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Individual-based modeling of amazon forests suggests that climate controls productivity while traits control demography
Get PDFClimate, species composition, and soils are thought to control carbon cycling and forest structure in Amazonian forests. Here, we add a demographics scheme (tree recruitment, growth, and mortality) to a recently developed non-demographic model—the Trait-based Forest Simulator (TFS)—to explore the roles of climate and plant traits in controlling forest productivity and structure. We compared two sites with differing climates (seasonal vs. aseasonal precipitation) and plant traits. Through an initial validation simulation, we assessed whether the model converges on observed forest properties (productivity, demographic and structural variables) using datasets of functional traits, structure, and climate to model the carbon cycle at the two sites. In a second set of simulations, we tested the relative importance of climate and plant traits for forest properties within the TFS framework using the climate from the two sites with hypothetical trait distributions representing two axes of functional variation (“fast” vs. “slow” leaf traits, and high vs. low wood density). The adapted model with demographics reproduced observed variation in gross (GPP) and net (NPP) primary production, and respiration. However, NPP and respiration at the level of plant organs (leaf, stem, and root) were poorly simulated. Mortality and recruitment rates were underestimated. The equilibrium forest structure differed from observations of stem numbers suggesting either that the forests are not currently at equilibrium or that mechanisms are missing from the model. Findings from the second set of simulations demonstrated that differences in productivity were driven by climate, rather than plant traits. Contrary to expectation, varying leaf traits had no influence on GPP. Drivers of simulated forest structure were complex, with a key role for wood density mediated by its link to tree mortality. Modeled mortality and recruitment rates were linked to plant traits alone, drought-related mortality was not accounted for. In future, model development should focus on improving allocation, mortality, organ respiration, simulation of understory trees and adding hydraulic traits. This type of model that incorporates diverse tree strategies, detailed forest structure and realistic physiology is necessary if we are to be able to simulate tropical forest responses to global change scenarios. © 2019 Fauset, Gloor, Fyllas, Phillips, Asner, Baker, Patrick Bentley, Brienen, Christoffersen, del Aguila-Pasquel, Doughty, Feldpausch, Galbraith, Goodman, Girardin, Honorio Coronado, Monteagudo, Salinas, Shenkin, Silva-Espejo, van der Heijden, Vasquez, Alvarez-Davila, Arroyo, Barroso, Brown, Castro, Cornejo Valverde, Davila Cardozo, Di Fiore, Erwin, Huamantupa-Chuquimaco, Núñez Vargas, Neill, Pallqui Camacho, Gutierrez, Peacock, Pitman, Prieto, Restrepo, Rudas, Quesada, Silveira, Stropp, Terborgh, Vieira and Malhi
Caracterização de locos DNA microssatélites isolados para o mapará (Hypophthalmus oremaculatus - Nani e Fuster, 1947) (Siluriformes: Pimelodidae): um peixe de importância comercial na amazônia brasileira
No full textPatterns of diversity and adaptation of mosquito disease vectors under environmental pressure.
No full textImpact of climatic and hydrological disturbances on blackwater floodplain forests in Central Amazonia
No full textExtreme climatic events and anthropic disturbances affect the hydrological regime of Amazonian rivers and connected floodplain forests. This study aims to investigate the impacts of the Balbina hydroelectric power plant on the floodplain forests of the Uatumã River, in the Central Amazon. For this, tree age and diameter increment from the most abundant tree species of three different topographic levels were obtained and analyzed in the affected area downstream of the Balbina dam (Uatumã River) and compared to an undisturbed site (Abacate River, affluent) considering age structure and mean diameter increments between the topographic levels and the two systems. The occurrence of old trees is much lower at the disturbed site compared to the undisturbed system. Especially at the middle topography of the Uatumã site, we observed tree species with high mean diameter increment indicating a strong disturbance. We suggest that the disturbances may be associated with extreme hydro-climatic events, such as extreme droughts that occurred during the El Niño years 1925/26 and 1982/83 and that these events may increase vulnerability of igapó floodplains to wildfires. Abstract in Portuguese is available with online material. © 2019 The Association for Tropical Biology and Conservatio
Ecoethos da Amazônia: interação e ludicidade juvenil mediada por um jogo de simulação
Get PDFEcoethos da Amazônia is a simulation game that explores the symbology of the five elements (Earth, Water, Air, Fire, and Care) by the use of tridimensional models. The set consisted of a circular space with four stations, each representing one of the four natural elements. The players must solvethe challengespresented to them in each station. The Water pollution station deals with waste and water supply; the Air station brings questions about greenhouse gas emission, carbon sequestration, and land use; the Earth station presents questions focused on biodiversity, relief, and water resources; the Fire station alternative energy options are explored, always considering the biodiversity, the physical-geographical, the social and the economic characterization of the environment. The aim of this study was to evaluate players’ experience and understanding of the concepts explored during the activity. The theoretical approach was based on the Gamer User Experience Evaluation and the Bloom Taxonomy. Participated in this study 168 students (6ºto9ºgrades) of public schools. Some pre-established categories were considered for the analysis: opinion about the experience, game layout, difficulties handling parts, feelings triggered, understanding the representation of the parts, playfulness, and potential in changing behavior. Ecoethos da Amazônia was considered a game that teaches, entertains and enables responsible interaction. The game engages the participant’s attention and the situations presented were challenging buteasy to understand. The results showed that the game experience can promote environmental responsibility while pointing out the potential of the game to raise awareness, inform and reflect on social and environmental issues. © 2019 Universidade Federal do Parana. All rights reserved
Relevância da anatomia da madeira e dimensões de árvores amazônicas na determinação e alometria do alburno
Get PDFHydrological processes in forest stands are mainly influenced by tree species composition and morpho-physiological characteristics. Few studies on anatomical patterns that govern plant hydraulics were conducted in tropical forest ecosystems. Thus, we used dye immersion to analyze sapwood area patterns of 34 trees belonging to 26 species from a terra firme forest in the central Brazilian Amazon. The sapwood area was related with wood anatomy and tree size parameters (diameter-at-breast-height - DBH, total height and estimated whole-tree volume). Exponential allometric equations were used to model sapwood area using the biometrical variables measured. Sapwood area traits (cross-section non-uniformity and heartwood visibility) varied significantly among and within species even though all were classified as diffuse porous. DBH was strongly and non-linearly correlated with sapwood area (R 2 = 0.46, P < 0.001), while no correlation was observed with vessel-lumen diameter (P = 0.94) and frequency (P = 0.58). Sapwood area and shape were also affected by the occurrence of vessel obstruction (i.e., tyloses), hollow stems and diseases. Our results suggest that sapwood area patterns and correlated variables are driven by intrinsic species characteristics, microclimate and ecological succession within the stand. We believe that individual tree sapwood characteristics have strong implications over water use, hydrological stand upsaling and biomass quantification. These characteristics should be taken into account (e.g., through a multi-point sampling approach) when estimating forest stand transpiration in a highly biodiverse ecosystem.Processos hidrológicos de povoamentos florestais são predominantemente influenciados pela composição de espécies arbóreas e suas características morfo-fisiológicas. No entanto, existem poucos estudos sobre os padrões anatômicos que determinam o sistema hidráulico de plantas em ecossistemas tropicais. Por isso, nosso objetivo foi o de analisar os padrões da área do xilema ativo em 34 árvores de 26 espécies de uma floresta de terra firme na Amazônia central por meio de imersão em solução de corante. A área do xilema ativo foi relacionada a características autoecológicas das espécies, anatomia da madeira e parâmetros de crescimento (diametro à altura do peito - DAP, altura total e volume total). Equações alométricas exponenciais foram utilizadas para ajustar a área do xilema às variáveis medidas. Características do alburno (área transversal não-uniforme e visibilidade do cerne) variaram significativamente entre e dentro de espécies, apesar de que todas as espécies apresentaram vasos difusos. DAP foi fortemente e não-linearmente correlacionado à área do alburno (R 2 = 0,46; P < 0,001), enquanto diâmetro (P = 0,94) e frequência (P = 0.58) de vasos não apresentaram nenhum grau de relacionamento. O tamanho e forma do alburno foram afetados pela ocorrência de obstrução de poros (tilose) e troncos ocos. Estes padrões sugerem que a área do xilema é influenciada por características intrínsicas de cada espécie, microclima e estágio sucessional dentro do povoamento. Nossos resultados implicam que características individuais de árvores podem fortemente influenciar o transporte de água e, consequentemente, os processos hidrológicos e a quantificação de biomassa do povoamento. Essas caracteristicas deveriam ser consideradas (por exemplo, por meio da coleta de amostras da área do xilema ativo ao longo da área transversal) ao estimar-se a transpiração de uma floresta altamente biodiversa
Growth models for two commercial tree species in upland forests of the Southern Brazilian Amazon
No full textDespite all efforts to promote sustainable use of timber resources in tropical forests, the current management criteria still require adjustments at a species level, considering specific growth patterns and ecological features. Forest management in upland forests (terra firme) of the Brazilian Amazon region generally applies for all commercial tree species a common minimum logging diameter (MLD) of 50 cm and a felling cycle (FC) varying according to the harvest intensity between 25 and 35 years. In this study, we define species-specific FCs and MLDs for the two commercial tree species Hymenaea courbaril L. (Fabaceae) and Handroanthus serratifolius (Vahl) S.O. Grose (Bignoniaceae) from the terra firme of the Southern Brazilian Amazon, applying growth models based on the relationships between estimated tree age, diameter, height and volume. A total of 37 transversal cross-sections (20 stem discs from Hymenaea and 17 from Handroanthus) were obtained at a height of 20–60 cm above soil level in a private forest concession close to the municipality of Novo Aripuanã in the southern region of the Amazonas state. The two species are common in terra firme forests and have high wood densities of 0.76–0.96 g cm −3 (H. courbaril) and 0.85–1.08 g cm −3 (H. serratifolius). The mean age of H. courbaril and H. serratifolius, estimated by ring counting, varied from 104 to 241 years and both species had similar mean diameter increments of 3.9 ± 0.5 mm year −1 and 4.1 ± 0.6 mm year −1 , respectively. Both species present similar tree growth in diameter, height and volume resulting in a FC of 24.2 years and a MLD of 64.9 cm for H. courbaril, and a FC of 26.0 years and a MLD of 69.5 cm for H. serratifolius. These results demonstrate the need to adjust the selective logging systems practiced in the Brazilian Amazon region towards a species-specific management of timber species to increase the sustainability of selective logging. © 201
Dietary analysis of three species of the genus anolis (sauria: dactyloidae) in ?LOS Tuxtlas,? Veracruz, mexico
No full textA review on crocodilian nesting habitats and their characterisation via remote sensing
No full textCrocodilians usually remain inside or near their nests during most vulnerable life stages (as eggs, neonates and reproductive females). Thus, protection of nesting sites is one of the most appropriate conservation actions for these species. Nesting sites are often found across areas with difficult access, making remote sensing a valuable tool used to derive environmental variables for characterisation of nesting habitats. In this study, we (i) review crocodilian nesting habitats worldwide to identify key variables for nesting site distribution: Proximity to open-water, open-water stability, vegetation, light, precipitation, salinity, soil properties, temperature, topography, and flooding status, (ii) present a summary of the relative importance of these variables for each crocodilian species, (iii) identify knowledge gaps in the use of remote sensing methods currently used to map potential crocodilian nesting sites, and (iv) provide insight into how these remotely sensed variables can be derived to promote research on crocodilian ecology and conservation. We show that few studies have used remote sensing and that the range of images and methods used comprises a tiny fraction of what is available at little to no cost. Finally, we discuss how the combined use of remote sensing methods-optical, radar, and laser-may help overcome difficulties routinely faced in nest mapping (e.g., cloud cover, flooding beneath the forest canopy, or complicated relief) in a relevant way to crocodilians and to other semiaquatic vertebrates in different environments. Keywords © 2019 Copyright 2019 by Koninklijke Brill NV, Leiden, The Netherlands