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In a warming Arctic, circumpolar long‐term monitoring programs are key to advancing ecological knowledge and informing environmental policies. Calls for better involvement of Arctic peoples in all stages of the monitoring process are widespread, although such transformation of Arctic science is still in its infancy. Seabirds stand out as ecological sentinels of environmental changes, and priority has been given to implement the Circumpolar Seabird Monitoring Plan (CSMP). We assessed the representativeness of a pan‐Arctic seabird monitoring network focused on the black‐legged kittiwake (Rissa tridactyla) by comparing the distribution of environmental variables for all known versus monitored colonies. We found that with respect to its spatiotemporal coverage, this monitoring network does not fully embrace current and future environmental gradients. To improve the current scheme, we designed a method to identify colonies whose inclusion in the monitoring network will improve its ecological representativeness, limit logistical constraints, and improve involvement of Arctic peoples. We thereby highlight that inclusion of study sites in the Bering Sea, Siberia, western Russia, northern Norway, and southeastern Greenland could improve the current monitoring network and that their proximity to local populations might allow increased involvement of local communities. Our framework can be applied to improve existing monitoring networks in other ecoregions and sociological contexts. [ABSTRACT FROM AUTHOR]

La variación geográfica en el tamaño y la abundancia de los insectos es un importante impulsor de los patrones en las interacciones de las especies y la biodiversidad en general. Los patrones de tamaño de los insectos se han asociado principalmente con los gradientes de temperatura, donde los climas más cálidos conducen a aumentos, disminuciones, o ausencia de cambios en el tamaño corporal de los insectos. También importante, aunque considerablemente menos estudiada, es cómo la precipitación (y, por lo tanto, la productividad primaria y la disponibilidad de recursos) puede limitar el tamaño corporal. En las laderas orientales de los Andes ecuatorianos, en consonancia con la temperatura que establece un límite superior para el tamaño de los insectos, estos son más grandes en la selva tropical de las tierras bajas en comparación con las elevaciones más altas. Este patrón altitudinal de insectos está estrechamente relacionado con la presencia de arañas sociales en estas áreas, que solo pueden sobrevivir en hábitats que albergan una gran cantidad de insectos grandes. Curiosamente, las tierras bajas de la costa en el oeste de Ecuador, con temperaturas cálidas similares, carece de arañas sociales en las áreas secas, lo que sugiere un papel secundario de la temperatura. Por lo tanto, probamos si las arañas sociales pueden estar ausentes de estas áreas debido al efecto de la lluvia y la productividad, en lugar de una combinación de temperatura y elevación, sobre el tamaño de los insectos. También consideramos la posibilidad de que la variación en la abundancia de insectos entre los sitios pueda evitar que se formen y persistan colonias de arañas sociales. Aquí usamos una combinación de cuatro técnicas de muestreo para estudiar las comunidades de insectos a lo largo de un gradiente de precipitación en el oeste de Ecuador. Encontramos que los insectos en sitios más húmedos son más grandes en comparación con los insectos en los sitios más secos, pero no más abundantes. La probabilidad de ocurrencia de arañas sociales en el oeste de Ecuador se predijo en gran medida por el tamaño de los insectos en lugar de la abundancia, de acuerdo con la hipótesis de que es el tamaño de los insectos lo que establece un límite para el tamaño de la colonia de arañas sociales. Juntos, estos resultados demuestran que la precipitación anual (por lo tanto, la productividad y la disponibilidad de recursos) puede desempeñar un papel tan destacado en los patrones de tamaño de los insectos como lo hace la temperatura a lo largo de los gradientes de elevación, por lo que es un factor importante que influye en la distribución de los sistemas de arañas sociales y los patrones de diversidad en general.

The alpha (α) and beta (β) components of gamma (γ) diversity, and the partitioning of β into nesting and turnover, contribute to understanding the factors that determine biological diversity. The objective of this study was to understand the factors affecting spatial changes in macroinvertebrate diversity in tropical high mountain Andean lakes, from the study of diversity components and beta diversity partitioning. For this, sampling was conducted in November 2018, in a lake located at 3740 m.a.s.l. Benthic macroinvertebrates were collected in 20 sites distributed in littoral, sublittoral and deep zones. In situ, depth, temperature, pH, conductivity and dissolved oxygen were measured; vertical profiles of oxygen and temperature were made. Richness components were evaluated using the γ=α+β model. Regression analysis between α and γ, dissimilarity analysis from the partitioning of beta diversity into turnover and nesting, Non-Metric Multidimensional Scaling (nMDS) and Percent Similarity (Simper) were performed. The results showed that α diversity by sites and lake zones is low relative to γ diversity, and β diversity is high. This indicates that high mountain tropical Andean lakes, despite their small size, are important for high macroinvertebrate diversity. Taxonomic richness depends on environmental variations in gradients vertically and horizontally. However, these lakes are vulnerable to natural and anthropogenic stressors such as global warming. [ABSTRACT FROM AUTHOR]

Introduction: Cloud forests are noted for their narrow distribution in tropical mountain systems. Floristically, they are complex and heterogeneous, with gaps in information that hinder the understanding of how their diversity and structure vary. Objective: To analyze patterns of diversity, structure, and composition of the cloud forest in Mexico. Methods: We counted and measured woody plants in forty 0.1 ha plots from five sites in approximately 200 km along the Sierra Madre of Chiapas, Mexico (1 700 - 2 100 m.a.s.l.). We used three statistical methods: analysis of variance (diversity true and structure among sites), simple regression and multivariate statistics (climate and elevation). Results: We recorded 4 021 individuals (220 species, 60 families). In true diversity, we only found differences for species richness, with a slight increase toward the central part of the area. Diversity was constant for common and dominant species. We found no differences in tree density or basal area between sites. However, there was less density and more basal area at higher elevations. Beta diversity and differentiation in floristic composition are high and important between plots of the same site, and they increase with distance between sites. Conclusions: Beta diversity and floristic differentiation significantly contribute to variation in the cloud forest. Climatic variables and altitude have different effects on diversity and structure. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Premise: Although ecological differentiation driven by altitude and soil is hypothesized to promote coexistence of sympatric tree species of Damburneya (Lauraceae), the mechanistic role of leaf functional variation on ecological differentiation among co‐occurring species remains unexplored. We aimed to determine whether the patterns of leaf trait variation reflect ecological differences among sympatric Damburneya species. We tested whether trait correlations underlying functional strategies and average species traits vary in response to local soil heterogeneity along an altitudinal gradient, potentially affecting species distributions. Methods: At two contrasting altitudes (100, 1100 m a.s.l.) in a Mexican tropical rainforest, we characterized soil chemical and physical properties and sampled four Damburneya species to quantify five leaf functional traits. We used linear models to analyze paired and multivariate trait correlations, spatial and interspecific effects on trait variation, and trait response to local soil heterogeneity. Relative contributions of intra‐ and interspecific variation to local trait variability were quantified with an ANOVA. Results: Soil nutrient availability was higher at low altitude, but all species had a high leaf N:P ratio across altitudes suggesting a limited P supply for plants. Species distribution differed altitudinally, with some species constrained to low or high altitude, potentially reflecting soil nutrient availability. Leaf traits responded to altitude and local soil properties, suggesting interspecific differences in functional strategies according to the leaf economics spectrum (conservative vs. acquisitive). Conclusions: The interspecific divergence in functional strategies in response to local environmental conditions suggests that trait variation could underlie ecological differentiation among Damburneya sympatric species. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Buffalo breeding has significantly increased in Brazil over recent years. However, few genetic evaluations have been conducted. Objective: To assess Genotype x Environment Interactions in the Mediterranean Water Buffalo in Brazil, for weight at 205 days of age, using reaction norm models via random regression. Methods: Data for buffaloes born between 1990 and 2014 were collected from five farms ascribed to the Brazilian Buffaloe Improvement Program, located in the North (1), Northeast (1), South (2) and Southeast (1) regions of Brazil. The initial database consisted of 5,280 observations at 205 days of age (W205). We assessed fit using two hierarchical reaction norm models: a two-step (HRNM2s) and a one-step (HRNM1s). Model fit was estimated using the Deviance Information Criterion, Deviance Based on Bayes Factors and Deviance based on Conditional Predictive Ordinate. The environmental descriptors were created to group individuals into common production environments based on year, season, herd and sex. Results: The best fit was obtained for the hierarchical reaction norm model with one-step (HRNM1s). Direct heritability estimates for this model ranged from 0.17 to 0.67 and the maternal heritability from 0.02 to 0.11 with increasing environmental gradient. Lower correlations among the sire classifications were obtained in comparison with HRNM1s in environments with low and high management, confirming the presence of genotype x environment interactions. Conclusion: We recommend a wider application of genetic evaluation in buffalo aimed at identifying optimal genotypes within specific environments. [ABSTRACT FROM AUTHOR]

The study of secondary xylem of Bulnesia retama along an aridity gradient allowed finding variations among different xylem cell types that can be used to predict tolerance of this species to aridity. The aim of this work was to carry out an anatomical description of the secondary xylem through cross sections, to analyse the variation of traits considered to be important for survival in arid environments, such as the percentage of vessels, fibres and parenchyma, fibre wall thickness, and wood density. The samples were obtained from primary branches of plants from four locations along an aridity gradient (Médanos Grandes, Bermejo, Marayes and Chepes, San Juan and La Rioja provinces, Argentina). Cross sections were observed with optical microscope and resulting digital images were analysed with ImageJ software. The results indicate that vessels are small, numerous and diagonally distributed, axial parenchyma is apotracheal diffuse. A significant increase in total fibre area and a decrease in parenchyma area with increases in aridity were observed. Total vessel area did not show any changes, while fibre wall thickness increased slightly with aridity. These traits suggest that B. retama has a highly drought-tolerant wood showing phenotypic plasticity along the aridity gradient, also registering a high-density xeromorphic wood. [ABSTRACT FROM AUTHOR]

Introduction: The characteristics of coastal wetlands are the result of hydrogeomorphological interactions between the continent and the ocean, which cause an environmental gradient, hat results in different vegetation types such as mangroves, freshwater marshes, swamp forests and palm swamps. Objective: To characterize the hydroperiod and physicochemical variables of water and soil and their effect on the distribution of vegetation in the Sistema de Humedales El Castaño. Methods: A total of 11 permanent sampling units (UM) were established by defined strata: five in the mangrove, two in swamp forest, two in freshwater marshes and two in the flooded pasture. From May 2016 to October 2017 the vegetation was characterized and the water levels and physicochemical parameters (superficial, interstitial and groundwater) were sampled monthly for: salinity, and pH; and the soil for: bulk density, humidity percentage, and redox potential. Results: Mangroves are the closest to the sea, have the lowest diversity (H: 1.66) and species richness (14), they are dominated by Laguncularia racemosa and Rhizophora mangle, have the highest values of interstitial and groundwater salinity, (> 10.8 ups), remain flooded for 4 to 12 months per year, and have a redox potential of 14.57 mV. Immediately, inland, there are remnants of the swamp forests (H: 2.18 and 18 species), dominated by Pachira aquatica, with 5 ups interstitial and groundwater salinity, flooded from 0 to 6 months per year, with a redox potential of 119.07 mV. These forests are followed inland by freshwater marshes (H: 1.92 and 16 species), dominated by Typha domingensis with 6.1 ups interstitial and groundwater salinity, flooded for 5 to 8 months per year and a redox potential of 125.9 mV. Finally, furthest inland is the flooded pasture, a modified herbaceous wetland for cattle grazing (H: 3.44 and 50 species) dominated by Paspalum conjugatum, where interstitial and groundwater salinity is less than 0.5 ups, it stays flooded for 5 to 9 months and the redox potential is 151.23 mV. Conclusions: In each type of vegetation, the structure, composition, and diversity are different, with a high turnover of species that indicates a gradient defined by salinity. The vegetation in the SHC follows the patterns of typical organization of the tropical coastal wetlands, mangroves, swamp forests and herbaceous wetlands, in this case the freshwater marshes and flooded pastures. The factor that define the distribution of the vegetation is the salinity and the gradient that is observed are a function of the hydrological dynamics that depends on the mixing of marine and freshwater. [ABSTRACT FROM AUTHOR]

The aim was to evaluate the effect of genotype environment interaction (IGA) on the weights adjusted to 365 (P365) and 550 (P550) days of age of Guzerat cattle by Bayesian hierarchical models of reaction norm. The database used was provided by the Associação Brasileira de Criadores de Zebu (ABCZ) and contained 15169 and 11183 records for P365 and P550, respectively. An animal model (MA) and hierarchical models of reaction norm with homogenous and heterogeneous variances in one step (MHNRHO1P and MHNRHE1P, respectively) and two steps (MHNRHO2P and MHNRHE2P, respectively) were fitted to assess the existence and effect of IGA. The MHNRHO1P was the best fit model. Estimates of heritability in MA were 0,37 and 0,29 for P365 and P550, respectively. Heritability ranged from 0,21 to 0,71 for P365 and 0,06 to 0,93 for P550 on MHNRHO1P along the environmental gradient. Spearman correlations between the sires for P365 and P550 ranged from 0,26 to 0,99 and from -0,99 to 0,99, respectively, and genetic correlations ranged from 0,70 to 1,00 and 0,40 to 1,00 for P365 and P550, respectively. There is IGA in Guzerá cattle in Northeast Brazil for P365 and P550, and it is necessary to consider the possibility of including this effect in genetic evaluations. [ABSTRACT FROM AUTHOR]

Potentially hazardous cyanobacterial blooming constitutes one of the most widespread problems experienced by aquatic systems worldwide. However, there are not any monitoring methods sensitive enough to be directly applicable to predict and manage blooming events. In order to fulfill this goal, both ecological and genetic concepts were combined to generate cyanobacteria monitoring tools. Two approaches were used: grouping organisms into functional groups and utilizing molecular analysis (real time quantitative PCR) as indicators of the presence of genes that encode the expression of cyanotoxins (mcy). Six bi-monthly sampling campaigns were performed to evaluate the suitability of these tools (2013-2014) at six locations composed of two sites each one, ranging downstream from Salto Grande, at the River Uruguay, to Punta del Este, at the Estuary River Plate. A remarkable gradient was observed in the meteorological, physical and chemical variables, as well as higher abundances in planktonic organisms both in Salto Grande and in Punta del Este. The most abundant population of toxic species in the whole gradient were found in Salto, and in particular those belonging to the Microcystis aeruginosa complex (MAC). The most relevant environmental variables to determine the gradient and the variation in biological variables were: salinity, temperature, wind and turbidity. The results of the new indicators (presence of MAC in the plankton net and mcy genes) were in agreement with the traditional ones (v.g. chlorophyll-a) demonstrating being much more sensitive in cases of the most severe blooming events than in the low abundance situations. The conjunction of results was applied to the construction of a monitoring and early warning system protocol.

Resumo: O objetivo deste trabalho foi verificar a presença da interação genótipos x ambientes (GxA) para peso aos 365 dias de idade, em bubalinos da raça Mediterrâneo, com o uso de modelos de normas de reação via regressão aleatória. O modelo animal padrão e os modelos de normas de reação foram testados, tendo-se avaliado o modelo hierárquico norma de reação (MNR) com um e com dois passos. O modelo hierárquico homocedástico de norma de reação com um passo (MHNRHO1P) apresentou o melhor ajuste, com base em três critérios de comparação. As estimativas de herdabilidade direta para esse modelo variaram de 0,19 a 0,78, conforme a melhoria do ambiente. Além disso, houve mudança dos valores genéticos diretos (efeito escala) de alguns reprodutores, o que indica a existência de interação GxA. As correlações de Spearman foram altas, tanto na comparação do modelo animal padrão com os MNR, como na comparação entre os níveis de baixa, média e alta qualidade no MHNRHO1p. Portanto, embora haja interação GxA, a classificação dos reprodutores não é significativamente afetada pelos modelos. A maioria dos bubalinos é formada por animais de genótipo robusto, que são menos sensíveis a mudanças ambientais.

El ''chivo cabezón'' Ariopsis sp. (aff. assimilis), es una especie estuarina endémica de la costa Caribe colombiana y del Oeste venezolano, pero está en peligro de extinción debido a la presión por pesca artesanal. Se estudió su alimentación y aspectos del uso del hábitat mediante su distribución espacial y estacional (densidad y biomasa) en la Bahía El Uno, golfo de Urabá (departamento de Antioquia), Colombia, a lo largo del gradiente ambiental definido por la pluma turbia del río Turbo (Ecorregión Darién). Los peces de tallas grandes se alimentaron principalmente de peces, crustáceos anomuros y camarones, presentando una tendencia a una dieta generalista, mientras que los pequeños lo hicieron principalmente de copépodos, siendo consumidores especialistas, evidenciando cambios ontogénicos en la alimentación de la población. Se plantea la hipótesis que esta especie puede presentar patrones de distribución y utilización del hábitat de forma secuencial en tiempo y espacio o programación estacional. La parte baja del estuario podría jugar un papel importante en la reproducción como hábitat de peces grandes, los cuales pueden incubar huevos principalmente durante la época seca, mientras que las zonas de la parte media y alta, que se encuentran bordeadas por bosque de manglar, se podrían considerar como zonas importantes de crianza, presentando mayor abundancia de peces pequeños en la época de lluvia.

Disturbances produced by volcanic eruptions are part of natural ecosystem dynamics. Soil formation and nutrient cycling depend on the decomposition both of organic matter buried under the ashes and on the litter produced after the disturbance. Here we evaluated leaf litter decomposition in Nothofagus dombeyi (coihue) forests affected by massive ash deposition from the 2011 eruption of the Volcán Puyehue-Cordón Caulle complex in NW Patagonia, Argentina. The study comprised two sites at different distances from the volcano, with different amounts of ash and annual precipitation (1600-1900 mm/year). In each site, two plots were delimited, with and without long-term livestock grazing (>50 years). N. dombeyi litter mass loss after one year was estimated in three positions (n=8 blocks/plot): on organic soil and under the ash layer, on organic soil after removal of ashes, and on top of the ash layer. Leaf litter beneath the ash layer was decomposed 74% faster in the wetter site than in the drier site. Decomposition was generally slower onto the ash layer surface than on the organic soil, and this effect was stronger in the wetter site near the volcano than in the driest and farthest site (19% vs. 9%). Litter decomposition on the soil layer was equivalent to treatments with or without the ash surface. Decomposition was slower in livestock-occupied plots than in livestock-free plots, but livestock history did not affect litter decomposition of ash topped soil vs. lower soil organic layers. Our results show that decomposer communities remain active in forest soils under ash-fall layers, thus maintaining nutrient supply to vegetation after volcanic eruptions. [ABSTRACT FROM AUTHOR]

Abstract Aim: Heterogenous environments can contribute to maintain biodiversity. Traditionally beta diversity studies have focused on determining the effect of environmental variables on the total dissimilarity of species composition. However, decomposing beta diversity in species replacement and nestedness could give new insights on mechanisms affecting spatial patterns of biodiversity. We aimed to answer two main questions about spatial patterns of fish diversity in a Neotropical basin: 1) whether some regions contribute differently to fish diversity, and 2) whether species turnover and nestedness are explained by environmental gradients. Methods Sampling sites in the main channel and tributaries of the Upper Paraná River were sampled between 2013 and 2015. We partitioned beta diversity and tested the relationship of turnover and nestedness with environmental variables. Results 74 species were captured. Some of these species were restricted to different sites, contributing to variation in species composition. Hill numbers showed a trend for higher diversity in the tributaries than in Paraná River sampling sites, and the partition of beta diversity revealed that species replacement drove dissimilarity in species composition. Only total beta diversity and turnover were related to environmental variables, mainly conductivity and turbidity. Conclusions Species diversity and composition of fish assemblages in the Upper Paraná River could be related to environmental gradients. Overall, our results suggest that Paraná River tributaries contribute to increase environmental heterogeneity, and hence to maintain a high diversity and variation in species composition. For that reason, we strongly recommend preserving highly heterogeneous habitats in the region.

Los índices disponibles para la evaluación del estado ecológico de los ríos en Colombia están basados principalmente en hipótesis subjetivas generalizadas acerca de la toleración de los macroinvertebrados, un proceso que presenta limitaciones. En este estudio se presenta la aplicación de un método para establecer un índice de calidad ecológica para sistemas lóticos, basado en abundancia de macroinvertebrados y variables fisicoquímicas. Se tomó como caso de estudio la cuenca del rio Negro (Colombia). Este nuevo índice se ha formulado como alternativa al BMWP-Col y consiste en la determinación de un gradiente ambiental a partir de un Análisis de Correspondencia Canónica de correlaciones entre abundancias y registros fisicoquímicos. Los puntajes de las estaciones -obtenidos en las correlaciones- son estandarizados y usados en un modelo de Promedios Ponderados (WA); en el modelo se ponderan también las abundancias para estimar los valores óptimos y de tolerancia de cada taxón. Con ellos y la abundancia se calcula los valores del Índice de Calidad Ecológica con base en macroinvertebrados acuáticos para la cuenca del rio Negro (ICE RN-MAE). Se utilizan los valores del índice junto con las concentraciones de fósforo total (FT) en un análisis de agrupamiento, para así clasificar los sitios de estudio. De ahí se obtienen finalmente los valores medios, máximos, mínimos y de desviación estándar del ICE RN-MAE y FT. Con ellos se definen los umbrales que corresponden a diferentes categorías de calidad ecológica (buena, regular y crítica).

Champotón River is an unknown area within the Mesoamerican hotspot in Southestern México. Reproductive traits and population structure of Astyanax aeneus were analyzed along an environmental gradient of the upper, middle and lower sections of the river, where diverse environmental factors were recorded. For this, nets were cast for 1h at each site and A. aeneus were collected from all sections with sweep nets (5 and 10m long by 5m deep, 0.03m mesh size) and a casting net (0.05m mesh size). At each study site and campaign, a total of 80 specimens (in average) were collected and were fixed in 10% formaldehyde for further analysis. Population structure by size was analyzed for each study site, based on the relative frequencies by standard length classes. The length-weight relationship was determined, and the identification of gonadal developmental stages, reproductive period, size at first sexual maturity, relative fecundity, sex ratio and somatic indexes (gonadosomatic, hepatosomatic and Fulton’s condition factor) were also assessed. Seven size classes were found in the upper and middle sections, and nine downstream, with seasonal and spatial pattern in size-class frequency distribution. Size at first maturity was 45.7mm for females and 40.8mm for males. The maximum relative fecundity was recorded at the downstream site and was positively correlated with body weight and standard length. Sex ratio (1.8:1 males: females) differed significantly from expected values (1:1). Gonadosomatic index scores indicated that the reproductive period of this species in the Champotón River was from April to July, during the warm and wet season. Hepatosomatic index was negatively correlated with the Gonadosomatic index, evidencing transfer of energy from the liver towards gamete production. This strategy enabled A. aeneus to maintain robustness during the study period with tiny changes in condition factor. A. aeneus in the Champotón River, as opposed to South American river congeneric species of similar size, shows early sexual maturity, a short reproductive period with high gonadosomatic index values, and high fecundity, a trade-off for the short reproductive period. Spatio-temporal segregation was evident: breeders congregate down- stream, while juveniles prefer the upper reaches. This pattern allows A. aenus to be successful in a river with high frequency of hurricanes.El Río Champotón es un área de desconocimiento científico dentro del hotspot de Mesoamérica en el sureste de México. Las características reproductivas y la estructura de la población de Astyanax aeneus fueron analizadas a lo largo de un gradiente ambiental en la porción dulceacuícola del río. Se estudiaron tres sitios: en la parte alta del río San Juan Carpizo, en la porción media San Antonio del Río y río abajo en Ulumal, en cinco períodos entre 2007 y 2008. Se registraron diversos factores ambientales en cada sitio de estudio. Los ejemplares de A. aeneus se recolectaron con redes de arrastre de 5 y 10m de largo por 5m de profundidad (0.03m malla) y atarraya (con luz de malla de 0.05m). Las redes fueron lanzadas durante 1 hora en cada sitio. En cada visita se recolectaron un promedio de 80 especímenes en cada sitio de estudio que se preservaron en formaldehído al 10% para su posterior análisis. Para cada sitio de estudio se analizó la estructura de la población por talla, con base en las frecuencias relativas de las clases de longitud estándar. Se determinó la relación peso-talla, se identificaron las etapas del desarrollo gonadal, la época reproductiva, el tamaño de primera madurez sexual, la fecundidad absoluta y relativa, la proporción de sexos y los índices somáticos (gonadosomático, hepatosomático y el factor de condición de Fulton). Se obtuvieron siete clases de talla en la parte alta y media del río y nueve río abajo, con un patrón de distribución estacional y espacial en las frecuencias de clase de tallas. La talla de primera madurez fue de 45.7mm en hembras y 40.8mm en machos. La máxima fecundidad absoluta se registró río abajo y se correlacionó positivamente con el peso corporal y la longitud estándar. La proporción de sexos (1.8:1 machos: hembras) difiere significativamente de los valores esperados (1:1). Los resultados del índice gonadosomático (IGS) indican que el período reproductivo en el Río Champotón es en julio, durante la temporada húmeda y cálida. El índice hepatosomático se correlacionó negativamente con el IGS, evidenciando la transferencia de energía desde el hígado hacia la producción de gametos. Esta estrategia permitió que A. aeneus mantuviera una condición robusta durante el periodo de estudio con pequeños cambios en el factor de condición. Nuestros resultados indican que A. aeneus en el río Champotón, a diferencia de otras especies del mismo género y de la misma talla en ríos de Sudamérica, presenta una maduración sexual precoz, una temporada reproductiva corta con elevados valores del IGS, y una elevada fecundidad, lo que compensa la temporada de reproducción corta. También se percibe una tendencia a la segregación espacial y temporal: los reproductores se congregan aguas abajo y los juveniles prefieren las partes más altas. Este patrón permite a A. aeneus tener éxito en un río con una alta frecuencia de huracanes.

El microhábitat epífito se encuentra expuesto a grandes variaciones microclimáticas debido al clima local así como a la estructura y dinámica del bosque. Consecuentemente, el establecimiento y desarrollo de las epífitas, así como su amplitud ecológica, dependen de la capacidad de modificar su fisiología, morfología y fenología frente a restricciones ambientales. En este estudio se describen las diferencias en la amplitud ecológica de epífitas vasculares en un gradiente de luz y humedad del sustrato en un relicto de bosque esclerófilo mediterráneo costero que se encuentra en la Península de Hualpén, Región del Biobío (36º47’S y 73º10’O). Abarcando la variación horizontal y vertical en la disponibilidad de luz y humedad del sustrato asociada a la estructura del bosque, se cuantificó la disponibilidad de estos recursos y se estimó la abundancia de cada especie epífita. Además se midieron los rasgos funcionales foliares contenido relativo de agua foliar (CRA), contenido de clorofila foliar (Chl) y masa foliar específica (LMA) a lo largo de los dos gradientes ambientales. Se encontraron siete especies de epífitas vasculares (dos Angiospermas y cinco Pteridófitas), algunas de ellas mostraron diferencias en su amplitud ecológica en ambos gradientes ambientales. Sarmienta scandens (Gesneriaceae), Asplenium trilobum (Aspleniaceae) y Pleopeltis macrocarpa (Polypodiaceae) fueron las especies más abundantes en el sitio y las que presentaron mayor amplitud ecológica en ambos gradientes ambientales. Para estas especies el cambio de Chl podría ser un importante mecanismo de aclimatación bajo variación de humedad del sustrato. Finalmente, aunque no se encontró relación entre la amplitud ecológica en el gradiente de luz y los rasgos de la hoja, los resultados sugieren que la composición de las especies se relaciona con la disponibilidad de luz en los árboles hospederos.

O objetivo deste trabalho foi avaliar a interação genótipo × ambiente (IGA) quanto ao peso ajustado aos 365 dias de idade, em bovinos da raça Nelore Mocha do Nordeste do Brasil, por meio de modelos de norma de reação, via regressão aleatória com abordagem bayesiana. Os modelos analisados incluíram o efeito fixo de idade da vaca (linear e quadrático) e os efeitos aleatórios genético aditivo e de grupo de contemporâneos. O modelo de norma de reação com variância residual homogênea e um passo (MHNRHO1P) proporcionou melhor ajuste aos dados do que os modelos com variância residual heterogênea e o modelo animal padrão (MA). As estimativas de variância genética (64,41±13,24 kg² a 842,31±58,29 kg²) e herdabilidade (0,11±0,01 a 0,63±0,02) aumentaram com a melhoria do gradiente ambiental. As correlações de Spearman variaram de 0,69 a 0,99, entre as classificações dos reprodutores com maiores valores genéticos nos MA e MHNRHO1P, nos diferentes ambientes, o que indica alteração na classificação, especialmente dos valores genéticos obtidos pelo MA nos ambientes superiores. A identificação desse nível de IGA torna necessárias as avaliações específicas dos indivíduos e rebanhos para os ambientes de baixo, médio e alto nível de produção.

Edge effects play a key role in forest dynamics in which the context of the anthropogenic matrix has a great influence on fragment connectivity and function. The study of the interaction between edge and matrix effects in nature is essential to understand and promote the colonization of some functional groups in managed ecosystems. We studied the dynamics of 7 species of frogs and salamanders occurring in 8 ecotones of tropical montane cloud forest (TMCF) which interact with adjacent managed areas of coffee and corn plantations in Guerrero, southern Mexico. A survey effort of 196 man/hours along 72 transects detected 58 individuals of 7 amphibian species and 12 environmental and structural variables were measured. The diversity and abundance of amphibians in the forest mostly depended on the matrix context adjacent to the forest patches. The forest interior provided higher relative humidity, leaf litter cover, and canopy cover that determined the presence of some amphibian species. The use of shaded coffee plantations was preferred by the amphibians over the corn plots possibly due to the maintenance of native forest arboreal elements, low management rate and less intensity of disturbance in the coffee plantations than in the corn plots. Shaded coffee plantations reduce the edge effects in TMCF, improve the connectivity between TMCF fragments and increase habitat quality for the forest interior amphibian species. Future wildlife management research should take into account edge and matrix effects to understand species dynamics which move along anthropogenic-natural ecotones in managed ecosystems, thus prioritizing sites to buffer edge effects and increase habitat quality in remaining natural ecosystems.El efecto de borde es un evento clave en la dinámica de algunos bosques, la matriz que rodea a los fragmentos de bosque tiene una gran importancia en el funcionamiento y conectividad de estos fragmentos. El conocimiento de las interacciones entre el efecto de borde y la matriz es indispensable para entender el proceso de colonización de numerosos grupos de organismos en ecosistemas manejados o perturbados. Estudiamos la dinámica de 7 especies de ranas y salamandras que habitan en 8 ecotonos de bosque mesófilo de montaña que se encuentran adyacentes a zonas de cultivo de café y maíz en el estado de Guerrero, México. Tras un esfuerzo de captura de 196 horas/hombre a lo largo de 72 trayectos registramos 58 individuos de anfibios pertenecientes a 7 especies y se midieron 12 variables ambientales y estructurales. Se observó que la diversidad y la abundancia de los anfibios dependen del tipo de matriz adyacente al bosque. El interior del bosque proporciona a los anfibios mayor humedad relativa, mayor cobertura del dosel y de hojarasca. Estos resultados muestran que los anfibios prefieren los cafetales sobre los cultivos de maíz, posiblemente por la presencia de elementos de la vegetación original en los cafetales de sombra y a lo reducido de su manejo en comparación a los cultivos de maíz. Los cafetales reducen los efectos del borde en estos fragmentos de bosque mesófilo, mejoran la conectividad entre ellos e incrementan la calidad del ambiente para las especies que habitan en el interior del bosque. La investigación sobre el manejo de fauna silvestre debería tomar en cuenta este tipo de hallazgos para comprender la dinámica de las especies que se mueven a lo largo de ecotonos antropogénico-naturales.

Foi caracterizada a heterogeneidade ambiental em uma área de floresta de galeria (7,55 ha), em Itutinga, MG, Brasil, pelas variações das propriedades químicas e físicas do solo, da topografia e da abertura de dossel. As propriedades do solo e a topografia foram estudadas em 28 parcelas de 10 x 30 m utilizadas em um levantamento da comunidade arbóreo-arbustiva da área. Para a abertura do dossel utilizaram-se duas transecções de 50 m de largura, compostas por parcelas contíguas de 10 x 10 m, cruzando a floresta de lado a lado, perpendicularmente ao curso d'água. Fotos hemisféricas foram tomadas sobre estacas alternadas das extremidades das parcelas. Os dados de solo e topografia foram analisados por meio de uma PCA (Análise dos Componentes Principais) e a abertura do dossel mediante gráficos de tendência e regressão linear. A variação mais importante em termos de solos e abertura do dossel se deu no sentido do distanciamento da borda da floresta e aproximação do curso d'água. Nesse sentido, a abertura do dossel diminuiu (b = -0,096; R2 = 0,34) e a umidade e acidez do solo aumentaram (Eixo 1 do PCA, autovalor = 9,713). Os maiores valores da abertura do dossel próximo à borda foram explicados pela entrada de luz lateral através da borda da floresta com o campo limpo circundante.

In Amazonia, topographical variations in soil and forest structure within "terra-firme" ecosystems are important factors correlated with terrestrial invertebrates' distribution. The objective of this work was to assess the effects of soil clay content and slope on ant species distribution over a 25 km² grid covering the natural topographic continuum. Using three complementary sampling methods (sardine baits, pitfall traps and litter samples extracted in Winkler sacks), 300 subsamples of each method were taken in 30 plots distributed over a wet tropical forest in the Ducke Reserve (Manaus, AM, Brazil). An amount of 26,814 individuals from 11 subfamilies, 54 genera, 85 species and 152 morphospecies was recorded (Pheidole represented 37% of all morphospecies). The genus Eurhopalothrix was registered for the first time for the reserve. Species number was not correlated with slope or clay content, except for the species sampled from litter. However, the Principal Coordinate Analysis indicated that the main pattern of species composition from pitfall and litter samples was related to clay content. Almost half of the species were found only in valleys or only on plateaus, which suggests that most of them are habitat specialists. In Central Amazonia, soil texture is usually correlated with vegetation structure and moisture content, creating different microhabitats, which probably account for the observed differences in ant community structure.Na Amazônia, variações topográficas em ecossistemas de terra-firme são variáveis comuns que afetam a distribuição de invertebrados terrestres. O objetivo deste trabalho foi avaliar os efeitos do conteúdo de argila no solo e da inclinação do terreno na distribuição de espécies de formigas em uma área de 25 km2 que cobre a variação topográfica natural. Usando três métodos de coleta complementares (iscas de sardinha, armadilhas de fosso e amostras de serapilheira extraídas de sacos de Winkler), foram coletadas 300 subamostras de cada método em 30 parcelas distribuídas em uma floresta tropical úmida na Reserva Ducke (Manaus, AM). Foram registrados 26.814 indivíduos em 11 subfamílias, 54 gêneros, 85 espécies e 152 morfoespécies (Pheidole representou 37% das morfoespécies). O gênero Eurhopalothrix foi registrado pela primeira vez nesta reserva. O número de espécies não foi correlacionado com a inclinação do terreno ou o conteúdo de argila, exceto para espécies na serapilheira. No entanto, a Análise das Coordenadas Principais indicou que a composição de espécies das armadilhas e da serapilheira esteve correlacionada com o conteúdo de argila. Aproximadamente metade das espécies foi encontrada somente nos baixios ou nos platôs, sugerindo que a maioria é especialista do habitat. Na Amazônia Central, a textura do solo está geralmente correlacionada com a estrutura da vegetação e o teor de umidade, criando micro-habitats heterogêneos que provavelmente contribuíram para as diferenças observadas na estrutura da comunidade de formigas.

Foi caracterizada a heterogeneidade ambiental em uma área de floresta de galeria (7,55 ha), em Itutinga, MG, Brasil, pelas variações das propriedades químicas e físicas do solo, da topografia e da abertura de dossel. As propriedades do solo e a topografia foram estudadas em 28 parcelas de 10 x 30 m utilizadas em um levantamento da comunidade arbóreo-arbustiva da área. Para a abertura do dossel utilizaram-se duas transecções de 50 m de largura, compostas por parcelas contíguas de 10 x 10 m, cruzando a floresta de lado a lado, perpendicularmente ao curso d’água. Fotos hemisféricas foram tomadas sobre estacas alternadas das extremidades das parcelas. Os dados de solo e topografia foram analisados por meio de uma PCA (Análise dos Componentes Principais) e a abertura do dossel mediante gráficos de tendência e regressão linear. A variação mais importante em termos de solos e abertura do dossel se deu no sentido do distanciamento da borda da floresta e aproximação do curso d’água. Nesse sentido, a abertura do dossel diminuiu (b = -0,096; R2 = 0,34) e a umidade e acidez do solo aumentaram (Eixo 1 do PCA, autovalor = 9,713). Os maiores valores da abertura do dossel próximo à borda foram explicados pela entrada de luz lateral através da borda da floresta com o campo limpo circundante.

A multi-trait animal model (15,904 data) and a reaction norm model (13,068 data) were studied, in order to estimate genetic parameters and environmental awareness of the weight at 18 months (P18) and (TDG) of Cuban Zebu during the performance test for future sires. The animals were born between 1981 and 2012 and were the offspring of 295 parents. Multi-trait animal model allowed to obtain the solutions of fixed effect of from the group of contemporaries, heritabilities and genetic tendencies of P18 and trial daily gain TDG. Later, a reaction norm model of sire type was considered, with the group of contemporaries (herd-year-three-month period of animal birth) as fix effect the effect of random regression of sire (cubic, square and linear Legendre polynomials) through an environmental gradient, expressed as solution of fix effect, so a total of 6 environmental classes were created. Estimated values of heritability, through the animal model, were 0.20 ± 0.02 and 0.28 ± 0.02 for TDG and P18, respectively, with a genetic correlation of 0.94 among them. Using the reaction norm model, the estimates varied from 0.13±0.04 to 0.43±0.08, and the highest corresponded to favorable environments or positive gradients. Correlation values, very close to 1, indicate the non-existence of genotype x environment interaction in most of the cases. However, there may be correlations lower than 0.8 in the most unfavorable environment, which indicates that sires selected in favorable environments may not have the same performance after passing to unfavorable environments. [ABSTRACT FROM AUTHOR]

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Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The New Granada sea catfish, Ariopsis sp. (aff. assimilis) is a species endemic to the Colombian Caribbean coast and the western coast of Venezuela, but it is endangered due to pressures from artisanal fishing. Diet and aspects of habitat use were studied through its spatial and temporal distribution patterns (density and biomass) in a coastal estuary along an environmental gradient defined by the turbid plume of the Turbo River (Darien Ecorregion). The largest sized fish fed mainly on fish, anomuran crustaceans and shrimps, exhibiting a tendency for a generalist diet, while the smaller fish fed mainly on copepods, being specialist feeders, indicating an ontogenic change in the diet of this population. We hypothesize that this species may present patterns of distribution and habitat use in a sequential form in time and space, or seasonal programming. The southern part of the of the estuary may play an important role in reproduction as habitat for the larger fish, which brood eggs mainly during the dry season, while the middle and northern zones, bordered by mangroves, may be important nursery areas, with larger peaks in abundance of smaller fish mainly during the rainy season. [ABSTRACT FROM AUTHOR]

Los ecosistemas de bosque y arbustal del Uruguay han sido clasificados solamente según criterios fisonómicos, y los factores que determinan su heterogeneidad todavía no se comprenden con claridad. El objetivo general del presente trabajo es describir la variación en la composición de especies de la vegetación leñosa de las sierras del este y noreste del Uruguay, e incluir, por primera vez, el análisis de los arbustales serranos. En tres predios ganaderos se seleccionaron los sitios de muestreo, que incluyeron el relevamiento de 122 parcelas. Mediante la combinación de análisis de clasificación jerárquico y análisis de especies indicadoras se identificaron cinco unidades principales de vegetación: arbustales de Myrceugenia euosma y de Baccharis dracunculifolia, y bosques de Syagrus romanzoffiana, de Myrsine coriacea y de Eugenia uniflora. El análisis de la composición florística reveló un gradiente florístico - fisonómico relacionado de forma estrecha con la profundidad del suelo y con la topografía. A su vez, parte de la variación correspondió a la geología de los sitios estudiados. A pesar de su alta uniformidad estructural, la vegetación leñosa de las sierras presenta heterogeneidad florística. Este trabajo brinda una tipología alternativa a la fisonómica; permite establecer criterios de extrapolación o de contextualización como base de experimentos, revela la heterogeneidad de las categorías fisonómicas conocidas y advierte, por lo tanto, sobre las limitaciones de su uso. Por último, este trabajo también abre perspectivas para realizar comparaciones con el sur de Brasil y para diseñar estrategias de conservación regional.

La sierra de Zapalinamé es un área natural protegida del sureste de Coahuila, en la transición entre el Desierto Chihuahuense y la Sierra Madre Oriental. En sus cañones, donde el clima es templado subhúmedo y templado semiseco, se desarrollan bosques de encino. Con la finalidad de conocer la distribución, la riqueza y la diversidad de especies de estos bosques, se establecieron 66 sitios circulares de 500 m2, donde se tomó información de la densidad, el diámetro y la cobertura de las plantas leñosas, y de la frecuencia de las hierbas. Se utilizó la densidad de plantas leñosas y la frecuencia de todos los gremios de plantas para calcular el índice de diversidad de Shannon-Wiener; la relación entre la diversidad y la riqueza de especies leñosas con las variables ambientales se analizó mediante regresión lineal. Se reconocieron dos asociaciones del encinar: bosque de Quercus greggii-Q. mexicana y bosque de Q. saltillensis-Q. laeta, ambos distribuidos en un intervalo altitudinal de 2,000 a 2,600 m. La precipitación media es de 324 mm y la temperatura media es de 16ºC. Los bosques de Q. saltillensis–Q. laeta presentan el índice de diversidad más alto, así como la mayor riqueza de hierbas y arbustos, debido a las condiciones ambientales particulares, a la mayor incidencia de disturbios antropogénicos y a la infiltración de especies provenientes del matorral submontano. El patrón de diversidad de especies y su relación con los gradientes ambientales muestra que la diversidad y la riqueza disminuyen con el aumento de altitud y de precipitación, pero que aumentan con el incremento de la temperatura. En estos encinares la riqueza de especies varía marcadamente, siendo las hierbas las de mayor riqueza, seguidas por los arbustos y al final los árboles. La diversidad alfa promedio para las parcelas de muestreo fue de 40 especies. El patrón en la diversidad parece resultar de una combinación de procesos ecológicos con la configuración espacial y el historial de manejo del área protegida. En el diseño de estrategias de conservación biológica se deberá considerar el control de los disturbios antropogénicos.

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wood of Quercus obtusata is described and the variation of nine quantitative wood characters is evaluated through tree height and diameter, elevation and 11 climatic parameters in four sites. Pearson correlation showed that only the narrow vessel element length is significantly correlated with tree height (rp = 0,70, p <0,02). The principal component analysis revealed that three components explain 76,46% of the total variation and ten variables are those with the highest loadings. Moreover, this analysis segregated the localities due to altitude and some climatic variables as for temperature and rainfall throughout the year, which have an effect on vessel elements length, as well as on fibres length and wall thickness. The driest locality, Arcos del Sitio, and in that of higher elevation, Santa Ana Jilotzingo, have the shortest vessel elements with wider diameter (561 µm and 552 µm respectively) than the most humid environment, Santa Catarina (621 µm). The fibres neither diminish in size with the elevation nor increase with tree height. The analyses suggest that the microclimatic parameters of each location need to be accounted when recommendations for Q. obtusata wood used as raw material or in reforestation programs are given. [ABSTRACT FROM AUTHOR]

The article focuses on the study that examines the community structure of bats at the Biosphere Reserve and Communitarian Land of Origin Pilon Lajas in Bolivia. The environmental gradient was placed in four vegetation formations including riverine forest (BR), old vázea forest (BT), lower Beni Yungas tall forest (BA), and Yungas-Amazonian transitional cloud forest (BN). The samples were exposed to 3,408 meters of mist net for 396 hours, and have captured a total of 578 individuals. Carollia perspicillata, Sturnira lilium and Carollia brevicauda were some of the most abundant species.

Amazonian várzea forests are characterized by a high diversity of species and adaptations against extended flooding. Waterlogging and submergence can last up to 210 days per year, with a water column of up to 6-7 m. The present paper gives an insight into the current knowledge of morpho-anatomical, phenological and physiological responses to flooding in várzea trees, into patterns of regeneration and seedling recruitment, and into differences found along the flooding gradient, and between populations of selected species. This knowledge may serve as a basic tool for forest management. The high selective logging already caused a substitution of timber species, with high damages in the remaining stands, calling for rigorous management plans. Since the regular inundation induces the formation of annual rings, and tree growth responds to the prolonged vegetation period with significantly wider ring widths in El Niño years as compared to neutral years, tree ring analysis can be used also for the development of models to predict tree growth and to determine minimum logging diameters and cutting cycles for timber species. [ABSTRACT FROM AUTHOR]