国家亚马逊研究所

Individual dietary specialization is a fundamental phenomenon for understanding ecological niche dynamics, but its expression may vary depending on temporal scale and environmental context. We investigated the diet of the Amazonian cichlid Mesonauta festivus (Heckel 1840) across four floodplain populations, combining stomach content analysis, which reflects short-term assimilation, with stable isotope analysis, which integrates long-term feeding patterns. While stomach contents indicated high individual specialization and marked spatial heterogeneity, isotopic data revealed trophic convergence over time and strong similarity among populations. Dietary differences between sexes were observed only in some localities and were not associated with morphological variation. Overall, the findings suggest that individual specialization in M. festivus is transient and influenced by extrinsic factors in the short term. This study emphasizes the importance of integrating complementary methodological approaches to better understand the trophic dynamics of fish in Amazonian floodplain ecosystems.

Human activities such as land use changes and ongoing climate changes are expected to affect the physical and chemical characteristics of water, its quality, and the ecosystem processes in these ecosystems. This study aimed to evaluate the independent and interactive effects of pH and temperature on microbial decomposition, caddisfly shredder consumption, and survival in Neotropical streams. We tested the following hypotheses: (i) pH and temperature would independently affect microbial decomposition and shredder activity, and (ii) their combined increase would produce interactive effects, reducing shredder consumption and survival. We found no significant influence of pH or temperature on microbial decomposition, suggesting that microbes in these systems are adapted to a wide range of environmental conditions. However, a synergistic effect of pH and temperature was observed on shredder consumption and survival, with the greatest activity occurring at circumneutral pH and reduced under elevated temperatures. These findings highlight the importance of considering multiple environmental stressors to understand ecosystem processes in neotropical aquatic environments, as well as to support actions for the sustainable management and use of water resources.

Pleurotus ostreatus is an edible mushroom widely recognized for its nutritional value and high content of bioactive compounds, including phenolics and polysaccharides, which confer potential antidiabetic and anti-obesity effects. These properties are mainly associated with its ability to modulate digestive enzymes involved in carbohydrate and lipid metabolism, as well as its antioxidant activity. This study applied a bioprocess-based approach to produce Amazonian P. ostreatus mycelial biomass via submerged fermentation, followed by the evaluation of its biochemical composition, antioxidant activity, and inhibitory effects on key digestive enzymes. Different combinations of carbon and nitrogen sources were investigated based on mycelial biomass production to determine the most suitable fermentation condition. To evaluate digestive enzyme inhibition, a 23 factorial experimental design was applied to assess the effects of carbon source, nitrogen source, and extraction solvent, as well as their interactions, on the inhibition of α-amylase, α-glucosidase, and pancreatic lipase. The mycelial biomass obtained under condition T4 (sucrose + peptone) showed strong α-glucosidase inhibition [(96.94 ± 0.49)

The aquatic biota of the Amazon is subject to considerable daily and seasonal fluctuations in its environment. The ability to adapt to changes in the environment, such as increased water temperatures, is essential for the survival and physiological performance of these organisms. The anticipated rise in temperature and CO2 levels, projected to reach 6 °C and 50

Dispersal behavior and survival are critical properties of animal populations and are known to determine the success of reintroduction and reinforcement programs. We tracked 53 juvenile Aquila fasciata (Bonelli's Eagle), including wild-hatched and captive-bred individuals released via two different protocols, to test how early-life experiences shape dispersal and fitness outcomes. Captive-bred eagles were released either on their rearing site near their natal enclosure and foster parents or at a distant site without the parents. Dispersal patterns diverged strongly by group: distant-released individuals dispersed farther, and in markedly more directional, migration-like patterns, reaching as far as East Africa and the Arabian Peninsula. In contrast, on-site and wild-hatched eagles remained closer to their natal areas, showing variable and shorter dispersal trajectories on average. Despite comparable ages at dispersal onset, habitat use differed significantly, with distant-released individuals consistently occupying drier desert habitats. These patterns suggest that post-fledging experience promotes philopatry and shapes movement decisions, likely via natal habitat preference induction. Wild-hatched eagles exhibited significantly higher survival rates and recruitment success than both captive-bred groups, which suffered elevated mortality primarily due to electrocution and other anthropogenic threats. Surprisingly, shorter-range dispersal by on-site releases did not improve survival, likely reflecting high risk from local infrastructure (notably high incidents of electrocution). The high mortality of captive-bred birds raises concerns about the long-term effectiveness of current release strategies and highlights the paramount importance of conserving existing wild breeding pairs and their territories. Our findings demonstrate that both dispersal and fitness outcomes are influenced by the timing and spatial context of the release to the wild, with strong implications for raptor conservation and reintroduction programs. In particular, we highlight the importance of acquiring natal habitat preference during the post-fledging dependence period and recommend that release protocols preserve continuity with natal habitat when possible. Ultimately, this study underscores that fine-scale management of early-life experience can have enduring consequences for the spatial ecology and viability of reintroduced populations. center dot Captive breeding helps save endangered species, but we need to understand how release methods affect survival and behavior of captive-bred animals. center dot We tracked 53 Aquila fasciata (Bonelli's Eagle)-both wild-hatched and captive-bred birds-released using two different methods to study their movements and survival. center dot Captive-bred eagles released far from their parents and rearing sites traveled much longer distances than wild-hatched eagles or eagles released near their rearing site, often reaching East Africa and Southern Arabia. center dot However, all captive-bred eagles had lower survival than wild birds, with most deaths caused by electrocution from powerlines. The high number of powerlines near the release sites likely obscured survival differences between the long-range and short-range dispersers. center dot These findings show that early life conditions and release strategies can shape the behavior and success of animals in the wild. This can help improve conservation efforts by guiding more effective release practices for threatened species. El comportamiento de dispersi & oacute;n y la supervivencia son propiedades cr & iacute;ticas de las poblaciones animales y se sabe que determinan el & eacute;xito de los programas de reintroducci & oacute;n y refuerzo poblacional. Seguimos a 53 juveniles de Aquila fasciata, incluyendo individuos nacidos en estado silvestre y criados en cautiverio, & eacute;stos & uacute;ltimos liberados mediante dos protocolos diferentes, para evaluar c & oacute;mo las experiencias tempranas moldean la dispersi & oacute;n y los resultados en t & eacute;rminos de aptitud biol & oacute;gica. Las & aacute;guilas criadas en cautiverio fueron liberadas ya sea en su sitio de crianza, cerca de su recinto natal y de sus padres adoptivos, o en un sitio distante y sin los padres. Los patrones de dispersi & oacute;n divergieron marcadamente entre grupos: los individuos liberados en un sitio distante se dispersaron m & aacute;s lejos y en trayectorias mucho m & aacute;s direccionales, similares a migraciones, llegando hasta & Aacute;frica oriental y la pen & iacute;nsula Ar & aacute;biga. En contraste, las & aacute;guilas liberadas en el sitio de crianza y las nacidas en estado silvestre permanecieron m & aacute;s cerca de sus & aacute;reas natales, mostrando trayectorias de dispersi & oacute;n m & aacute;s cortas y variables en promedio. A pesar de presentar edades comparables al inicio de la dispersi & oacute;n, el uso del h & aacute;bitat difiri & oacute; significativamente, ya que los individuos liberados en un sitio distante ocuparon de manera consistente h & aacute;bitats des & eacute;rticos m & aacute;s secos. Estos patrones sugieren que la experiencia posterior al emplumamiento promueve la filopatr & iacute;a y moldea las decisiones de movimiento, probablemente mediante la inducci & oacute;n de una preferencia por el h & aacute;bitat natal. Las & aacute;guilas nacidas en estado silvestre presentaron tasas de supervivencia y & eacute;xito de reclutamiento significativamente mayores que ambos grupos criados en cautiverio, los cuales sufrieron mortalidad elevada principalmente por electrocuci & oacute;n y otras amenazas antropog & eacute;nicas. Sorprendentemente, la dispersi & oacute;n a menor distancia de los individuos liberados en el sitio de crianza no mejor & oacute; la supervivencia, lo que probablemente refleja el alto riesgo asociado a la infraestructura local (en particular, una alta incidencia de electrocuciones). La alta mortalidad de las aves criadas en cautiverio genera preocupaci & oacute;n sobre la eficacia a largo plazo de las estrategias actuales de liberaci & oacute;n y resalta la importancia primordial de conservar las parejas reproductoras silvestres existentes y sus territorios. Nuestros resultados demuestran que tanto la dispersi & oacute;n como los resultados en t & eacute;rminos de aptitud biol & oacute;gica est & aacute;n influidos por el momento y el contexto espacial de la liberaci & oacute;n al medio natural, con importantes implicancias para la conservaci & oacute;n de rapaces y los programas de reintroducci & oacute;n. En particular, destacamos la importancia de adquirir una preferencia por el h & aacute;bitat natal durante el per & iacute;odo posterior al emplumamiento y recomendamos que los protocolos de liberaci & oacute;n preserven, cuando sea posible, la continuidad con el h & aacute;bitat natal. En & uacute;ltima instancia, este estudio subraya que el manejo a escala fina de las experiencias tempranas puede tener consecuencias duraderas para la ecolog & iacut