Densidad y dimensiones de la fibra de Gmelina arborea en árboles de rápido crecimiento en Costa Rica: relación con el rango de de crecimiento

The objective of this research was to determine growth rate effects measured in tree diameter on wood density parameters (mean, minimum, maximum and intra-ring variation) and in fiber dimensions (wall thickness, fiber width, lumen diameter and fiber length) of trees from fast growth plantations. Thirty mature trees were sampled from thirty different fast-growth plantations with a wide growth rate in Costa Rica. A disc was cut from each tree at DBH. The wood density parameters and fiber dimensions were determined in each growth ring. Some wood density parameters and fiber dimensions were related with growth rate. The minimum and mean density, cell wall thickness, fiber width and lumen diameter decreased with increase in growth rate. Intra-ring wood density variation increased with growth rate but the weak correlation was established. Maximum wood density was not found correlation with growth rate. A pronounced decrease was presented in minimum and mean density from 0 to 20 mm/year and after to 45 mm/year. A pronounced decrease and increase with increase in growth rate were presented in the fiber length and intra-ring wood density, respectively. Lumen diameter and fiber width presented few variations, until 40 mm/year; however, they showed decrease after this growth rate value.La Gmelina arborea es utilizada en plantaciones debido a que las practicas silviculturales producen altas tasas de crecimiento del árbol. El presente trabajo tiene el objetivo de establecer los efectos de la tasa de crecimiento en los parámetros de densidad de la madera (media, máxima, mínima y la variación intra-anillo) y las dimensiones de la fibra (largo, ancho, diámetro del lumen y espesor de pared) en árboles de plantaciones de rápido crecimiento. Fueron seleccionadas treinta árboles de treinta 30 plantaciones diferentes próximas al turno de rotación con una amplia tasa de crecimiento. Un disco a la altura del pecho fue cortado en cada uno de los árboles. Los parámetros de densidad y dimensiones de las fibras fueron determinadas en cada anillo de crecimiento. Algunos de los parámetros de la densidad y las dimensiones de la fibra fueron correlacionados con la tasa de crecimiento. La densidad mínima y el promedio, espesor de pared celular y diámetro del lumen diminuyen con el incremento de la tasa de crecimiento. La variación intra-anillo incremento, pero una débil correlación fue encontrada. La densidad máxima no presentó correlación. Una gran disminución de la densidad mínima y la densidad media fue encontrada cuando la tasa de crecimiento se encuentra entre 0 y 20 mm/año o superior a 45 mm/año. Un pronunciado decrecimiento e incremento con el incremento de la tasa de crecimiento fue encontrado en la longitud de la fibra y la variación intra-anillo, respectivamente. El diámetro del lumen y ancho de la fibra presentaron pocas variaciones cuando la tasa de crecimiento es menor a 40 mm/año, sin embargo, estos mostraron un decrecimiento luego del mencionado valor

Efecto de la fertilización a la pradera en la densidad básica de la madera de Pinus radiata. D. Don.

The effects of pasture fertilization on basic density of Pinus radiata wood growing in silvopastoral sistem, for two trials submitted to different fertilization schemes: fertilized pasture and unfertilized pasture, are shown in this study. In addition, the different social classes existing in the dominant, intermediate and suppressed stands, are considered. To determine the basic density of wood, disks extracted at a diameter breast height, where annual rings were separated, measuring for each one of them its green volume and dry weight, were used. Statistical analyses showed that density of wood was effected by pasture fertilization, remaining its effect for a period of two and three years depending on the social class. Pasture fertilization effects are higher in the suppressed trees, lower in the intermediate trees, and without any effect in the dominant trees. As a general conclusion it was determined that pastures fertilization decreases basic density on Pinus radiata, especially during its first 10 years of tree growth. It was also found that on trees growing on pastures, there is no significant variation on basic density of wood during their first 10 years of growth. This behavior is the result of the intensive management of the trees forcing them to compete for light for forage development.El presente estudio muestra las diferencias en la densidad básica de la madera del Pinus radiata, para dos ensayos sometidos a diferentes esquemas de fertilización: pradera fertilizada y pradera sin fertilizar. Además, se consideran las diferentes clases sociales presentes en los rodales: dominantes, intermedios y suprimidos. Para la determinación de la densidad básica se utilizaron rodelas extraídas al diámetro a la altura del pecho, en la cual los anillos de crecimiento fueron separados, determinando para cada uno de ellos su volumen en estado verde y su peso seco al horno. Los análisis estadísticos demostraron que la densidad disminuye luego de la fertilización, prolongándose el efecto por un período de dos a tres años dependiendo de la clase social. Los efectos de la fertilización son mayores en los árboles suprimidos, menores en los intermedios y sin efecto en los árboles dominantes. Como conclusión general se estableció que la fertilización de la pradera disminuye la densidad básica del Pinus radiata, sobre todo en los primeros 10 años de crecimiento del árbol. Así también se encontró que los árboles creciendo en praderas durante sus primeros 10 años de crecimiento no se producen variaciones significativas en la densidad básica de la madera. Este comportamiento es producto del manejo intensivo que se somete los árboles, en virtud de buscar una mayor cantidad de luz para el desarrollo del forraje

The relationships between biotic uniqueness and abiotic uniqueness are context dependent across drainage basins worldwide

[EN] Context: Global change, including land-use change and habitat degradation, has led to a decline in biodiversity, more so in freshwater than in terrestrial ecosystems. However, the research on freshwaters lags behind terrestrial and marine studies, highlighting the need for innovative approaches to comprehend freshwater biodiversity. Objectives: We investigated patterns in the relationships between biotic uniqueness and abiotic environmental uniqueness in drainage basins worldwide. Methods: We compiled high-quality data on aquatic insects (mayflies, stoneflies, and caddisflies at genus-level) from 42 drainage basins spanning four continents. Within each basin we calculated biotic uniqueness (local contribution to beta diversity, LCBD) of aquatic insect assemblages, and four types of abiotic uniqueness (local contribution to environmental heterogeneity, LCEH), categorized into upstream land cover, chemical soil properties, stream site landscape position, and climate. A mixed-effects meta-regression was performed across basins to examine variations in the strength of the LCBD-LCEH relationship in terms of latitude, human footprint, and major continental regions (the Americas versus Eurasia). Results: On average, relationships between LCBD and LCEH were weak. However, the strength and direction of the relationship varied among the drainage basins. Latitude, human footprint index, or continental location did not explain significant variation in the strength of the LCBD-LCEH relationship. Conclusions: We detected strong context dependence in the LCBD-LCEH relationship across the drainage basins. Varying environmental conditions and gradient lengths across drainage basins, land-use change, historical contingencies, and stochastic factors may explain these findings. This context dependence underscores the need for basin-specific management practices to protect the biodiversity of riverine systemsSIOpen Access funding provided by University of Oulu (including Oulu University Hospital). The work for this article was supported by the Academy of Finland’s grant to JHeino for the project GloBioTrends (Grant No. 331957). JGG was funded by the European Union Next Generation EU/PRTR (Grant No. AG325). Work by LMB has been continuously supported by the National Council for Scientifc & Technological Development (CNPq) and Fundação de Amparo à Pesquisa do Estado de Goiás (FAPEG) (grants 308974/2020–4 and 465610/2014–5). PB and ZC were fnancially supported by the National Research Development and Innovation Ofce (NKFIH FK 135 136), and PB was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences BO-00106–21. LB thanks the National Council for Scientifc and Technological Development (CNPq) for the Scientifc Initiation Fellowship for JVASS and the productivity fellowship in research to LSB (process nº. 305929/2022–4). MC was awarded National Council for Scientifc & Technological Development (CNPq) research productivity grant 304060/2020–8 and received grants (PPM 00104–18, APQ-00261–22) from the Fundação de Amparo à Pesquisa do Estado de Minas Gerais. SD and JRGM acknowledge funding by the Leibniz Competition (Grant No. J45/2018) and the German Federal Ministry of Education and Research (BMBF grant agreement number no. 033W034A). DRM was supported by National Council for Scientifc & Technological Development (CNPq) (Grant No. PQ-309763–2020-7). DMPC received a postdoctoral scholarship from P&D Aneel- Cemig GT-611. PH was partially funded by the eLTER PLUS project (Grant Agreement No. 871128). LJ is grateful to 33 Forest, CIKEL Ltd. and Instituto de Floresta Tropical (IFT), Biodiversity Research Consortium Brazil-Norway (BRC), and Norsk Hydro for the fnancial and logistical support for sampling. Brazilian National Council for Scientifc and Technological Development (CNPq) is acknowledged for fnancing the projects and for granting a research productivity fellowship to LJ (304710/2019–9). APJF was supported by Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq, Brazil, process no. 449315/2014–2 and 481015/2011–6). RL also received a research productivity fellowship from CNPq (grant # 312531/2021–4). MSL received a postdoctoral scholarship from ANEEL/CEMIG (Project GT-599). Part of feld sampling and aquatic insects processing were funded by Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq; 403758/2021–1); Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM; Programa Biodiversa) and INCT ADAPTA II – (CNPq: 465540/2014–7; FAPEAM: 062.1187/2017). NH (308970/2019–5) received productivity fellowships from CNPq. RTM received a fellowship from Biodiversa/FAPEAM (01.02.016301.03271/2021–93). KLM acknowledges fnancial support from the Swiss Federal Ofce for the Environment to undertake data collection. Funding for the Segura River basin project was provided by the Seneca Foundation and the European Fund of Regional Development (PLP10/FS/97). FOR was supported by CNPq research grant. TS was partially funded by grant 13/50424–1 and 21/00619–7 from the São Paulo Research Foundation (FAPESP), and by grant 309496/2021–7 from the Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq). FVN was supported by grant #2021/13299–0, São Paulo Research Foundation (FAPESP). ALA acknowledges Brazilian National Council for Scientifc and Technological Development (CNPq, Brazil) for granting a postdoctoral scholarship to her (process number: 167873/2022–9

Challenges Using Extrapolated Family-level Macroinvertebrate Metrics in Moderately Disturbed Tropical Streams: a Case-study From Belize

Family-level biotic metrics were originally designed to rapidly assess gross organic pollution effects, but came to be regarded as general measures of stream degradation. Improvements in water quality in developed countries have reignited debate about the limitations of family-level taxonomy to detect subtle change, and is resulting in a shift back towards generic and species-level analysis to assess smaller effects. Although the scale of pollution characterizing past condition of streams in developed countries persists in many developing regions, some areas are still considered to be only moderately disturbed. We sampled streams in Belize to investigate the ability of family-level macroinvertebrate metrics to detect change in stream catchments where less than 30% of forest had been cleared. Where disturbance did not co-vary with natural gradients of change, and in areas characterized by low intensity activities, none of the metrics tested detected significant change, despite evidence of environmental impacts. We highlight the need for further research to clarify the response of metrics to disturbance over a broader study area that allows replication for confounding sources of natural variation. We also recommend research to develop more detailed understanding of the taxonomy and ecology of Neotropical macroinvertebrates to improve the robustness of metric use

The relationships between biotic uniqueness and abiotic uniqueness are context dependent across drainage basins worldwide

Context: Global change, including land-use change and habitat degradation, has led to a decline in biodiversity, more so in freshwater than in terrestrial ecosystems. However, the research on freshwaters lags behind terrestrial and marine studies, highlighting the need for innovative approaches to comprehend freshwater biodiversity. Objectives: We investigated patterns in the relationships between biotic uniqueness and abiotic environmental uniqueness in drainage basins worldwide. Methods: We compiled high-quality data on aquatic insects (mayflies, stoneflies, and caddisflies at genus-level) from 42 drainage basins spanning four continents. Within each basin we calculated biotic uniqueness (local contribution to beta diversity, LCBD) of aquatic insect assemblages, and four types of abiotic uniqueness (local contribution to environmental heterogeneity, LCEH), categorized into upstream land cover, chemical soil properties, stream site landscape position, and climate. A mixed-effects meta-regression was performed across basins to examine variations in the strength of the LCBD-LCEH relationship in terms of latitude, human footprint, and major continental regions (the Americas versus Eurasia). Results: On average, relationships between LCBD and LCEH were weak. However, the strength and direction of the relationship varied among the drainage basins. Latitude, human footprint index, or continental location did not explain significant variation in the strength of the LCBD-LCEH relationship. Conclusions: We detected strong context dependence in the LCBD-LCEH relationship across the drainage basins. Varying environmental conditions and gradient lengths across drainage basins, land-use change, historical contingencies, and stochastic factors may explain these findings. This context dependence underscores the need for basin-specific management practices to protect the biodiversity of riverine systems

Efecto de la fertilización a la pradera en densidad básica de la madera de "Pinus radiata" D. Don

El presente estudio muestra las diferencias en la densidad básica de la madera del Pinus radiata, para dos ensayos sometidos a diferentes esquemas de fertilización: pradera fertilizada y pradera sin fertilizar. Además, se consideran las diferentes clases sociales presentes en los rodales: dominantes, intermedios y suprimidos. Para la determinación de la densidad básica se utilizaron rodelas extraídas al diámetro a la altura del pecho, en la cual los anillos de crecimiento fueron separados, determinando para cada uno de ellos su volumen en estado verde y su peso seco al horno. Los análisis estadísticos demostraron que la densidad disminuye luego de la fertilización, prolongándose el efecto por un período de dos a tres años dependiendo de la clase social. Los efectos de la fertilización son mayores en los árboles suprimidos, menores en los intermedios y sin efecto en los árboles dominantes. Como conclusión general se estableció que la fertilización de la pradera disminuye la densidad básica del Pinus radiata, sobre todo en los primeros 10 años de crecimiento del árbol. Así también se encontró que los árboles creciendo en praderas durante sus primeros 10 años de crecimiento no se producen variaciones significativas en la densidad básica de la madera. Este comportamiento es producto del manejo intensivo que se somete los árboles, en virtud de buscar una mayor cantidad de luz para el desarrollo del forraje

Efecto de la fertilización a la pradera sobre la delimitación y características del período juvenil de Pinus radiata D. Don

This study presents the effects of prairie fertilization on the juvenile wood delimitation, on wood basic density, late wood percentage and on ring wide for Pinus radiata in Chile. Wood samples were taken at diameter at breast height (DBH). Two silvopastoril trails were evaluated, one corresponding to a fertilized prairie and the other to a non-fertilized prairie. In addition, tree height dominance was considered on each prairie (dominants, intermediate, and suppressed). Results showed at f irst, that production of juvenile wood in Pinus radiata growing on silvopastoril cultivation ceases between the 7th and the 11th year of age. At second, it was found that prairie fertilization had no significant effects on juvenile wood formation. At third, prairie fertilization tended to produce wood of low basic density and low percentages of late wood, but greater ring width. Finally, the end of the juvenile period occurred when the current annual increment in tree height and DBH reached the maximum.El presente estudio muestra los resultados del efecto de la fertilización de la pradera en la delimitación de la madera juvenil, así como el efecto sobre la densidad básica, el porcentaje de leño tardío y el ancho de anillo durante ese período de crecimiento. Los resultados son concluyentes para muestras cortadas a la altura del pecho. Se utilizaron dos ensayos silvipastorales, uno correspondiente a una pradera fertilizada y otro a una pradera sin fertilizar. Además, en cada tipo de pradera se consideraron los diferentes estratos arbóreos: dominantes, intermedios y suprimidos. Se demuestra, en primer lugar, que el límite de producción de madera juvenil en Pinus radiata cuando crece en silvipastoreo se encuentra en un rango de edad de 7 a 11 años. En segundo lugar, la fertilización de la pradera no produce un cambio significativo en la duración de la producción de madera juvenil. En tercer lugar, la fertilización de la pradera tiende a producir madera de menor densidad básica, menor porcentaje de leño tardío y un ancho de anillo de crecimiento mayor. Además, otro resultado importante indica que la finalización del período juvenil se da cuando el incremento corriente anual en altura y en diámetro alcanza su máximo