in eastern Amazonia and the Guiana Shield. The low diversity on nutrient-poor white sand soils in the Amazon basin is not necessarily due to their low nutrient status but is, at least partly, caused by their small extent and fragmented nature.

Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness. Methods The ~6-million-km 2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the mean rank-abundance data to Fisher’s log-series distribution. Results Our analyses suggest that lowland Amazonia harbors 3.9 × 10 11 trees and ~16,000 tree species. We found 227 “hyperdominant” species (1.4% of the total) to be so common that together they account for half of all trees in Amazonia, whereas the rarest 11,000 species account for just 0.12% of trees. Most hyperdominants are habitat specialists that have large geographic ranges but are only dominant in one or two regions of the basin, and a median of 41% of trees in individual plots belong to hyperdominants. A disproportionate number of hyperdominants are palms, Myristicaceae, and Lecythidaceae. Discussion The finding that Amazonia is dominated by just 227 tree species implies that most biogeochemical cycling in the world’s largest tropical forest is performed by a tiny sliver of its diversity. The causes underlying hyperdominance in these species remain unknown. Both competitive superiority and widespread pre-1492 cultivation by humans are compelling hypotheses that deserve testing. Although the data suggest that spatial models can effectively forecast tree community composition and structure of unstudied sites in Amazonia, incorporating environmental data may yield substantial improvements. An appreciation of how thoroughly common species dominate the basin has the potential to simplify research in Amazonian biogeochemistry, ecology, and vegetation mapping. Such advances are urgently needed in light of the >10,000 rare, poorly known, and potentially threatened tree species in the Amazon.

Andean streams drain metal-rich bedrock and are subjected to an extreme altitude gradient, which may create highly selective conditions for life. The aim of the present study was to evaluate the combined effects of metals and altitude on benthic macroinvertebrate community composition in Andean streams. Metal-rich sites were characterized by high metal concentrations and low pH, and high-altitude sites were characterized by high ultraviolet-B radiation and low concentrations of dissolved organic matter. Canonical correspondence analysis indicated that the patterns in faunal composition were best explained by metals followed by altitude, with dipterans and collembolans occurring mostly under harsh conditions of high altitude and high metal levels. Interaction between metals and altitude was most evident at metal-rich sites. It is suggested that in Andean streams, metal leaching from igneous rock and altitude may be important factors confining benthic macroinvertebrate communities, reducing their numbers and changing their composition toward specialized taxa.

As part of a land-ecological survey of the middle Caqueta basin in Colombian Amazonia, a total of 41 well drained upland soil profiles under primary rain forest was studied. Two soil groups were recognised on the basis of principal components analysis (PCA). Soils pertaining to the first group cover about 45–60% of the well drained uplands and classify as Afsols and Acrisols. They are characterised by fine textured, reddish B horizons, and are low in exchangeable bases, but high in exchangeable Al. Furthermore, they contain relatively high total nutrient reserves. Soils pertaining to the second group cover about 35–50% of the well drained uplands and classify as Acrisols and Ferralsols. These soils are characterised by medium textured, yellowish B horizons within 100 cm depth, are low in exchangeable bases and Al, and show very low total nutrient reserves. The soils of the Ali-Acrisol group are mostly developed in Andean-origin deposits of the low terraces of the Caqueta River and the Tertiary Pebas formation. The soils of the Acri-Ferralsol group are mostly developed on shield-derived medium to coarse textured Tertiary deposits and are also found on Palaeozoic sandstone outcrops. The differences between the soils of the two groups are, therefore, principally related to variation in the parent materials and reflect the principal geological structure of the middle Caqueta area. A similar kind of well drained upland soil differentiation is found in the Colombian Amazon area as a whole, including footslope areas near the Andes, and probably also in adjacent parts of Peru and Brazil. The presence of the soils of the Acri-Ferralsol group in the middle Caqueta area and in NW Amazonia is in conflict with general statements that well drained upland soils in upper Amazonia would be less weathered than those from central or eastern Amazonia. The reddish or yellowish colour of the B horizon within a depth of 100 cm provides a practical field characteristic to distinguish the two groups of soils. The colour of the B horizons seems mainly related to dynamics of the soil organic matter. In sandy profiles of the soils from the Acri-Ferralsol group a slight degree of podzolisation may occur in the topsoil. Current international soil classification systems do not adequately separate the two well drained upland soil groups in the middle Caqueta area beacuse total nutrient reserves are not sufficiently incorporated and too much emphasis is laind on th presence of a clay increase.

A comparative litter fall study was made in five rain forest stands along a gradient of humus form development and soils in the Amazon lowlands of east- ern Colombia. The total fine litter fall was highest in a plot on a well drained soil of the flood plain of the Ca- quetfi River (1.07 kgm -2 • y-l), lower in three plots on well drained upland soils (0.86, 0.69, and 0.68 kgm -2 • y-l), and lowest in a plot on a poorly drained, upland podzolised soil (0.62 kgm -2 • y-l). In the four upland plots, leaf litter fall patterns were highly associated, which points at climatic regulation. Litter resource qual- ity, as represented by nutrient concentrations and ar- ea/weight ratio of the leaf litter fall, was comparatively high in the flood plain plot. In the upland plots, concen- trations and fluxes of Ca, Mg, K, and P were as low as in oligotrophic central Amazonian upland forests. This questions generalisations that the western peripheral re- gion of the Amazon basin should be less oligotrophic than central Amazonia. The upland plot on the podzoli- sed soil showed the lowest concentrations and fluxes of N. Mean residence times of organic matter and nutrients in the L horizons hardly differed between the five plots, suggesting that edaphic properties and litter resource quality are of little importance in the first step of de- composition. Mean residence time of organic matter in all ectorganic horizons combined (estimated on the basis of litter input and necromass on the forest floor, and un- corrected for dead fine root input) varied from 1.0 y in the flood plain forest, 1.1-3.3 y in the well drained up

QuestionIt is presumed that environmental stress is more pronounced at higher altitudes in Andean forests due to lower rates of temperature-constrained processes of growth, nutrient uptake and decomposition. Because community assembly theory predicts a low variation in viable traits under conditions of strong ecological filtering, we asked if the diversity in plant traits related to productivity and reproduction would decrease upslope.LocationGuaramacal National Park in the Andes of Venezuela (9°05-21′N, 70°-20′W).MethodsWe studied altitudinal patterns in the number of trait states of seven categorical traits found among vascular plants (DBH ≥ 2.5 cm) in 35 0.1-ha plots between 1330 and 2890 m. Information on plant traits was obtained from literature and herbaria. To test the altitudinal correlations, we permuted the plot-to-species matrix by randomly selecting species from the entire species pool (conserving the species richness and the species-abundance pattern in each plot), applying no restrictions and by creating plot-wise null assemblages of species that most likely occurred near a particular plot. In addition, the altitudinal pattern of trait states was examined using fourth-corner analysis.ResultsBoth null model tests yielded similar results. The trait state diversity in fruit size decreased upslope. Plants with small fruits were mostly, but not exclusively, found at higher altitudes, whereas plants with large fruits occurred only at lower elevations. Leaf size showed more states at higher altitudes but this pattern disappeared when rare leaf size classes were down-weighted. The upslope decrease in fruit size might be explained by the relatively low tree height of the upper montane rain forests, the increased selection for large seeds at high temperatures downslope, and the upslope decrease of large-leaved taxa (in view of Corner's rule).ConclusionsThe functional diversity of important plant traits changed with altitude at Guaramacal. Altitudinal effects on plant trait responses should be controlled for in studies that monitor the degradation of functional diversity in Andean forests in relation to human influence.

The species composition of vascular epiphytes and phorophytes (trees and lianas) was studied in ten 0.1-ha forest plots distributed over three landscape units (floodplains, swamps and well-drained uplands) in Colombian Amazonia. The aim was to analyse how host-preferences contributed to the patterns in epiphyte assemblages among the landscape units. In the plots 82 species (3310 plants) were holo-epiphytes, 11 species were primary hemi-epiphytes (179 plants) and 61 were secondary hemi-epiphytes (2337 plants). A total of 411 species of tree and liana were recorded as phorophytes. Detrended Correspondence Analysis and Mantel tests showed that the species composition of holo-epiphytes and secondary hemi-epiphytes differed among the landscape units. For both groups the effect of landscape unit on species composition strongly decreased after controlling for the phorophyte composition in the plots. The phorophyte composition significantly explained epiphyte composition and this effect was not removed after accounting for the effect of landscape unit. At the level of individual species, randomization tests yielded only few significant epiphyte–phorophyte associations. For 84% of the epiphyte species the average indicator of patchiness was below 1.5 demonstrating that most epiphyte individuals occurred scattered over different phorophytes. This probably hampered the analyses of host preferences for individual epiphyte species.

The distribution of 56 Pinus species in Mexico was modelled with MAXENT. The pine species were classified as threatened according to IUCN criteria. Our aim was to ascertain whether or not threatened pine species were adequately represented in protected areas. Almost 70% of the species had less than 10% of their modelled distribution area protected. None of the pine species reached their representation targets. Threatened pine species were less widely distributed, occurred at lower maximum elevations, and were less well represented in protected areas than other pine species. The results suggest that the present system of protected areas in Mexico fails to protect pine species adequately. Conservation targets should be especially directed to species with narrow distributions which occur at low altitudes, such as Pinus. attenuata, P. cembroides subsp. cembroides var. lagunae, P. radiata var. binata, P. rzedowskii, and P. muricata.

High altitude creates unique challenging conditions to biota that limit the diversity of benthic communities. Because environmental pollution may add further stress to life at high altitude, the present study explored the effect of metal pollution on the macroinvertebrate community composition in Andean streams between 3,500 to 4,500 meters above sea level (masl) during wet and dry seasons. At polluted sites, showing a high conductivity and a low pH, metal concentrations (e.g., Al, 13.07 mg/L; As, 3.49 mg/L; Mn, 19.65 mg/L; Pb, 0.876 mg/L; Zn, 16.08 mg/L) ranged from 8-fold up to 3,500-fold higher than at reference sites. The cumulative criterion unit allowed quantifying the potential toxicity of metal mixtures at the contaminated sites. Principal component analysis of physical chemical variables showed that reference sites were more likely to be structured by transparency, water discharge, and current velocity, while polluted sites appeared to be determined by metals and conductivity. Canonical correspondence analysis indicated a strong influence of highly correlated metals in structuring invertebrate communities, which were dominated by dipterans, coleopterans, collembolans, and mites at polluted sites. At reference sites crustaceans, ephemeropterans, plecopterans, and trichopterans were the most representative taxa. We concluded that severe metal pollution induced changes in macroinvertebrate community composition in high-altitude Andean streams, with a replacement of sensitive taxa by more tolerant taxa. Yet relatively species-rich communities persisted under harsh conditions.

The sequence of Late-glacial and Holocene alluvial sedimentation in the middle Caqueta River Basin of Colombian Amazonia is described, based on the study of the sediments and palynology of several river bank sections and on 30 radiocarbon dates. An early Late-glacial sedimentation cycle is recognised, followed by a minor late Late-glacial erosion phase. The Holocene valley fill consists of grey clays (often present in the lower part of the sections) deposited in open water and silty clays often with faint yellow mottling, deposited under a regime of seasonal flooding. The base of the Holocene sections is formed by sands, where exposed. In two places the transition of sand to open-water grey clay was dated around 10 000 yr BP and there is a suggestion that open water may have been more common at the beginning of the Holocene than later, when sedimentation by seasonal flooding became important. In many places much of the earlier Holocene sediments may have been removed by erosion and replaced by younger sediments, by a process of lateral aggradation. A considerable part of the present valley fill is younger than ca. 3500 yr. However, in several places older Holocene sediments are found, apparently only little affected by later erosion, lying below younger varzea silty clays. During the Holocene more organic sediments were formed in periods with reduced river discharge, related to drier climates in the Andes and possibly in Amazonia. These dry periods, deduced from data in the Caqueta River area, correspond well with dry phases in other parts of northwestern South America (e.g. between approximately 2700-1900 yr BP and approximately 3200-3800 yr BP). Rates of average net sedimentation, calculated from dated sections that apparently lack major hiatuses caused by erosion, were high in the lower Holocene, low during the middle Holocene and increase again in the upper Holocene. Levee deposits became coarser and the high river level of the Caqueta increased during the late Holocene. These phenomena may be explained by the increasing influence of man on the vegetation cover in the Andean headwater areas and possibly also in the Amazonian catchment area of the Caqueta River.

The late Quaternary history of the middle Caqueta River area in Colombia, northwestern Amazonia is described, based on observations of river bank sections, radiocarbon dates and palynological analyses of organic layers in floodplain and low terrace sediments of the Caqueta River. It is shown that the Late Pleistocene and Holocene climatic changes that took place in the Andean Cordilleras, were related to the depositional and erosional history of the Caqueta River in the Colombian Amazonian lowlands. The low terrace sediments consist of sandy and gravelly deposits covered by clays that sometimes contain lenses of peaty material. From these organic low terrace sediments, seven finite radiocarbon dates were obtained of Middle Pleniglacial age, between 56 000 and 30 000 yr BP. The coarse textured basal deposits of the low terrace apparently stem from the early part of the Middle Pleniglaciai period, during which the effective rainfall in the Andes was relatively high and the Andean glaciers had a considerable extension. Palynological data from silty sediments with organic remains at one site, show an interval when drier and more open types of vegetation on poor soils must have covered a larger area than today, but Amazonian forest was still the dominating type of vegetation. This interval might correspond to one of the Middle Pleniglacial savanna intervals from eastern Amazonia (Carajas). No organic sediments from the Upper Pleniglacial period were found and hence radiocarbon dates were not obtained. In the Andes this period had a very cold climate with low effective rainfall and in the east Amazonian Carajas area it is characterised by the relative extension of open savanna vegetation. The river run-off and sediment transport must have been much lower than in the Middle Pleniglacial and the Caqueta River cut itself down in its own sediments. Two Late-glacial radiocarbon datings obtained at one site (ca. 12 500 yr BP) indicate the existence of a Late-glacial sedimentation phase, separated from the Holocene sequence by a minor erosional phase. Organic layers in the Holocene floodplain sediments yielded 28 radiocarbon dates between 10 000 and 355 yr BP. Holocene sedimentation started with the rapid deposition of (sandy) clay possibly in a partly permanently inundated Caqueta valley. During the major part of the Holocene (silty) clays were deposited, with a dominant seasonal inundation cycle.