Search

Los ríos de flujo libre (RFL) se caracterizan por su conectividad fluvial íntegra y por proveer múltiples beneficios a las comunidades asentadas en ellos. Sin embargo, a nivel mundial estos tipos de ríos se encuentran amenazados por la construcción de obras de infraestructura. En ocasiones, la pluralidad de valores que las comunidades le atribuyen a estos ríos no se toma en cuenta, particularmente al momento de planificar proyectos de desarrollo, lo que podría detonar conflictos ambientales. Se analizaron los valores sociales asociados con el río Los Horcones (RLH) entre dos localidades, río arriba (Las Juntas y Los Veranos) y río abajo (Boca de Tomatlán). A partir del análisis de 35 entrevistas y el uso redes semánticas, se encontró que ambas comunidades tienen un interés común por la protección y conservación del río Los Horcones. Sin embargo, se observa una ponderación diferencial de valores específicos por localidad. Río abajo (Boca de Tomatlán) predominan los valores intrínsecos y relacionales, dado que el RLH es fundamental para la diversificación de sus medios de vida. En contraste, río arriba (Las Juntas y Los Veranos) predominan los valores relacionales e instrumentales debido a la dependencia económica del turismo de naturaleza que se realiza en el RLH. El reconocimiento de la pluralidad de valores asociados con los ríos de flujo libre es esencial para la formulación de estrategias de manejo y conservación de los recursos hídricos.

Biodiversity is confronted globally by multiple stressors. Environmental policies must regulate these stressors to achieve targets, but how should that be done when the outcomes of limits on one stressor are contingent on other stressors, about which there is imperfect knowledge? Deriving regulatory frameworks that incorporate these contingencies is an emerging challenge at the science–policy interface. To be fit for implementation, these frameworks need to facilitate the inherently sociopolitical process of policy implementation and account transparently for uncertainty, such that practitioners and other stakeholders can more realistically anticipate the range of potential outcomes to policy. We developed an approach to quantify stressor limits that explicitly accounts for multistressor contingencies. Using an invertebrate data set collected over 30 years throughout New Zealand, we combined ecological and ecotoxicological models to predict biodiversity loss as a function of one stressor, treating multistressor contingencies as a form of uncertainty about the outcomes of limits on that stressor. We transparently accounted for that uncertainty by presenting regulatory limits as bands bounded between optimistic and pessimistic views that practitioners may have about the local context within which limits are applied. In addition to transparently accounting for uncertainties, our framework also leaves room for practitioners to build stakeholder consensus when refining limits to suit different local contexts. A criticism of this open, transparent approach is that it creates too much scope for choosing limits that are lenient on polluters, paralyzing on‐the‐ground management of multiple stressors, but we demonstrate that this is not necessarily the case. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems and their bordering wetlands and riparian zones are vital for human society and biological diversity. Yet, they are among the most degraded ecosystems, where sharp declines in biodiversity are driven by human activities, such as hydropower development, agriculture, forestry, and fisheries. Because freshwater ecosystems are characterized by strongly reciprocal linkages with surrounding landscapes, human activities that encroach on or degrade riparian zones ultimately lead to declines in freshwater–riparian ecosystem functioning. We synthesized results of a symposium on freshwater, riparian, and wetland processes and interactions and analyzed some of the major problems associated with improving freshwater and riparian research and management. Three distinct barriers are the lack of involvement of local people in conservation research and management, absence of adequate measurement of biodiversity in freshwater and riparian ecosystems, and separate legislation and policy on riparian and freshwater management. Based on our findings, we argue that freshwater and riparian research and conservation efforts should be integrated more explicitly. Best practices for overcoming the 3 major barriers to improved conservation include more and sustainable use of traditional and other forms of local ecological knowledge, choosing appropriate metrics for ecological research and monitoring of restoration efforts, and mirroring the close links between riparian and freshwater ecosystems in legislation and policy. Integrating these 3 angles in conservation science and practice will provide substantial benefits in addressing the freshwater biodiversity crisis. [ABSTRACT FROM AUTHOR]

In this brief, non-exhaustive essay, we review major adaptive changes in reproductive and developmental traits of decapod crustaceans, which have passed through evolutionary transitions from ancestral life in coastal marine environments to brackish, limnic, polar, or deep-sea habitats. Two major approaches can be recognised in studies of life-history evolution, focussing on: (1) developmental changes in adaptive physiological or biochemical traits of successive ontogenetic stages, comparing, for instance, osmoregulatory capabilities in larvae, juveniles, and adults ("ontogeny of adaptations" perspective); (2) adaptive changes in the modes of reproduction and development, e.g., enhanced maternal energy investment in egg production, abbreviated, non-feeding larval development ("adaptations in ontogeny"). Using both scientific approaches, Christoph D. Schubart has significantly contributed to our understanding of evolutionary transitions in crustaceans. In our essay, we pay particular attention to the significance of nutritional selection factors in relation to presumably adaptive developmental, physiological, and biochemical traits in different life-history stages. In this context, we highlight the key roles of lipids and carotenoid pigments, in particular of essential polyunsaturated fatty acids (PUFAs) and astaxanthin. While PUFAs and other lipid compounds have received wide scientific attention, we propose that future studies should further analyse also the potential role of astaxanthin and other essential carotenoids. [ABSTRACT FROM AUTHOR]

Despite their ecological importance, research on symbionts of amphipods has been limited in South America. The present study provides a comprehensive overview of symbiont organisms in the freshwater amphipods of the genus Hyalella in South America. Our findings reveal various taxa such as Apicomplexa, Microspora, Peritrichia, Folliculinidae, trematodes, nematodes, cestodes and acanthocephalans, often involving complex life cycles. Studies on symbionts have been done almost exclusively in Argentinean Patagonia. The present overview allows us to know the species that use amphipods, to elucidate their lifecycles and to know their occurrence values. [ABSTRACT FROM AUTHOR]

Este trabajo presenta el estado del conocimiento de los coleópteros acuáticos de Colombia, con énfasis en los listados de especies de 17 familias registradas en el territorio colombiano, los cuales han sido provistos por el Grupo Coleoptera de Colombia y publicados por el SiB-Colombia. Se aporta información actualizada de riqueza, diagnosis, hábitat y distribución geográfica de todas las familias de coleópteros acuáticos presentes en Colombia. Se registraron 241 especies en 112 géneros, los cuales son considerados como coleópteros acuáticos verdaderos, falsos o riparios según su asociación con los cuerpos de agua.

Último estadio larvario de Neocordulia volxemi (Selys, 1874) (Odonata, Libelluloidea) del sureste del Brasil. Neocordulia es un género neotropical que comprende 16 especies distribuidas en América del Sur y América Central. Hasta la fecha, solo se han descrito siete larvas de este género. En este artículo describimos el último estadio larvario de Neocordulia volxemi (Selys, 1874), recogida en la zona de protección ambiental de la cuenca del río Uberaba en el estado de Minas Gerais, en el Brasil. Se encontraron adultos de color verde metálico volando en una zona forestal de una unidad de conservación, mientras que la larva se encontró en una cascada rodeada de paredes rocosas. La zona, que es un vestigio de Cerrado, se encuentra actualmente amenazada por pastos degradados y el aumento de los monocultivos.

The postmortem diagnosis of death by drowning is one of the most difficult issues in forensic pathology. We investigated possible evidence differentiating saltwater drowning from freshwater drowning by histopathological changes in brain, heart, lungs, liver, and kidneys tissues. A cross section descriptive study was carried out on eighteen 12-week-old male Wistar rats; they were divided equally into 3 groups. Group 1: control group; Group 2: death by drowning in freshwater; Group 3: death by drowning in saltwater. Immediately after death, all tested organs were removed and fixed for histopathological examination. The brain of freshwater group depicted degenerated neurocytes with dystrophic changes in the form of shrunken cell, pyknotic nuclei and deeply eosinophilic cytoplasm. The heart showed clear evidence of myocyte injuries in saltwater drowning compared to the control and freshwater groups. The kidneys of rats drown in saltwater revealed more glomerular destruction with no differences in tubulo-interstitial changes in comparison with those drown in freshwater. In the lungs, the changes in freshwater were restricted to the alveoli, and the bronchial changes were more distinctive in saltwater. No disturbed liver architecture was seen in both test groups, however hydropic degeneration, congested vessels, and sinusoids were more distinct in saltwater group. In conclusion, diagnostic differentiation between fresh and saltwater drowning was reliable in rats' lungs and heart with minimal differentiation in liver, kidneys, and brain. Further studies of drowning with different staining techniques will help to clarify the potential role of histopathological changes in body organs as indicator of drowning. [ABSTRACT FROM AUTHOR]

A central tenet of landscape ecology is that mobile species depend on complementary habitats, which are insufficient in isolation, but combine to support animals through the full annual cycle. However, incorporating the dynamic needs of mobile species into conservation strategies remains a challenge, particularly in the context of climate adaptation planning. For cold‐water fishes, it is widely assumed that maximum temperatures are limiting and that summer data alone can predict refugia and population persistence. We tested these assumptions in populations of redband rainbow trout (Oncorhynchus mykiss newberrii) in an arid basin, where the dominance of hot, hyperproductive water in summer emulates threats of climate change predicted for cold‐water fish in other basins. We used telemetry to reveal seasonal patterns of movement and habitat use. Then, we compared contributions of hot and cool water to growth with empirical indicators of diet and condition (gut contents, weight–length ratios, electric phase angle, and stable isotope signatures) and a bioenergetics model. During summer, trout occurred only in cool tributaries or springs (<20 °C) and avoided Upper Klamath Lake (>25 °C). During spring and fall, ≥65% of trout migrated to the lake (5–50 km) to forage. Spring and fall growth (mean [SD] 0.58% per day [0.80%] and 0.34 per day [0.55%], respectively) compensated for a net loss of energy in cool summer refuges (–0.56% per day [0.55%]). In winter, ≥90% of trout returned to tributaries (25–150 km) to spawn. Thus, although perennially cool tributaries supported thermal refuge and spawning, foraging opportunities in the seasonally hot lake ultimately fueled these behaviors. Current approaches to climate adaptation would prioritize the tributaries for conservation but would devalue critical foraging habitat because the lake is unsuitable and unoccupied during summer. Our results empirically demonstrate that warm water can fuel cold‐water fisheries and challenge the common practice of identifying refugia based only on summer conditions. Article impact statement: Warm downstream habitats may be critical for cold‐water fisheries but are overlooked by climate adaptation planning. [ABSTRACT FROM AUTHOR]

Benthopelagic species had a mean (SD) of 35 particles/fish (22) (median = 27 particles) compared with a mean of 62 particles/fish (110) for demersal species (median = 25 particles). Particle characteristics Fish in the Great Lakes we examined contained a broad range of particle morphologies; diversity was greatest in fish from Lake Ontario. Keywords: anthropogenic particle; freshwater; Great Lake; ingestion; microplastics; plastics; agua dulce; Grandes Lagos; ingesta; microplásticos; partícula antropogénica; plásticos EN anthropogenic particle freshwater Great Lake ingestion microplastics plastics agua dulce Grandes Lagos ingesta microplásticos partícula antropogénica plásticos 1 11 11 03/02/22 20220201 NES 220201 INTRODUCTION Microplastics (MPs) have been observed in all ecosystems (Koelmans et al., 2019; Law, 2017; Wang et al., 2019), and contamination in fish, an indicator of ecosystem functioning (Foley et al., 2018; Wang et al., 2020; Wright et al., 2013), is widespread. The highest mean was 59 particles/fish (SD 104) (median = 26) in Lake Ontario, and the maximum abundance of anthropogenic particles in bony fish globally is 915 particles/fish. [Extracted from the article]

Introduction: One of the significant threats to aquatic ecosystems is introducing non-native species in natural environments. This represents one of the principal causes of biodiversity loss in the world. Pangasianodon hypophthalmus is an introduced species in Colombia that shares life characteristics and habitat with endangered native species, such as Ageneiosus pardalis, Sorubim cuspicaudus, and Pseudoplatystoma magdaleniatum. However, its distribution is little-known, and scientists have barely explored the effects on the native fauna. Objectives: To evaluate the P. hypophthalmus invasive potential in some of the Colombian basins, which drain into the Caribbean Sea. Methods: Using records available in various databases, we performed a niche conservatism analysis between the native and introduced records of P. hypophthalmus using the R package Ecospat. Subsequently, we modeled the potential invasion area of P. hypophthalmus and the distribution areas of three native species, performing ecological niche modeling (ENM) using the Maxent algorithm. Finally, we calculated a geographic niche overlap between the non-native and native species. Results: The Ecospat spatial analysis indicated that P. hypophthalmus retains some environmental niche attributes through space. For this reason, we can use ENM as an approximation to its range of distribution in the invaded area. Our results using ENM demonstrated that the four species analyzed prefer low and slightly rocky regions; therefore, the geographical overlap of the three native species’ ecological niches and the introduced species exceed 80 %. Conclusions: There are adequate conditions in the study basins to fully establish the species P. hypophthalmus, representing a high risk for aquatic ecosystems and native ichthyofauna. Knowledge of the potential distribution areas is essential to implement control of the species. [ABSTRACT FROM AUTHOR]

El presente estudio reporta la diversidad ictiológica de la quebrada Mayapo en base a material depositado en la Colección Ictiológica del Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos (MUSM), en los años 2005, 2009 y 2010, proveniente de 30 puntos de muestreo de la quebrada Mayapo y afluentes ubicados entre los 256 y 557 m de altitud. Se identificaron 60 especies agrupadas en 39 géneros, 16 familias y cuatro órdenes, siendo los órdenes Characiformes y Siluriformes y las familias Characidae y Loricariidae los grupos más representativos. La diversidad de especies fue moderada, en comparación a otras evaluaciones en la Amazonia peruana. La composición taxonómica siguió el patrón predominante en aguas continentales de la Región Neotropical y en la Amazonia peruana. Se registraron especies de importancia pesquera, hábitos migratorios y distribución restringida.

Introduction: Crustaceans have economic and ecological importance and the role of caridean crustaceans in lentic environments is crucial to maintain the trophic structure. The species Atya scabra is occasionally associated with fisheries, especially in Northeast and Northern Brazil. Objective: To determine the population structure, reproductive period, patterns of growth and distribution of size classes among sexes in a population of the prawn A. scabra in the De Contas River, Bahia, Brazil. Methods: Individuals were sampled in a period of one year by passing sieves through marginal vegetation and using dragnets. In the laboratory, we recorded the sex of the individuals and measured them using a pachymeter with 0.001 mm precision. The dimensions measured were CL (carapace length), TL (total length) and CW (carapace width). In order to analyze data, linear models for the relationships CL x CW were constructed and the type of allometry for each sex was determined. Individuals were grouped into size classes of 5 mm intervals. A chi-square test (χ²) was used to test deviation from the 1:1 sex ratio. The proportion of ovigerous females was registered for each month to determine the breeding period. Results: A total of 517 individuals were collected, 328 were males and 186 females of which 169 were ovigerous. Males showed a polymodal distribution in size classes and were significantly larger than females, which presented a unimodal distribution in size classes. The observed growth patterns demonstrated that both sexes present negative allometry. However, sexual dimorphism was detected when comparing the growth parameters. Ovigerous females were sampled the entire year and size-frequency data demonstrated that recruitment also occurs throughout the year, which allowed us to classify their reproduction as continuous. Conclusions: Our data is essential to draw sustainable fishery management strategies. We suggest a minimum capture size of 70 mm and capture restrictions from May to August. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Científico Centro de Museos de Historia Natural is the property of Universidad de Caldas 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.)

Protected areas are an important part of broader landscapes that are often used to preserve biodiversity or natural features. Some argue that protected areas may also help ensure provision of ecosystem services. However, the effect of protection on ecosystem services and whether protection affects the provision of ecosystem services is known only for a few services in a few types of landscapes. We sought to fill this gap by investigating the effect of watershed protection status and land use and land cover on biodiversity and the provision of ecosystem services. We compared the ecosystem services provided in and around streams in 4 watershed types: International Union for Conservation of Nature category II protected forests, unprotected forests, unprotected forests with recent timber harvesting, and unprotected areas with agriculture. We surveyed 28 streams distributed across these watershed types in Quebec, Canada, to quantify provisioning of clean water, carbon storage, recreation, wild foods, habitat quality, and terrestrial and aquatic biodiversity richness and abundance. The quantity and quality of ecosystem services and biodiversity were generally higher in sites with intact forest—whether protected or not—relative to those embedded in production landscapes with forestry or agriculture. Clean‐water provision, carbon storage, habitat quality, and tree diversity were significantly higher in and around streams surrounded by forest. Recreation, wild foods, and aquatic biodiversity did not vary among watershed types. Although some services can be provided by both protected and unprotected areas, protection status may help secure the continued supply of services sensitive to changes in land use or land cover. Our findings provide needed information about the ecosystem service and biodiversity trade‐offs and synergies that result from developing a watershed or from protecting it. Article impact statement: Streams surrounded by forest—protected or not—support more ecosystem services and biodiversity than streams in production landscapes. [ABSTRACT FROM AUTHOR]

Water pollution is a consequence of the industrialization and the society's development due to the constant pouring of domestic and industrial wastewater without a previous treatment; these facts contribute to the environment deterioration and the diversity lost. Three sampling stations of Almendares River (Havana, Cuba) with different pollution levels were studied for one year, to characterize the structure of rapid growth culturable heterotrophic bacterial community. For isolation, serial dilutions of water samples were grown in nutrient agar and incubated at 30°C for 72h. Representative different morphology colonies were isolated and purified on the same culture medium. A total of 60 isolates were obtained and were identified by API system as belonging to the genera Acinetobacter, Arthrobacter, Bacillus, Micrococcus, Staphylococcus, Alcaligenes, Citrobacter and Pseudomonas, prevailing the phyla Firmicutes, Actinobacteria and Proteobacteria. The genus Arthrobacter was isolated more frequently in the sampling station Paila, compared with the rest of the Almendares River stations, while the genera Acinetobacter and Bacillus were isolated more frequently in Río Cristal and Puente de Hierro stations. To characterize the bacterial community structure were used indexes of species richness (S*), Simpson (L') and Shannon-Wiener (H'). The indexes of Simpson and Shannon-Wiener showed significant differences among the bacterial diversity of the three sampling stations. No significant differences were detected by analyzing the species richness. The results showed the influence of pollution on bacterial diversity, which is significantly affected from upstream to downstream in Almendares River. [ABSTRACT FROM AUTHOR]

Objective: to describe clinical and epidemiological aspects of freshwater stingray injuries in the city of Belém, Pará, brazilian amazon. Method: descriptive, epidemiological and observational study, carried out between 1999 and 2008, using medical records from hospitals in the districts of Mosqueiro, Outeiro and Cotijuba, in Belém. Results: the majority of injuries occurred in males (67.9%) being 84.8% during leisure, mainly in the dry season (July to December) (88.6%), during the day (92.9%) affecting the feet (88.4%) primarily. Participants received medical assistance in the first hour after the accident (84.4%), with local pain (99.2%) being the main complaint. 11.3% of patients had systemic manifestations. Among the complications during evolution, local infection and infection with necrosis were the most frequent (1.7%). Wound debridement was performed in 89.2% of patients. Conclusion: stingray injuries represent an important health problem for the population of the Brazilian Amazon. Understanding its epidemiological and clinical characteristics may improve patient care in the region. [ABSTRACT FROM AUTHOR]

Thorichthys panchovillai, new species, is described, from distinctive of the tributaries of the River Coatzacoalcos basin, Mexico. The new species is diagnosed by a set of characters: dorsal fin rays XVI, 8 – 9; anal fin rays VII, 6 – 7; pectoral fin rays, I, 11 – 12; total gill-rakers on the first branchial cleft 11 – 12; subopercular stain present although weakly intensified, it exposes a notable sexual dimorphism that distinguishes it from others: the female possess a black blotch between the fifth and sixth dorsal spine.

Pacific and Atlantic-slope rivers of the Isthmus of Tehuantepec in Mexico contain two cichlid species of the genus Vieja relevant to the current study, V. zonata and V. coatlicue, respectively. The Atlantic-slope species was initially considered a population of uncertain taxonomic status and recently described as a distinct species based on three putatively diagnostic morphological characters. The objective of this study was to combine new and existing genetic data, along with reanalysis of morphological characters, to test the distinctiveness of V. coatlicue. Little genetic variability and no geographic structuring were recovered. Additionally, putatively diagnostic morphological character states were present across both species, failing to separate the forms. The synthesis of molecular and morphological data supports the recognition of V. coatlicue as a junior synonym of V. zonata. [ABSTRACT FROM AUTHOR]

Pomacea flagellata es un caracol conspicuo de zonas tropicales y subtropicales de América, que se ha consumido desde tiempos prehispánicos y actualmente es considerado sobreexplotado. Se realizó un experimento de cultivo de cuatro meses para determinar: la selección del substrato por la hembra, el tamaño de las huevas, el nivel del agua elegido para colocar la masa de huevos, el número de crías, y el tiempo de eclosión. Se utilizaron tres tinas de plástico que se llenaron con 100 L de agua, por duplicado y se colocaron tres sustratos: raíces de mangle, carrizo y tubo de PVC. Se registraron 57 huevas, 26 de ellas eclosionaron produciendo 5037 crías. Hubo más huevas en la “pared” de las tinas, donde se registraron 35 huevas, en raíces de mangle (18), en PVC 3 y en carrizo una hueva. Hubo diferencias significativas en la selección del sustrato, mientras que no se observaron diferencias significativas entre el número de huevas y las proporciones de sexos. La longitud promedio de la masa fue 32.99 ± 10.92, el ancho 16.44 ± 5.1 y grosor 8.08 ± 3.87 mm. La altura promedio de la puesta fue 15.66 ± 3.42 cm, con un tiempo medio de eclosión, de 13.30 ± 2.6 días, obteniéndose entre 94 a 301 crías por desove. Los caracoles utilizaron preferentemente las paredes de las tinas y es difícil determinar si no seleccionan sustrato para la puesta. El nivel del agua empleado es óptimo y permite que los organismos puedan colocar las masas de huevo, la producción de crías es adecuada y suficiente para iniciar programas de cultivo de producción de carne o de repoblación del medio natural.

Objective: To identify microalgae morphologically from Bosque Azul Lake from Montebello Lakes National Park, Chiapas. Design/methodology/approach: The samples were collected in April 2018 using a conical network by horizontal dragging for five minutes at 30 cm below the water surface. The samples were inoculated in test tubes in Guillard F/2 and BBM culture media to observe the presence of microalgae in optical microscope (10X and 40X). For the isolation, striation technique and serial dilutions in relation to 1:10 was applied, white LED lamps of 18 watts were used as a source of illumination, a photoperiod of 12:12 and a temperature of 25°C±2. For the morphological identification, semipermanent preparations were made for observation in two types of microscope: one of phase contrast and another of differential interference (20X, 40X and 100X). The morphologiccal characteristics were compared with specialized bibliography according to their microalgal group. Results: It was possible to isolate and morphologically identify two microorganisms from the Bosque Azul lake, belonging to the Lagunas de Montebello National Park, a Pectinodesmus pectinatus microalgae and a cyanobacterium Limnothrix planctonica. Limitations of the study/implications: It is necessary to investigate the implications of these microalgae groups in the trophic state of the Bosque Azul lake, as well as the possible toxicity that Limnothrix planctónica may cause in the lake fish's. Findings/conclusions: There are reports of lipid accumulation in Pectinodesmus pectinatus that could be used for the production of biofuels such as biodiesel. In the other hand, Limnothrix planktonic has been reported as a producer of metabolites with biotechnological potential in the production of lipids, pigments, carbohydrates and exopolysaccharides. Both microorganisms are the first reports in Chiapas and in the case of Limnothrix planctónica, the first report in Mexico. [ABSTRACT FROM AUTHOR]

A species' reproductive tactics and life history strategy are the result of a complex evolutionary interplay where individuals constantly adjust their energy investment in accordance with the environmental conditions. Fecundity is a key feature of life that reflects the amount of energy that an individual invests in reproduction. Little is known about the response of this life history feature of species that persist in reservoirs, and for this reason, fecundity and some variables related to it were analyzed for some of the most abundant species within the fish assemblage in the area of influence of the cascading reservoirs Porce II and Porce III. Sampling was carried out from September 2011 to December 2016, during contrasting climatic periods (dry and rainy seasons), in 31 sites distributed throughout Porce II and Porce III reservoirs, and also including the river channel and tributary streams of the reservoirs. It was found that Astyanax microlepis had the highest value of total fecundity (20.202 eggs on average), while Poecilia reticulate had the lowest values (15 embryos). A relation was found between the number of eggs and the size of the fish (standard length and body weight). The fecundity of the species analyzed was similar among those phylogenetically related (species of the same family), and in turn, it was determined that this reproductive trait was specific to each species. [ABSTRACT FROM AUTHOR]

En los últimos años los humedales costeros de Jalisco han sufrido transformaciones en las confluencias y en las cuencas a las que están asociados. El esquema de la gestión costera sugiere incluir la zona de estudio y las áreas adyacentes en un mismo sistema. Por lo tanto, este trabajo plantea analizar los procesos de cambio de cobertura y uso del suelo en dos cuencas costeras, Arroyo Seco (CAS) y María García (CMG). Se consideraron dos periodos, 1971-1996 y 1996-2014. En total, en la CAS los bosques tropicales perdieron 4 000 ha y en la CMG 7 100 ha. Por otro lado, los usos agropecuarios aumentaron el 55% y el 175%, respectivamente. Hay dos factores detonantes de cambio: en la CMG la construcción del distrito de riego 093 generó importantes pérdidas de bosques tropicales; en la CAS el desarrollo turístico modificó las estructuras del paisaje en las confluencias de la laguna Barra de Navidad. Los principales procesos observados fueron la deforestación y la transición forestal, recuperándose solo el 30% de las superficies de bosques tropicales.Mediante la aplicación de un modelo lineal generalizado se encontró que la deforestación, a diferencia de la transición forestal, está influenciada por valores más bajos de pendientes, altitud, distancia a localidades y a vías de comunicación, pero el modelo que mejor explica este proceso incluye las variables altitud, cuenca y periodo, debido a las características intrínsecas de cada periodo y cada cuenca.

En el presente trabajo se describen 13 especies de algas de agua dulce, colectadas en las Cascadas de Barranco, Departamento de Lima. Las especies estudiadas constituyen nuevos registros para la zona y 8 de ellas lo son para la flora peruana.

El agua es un elemento esencial para la vida de todos los seres vivientes del planeta, además es un derecho humano fundamental (1). El 97.2% del agua en el planeta Tierra es salina y solo el 2.5% corresponde a agua fresca; de ese 2.5%, 30% es subterránea, 68% está en los glaciares y otras capas de nieve y solo el 1.2% es superficial y se encuentra en ríos, lagos y otras formas de agua de superficie (2). El agua potable está amenazada por la continua contaminación que genera la actividad humana y por la disminución de los recursos hídricos como consecuencia del calentamiento global (3). Según la Organización Mundial de la Salud, desde el año 2015 solo el 89% de la población mundial tiene acceso a agua apta para consumo y se anticipa que este porcentaje continuará disminuyendo (4), aunque se estima que la situación ya es crítica para 260 millones de personas que carecen de agua apta para el consumo (5).

ABSTRACT Since temperature is a key condition in the initiation of cercarial emergence, the objective of the work reported here was to evaluate the effect of that variable on the shedding of two morphologic and taxonomic types of cercariae. Bioassays were accordingly performed with snails naturally infected with either monostome or pleurolophocercous cercariae because those two cercarial types were found to be the most prevalent in the environment under study. The snails were placed in 6-ml circular plastic dishes with soft plastic stoppers containing 3 ml of reconstituted water and then sequentially exposed for 24 h to a 14:10-h light:dark cycle at 20, 25, or 30 °C. The data were analyzed at a significance level of p

Variation in shape among a living and 2 extinct aquatic snails of the genus Aylacostoma, using a geometric morphometric method of thin plate splines and multivariate analysis was investigated. The analysis was performed to evaluate the diagnostic capability of this method and to explore shell shape differences, due to the lack of other data, in an attempt to answer why only 1 of the species persisted in the wild. Sixteen landmarks in a bi-dimensional space for 32 shells of type, paratype and reference specimens deposited in museums of Argentina were defined. Analysis was successful in assigning individual specimens to particular species. Statistically significant differences in last whorl, aperture, and spire were found for the first 4 non-uniform components explaining an 85% of local variation observed. Differences could be related to a differential use of habitat and/or to the degree of exposure to water current. More globose shell found in the extinct species could be associated to habitats and substrata with the highest water currents, whereas the more stylized shell in the third species could be related to a preference for more protected habitats, like those where it presently occurs.La variación de forma entre una especie viviente y dos extintas de caracoles acuáticos del género Aylacostoma, fue investigada mediante el método de morfometría geométrica de "thin plate splines" y análisis multivariado. El análisis se realizó para evaluar la capacidad diagnóstica del método y explorar las diferencias de forma de conchilla, debido a la falta de otros datos, en un intento por responder por qué sólo una de las especies persistió en la naturaleza. Dieciséis "landmarks" fueron definidos en un espacio bi-dimensional para 32 conchillas de ejemplares tipo, paratipo y de referencia depositados en museos de Argentina. El análisis fue exitoso en la asignación de los individuos a especies particulares. Se encontraron diferencias significativas en el último anfracto, apertura y espira respecto de los 4 primeros componentes no uniformes, que explicaron el 85% de la variación observada. Estas diferencias podrían vincularse a un uso diferencial del hábitat y/o al grado de exposición a la corriente. La conchilla más globosa en las especies extintas pudo estar asociada a hábitats y sustratos con mayores corrientes, mientras que la conchilla más estilizada en la tercera especie podría estar relacionada con la preferencia por hábitats más protegidos, como los que actualmente habita.

Benthic macroinvertebrate fauna plays a major role in river ecosystems, especially those of tropical islands. Since there is no information on the distribution of benthic invertebrates along a Jamaican river, we report here on the composition of the benthic fauna of the Buff Bay river, on the Northern coast of Jamaica. A total of 14 samples were collected from five sites, using kick nets and a Surber sampler, between May 1997 and October 1998. We also examined the applicability of the rhithron/potamon model, and some of the premises of the River Continuum Concept (RCC) in relation to the distribution of invertebrate taxa. The results showed a total of 38 taxa of identified invertebrates. A group of dominant taxa, composed mainly of immature stages of insects, occurred at all sites. Two notable characteristics of the river were the absence of a true potamonic fauna and the low representation of the shredder functional feeding group in the community We conclude that, while there was minor variation in the composition of the benthic macroinvertebrate fauna among the sites, this was a response to local conditions within the river system. The characteristics of the community did not conform to either of the models.

La fauna de peces de agua dulce del norte de África es escasa comparada con otras regiones del mundo debido fundamentalmente a factores históricos y climáticos. El oeste del norte de África es más diverso que las regiones del centro y del este. En la cuenca del río Sebou habitan actualmente poblaciones de blenios de agua dulce que han sido tradicionalmente adscritas a la especie Salaria fluviatilis. En este estudio demostramos morfológica y molecularmente que estas poblaciones marroquíes constituyen una nueva especie, para la cual proveemos una descripción formal. Los siguientes caracteres diagnósticos distinguen a la nueva especie descrita del resto de especies de blenios de agua dulce: cabeza sin una fila diagonal de puntos oscuros o manchas en las mejillas; tentáculo supraocular grueso y simple (no ramificado); 13-15 dientes en la mandíbula superior y 14-16 en la inferior; 16-17 radios blandos en la aleta anal; distancia preorbital corta (índice cefálico: 2.9-3.8); altura de la region anterior de la aleta dorsal corta (índice dorsal: 0.8-1.3) y 34 vértebras. Las distancias genéticas mitocondriales y nuclear entre la nueva especie de Salaria y las otras dos especies son altas, especialmente en la región control (18%), mientras que estas distancias genéticas variaron entre 2-3% para el gen nuclear S7. Estos caracteres morfológicos y moleculares diferencian a la nueva especie del resto de blenios de agua dulce del género (Salaria fluviatilis y S. economidisi). La nueva especie está confinada a la cuenca del río Sebou en Marruecos y debería ser considerada como En Peligro (EN) de acuerdo a las categorías de la lista roja.

Los humedales boscosos de agua dulce son áreas naturalmente inundadas o saturadas, que sustentan vegetación boscosa hidrófila, están presentes en todo el mundo, y en Chile son conocidos como "pitrantos, hualves o hualhues". El presente estudio entrega el estado del conocimiento de estos humedales en Chile, mediante una descripción de sus características biológicas, fisicoquímicas e hidrodinámicas, identificando las principales amenazas para su conservación y las principales necesidades de investigación. Estos ambientes pueden presentar inundación permanente o temporal, dependiendo de un conjunto de procesos microclimáticos, biológicos y edafológicos. Su vegetación, del tipo hidrófila boscosa, es dominada por especies de la familia Myrtaceae. Tanto el comportamiento hídrico como la estructura vegetacional destacan dentro de los aspectos que determinan directamente las características fisicoquímicas del agua y los patrones de distribución de las comunidades biológicas. Los humedales boscosos de Chile han sido ampliamente estudiados desde un punto de vista vegetacional y florístico, pero carecen de estudios limnológicos, hidrológicos o faunísticos básicos, de lo cual deriva un total desconocimiento en relación a su funcionamiento a nivel ecosistémico y los efectos que pueden tener las actividades humanas en sus cuencas (e.g., agrícola, ganadera, forestal) sobre sus componentes hídricos y biológicos. A pesar de ser ecosistemas de gran relevancia cultural y ecológica, se identifican importantes falencias en cuanto a su estado de conservación, al no encontrarse protegidos por las actuales herramientas de conservación existentes en el país. Por lo tanto, emergen como ecosistemas únicos, de relevancia mundial, prácticamente desconocidos en Chile y de gran interés para el desarrollo de numerosas líneas de investigación, aunque su alta susceptibilidad ante perturbaciones de origen antrópico amenaza su permanencia en el tiempo.Forested freshwater wetlands are naturally flooded or saturated areas with hydrophilic forest vegetation which is worldwide distributed and is known as "pitrantos, hualves o hualhues" in Chile. This paper gives to know the state of art of these wetlands in Chile, through a description of its biological, physical-chemical and hydro-dynamic characteristics, identifying the main threats to its conservation and the main research needs. These environments can be permanently or temporarily flooded, depending on microclimatic, biological and edaphical processes. Its vegetation is dominated by species of the family Myrtaceae. Both hydric behavior and vegetation structure are major aspects that directly determine the water physical-chemical characteristics and the distribution patterns of biological communities. Chile's forested wetlands have been studied broadly from a vegetation and floristic point of view, but basic studies on limnology, hydrology or fauna are lacking, which results on a total lack of knowledge about its functioning at the ecosystem level and the effects that human activities on basins (e.g., agricultural, stockbreeding, forest) could have on its hydric and biological components. In spite of being ecosystems of great cultural and ecological significance, important weakness can be identified on its state of conservation, as they are not protected by conservation tools that exist in Chile nowadays. Therefore, forested wetlands emerge as unique ecosystems of global importance, nearly unknown in Chile and of great interest on developing an important number of research lines, even though their high susceptibility facing anthropic disturbances threaten their continuance.

La movilidad espacial entre fragmentos de hábitats puede presentar cambios significativos para los organismos asociados al sistema bentónico. Los insectos de agua dulce logran la dispersión usando una serie de mecanismos que presentan variación con respecto a las características propias del individuo o del ambiente; estos pueden categorizarse como activos o pasivos y tienen importantes consecuencias en los procesos de colonización, flujo genético y divergencia evolutiva. En esta revisión, se pretende explorar los estudios de dispersión de insectos bentónicos basados en estudios empíricos, acercamientos teóricos y ejemplos de dispersión tanto en zonas tropicales como templadas. Se discute como la dispersión puede ocurrir en insectos acuáticos, sus consecuencias y adaptaciones, al igual que las ventajas y desventajas de los métodos convencionales con respecto a técnicas moleculares recientes. Así mismo, se muestran algunos aspectos sobre cómo las actividades humanas pueden impedir o disminuir la dispersión entre diferentes sistemas lóticos mediante la fragmentación del hábitat. En general, se plantean nuevas preguntas acerca de los mecanismos y patrones de dispersión en invertebrados de agua dulce y como estos pueden ser extrapolables a otros taxones, puesto que las presiones selectivas dentro de los sistemas acuáticos como hábitats discretos, son similares.

A new freshwater leech species Helobdella fantasmae n. sp. is described. This description is based on the examination of 12 specimens collected in Laguna Fantasma, Bariloche (41° 05'S 71° 28'W), during December 2002. Leeches were found attached to submerged plants. They were relaxed with gradual addition of 70% ethanol, fixed in 10% formalin, stored in 70% ethanol and stained with borax carmine. Examination of external morphology, dissections and microphotographs were accomplished with a Leica Wild M3Z stereo microscope aided with an Olympus C-4000 digital camera. H. fantasmae n. sp. differs from other species of the genus by the presence of 1 pair of eyes on somite III, crop without gastric chambers, digitiform caeca and postcaeca., short sperm ducts reaching the back of somite XV, atrium pyriform, short ovisacs reaching somite XIII. This is the first record of leeches from an ephemeral wetland in North Patagonia. This finding expands current knowledge of the biodiversity of Hirudinea in South America, increasing the number of known Helobdella spp. from the Río Negro province (North Patagonia) to 10 species.Se describe una especie de sanguijuela dulceacuícola Helobdella fantasmae n. sp. Esta descripción se basa en el examen de 12 ejemplares recolectados en la Laguna Fantasma, Bariloche (41° 05'S 71° 28'O) durante diciembre de 2002. Los individuos se hallaron asociados a la vegetación sumergida. Fueron relajados con la adición gradual de etanol 70%, fijados en formalina al 10%, preservados en etanol 70% y teñidos con carmín borácico. El examen de la morfología externa, disecciones y microfotografías fueron realizados con la ayuda de un estereomicroscopio Leica Wild M3Z con cámara digital Olympus C-4000. H. fantasmae n. sp. difiere de otras especies del género por los siguientes caracteres: un par de ojos en el somito III, estómago recto sin cámaras, ciegos laterales ni postciegos, espermiductos cortos que descienden hasta el somito XV, atrio piriforme, ovisacos cortos que se extienden hasta el somito XIII. Este es el primer registro de hirudíneos en un humedal efímero del norte patagónico. El hallazgo incrementa el conocimiento actual de la diversidad biológica de hirudíneos sudamericana alcanzando las 10 especies de Helobdella spp. descritas hasta el momento para la provincia de Río Negro (Norte de la Patagonia).

En esta contribución se presenta una recopilación de las especies ibéricas de nematodos de suelo y de agua dulce, la primera de este tipo realizada hasta el momento. El inventario actual lo componen 981 especies de 236 géneros, 77 familias y 12 órdenes. Los datos correspondiente a la fauna ibérica de nematodos se compara con la de otros táxones de la biota ibérica. Se analizan y se discuten distintos aspectos cuantitativos y cualitativos de la fauna nematológica, con especial énfasis en el tipo de información disponible sobre cada especie, y se concluye que casi una tercera parte de las especies ibéricas permanecen insuficientemente caracterizadas, razón por la cual requieren de estudios adicionales. La endemicidad de las especies es así mismo objeto de atención: 143 especies, un 14.6% del total están restringidas en su distribución al ámbito ibérico, en su mayor parte pertenecientes a los órdenes Dorylaimida (87) y Tylenchida (29), por otra parte los más diversificados de entre los pertenecientes al filo. El interés básico y aplicado del conocimiento de la fauna de nematodos es comentado e ilustrado con aportaciones recientes y ejemplos. Por último, se presenta una lista de todas las especies de la fauna ibérica, ordenadas alfabéticamente por su epíteto específico.

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.)

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.)

The liver is an organ notable for its sensitivity to a great variety of environmental factors. It is composed of a parenchyma divided into irregular lobules by the exocrine pancreas or hepatopancreas; the pancreatic cells are arranged around a branch of the portal vein. The hepatocytes are radially arranged in cords around a central sinusoid. The liver histomorphology and the organization of exocrine pancreatic tissue of O. jenynsii (Günther, 1864) is similar to the acinar morphology of many teleosts, including freshwater and marine species. The aim of the present work was to carry out the histological analysis of the liver of Oligosarcus jenynsii, one of the most common species inhabiting Los Padres Lake (Buenos Aires Province, Argentina).El dientudo Oligosarcus jenynsii (Günther, 1864) es una de las especies más comunes que habita en la Laguna de Los Padres. Se ha realizado el análisis histológico del hígado del dientudo, un órgano destacable por su sensibilidad a una variedad de factores del medio ambiente. El hígado está compuesto por un parénquima con hepatocitos dispuestos en cordones alrededor de un sinusoide central. El parénquima se halla dividido en lóbulos irregulares por el páncreas exócrino o hepatopáncreas, que posee una disposición acinar y cuyas células se organizan alrededor de una rama de la vena porta. La histomorfología del hígado y la organización del tejido pancreático exócrino de Oligosarcus jenynsii es similar a la de muchos peces teleósteos, tanto marinos como de agua dulce.

Copyright of Iheringia. Série Zoologia is the property of Fundacao Zoobotanica do Rio Grande do Sul 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 Chilean fauna of amphipods has been poorly studied. Freshwater amphipods in Chile have a single genus in epigean environments. Seven species of the genus Hyalella are reported for Chile: H. simplex; H. fossamancinii, H. kochi; H. chiloensis; H. costera; H. araucana, and H. franciscae. A short diagnosis, a key and figures are given for each speciesLa fauna de anfípodos chilenos ha sido pobremente estudiada. En el caso de los de agua dulce y de ambientes epigeos, el grupo está representado solo por un género. Se reportan siete especies del género Hyalella para Chile: H. simplex; H. fossamancinii, H. kochi; H. chiloensis; H. costera; H. araucana, y H. franciscae. Se entrega una breve diagnosis, una clave y figuras para cada especie

Parmotrema rubifaciens is recorded in this paper for the first time for Paraguay, expanding its known geographic distribution approximately 430 km southeast from its nearest locality. The species is characterized, illustrated, and compared with most related taxa. In addition, a map of its geographic distribution in the Neotropics is presented. [ABSTRACT FROM AUTHOR]

Sponges are important for maintaining ecosystem function and integrity of marine and freshwater benthic communities worldwide. Despite this, there has been no assessment of their current global conservation status. We assessed their status, accounting for the distribution of research effort; patterns of temporal variation in sponge populations and assemblages; the number of sponges on threatened species lists; and the impact of environmental pressures. Sponge research effort has been variable; marine sponges in the northeastern Atlantic and Mediterranean and freshwater sponges in Europe and North America have received the most attention. Although sponge abundance has increased in some locations since 1990, these were typically on coral reefs, in response to declines in other benthic organisms, and restricted to a few species. Few data were available on temporal trends in freshwater sponge abundance. Despite over 8500 described sponge species, only 20 are on threatened species lists, and all are marine species from the northeastern Atlantic and Mediterranean. Of the 202 studies identified, the effects of temperature, suspended sediment, substratum loss, and microbial pathogens have been studied the most intensively for marine sponges, although responses appear to be variable. There were 20 studies examining environmental impacts on freshwater sponges, and most of these were on temperature and heavy metal contamination. We found that most sponges do not appear to be threatened globally. However, little information is available for most species and more data are needed on the impacts of anthropogenic-related pressures. This is a critical information gap in understanding sponge conservation status. Estado Global de la Conservación de Esponjas [ABSTRACT FROM AUTHOR]

This is to report the first record for Colombia of two species of fresh-water crabs of the Kingsleyini Bolt, 1970 tribe. The species Prionothelphusa eliasi Rodríguez, 1980 and Orthothelphusa holthuisi (Rodríguez, 1967) had previously been recorded only for Venezuela.Se establece el primer registro para Colombia de la tribu Kingsleyini Bott, 1970, representado por las especies Prionothelphusa eliasi Rodríguez, 1980 y Orlhothelphusa holthuisi (Rodríguez, 1967). Estas especies solo habían sido registradas para Venezuela.

Understanding the risk of a local extinction in a single population relative to the habitat requirements of a species is important in both theoretical and applied ecology. Local extinction risk depends on several factors, such as habitat requirements, range size of species, and habitat quality. We studied the local extinctions among 31 dragonfly and damselfly species from 1930 to 1975 and from 1995 to 2003 in Central Finland. We tested whether habitat specialists had a higher local extinction rate than generalist species. Approximately 30% of the local dragonfly and damselfly populations were extirpated during the 2 study periods. The size of the geographical range of the species was negatively related to extinction rate of the local populations. In contrast to our prediction, the specialist species had lower local extinction rates than the generalist species, probably because generalist species occurred in both low- and high-quality habitat. Our results are consistent with source-sink theory. Riesgo de Extinción Local de Odonatos de Agua Dulce Generalistas y Especialistas de Hábitat [ABSTRACT FROM AUTHOR]

Habitat characteristics mediate predator-prey coexistence in many ecological systems but are seldom considered in species introductions. When economically important introduced predators are stocked despite known negative impacts on native species, understanding the role of refuges, landscape configurations, and community interactions can inform habitat management plans. We measured these factors in basins with introduced trout (Salmonidae) and the Cascades frog (Rana cascadae) to determine, which are responsible for observed patterns of co-occurrence of this economically important predator and its native prey. Large, vegetated shallows were strongly correlated to co-occurrence, and R. cascadae larvae occur in shallower water when fish are present, presumably to escape predation. The number of nearby breeding sites of R. cascadae was also correlated to co-occurrence, but only when the western toad (Anaxyrus boreas) was present. Because A. boreas larvae are unpalatable to fish and resemble R. cascadae, they may provide protection from trout via Batesian mimicry. Although rescue-effect dispersal from nearby populations may maintain co-occurrence, within-lake factors proved more important for predicting co-occurrence. Learning which factors allow co-occurrence between economically important introduced species and their native prey enables managers to make better-informed stocking decisions. Factores que Median la Co-Ocurrencia de un Pez Introducido con Valor Económico y su Presa, una Rana Nativa [ABSTRACT FROM AUTHOR]

Increased concern over climate change is demonstrated by the many efforts to assess climate effects and develop adaptation strategies. Scientists, resource managers, and decision makers are increasingly expected to use climate information, but they struggle with its uncertainty. With the current proliferation of climate simulations and downscaling methods, scientifically credible strategies for selecting a subset for analysis and decision making are needed. Drawing on a rich literature in climate science and impact assessment and on experience working with natural resource scientists and decision makers, we devised guidelines for choosing climate-change scenarios for ecological impact assessment that recognize irreducible uncertainty in climate projections and address common misconceptions about this uncertainty. This approach involves identifying primary local climate drivers by climate sensitivity of the biological system of interest; determining appropriate sources of information for future changes in those drivers; considering how well processes controlling local climate are spatially resolved; and selecting scenarios based on considering observed emission trends, relative importance of natural climate variability, and risk tolerance and time horizon of the associated decision. The most appropriate scenarios for a particular analysis will not necessarily be the most appropriate for another due to differences in local climate drivers, biophysical linkages to climate, decision characteristics, and how well a model simulates the climate parameters and processes of interest. Given these complexities, we recommend interaction among climate scientists, natural and physical scientists, and decision makers throughout the process of choosing and using climate-change scenarios for ecological impact assessment. Selección y Uso de Escenarios de Cambio Climático para Estudios de Impacto Ecológico y Decisiones de Conservación [ABSTRACT FROM AUTHOR]