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The article provides information on the species composition and quantitative indicators of zooplankton in two small mountain reservoirs of the Tuva Republic: the Eerbek and Turan. They reflect the first and the third years of the ecosystem existence after seasonal drawdown. Regulation shows a typical pattern in the distribution of zooplankton in the reservoirs: an increase in density in the dam section. In general, the reservoir zooplankton has a floodplain type of formation. The existence periods of reservoirs influences the zooplankton structure and its development: regulation in the first year determines the development of crustacean zooplankton (represented mainly by cladocerans), usually with monodominance; over three years, all main groups of zooplankton develop, but drawdowns interrupt the formation on the normal ecosystem in the reservoir.

Floating meadows are widespread globally, but ecological information on their vegetation structure and functions is lacking. We examined the structure and composition of the vegetation of the floating meadows of Keibul Lamjao National Park, Manipur, located in the Indo-Burma Biodiversity Hotspot. The floating meadows in the park are crucial for the survival of the globally threatened Eld’s deer (Rucervus eldii) and the hog deer (Axis porcinus). Vegetation data were collected from 936 plots of size 0.5 m × 0.5 m during winter and summer. The vegetation data were analyzed using two-way indicator species analysis (TWINSPAN) with PC-ORD version 4.20. Nine plant communities were observed in summer and eight in winter, with two communities being common to the two seasons. The overall Shannon and Simpson diversity indices, species richness and evenness of the communities varied significantly between summer and winter. The evenness (0.713) and diversity (H′, 1.335) indices in summer indicate high species diversity, which is mainly due to homogenous distribution of the species. The Ivlev Electivity Index (IVI) indicates that plant communities have a specific preference for meadow thickness, i.e., communities that prefer thick meadows avoid thin meadows. Competition among plant communities in terms of moisture and nutrient availability appears to be low due to the hypereutrophic condition of the lake and the floating nature of the meadows. But Capillipedium spp., Phragmites karka, Leersia hexandra and Zizania latifolia appear to exhibit monodominance, as indicated by their frequency and abundance in most of the communities. Protection of areas with thick meadow from further deterioration is crucial for the long-term conservation of the Eld’s deer and associated wild ungulates.

The invasive liana Euonymus fortunei (Turcz.) Hand.-Maz. (wintercreeper) is an emerging invader that through monodominance of woodlands can drastically reduce native species diversity and alter nutrient cycling. We studied how the vegetation and soils of invaded (INV), “native” (NAT), and wintercreeper removal (REM) site treatments influenced seed germination and seedling survival of this invader. The effect of aril (with vs. without) was also tested for wintercreeper seeds under field and in vitro conditions as a proxy for gravity vs. animal dispersal of seed, respectively. Germination was significantly delayed for seeds sown with an aril (vs. without), as well as those sown in INV soils (vs. NAT or REM), but neither site nor aril affected total germination. The proportion of germinated seedlings that survived after the first winter was significantly different based on site (p = 0.054) and aril (p = 0.071) treatments, with lower survival resulting from seeds sown without arils, and for seeds sown in INV sites. Magnesium (Mg) concentrations were significantly higher among INV soils (vs. NAT) and provide further support that wintercreeper is a driver of soil nutrient change. Our findings that aril-enclosed (gravity-dispersed) seeds yielded greater survival, despite being locally dispersed within invaded sites (where survival was lowest), support the historically slow rate of spread for this species.

Monodominant forests are characterized by the strong influence of a single species on the structure and diversity of the community. In the tropics, monodominant forests are rare exceptions within the generally highly diverse tropical forest biome. Some studies have shown that tree monodominance may be a transient state caused by successional and demographic variation among species over time. Working in a Brosimum rubescens Taub. (Moraceae) monodominant forest at the southern edge of Amazonia, we tested the hypotheses that local-scale variation in intra- and interspecific spatial patterns of dominant tree species is affected by i) demographic rates of recruitment and mortality following severe droughts, ii) local variation in edaphic properties, and iii) occupation of species in the vertical layer of the forest. We quantified intra- and interspecific spatial patterns and edaphic associations of the five most abundant species using aggregation and association distance indices, and examined changes over time. We found some support for all hypotheses. Thus, intra- and interspecific spatial patterns of most species varied over time, principally after severe drought, emphasizing species-level variability and their interactions in sensitivity to this disturbance, even as B. rubescens monodominance was maintained. While positive and negative spatial associations with edaphic properties provide evidence of habitat specialization, the absence of negative spatial associations of B. rubescens with edaphic properties indicates that this species experiences little environmental restriction, and this may be one of the factors that explain its monodominance. Spatial repulsion and attraction between species in the same and in different vertical layers, respectively, indicates niche overlap and differentiation, while changes over time indicate that the relationships between species are dynamic and affected by drought disturbance.

Soil has been proposed as a driver explaining the development of monodominant forests in the tropics, for example, Gilbertiodendron dewevrei forests (GDF) in central Africa. The aim of this study was to compare the physical and chemical properties of soils under GDF with those under an adjacent mixed forest (AMF), while controlling for topography. To this end, we set up sixteen 0.25-ha plots according to forest type and topography (plateau vs. bottomland), in the Yoko forest reserve, Democratic Republic of Congo. In each plot, we measured litter thickness and collected a total of 80 soil samples at depths of 0–5, 5–10, 10–20, 20–40 and 120–150 cm, for standard physical and chemical analyses. When controlling for topography and soil texture, we found that most of the chemical properties of soils under GDF did not differ from those of soils under AMF, particularly acidity, cation concentration, total N and the C:N ratio. The litter layer was 2.3 times thicker under GDF than under AMF stands, and, for a given texture, soils under GDF had a slightly higher organic C concentration in the 0–5 cm soil layer. This study suggests that G. dewevrei stands modify organic matter dynamics, which may be important in maintaining its monodominance.

Plant-soil feedback (PSF) can structure plant communities, promoting coexistence (negative PSF) or monodominance (positive PSF). At higher trophic levels, predators can alter plant community structure by re-allocating resources within habitats. When predator and plant species are spatially associated, predators may alter the outcome of PSF. Here, I explore the influence of plant-associated predators on PSF using a generalised cellular automaton model that tracks nutrients, plants, herbivores and predators. I explore key contingencies in plant-predator associations such as whether predators associate with live vs. senesced vegetation. Results indicate that plant-associated predators shift PSF to favour the host plant when predators colonise live vegetation, but the outcome of PSF will depend upon plant dispersal distance when predators colonise dead vegetation. I apply the model to two spider-associated invasive plants, finding that spider predators should shift PSF dynamics in a way that inhibits invasion by one forest invader, but exacerbates invasion by another.

The viability of propagules during topsoil stockpiling is a limiting factor in ecological restoration projects and little is known about the species distributed in the campos de altitude. This work was carried out to investigate the viability of propagules present in the topsoil under campos de altitude vegetation, stockpiled for up to 12 months after the stripping of areas to be mined. In the south of Minas Gerais, Brazil, between November 2011 and November 2012, four collections of the seed bank were carried out, considering three depths (0 to 10, 90 to 100, and 190 to 200 cm) of the plot of stockpiled topsoil. Using the multivariate analysis, it was verified that the depth factor does not statistically affect the abundance of emerged individuals, while the factor time of stockpiling negatively affects the viability of the seeds. Some species were affected by the stockpiling conditions, only emerging in some collections, while others (Achyrocline satureioides, Ageratum fastigiatum, Baccharis dracunculifolia, Borreria capitata, Echinolaena inflexa and Melinis minutiflora) had individuals emerged in all collection periods. This study points out the need for the return of the topsoil until the fourth month of stocking, under the risk of monodominance, with a prevalence of species more adapted to predominant conditions of campos de altitude. RESUMO A viabilidade dos propágulos durante a estocagem de topsoil é um fator limitante em projetos de restauração ecológica, e pouco se sabe sobre as espécies distribuídas nos campos de altitude. Este trabalho foi realizado com o objetivo de investigar a viabilidade de propágulos presente no topsoil sob vegetação de campos de altitude, estocado por até 12 meses após o decapeamento de áreas a serem mineradas. Entre o período de novembro de 2011 a novembro de 2012 foram realizadas quatro coletas do banco de sementes, sendo consideradas três profundidades (0 a 10, 90 a 100 e 190 a 200 cm) da leira de topsoil estocada. Utilizando a análise multivariada, verificou-se que o fator profundidade não afeta estatisticamente a abundância de indivíduos emergidos, enquanto o fator tempo de estocagem afeta negativamente a viabilidade das sementes. Algumas espécies foram afetadas pelas condições de estoque do topsoil, emergindo somente em algumas coletas, enquanto outras (Achyrocline satureioides, Ageratum fastigiatum, Baccharis dracunculifolia, Borreria capitata, Echinolaena inflexa e Melinis minutiflora) tiveram indivíduos emergidos em todos os períodos de coleta. Este estudo aponta a necessidade do retorno do topsoil até o quarto mês de armazenamento, sob o risco de ocorrer monodominância, com predominância de espécies mais adaptadas as condições campestres.

Contains fulltext : 225690.pdf (Publisher’s version ) (Open Access) Abstract Plant-soil legacies consisting of species-specific microbial communities are hypothesized to play a critical, structuring role in plant species coexistence processes. Plant species are thought to perform worse on soil conditioned by the same species compared to soil of other species, which serves as a self-limitation mechanism and averts monodominance of strong competitors. Here, we test in a multispecies community setting, whether root colonization and resource utilization of soil patches with distinct soil legacies are consistent with this hypothesis. We grew eight grassland species together in an outdoor mesocosm set-up in unconditioned soil and created soil patches in these communities conditioned by one of four plant species, or a soil mixture of all four. During two subsequent growing seasons, we tested the effect of these conditioned soil patches on below-ground root colonization into the patches of each surrounding plant species using a novel sequencing-based approach. In addition, we tested the effect of soil conditioning on local root functioning by injecting tracers into the soil patches and measuring the recovery in above-ground biomass. Against expectations, plant species did not place less roots in own soil patches compared to foreign soil patches, nor did species take up less tracer from own compared to foreign soil patches. Using structural equation modelling, we found that tracer uptake of the plant species was to a varying degree explained by root densities in the various soil patches and by differing soil nutrient availability of the soil patches. We conclude that soil legacy effects are inextricably connected to soil nutrient availability, which needs to be taken into account in plant-soil feedback research to understand the processes that shape plant communities. Synthesis. We found that soil legacy effects in complex, multispecies semi-field conditions did not match expectations based on theory and experiments in controlled conditions. Among the many complicating factors that may modify or even overrule soil legacy effects in semi-field settings, we identified soil nutrient availability as a critical force that may, together with soil biota, shape plant species coexistence processes. 13 p.

Understanding the dynamics of dominant tree species in tropical forests is important both for biodiversity and carbon-related issues. We focus on the Congo Basin (East of Kisangani) to investigate the respective roles of topographic/soil gradients and endogenous dynamics in shaping local variations in dominance. We used a dataset of 30 1-ha plots, in which all trees above 10 cm diameter at breast height (DBH) were censused. Soil samples were analyzed for standard pedologic variables and a digital elevation model permitted to infer topography and hydromorphy. We found that this forest is characterized by variations in the abundance of three dominant species:Petersianthus macrocarpus(P.Beauv.) Liben (PM),Gilbertiodendron dewevrei(De Wild.) J.Leonard (GD) andJulbernardia seretii(De Wild.) Troupin (JS). These variations occur independently of substratum or topography variations. At plot level, the local relative abundance never reached 50%, the threshold for monodominance proposed in the literature, but rather progressively increased to reach higher values for canopy trees (>60 cm DBH), where this threshold could be exceeded. We found no sign of shifting compositional dynamics, whereby the dominant species would switch between the canopy and the undergrowth. Our results, therefore, support the possibility of the existence of stable dominance states, induced by endogenous processes, such as biological positive feedbacks fostering monodominance. We also document a strong relation between monodominance level and alpha diversity, when giving more weight to abundant species which is expected (R-2 = 0.79) but also when giving more weight to rare species (R-2 = 0.37), showing that monodominance influences tree species richness patterns. Structural differences existed between groups, with the PM group having more (and on average smaller) stems and lighter wood on average, but paradoxically also higher biomass and basal area.

Understanding the dynamics of dominant tree species in tropical forests is important both for biodiversity and carbon-related issues. We focus on the Congo Basin (East of Kisangani) to investigate the respective roles of topographic/soil gradients and endogenous dynamics in shaping local variations in dominance. We used a dataset of 30 1-ha plots, in which all trees above 10 cm diameter at breast height (DBH) were censused. Soil samples were analyzed for standard pedologic variables and a digital elevation model permitted to infer topography and hydromorphy. We found that this forest is characterized by variations in the abundance of three dominant species: Petersianthus macrocarpus (P.Beauv.) Liben (PM), Gilbertiodendron dewevrei (De Wild.) J.Leonard (GD) and Julbernardia seretii (De Wild.) Troupin (JS). These variations occur independently of substratum or topography variations. At plot level, the local relative abundance never reached 50%, the threshold for monodominance proposed in the literature, but rather progressively increased to reach higher values for canopy trees (&gt, 60 cm DBH), where this threshold could be exceeded. We found no sign of shifting compositional dynamics, whereby the dominant species would switch between the canopy and the undergrowth. Our results, therefore, support the possibility of the existence of stable dominance states, induced by endogenous processes, such as biological positive feedbacks fostering monodominance. We also document a strong relation between monodominance level and alpha diversity, when giving more weight to abundant species which is expected (R&sup2, = 0.79) but also when giving more weight to rare species (R&sup2, = 0.37), showing that monodominance influences tree species richness patterns. Structural differences existed between groups, with the PM group having more (and on average smaller) stems and lighter wood on average, but paradoxically also higher biomass and basal area.

Negative plant-soil feedback (PSF) , where plant performance is reduced in soils conditioned by conspecifics, are widely documented in plant communities. However, the strength and sometimes direction of PSF can vary widely, presumably due to environmental context. We hypothesized that soil fertility and light availability influence the direction and strength of plant-soil feedback experienced by tree seedlings. We conducted a 10-week greenhouse experiment and assessed survivorship of black cherry (Prunus serotina) in low (~1% full sun) vs. high (~18% full sun) light availability and in non-sterile vs. sterile soils collected under the canopy of conspecific vs. heterospecific adult trees at five sites that vary in nutrient availability in Manistee National Forest, Michigan, USA. Northern red oak (Quercus rubra) also was included in the experiment, but no seedlings died and thus there are no survivorship responses to report. Prunus serotina seedlings experienced microbe-mediated negative plant-soil feedback in low fertility sites (higher C:N ratios and lower NH4+) but positive feedback at high fertility sites, but these feedbacks occurred only under high light availability. Consistent with these results, microbe-mediated negative PSF increased with soil Fe3+ and C:N ratios and decreased with NH4+. Thus lower fertility soils, characterized by high C:N and Fe3+availability and low NH4+, are associated with stronger negative conspecific feedback for P. serotina seedlings. Conversely, higher fertility soils flip the feedback to positive. Our results demonstrate the important role of environmental context, specifically light and soil nutrient availability, on the magnitude and direction of conspecific plant soil feedback. Thus, PSF is likely an important driver in plant community dynamics that may be either destabilizing (promote species coexistence) or stabilizing (promote monodominance) depending upon environmental context.

Flood and fire act as ecological filters which can interact to shape forest structure and species composition. Our objective was to investigate how the interaction between fire and flood influences richness, abundance, basal area and species composition of the tree community and the monodominant belts of Attalea phalerata Mart. in forest islets of the Pantanal wetland. We used satellite images to find 12 forest islets without fire events from 1998 to 2014, and 12 forest islets burned only once in the same period in a fire event in 2009. In these forest islets, we set up a transect with 10 to 14 contiguous 5 × 10 m plots and sampled all trees with a diameter at breast height of ≥ 4.7 cm. We also measured the watermark height. Flooding influenced species richness and abundance, increased toward wetter areas of the forest islet flood gradient. In contrast, the interaction between fire and flood inverted that trend, with richness and abundance increasing in flood-free areas. Total basal area increases in the more flooded areas of the gradient. The fire or the interaction between fire and flooding did not influence the basal area. The relative abundance of A. phalerata increased with flood level and even more under the fire-flood interaction. We conclude that the interaction between fire and flood influences forest islet structure and species composition; moreover, it favors A. phalerata monodominance.

Monodominant patches of forest dominated by Gilbertiodendron dewevrei are commonly found in central African tropical forests, alongside forests with high species diversity. Although these forests are generally found sparsely distributed along rivers, their occurrence is not thought to be (clearly) driven by edaphic conditions but rather by trait combinations of G. dewevrei that aid in achieving monodominance. Functional community structure between these monodominant and mixed forests has, however, not yet been compared. Additionally, little is known about nondominant species in the monodominant forest community. These two topics are addressed in this study. We investigate the functional community structure of 10 one-hectare plots of monodominant and mixed forests in a central region of the Congo basin, in DR Congo. Thirteen leaf and wood traits are measured, covering 95% (basal area weighted) of all species present in the plots, including leaf nutrient contents, leaf isotopic compositions, specific leaf area, wood density, and vessel anatomy. The trait-based assessment of G. dewevrei shows an ensemble of traits related to water use and transport that could be favorable for its location near forest rivers. Moreover, indications have been found for N and P limitations in the monodominant forest, possibly related to ectomycorrhizal associations formed with G. dewevrei. Reduced leaf N and P contents are found at the community level for the monodominant forest and for different nondominant groups, as compared to those in the mixed forest. In summary, this work shows that environmental filtering does prevail in the monodominant G. dewevrei forest, leading to lower functional diversity in this forest type, with the dominant species showing beneficial traits related to its common riverine locations and with reduced soil N and P availability found in this environment, both coregulating the tree community assembly.

Environmental filters affect species diversity. Understanding their influence on plant communities is one of the main challenges of ecology in the search for solutions to the management and conservation of floodable savannas. To shed more light on this challenge, the present work asked if the interactions between flood and fire influence the richness of community and favor the abundance and basal area of the monodominant Pantanal species Tabebuia aurea. We also asked what role earth-mounds play in this process. To address these questions, we used Landsat-5 and -8 and Resourcesat-1 satellite data; to access the fire history in monodominant stands of T. aurea in the Pantanal from 2003 to 2017. We chose 37 areas with 2 to 9 annual fire episodes. A total of 125 25 × 25 m plots were established in the different areas, to sample arboreal strata. We sampled all individuals ≥3.18 cm in diameter at breast height (dbh). In each plot, we measured height by the watermark from the last flooding on each individual as a proxy of inundation level. We applied generalized linear model (GLM) analyses to compare effects of flood and fire on abundance, richness and basal area, on and off earth-mounds using negative binomial, Poisson and Gaussian distribution, respectively. We sampled 2411 individuals distributed among 19 families, 31 genera and 36 species. Under higher fire frequency, abundance, richness and basal area of all species decreased with increase of water level. However, the abundance and basal area of Tabebuia aurea remained higher than those of other species. Under lower fire frequency, the abundance and richness of all species in the community increased with water level. Basal area, however, decreased with increasing water level, such that individuals with larger basal area were found under lower fire frequency. Under high fire frequency earth-mounds protected T. aurea individuals from fire and flood. Earth-mounds influenced species richness and basal area only under medium-low fire frequency. Results show that monodominance of T. aurea benefits from the interaction between fire and flood, with some help from earth-mounds. Individuals of other tree species, show tolerance to high flood levels or high fire frequencies, but not the interaction between fire and flood. This dynamic strengthens the monodominance of T. aurea, as the number of individuals also increases. Our results show that flood and fire are important to the conservation of this monodominant community.

Made available in DSpace on 2020-12-12T01:40:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such “monodominant” forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors. Biodiversity Dynamics Naturalis Biodiversity Center, PO Box 9517 Systems Ecology Free University, De Boelelaan 1087 Department of Biological Sciences Humboldt State University, 1 Harpst Street Programa de Pós-Graduação em Ecologia e Conservação Universidade do Estado de Mato Grosso Department of Ecological Modelling Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15 Institute of Forest Growth and Computer Sciences Technische Universitaet Dresden, Postfach 1117 AMAP IRD CIRAD CNRS INRA Université de Montpellier, TA A-51/PS2, Bd. de la Lironde, A comprehensive Coordenação de Biodiversidade Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo, 2936, Petrópolis Programa Professor Visitante Nacional Sênior na Amazônia - CAPES Universidade Federal Rural da Amazônia, Av. Perimetral, s/n Coordenação de Botânica Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, C.P. 399 EMBRAPA – Centro de Pesquisa Agroflorestal de Roraima, BR 174, km 8 – Distrito Industrial School of Geography University of Leeds, Woodhouse Lane Grupo de Investigación en Biodiversidad Medio Ambiente y Salud-BIOMAS Universidad de las Américas, Campus Queri Keller Science Action Center The Field Museum, 1400S. Lake Shore Drive Departamento de Botânica Instituto de Pesquisas Científicas e Tecnológicas do Amapá - IEPA, Rodovia JK, Km 10, Campus do IEPA da Fazendinha Herbario Amazónico Colombiano Instituto SINCHI, Calle 20 No 5-44 Coordenação de Pesquisas em Ecologia Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo, 2936, Petrópolis Dep. 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 Naturalis Biodiversity Center, PO Box 9517 Coordenação de Dinâmica Ambiental Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo, 2936, Petrópolis Science and Education The Field Museum, 1400S. Lake Shore Drive Jardín Botánico de Missouri Departamento de Ecologia Universidade Estadual Paulista - UNESP – Instituto de Biociências – IB, Av. 24A, 1515, Bela Vista Divisao de Sensoriamento Remoto – DSR Instituto Nacional de Pesquisas Espaciais – INPE, Av. dos Astronautas, 1758, Jardim da Granja 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 Bela Vista Centro de Biociências Departamento de Ecologia Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho, 3000 Departamento de Biologia Universidade Federal de Rondônia, Rodovia BR 364s/n Km 9,5 - Sentido Acre, Unir Programa de Pós- Graduação em Biodiversidade e Biotecnologia PPG- Bionorte Universidade Federal de Rondônia, Campus Porto Velho Km 9,5 bairro Rural Department of Biology and Florida Museum of Natural History University of Florida Centre for Tropical Environmental and Sustainability Science and College of Science and Engineering James Cook University Instituto de Investigaciones de la Amazonía Peruana (IIAP), Av. A. Quiñones km 2,5 Instituto Boliviano de Investigacion Forestal, Av. 6 de agosto #28, Km. 14, Doble via La Guardia, Casilla 6204 Geography College of Life and Environmental Sciences University of Exeter, Rennes Drive Departamento de Ciencias Forestales Universidad Nacional de Colombia, Calle 64 x Cra 65 Agteca-Amazonica Facultad de Ciencias Agrícolas Universidad Autónoma Gabriel René Moreno Natural History Museum University of Oslo, Postboks 1172 International Center for Tropical Botany (ICTB) Department of Biological Sciences Florida International University, 11200 SW 8th Street, OE 243 Cirad UMR Ecofog AgrosParisTech CNRS INRA Univ Guyane, Campus agronomique Centro de Investigaciones Ecológicas de Guayana Universidad Nacional Experimental de Guayana, Calle Chile, urbaniz Chilemex Prédio da Botânica e Ecologia Embrapa Recursos Genéticos e Biotecnologia Parque Estação Biológica, Av. W5 Norte Projeto Dinâmica Biológica de Fragmentos Florestais Instituto Nacional de Pesquisas da Amazônia - INPA, Av. André Araújo, 2936, Petrópolis Laboratório de Ecologia de Doenças Transmissíveis da Amazônia (EDTA) Instituto Leônidas e Maria Deane Fiocruz, Rua Terezina, 476, Adrianópolis Programa de Pós-graduação em Biodiversidade e Saúde Instituto Oswaldo Cruz - IOC/FIOCRUZ Pav. Arthur Neiva – Térreo, Av. Brasil, 4365 – Manguinhos Instituto de Ciências Biológicas Universidade Federal do Pará, Av. Augusto Corrêa 01 Programa de Pós-Graduação em Ecologia Universidade Federal do Pará, Av. Augusto Corrêa 01 Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro s/no. Diretoria Técnico-Científica Instituto de Desenvolvimento Sustentável Mamirauá, Estrada do Bexiga, 2584 Programa de Ciencias del Agro y el Mar Herbario Universitario (PORT) UNELLEZ-Guanare 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, Petrópolis Institute of Biodiversity and Ecosystem Dynamics University of Amsterdam, Sciencepark 904 Endangered Species Coalition, 8530 Geren Rd. Museo de Historia Natural Noel Kempff Mercado Universidad Autónoma Gabriel Rene Moreno, Avenida Irala 565 Casilla Post al 2489 Facultad de Ciencias Forestales y Ambientales Instituto de Investigaciones para el Desarrollo Forestal Universidad de los Andes, Via Chorros de Milla Inventory and Monitoring Program, National Park Service, 120 Chatham Lane Center for Conservation and Sustainability Smithsonian Conservation Biology Institute, 1100 Jefferson Dr. SW, Suite 3123 Universidade Federal do Amapá Ciências Ambientais, Rod. Juscelino Kubitschek km2 Department of Integrative Biology University of California Biologia Vegetal Universidade Estadual de Campinas, Caixa Postal 6109 Department of Global Ecology Carnegie Institution for Science, 260 Panama St. Institute of Molecular Plant Sciences University of Edinburgh, Mayfield Rd Tropical Diversity Section Royal Botanic Garden Edinburgh, 20a Inverleith Row Department of Ecology University of Brasilia Programa de Pós-Graduação em Ciência Ambientais Universidade Federal do Pará, Rua Augusto Corrêa 01 Faculty of Natural Sciences Department of Life Sciences Imperial College London, Silwood Park, South Kensington Campus Ecosistemas Biodiversidad y Conservación de Especies Universidad Estatal Amazónica, Km. 2 1/2 vía a Tena (Paso Lateral) Universidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de Genética Ecologia e Evolução, Av. Antônio Carlos, 6627 Pampulha Department of Biology University of Miami Fairchild Tropical Botanic Garden Diretoria de Pesquisas Científicas Instituto de Pesquisas Jardim Botânico do Rio de Janeiro Instituto de Biociências - Dept. Ecologia Universidade de Sao Paulo - USP Rua do Matão, Trav. 14, no. 321, Cidade Universitária Lancaster Environment Centre Lancaster University Environmental Change Institute University of Oxford Empresa Brasileira de Pesquisa Agropecuária Embrapa Amapá, Rod. Juscelino Kubitschek km 5 Grupo de Investigación en Tecnologías de la Información y Medio Ambiente Instituto Tecnológico de Antioquia - Institución Universitaria, Calle 78B No. 72A-220 Universidad Regional Amazónica IKIAM, Km 7 via Muyuna Escuela de Biología Herbario Alfredo Paredes Universidad Central, Ap. Postal 17.01.2177 Taxonomy and Systematics Naturalis Biodiversity Center, PO Box 9517 Museu Universitário/Centro de Ciências Biológicas e da Natureza/Laboratório de Botânica e Ecologia Vegetal Universidade Federal do Acre Institute of Biological and Health Sciences Federal University of Alagoas, Av. Lourival Melo Mota, s/n, Tabuleiro do Martins Iwokrama International Centre for Rainforest Conservation New York Botanical Garden, 2900 Southern Blvd, Bronx School of Geosciences University of Edinburgh, 201 Crew Building, King’s Buildings Natural Capital and Plant Health Royal Botanic Gardens Kew Servicios de Biodiversidad EIRL, Jr. Independencia 405 Herbario Nacional de Bolivia Universitario UMSA, Casilla 10077 Correo Central Center for Conservation and Sustainable Development Missouri Botanical Garden, P.O. 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The upper canopy of some rain forests in New Caledonia is dominated by single species. These monodominants are commonly secondary species, their dominance not persisting without disturbance. We tested whether dominance is associated with efficient uptake and use of nutrients (N, P and K), comparing between seedlings of monodominants (Nothofagus spp., Arillastrum gummiferum and Cerberiopsis candelabra) and 14 subordinates, grown in a nursery house. We also tested whether this trend applies more broadly to shade-intolerant trees that regenerate episodically (ER species) versus shade-tolerant trees that regenerate continuously (CR species). In the sun treatment, monodominants had higher photosynthetic nutrient-use efficiency and productivity for N and K, and uptake efficiency for N, P and K, than subordinates; ER species had higher photosynthetic nutrient-use efficiency for N, P and K, and uptake efficiency for N and P, than CR species. Uptake efficiency and productivity per nutrient mass were uncorrelated across species, yet Nothofagus spp., A. gummiferum and C. candelabra combined high levels of both traits for N, and Nothofagus spp. and A. gummiferum combined moderate to high levels for P, in sun-grown seedlings. This trait combination may contribute substantially to competitiveness and post-disturbance dominance on these nutrient-poor soils.

Contents Summary 1076 I. Introduction 1076 II. Historical overview 1077 III. Identities and distributions of tropical ectomycorrhizal plants 1077 IV. Dominance of tropical forests by ECM trees 1078 V. Biogeography of tropical ECM fungi 1081 VI. Beta diversity patterns in tropical ECM fungal communities 1082 VII. Conclusions and future research 1086 Acknowledgements 1087 References 1087 SUMMARY: Ectomycorrhizal (ECM) associations were historically considered rare or absent from tropical ecosystems. Although most tropical forests are dominated by arbuscular mycorrhizal (AM) trees, ECM associations are widespread and found in all tropical regions. Here, we highlight emerging patterns of ECM biogeography, diversity and ecosystem functions, identify knowledge gaps, and offer direction for future research. At the continental and regional scales, tropical ECM systems are highly diverse and vary widely in ECM plant and fungal abundance, diversity, composition and phylogenetic affinities. We found strong regional differences among the dominant host plant families, suggesting that biogeographical factors strongly influence tropical ECM symbioses. Both ECM plants and fungi also exhibit strong turnover along altitudinal and soil fertility gradients, suggesting niche differentiation among taxa. Ectomycorrhizal fungi are often more abundant and diverse in sites with nutrient-poor soils, suggesting that ECM associations can optimize plant nutrition and may contribute to the maintenance of tropical monodominant forests. More research is needed to elucidate the diversity patterns of ECM fungi and plants in the tropics and to clarify the role of this symbiosis in nutrient and carbon cycling.

Some species-rich secondary forests in New Caledonia have a monodominant canopy. Here we investigate growth and biomass allocation traits that might explain single-species’ dominance of these post-disturbance stands, and their later decline in the absence of large-scale disturbance. Seedlings of 20 rain-forest trees were grown in two light treatments in a nursery house. In the sun treatment, monodominants grew faster (56.7 ± 1.4 mg g−1 wk−1) than subordinates (40.2 ± 2.6 mg g−1 wk−1). However, some episodically regenerating (ER) subordinates had high growth rates similar to those of monodominants. In the shade treatment, monodominants and subordinates had similar growth rates (33.7 ± 2.6 and 34.0 ± 1.9 mg g−1 wk−1 respectively). Notably, monodominants in both sun and shade treatments had lower root mass fraction (0.29 ± 0.02 and 0.27 ± 0.02 g g−1 respectively) than subordinates (0.39 ± 0.02 and 0.37 ± 0.02 g g−1). Fast growth in sunny conditions is probably imperative for these relatively shade-intolerant ER monodominants. In field conditions, high shoot mass fraction combined with efficient root performance may facilitate faster growth in monodominants competing with other ER species in sunlit sites. Slower growth in shade may contribute to loss of dominance over time in undisturbed forests.

Monodominant tropical forests occur on several continents, including the Brazilian Amazon. In this study, we tested the hypothesis that seedling escape from leaf herbivory contributes to the maintenance of the monodominant Brosimum rubescens forest. The study was undertaken both in a monodominant forest of B. rubescens and in an adjacent seasonal forest in the transitional zone between the Cerrado and the Amazonian forest biomes. Percentage of leaf area damaged and herbivory rates were evaluated on young and mature leaves of seedlings of Brosimum rubescens, Protium pilosissimum and Tetragastris altissima in the understory and in the gap between the monodominant and seasonal forests. Little evidence of any significant relationship between leaf herbivory and seedling density indicates that the monodominant species does not follow the hypothesized pattern of an intensive herbivore attack in areas of higher seedling density. The escape of Brosimum rubescens from herbivore pressure under conditions of high see...

Monodominance in the tropics is often seen as an unusual phenomenon due to the normally high diversity in tropical rain forests. Here we studied Parashorea chinensis H. Wang (Dipterocarpaceae) in a seasonal tropical forest in south-west China, to elucidate the mechanisms behind its monodominance. Twenty-eight 20 × 20-m plots were established in monodominant and mixed forest in Xishuangbanna, Yunnan province. All individuals ≥1 cm stem diameter and 16 soil variables were measured. Parashorea chinensis forest had a significantly higher mean tree dbh compared with mixed forest. Diversity did not differ significantly between the two forest types. However, within monodominant patches, all diversity indices decreased with an increase in P. chinensis dominance. Floristic composition of P. chinensis forest did differ significantly from the mixed forest. These differences were associated with more fertile soils (significantly higher pH, Mn, K and lower carbon pools and C:N ratio) in the P. chinensis forest than the mixed forest. In contrast to current paradigms, this monodominant species is not associated with infertile, but with fertile soils. Parashorea chinensis seems to be especially associated with high manganese concentrations which it can tolerate, and with edaphic conditions (water, K) that allow this tall and exposed emergent species to maintain its water balance. This is in contrast with most previous studies on monodominance in the tropics that found either no effect of soil properties, or predict associations with nutrient-poor soils.

Steady state occurs mainly under less pronounced abiotic variation, leading to low diversity and nonsuccessional change, opposite from the nonequilibrium concept. Permanent circulation of a waterbody creates a low disturbance status but does not represent a disturbance because it does not change the diversity and dominance of species. Phytoplankton composition was analyzed in a shallow Brazilian coastal lagoon, Peri (Santa Catarina State, Brazil), in the cold-dry and hot-rainy periods during 2009–2010. Uninterrupted steady state conditions occurred along with the monodominance of the cyanobacteria Cylindrospermopsis raciborskii , which dominated under a nonstratification regime and low availability of dissolved nutrients. Primary production measured as resource-use efficiency indicated a capacity for this species to convert phosphorus into biomass as well as its ability to effective exploit resources. Differences in temperature and nitrogen availability seemed to be the driving parameters for interseasonal changes in the phytoplankton community in Peri Lagoon. Models of competition that predict greater diversity, which lead to greater levels of primary productivity and more complete utilization of limiting resources, were not confirmed in this study. The presence of the dinoflagellate Peridinium umbonatum and C . raciborskii together is suggested to represent shallow, mixed, turbid, and nutrient-deficient ecosystems. Although competitive exclusion would be the primary mechanism that selects for species equilibrium, higher adaptability by a few species under selective conditions seems to be the most important factor in the occurrence of steady states.

In New Caledonia, rain forests with an upper canopy dominated by single species of Nothofagus occur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in six Nothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that these Nothofagus forests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes the Nothofagus canopy is predicted to develop into a mixed canopy, unless moderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but only Calophyllum caledonicum did so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests.

Aim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, poten- tially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location Pan-tropical.

International audience; Convergence occurs in both species traits and community structure, but how convergence at the two scales influences each other remains unclear. To address this question, we focus on tropical forest monodominance, in which a single, often ectomycorrhizal (EM) tree species occasionally dominates forest stands within a landscape otherwise characterized by diverse communities of arbuscular mycorrhizal (AM) trees. Such monodominance is a striking potential example of community divergence resulting in alternative stable states. However, it is observed only in some tropical regions. A diverse suite of AM and EM trees locally codominate forest stands elsewhere. We develop a hypothesis to explain this geographical difference using a simulation model of plant community assembly. Simulation results suggest that in a region with a few EM species (e.g., South America), EM trees experience strong selection for convergent traits that match the abiotic conditions of the environment. Consequently, EM species successfully compete against other species to form monodominant stands via positive plant-soil feedbacks. By contrast, in a region with many EM species (e.g., Southeast Asia), species maintain divergent traits because of complex plant-soil feedbacks, with no species having traits that enablemonodominance. An analysis of plant trait data from Borneo and Peruvian Amazon was inconclusive. Overall, this work highlights the utility of geographical comparison in understanding the relationship between trait convergence and community convergence.

Bamboos play an important role in forest dynamics, but management strategies are needed to avoid monodominance. Understanding how climate change would influence the geographic distribution of bamboos could provide management tools for habitat conservation, as well as prevent the expansion of this group. We investigated the distribution patterns of Merostachys species that are endemic to the Brazilian Atlantic Forest, under current and future climate scenarios. We obtained occurrence records based on field collection, herbaria data and online databases. We used the Maxent algorithm to model potential distribution. Future scenarios considered the IPCC forecasted climate for 2070. Our models showed that a reduction in suitable areas for Merostachys species will likely occur, but the existence of suitable areas under climate changes in the Brazilian Atlantic Forest indicates climatic stability in some areas of occurrence of these species in their richness center. Since the fact that in places with local dominance of woody bamboos there is a decrease in the diversity of other plant species, the occurrence of Merostachys throughout the suitable areas may represent risks to biodiversity conservation. Investigations of the synergistic effects of climate change and the local dominance of woody bamboos are required. Therefore, management measures may be very important to control the occurrence of woody bamboos in the Brazilian Atlantic Forest, mainly in climatically stable areas.

Many alien species become invasive because they lack coevolutionary history with the native community; for instance, they may lack specialized enemies. These evolutionary advantages may allow the invader to establish and persist when rare within a community and lead to its monodominance through positive frequency dependence, i.e. increasing per capita population growth rate with increasing frequency of conspecifics. However, this advantage could degrade through time due to evolutionary and ecological changes in the invasive and native plant and microbial communities. We investigated survival rates and individual biomass as proxies for per capita population growth rates for the invasive grass, Microstegium vimineum, across a gradient of conspecific frequencies (10-100% relative cover of M. vimineum) within 12 sites that varied in time since invasion. We expected M. vimineum frequency dependence to become more negative and its proxies for population growth at low conspecific frequency to decline across invasion history. We also explored the belowground fungal community associated with M. vimineum, since we hypothesized that changes in M. vimineum population dynamics may result from shifting microbial interactions over time. Microstegium vimineum frequency dependence changed from negative to neutral across invasion history and the shift was driven by a decline in survival at low frequency. Changes in M. vimineum root fungal community were associated with time since invasion. Our results do not support a shift in frequency dependence from positive to negative across invasion history. However, our results suggest M. vimineum populations may be less prone to persist at older invaded sites and thus more vulnerable to management intervention.

Ants act in different trophic levels and are important due to their abundance, distribution and diversity in a variety of habitats, exercising influence on many different organisms and ecosystems. Thus, this study compared temporal variation on the structure and composition of the Formicidae community in canopies of Callisthene fasciculata (Spr.) Mart. (Vochysiaceae) during high water and dry periods, in the Pantanal of Pocone, Mato Grosso, Brazil. Ant sampling was performed on 12 specimens of C. fasciculata , in 2010 and 2011, using canopy fogging with insecticide, in a total of 120m² of sampled canopy. Altogether, 2,958 ants were collected. The 2,943 adults were distributed in four subfamilies, 12 genus and 26 species. Myrmicinae (18.7 ind./m 2 ) was the most representative taxon, followed by Formicinae (3.2 ind./m 2 ), Dolichoderinae (2.2 ind./m 2 ) and Pseudomyrmecinae (0.3 ind./m 2 ). The community is made up of six trophic groups, in which omnivorous (23.5 ind./m 2 ) were the most prevalent, followed by minimum hypogeical generalists (0.5 ind./m 2 ) and arboreal generalist predators (0.3 ind./m 2 ). Although the results showed that Formicidae community richness, associated to C. fasciculata canopies, does not represent a significant difference among the seasonal periods, there are differences as to species distribution and grouping in trophic guilds on the host plant over the seasonal periods, indicating the influence of temporal variation, and therefore, habitat conditions on this community.

Tropical forests are highly diverse ecosystems, but within such forests there can be large patches dominated by a single tree species. The myriad presumed mechanisms that lead to the emergence of such monodominant areas is currently the subject of intensive research. We used the most generic of these mechanisms, large seed mass and low dispersal ability of the monodominant species, in a spatially explicit model. The model represents seven identical species with long-distance dispersal of small seeds, competing with one potentially monodominant species with short-distance dispersal of large seeds. Monodominant patches emerged and persisted only for a narrow range of species traits; these results have the characteristic features of phase transitions. Additional mechanisms may explain monodominance in different ecological contexts, but our results suggest that percolation-like phenomena and phase transitions might be pervasive in this type of system., M.K. was supported by ERC advanced grant no. 233066. P.B. gratefully acknowledges the support of the German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig supported by the German Research Foundation (FZT 118).

Because wind pollination is inefficient over longer distances, plants dependent on it may suffer Allee effects (lower individual reproductive fitness with lower density). However, at higher density, individual reproductive fitness may suffer because of intraspecific competition. We investigate density-dependent effects, via stand size, on cone and seed production and seed germinability in a conifer endemic to tropical Australia. Callitris intratropica R.T. Baker & H.G. Smith is an obligate-seeding tree that often occurs in monodominant stands embedded within savannas and on the fringes of monsoon forests. We found that isolated trees (50–300 m from stands) were taller, of broader profile, and produced approximately twice the number of cones (~407 cones per tree) as those in large stands (~173 cones per tree), suggesting that monodominance generates intraspecific competition. The number of seeds per cone (27 seeds) was not related to stand size. However, a contrasting effect in which seed germinability was higher in large stands (~20 vs.

The study was conducted in a Brosimum rubescens Taub. monodominant forest in Nova Xavantina, Mato Grosso state (14°49.8′S and 52°9.6′W), in the transition zone between the Cerrado and Amazonian Forest in central Brazil. The structure and dynamics of the natural regeneration was compared over a five-year period to identify patterns that affect seedling establishment and explain the maintenance of B. rubescens dominance. We raised the following questions: how does the structure and dynamics of a monodominant forest regeneration vary over time? What patterns affect seedling establishment and help to explain the maintenance of the monodominance of B. rubescens ? Natural regeneration was sampled in 30 plots of 1 m × 1 m (seedlings), 2 × 2 (saplings), 5 × 5 (poles) and 10 × 10 (treelets). In the first inventory, the natural regeneration structure was characterized by a higher concentration of individuals in lower height classes and the largest number of seedlings of B. rubescens may be related to rainfall distribution in previous years. Seedling establishment may be limited by drier periods such as “El Nino” events, or by specific light conditions reaching the forest floor. Formation of a persistent seedling bank may provide a competitive advantage for the regeneration of B. rubescens in conditions of gaps pre-opening thus contributing to monodominance maintenance.

Known for its high degree of biodiversity, the tropics have a number of sites in which one or few species dominate large areas, as occurs in the Pantanal wetland, Brazil, with the ‘caranda' palm, Copernicia alba, in monodominant formations known regionally as ‘carandazal'. The aim of the present study was to analyze variations in species richness and diversity of herbs, shrubs and trees in two communities dominated by Copernicia albawith different flood patterns and determine whether soil fertility and time of inundation are associated with tree/shrub species composition and abundance. Vegetation was analyzed in 50 plots measuring 100m 2 in each area, with the determination of the tree/shrub component (CBH ? 5cm). Three subplots measuring 1m 2 were demarcated within each plot for the sampling of herbs, sub-shrubs, shrubs (CBH 2 plot. Associations between soil data, time of inundation and absolute density of tree/shrub vegetation were tested using canonical correspondence analysis (CCA). For the tree/shrub component, a total of 22 species belonging to 12 families were sampled in the two communities. Richness was greater in the area submitted to a lesser time of inundation. Copernicia albahad the greatest importance values in both study areas, followed by Tabebuia aureain one community and Mimosa glutinosain the other. In the subplots, 178 species belonging to 39 families were sampled, for which Fabaceae, Poaceae, Asteraceae and Cyperaceae figured prominently. The herbaceous component predominated over the others in species richness in both areas, but similarity was low. CCA detected associations between soil fertility, time of inundation and composition of tree/shrub species. The richness of the tree/shrub component was greater in the area with a shorter inundation time, which makes this event an important factor in the determination of C. albamonodominance in the Pantanal wetland. The herbaceous component demonstrated a high degree of richness and diversity in both communities, although there are differences in the inundation pattern between the two areas.

The main interest in studying monodominant forests in the tropics (i.e. single-dominant forest sensu Richards 1996 and Connell & Lowman 1989) is that processes leading to monodominance may highlight mechanisms controlling species diversity (Hart et al. 1989). Among the various cases of monodominant forest (Hart 1990), the most intriguing are the rare ones that stand in contact with a considerably more diverse forest, without apparent environmental boundaries, and for many generations (i.e. type I sensu Connell & Lowman 1989). Rather than a single mechanism, it is likely that this type of monodominance results from a suite of interacting traits (Torti et al. 2001). This has been well illustrated for the neotropical tree Dicymbe corymbosa whose monodominance relies on: (1) ectomycorrhizal symbiosis (Henkel et al. 2002) linked to (2) mast fruiting (Henkel et al. 2005), (3) high seedling survival rate (Henkel et al. 2005, McGuire 2007a, 2007b) and, potentially, (4) slow litter decomposition (Mayor & Henkel 2006, McGuire et al. 2010), moreover, (5) the reiterative habit of D. corymbosa slows the gap dynamics, and reduces species richness (Woolley et al. 2008). Thus, a comprehensive understanding of monodominance may only emerge from the comparison of many case studies to point out shared mechanisms. Here, we report a new case of a monodominant species: Spirotropis longifolia (DC.) Baill.