Search

El anfípodo Hyalella patagonica está muy extendido en aguas interiores andinas de la Patagonia argentina y chilena, esta especie habita en zonas litorales de ríos, arroyos, lagos y lagunas, que según la literatura tienen patrones de distribución espacial principalmente agregados. El objetivo del presente estudio es aplicar diferentes tipos de modelos de agregación para explicar la distribución espacial de H. patagonica colectada en un arroyo del norte de la Patagonia. Se aplicaron diferentes tipos de coeficientes de dispersión para comprender el patrón espacial de H. patagonica. Los resultados revelaron que la población de H. patagonica tiene una distribución agregada, pero no necesariamente una distribución binomial negativa, que es frecuente en el modelo probabilístico asociado a la distribución espacial agregada. Los resultados serían similares a los patrones observados para el género Hyalella en aguas interiores de la Patagonia.

The Chilean Patagonian lakes are characterized by their marked oligotrophic or oligomesotrophic status and low zooplankton species abundances, many of these lakes with oligomesotrophic status is associated to human intervention due towns in their shores. The aim of the present study was determine the relations between spectral properties (LANDSAT/OLI), chlorophyll and plankton abundances in two north Patagonian lakes, Villarica, that has two towns in its shore, and Caburgua, that has native forest in its shores as basis of environmental pollution monitoring tools. The results revealed that Villarica lake has high reflectances in near infrared, red and green bands, high chlorophyll (a, b and c) concentrations, and high bacterial and plankton abundances, whereas Caburgua lakes has low reflectance in the same bands, and low chlorophyll concentrations, low bacterial and plankton abundances, with exception to high mixotrophic ciliates. The obtained results agree with limnological observations about both lakes, and the comparison with spectral properties agree with similar observations for glacial north Patagonian lakes about spectral properties and zooplankton community.

The decapod fauna in the intertidal zone of the rocky shores of Chile is highly diverse, especially along the northern and central mainland coasts, where the influence of the cold Humboldt Current results in high productivity. One of the most abundant species in these ecosystems is the decapod Cyclograpsus cinereus Dana, 1851. The aim of the present study, carried out in the spring and summer seasons between 2018 and 2020, was to determine the spatial distribution patterns of the decapod C. cinereus in different sites along the rocky shores of Antofagasta bay, northern Chile, in order to establish probabilistic models that explain its distribution at each site. Individuals were counted in random quadrants in the intertidal zone. The data thus obtained were processed by application of the variance/mean ratio to determine whether the distribution of individuals was random, aggregated or uniform, associated with Poisson, negative binomial or positive binomial distributions, respectively. The data revealed aggregated (negative binomial) distribution in 15 sampling events, and uniform (positive binomial) distribution in 4 events. The sampling sites were located on rocky shores in four sectors of an urban zone, and two in a protected zone; no significant differences were found between the densities of the sites in the two zones. The results of the interpretative probabilistic models indicated aggregated distribution patterns, agreeing with previously reported interpretative probabilistic models for the distribution of decapods on the rocky shores of central and southern Chile.

The brine shrimp Artemia in Chile has been studied since the 1980s, initially on populations inhabiting shallow coastal and inland mountain ponds, and saltworks in northern and central Chile. Based on morphometric and molecular evidence, these populations were identified as A. franciscana. In the 1990s, A. persimilis was recorded from southern Patagonia, a species previously considered endemic to Argentina. Recently, two new populations of A.franciscana have been recorded, from one saline coastal pond in northern Chile and from a saltwork in central Chile. The scope for further research to increase both understanding of the strain characterization and basic population ecology descriptions of the Chilean brine shrimps and improve their conservation status is discussed. It is suggested that future studies should investigate first the management of local brine shrimp population for local aquaculture or conservation resources, other direction would be the effects of ultraviolet radiation (UVR) exposition that is notoriously high in brine shrimp habitats. This last factor is very important because the UVR is an important mutagen on the genetic structure of the populations. In this scenario, it is suggest a carefully management for introduced brine shrimp populations for local aquaculture for avoid alterations in native populations that due their genetic isolation would need conservation procedures for avoid local extinctions.El camarón de salmuera o Artemia ha sido estudiado en Chile desde la década de 1980, las primeras descripciones de poblaciones fueron para lagunas someras en zonas costeras y de montana, y en salinas artificiales en la zona central y norte de Chile. Sobre la base de evidencias morfométricas y moleculares estas poblaciones fueron descritas como A. franciscana. En la década de 1990, se describió la presencia de A. persimilis en la zona sur de la Patagonia, lo cual fue una ampliación del rango de distribución significativa, pues esta especie se le consideró endémica de Argentina. Recientemente dos nuevas poblaciones de A. franciscana fueron reportadas en una laguna somera en el norte y para una salina artificial en la zona central. El objetivo del presente estudio fue realizar una investigación para entender la caracterización de poblaciones y ecología básica de las poblaciones chilenas del camarón de salmuera y discutir como mejorar el estado de la conservación de estas. Se discute que a futuro los estudios se deberían enfocar primero al manejo de poblaciones nativas para acuicultura local o como un recurso para su conservación, otras orientaciones de estudio, podrían ser los efectos de la radiación ultravioleta (UVR) que es notoriamente alta en los hábitats del camarón de salmuera. Este último factor es importante porque la radiación ultravioleta es un agente mutágeno importante en la estructura genética de las poblaciones. En este escenario, se sugiere un manejo cuidadoso de las poblaciones introducidas del camarón de salmuera para la acuicultura local, con el fin de evitar alteraciones en las poblaciones nativas que debido a su aislamiento genético necesitarían procedimientos para su conservación con el fin de evitar extinciones locales.

Los copépodos calanoideos son abundantes en los ensambles zooplanctónicos de aguas continentales de la Patagonia, y en este contexto, se analizaron parámetros de fertilidad en cuatro especies de calanoideos representativos de aguas continentales de la Patagonia (37°-52° S) con el objetivo de determinar los parámetros de fertilidad en poblaciones de copépodos representativas de la Patagonia chilena. Para este propósito se consideraron dos a cuatro poblaciones de las siguientes especies: Boeckella gracilipes, B. michaelseni, B. poppei, y Tumeodiaptomus diabolicus, se consideraron individuos hembras con huevos a las que se midió el largo total, número de huevos y la razón entre número de huevos con el largo total. Los resultados mostraron que a nivel de especies B. poppei fueron significativamente diferentes para las otras tres especies. A nivel de poblaciones, se encontraron diferencias a nivel de poblaciones en algunas especies. Los resultados que los parámetros reproductivos variaron en función de los parámetros ambientales variaron en función de las condiciones ambientales de las poblaciones y estaría asociado con las condiciones ecológicas tales como estructuras poblacionales y las propiedades de las comunidades zooplanctónicas.The calanoids copepods are abundant in zooplankton assemblages in Patagonian inland waters, and within context the aim of determine the fertility parameters on populations of copepods representative of different inland water of Chilean Patagonia (37°-52° S). For this purpose, it was considered two to four populations of the the following species: Boeckella gracilipes, B. michaelseni, B. poppei, and Tumeodiaptomus diabolicus, it was considered for female individuals the total length, eggs number, and ratio between total length. The results revealed at species level that B. poppei was significantly different in comparison to another species in all of the three species. At populations level it was found differences in three species considered. The results revealed that the reproductive parameters are variable in function of the environmental conditions of the populations. The results denoted that the reproductive parameters are markedly influenced by environmental conditions, and it would be associated with ecological consequences such as populational structures and properties of zooplankton community ecology.

Microplastic pollution has become a global concern, with potential negative impacts on various ecosystems and wildlife species. Among these species, ducks (Anas platyrhynchos) are particularly vulnerable due to their feeding habits and proximity to aquatic environments contaminated with microplastics. The current study was designed to monitor microplastic (MP) pollutants in the freshwater ecosystem of the Panjkora River, Lower Dir, Pakistan. A total of twenty (20) duck samples were brought up for four months and 13 days on the banks of the river, with no food intake outside the river. When they reached an average weight of 2.41 ± 0.53 kg, all samples were sacrificed, dissected, and transported in an ice box to the laboratory for further analysis. After sample preparation, such as digestion with 10% potassium hydroxide (KOH), density separation, filtration, and identification, the MP content was counted. A total of 2033 MP particles were recovered from 20 ducks with a mean value of 44.6 ± 15.8 MPs/crop and 57.05 ± 18.7 MPs/gizzard. MPs detected in surface water were 31.2 ± 15.5 MPs/L. The major shape types of MPs recovered were fragments in crop (67%) and gizzard (58%) samples and fibers in surface water (56%). Other types of particles recovered were fibers, sheets, and foams. The majority of these detected MP particles were in the size range of 300–500 µm (63%) in crops, and 50–150 µm (55%) in gizzards, while in water samples the most detected particles were in the range of 150–300 µm (61%). Chemical characterization by FTIR found six types of polymers. Low-density polyethylene (LDPE) had the greatest polymer detection rate (39.2%), followed by polyvinyl chloride (PVC) (28.3%), high-density polyethylene (HDPE) (22.7%), polystyrene (6.6%), co-polymerized polypropylene (2.5%), and polypropylene homopolymer (0.7%). This study investigated the presence of microplastics in the crops and gizzards of ducks, as well as in river surface water. The results revealed the significant and pervasive occurrence of microplastics in both the avian digestive systems and the surrounding water environment. These findings highlight the potential threat of microplastic pollution to wildlife and ecosystems, emphasizing the need for further research and effective mitigation strategies to address this pressing environmental concern.

The intertidal crustaceans on the Chilean coast are characterized by high diversity and niche specialization. The present study applied a size overlap null model for intertidal decapod communities at four different sites on the Chilean coast. The results revealed that there is a size overlap for the four sites, though body size is significantly different for each location. This means that the reported species would share their ecological niches. The results agree with the first classic environmental descriptions for Chilean intertidal decapods at a local scale and support the observations for similar species on the southern Pacific and southern Atlantic coasts.

Background: Forest ecosystems provide services that are important for human use; one of the most critical ecosystem services is the provision and regulation of water. Basins with high forest improves hydrological functionality by promoting reduction in surface runoff, increase infiltration and aquifer recharge, and ensures base flow regulation amongst others. On the other hand, the conversion towards highly anthropized productive systems is usually accompanied by precarious environmental management that alters the hydrological cycle and reduction in water quality in basins. Aim: The goal of this study was to analyze land use changes and their effect on water efficiency index (WEI) in three sub-basins. Methodology: The methodology included a multi-temporal analysis of satellite images to identify land uses, also the use of SWAT (Soil and Water Assessment Tool) model for hydrological analysis in each sub-basin, information needed for calculating the WEI. Results: The results revealed the existence of no significant difference in terms of WEI between the sub-basins with predominant tree cover of native or artificial, being higher (0.89) than the WEI values reported by the sub-basin with agricultural land use (0.65). It is concluded that hydrological functions are more efficient in basins with forest cover, made up of native or exotic species, than agricultural land use with annual crop rotations. The results contribute to decision making on public policies associated to the rural productive activities. Concluded: Finally, we conclude the necessity of the promotion of forest plantation management techniques that avoid clear-cutting and multiple rotations in basin headwaters and riparian areas.

Abstract Temporary pools are freshwater bodies of significant interest due to their high species diversity, and the colonization and extinction processes observed at temporal scales. The aim of the present study was to perform a short-term ecological comparison in a group of shallow temporary pools in northern Chilean Patagonia in two periods, August and September 2018. The results revealed marked differences in terms of species richness in the study pools at different conductivities and chlorophyll a concentrations. The dominant species was the calanoid copepod Boeckella gracilis Daday, 1902, while the presence of the rare Anostracan Branchinecta rocaensis Cohen, 1982 was reported in conditions of low chlorophyll a and low conductivity. The community was studied using co-occurrence null models that revealed the absence of structured patterns in species associations, and the presence of niche overlap, with many repeated species that have a similar ecological niche. The present results are identical with observations from temporary pools in southern Chilean Patagonia.

Abstract The oyster culture has the incrusting organism as problem for production, in this context, it evaluated as biological control against incrusting organism and sediments the introduction of gastropod Tegula atra (Lesson, 1830) in Chilean oysters (Triostrea chilensis Phillippi, 1844) cultures in conditions of starvation presence and absence located in floating cages and bottom cultures. The predation and mechanic effect on T. atra grazing generated a decreasing in seven days of 19.8% and 13.7% of incrusting organisms in cage culture and bottom sediments by effects of gastropods without starvation respectively. Whereas it had a decrease of 12.6% and 11.4% of incrusting organisms in cage culture and bottom sediments by effects of gastropods with starvation respectively. The incrusting organism removed were mainly algae, colonial ascidia, polychaeta, bryozoan and small crustaceans.

Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mountains and platforms, mainly in Subantarctic and Antarctic waters of the southern hemisphere, including the Southeast Pacific, Atlantic and Indian oceans and in areas surrounding the peninsular platforms of subantarctic islands. The aim of this work was to determine and characterize the gastrointestinal parasitic and microbial fauna of specimens of D. eleginoides captured in waters of the south-central zone of Chile. The magnitude of parasitism in D. eleginoides captured in waters of the south-central zone of Chile is variable, and the parasite richness is different from that reported in specimens from subantarctic environments. Next-generation sequencing (NGS) of the microbial community associated to intestine showed a high diversity, where Proteobacteria, Firmicutes, and Bacteriodetes were the dominant phyla. However, both parasitic and microbial structures can vary between fish from different geographic regions

The southern king crab, Lithodes santolla, is an important fishery resource in the inner seas of Chilean Patagonia. The fishing gear used to catch southern king crab (bait trap) and its operation at different depths over several months provide the opportunity to gather information about relative abundance. The aim of the present study was to analyze the information collected from the catches of southern king crab and its associated fauna in the Magdalena Fjord to study the biodiversity and ecology of scavenging decapod crustaceans. Specifically, the study aimed to determine the bathymetric patterns of abundance by species, to model the abundance by season (winter and spring) and to determine the structuring pattern of scavenging decapods assemblage. Samples were collected between June and November 2019 by deploying traps in four bathymetric strata: 1 = 0–50 m; 2 = 51–100 m; 3 =101–150 m; 4 = 151–200 m. We registered a total of 673 decapod specimens associated with the southern king crab fishery, representing five species: Lithodes santolla (n = 96), Libidoclaea smithii (n = 10), Metacarcinus edwardsii (n = 58), Munida gregaria (n = 507) and Peltarion spinulosum (n = 2). The abundance of decapod species varied by month and bathymetric strata. We found bathymetric patterns for L. santolla abundance, M. gregaria, M. edwardsii, and total species abundance. The most informative model to explain scavenging decapod abundance by generalized linear model (GLM) included species and season. The null model of species co-occurrence analysis revealed that all species associations during the sampled months were random. Our study is the first that provides evidence about patterns of bathymetrical and temporal variation of scavenging decapod abundance and expands the body of knowledge regarding the biodiversity of scavenger decapods in the Magdalena Sound.

Pilgerodendron uviferum (D. Don) Florin is an endemic, threatened conifer that grows in South America. In the sub-Antarctic territory, one of the most isolated places in the world, some forest patches remain untouched since the last glaciation. In this study, we analyze the tree structure and tree diversity and characterize the environmental conditions where P. uviferum-dominated stands develop within the Magellanic islands in Kawésqar National Park, Chile. An environmental matrix using the databases WorldClim and SoilGrids and local topography variables was used to identify the main environmental variables that explain the P. uviferum-dominated stands. PCA was used to reduce the environmental variables, and PERMANOVA and nMDS were used to evaluate differences among forest communities. The results show that two forest communities are present within the Magellanic islands. Both forest communities share the fact that they can persist over time due to the high water table that limits the competitive effect from other tree species less tolerant to high soil water table and organic matter. Our results contribute to knowledge of the species’ environmental preference and design conservation programs.

En Chile, el principal insumo usado como alimento para abalones son las algas Gracilaria chilensis y Macrocystis pyrifera. Estas algas experimentan una notable baja de disponibilidad en otoño e invierno, lo cual trae consigo un aumento considerable de los precios, al tener que depender del abastecimiento desde áreas cada vez más alejadas de los centros de cultivo de abalones y, eventualmente, generando impactos ecológicos indirectos en sus poblaciones. El objetivo fue elaborar y evaluar un ensilado del alga G. chilensis para la alimentación de abalón rojo (Haliotis rufescens), determinando la cantidad de lixiviados generados durante el proceso, el cambio en la composición proximal del alga, la preferencia y consumo del abalón rojo de ensilado de G. chilensis. Se logró un producto ensilado de buenas características físicas, químicas y de conservación, así como una buena aceptación por parte del abalón.

The Chilean inland water crustaceans are characterized by a combination of endemic and cosmopolitan species: some occur throughout the territory of continental Chile, while others are restricted to specific latitudinal regions. This study examined the zoogeographical patterns exhibited by Chilean inland water crustaceans. We considered six regions: Northern Chile (18°-27°S), North-Central Chile (27°-30°S), Central Chile (30°-38°S), Northern Patagonia (38°-41°S), Central Patagonia (41°-51°S), and Southern Patagonia (51°-55°S), and these were identified based on literature records of inland water crustaceans. The classification analysis generated dendrograms for the following groups considered in this categories: all inland water crustaceans (Branchiopoda, Copepoda and Malacostraca), the zooplanktonic crustaceans (Branchiopoda and Copepoda), the Malacostraca alone, and each group separately. Analysis of total data and of the zooplankton group taxa alone revealed the existence of a main grouping consisting of the three Patagonian zones plus Central Chile, that is distinct from that of Northern Chile and North-Central Chile. Similarly, analysis of the malacostracan data revealed the existence of two main groups, one comprising the three Patagonian zones plus Central Chile, contrasted with a second group of Northern and North-Central Chile combined. Our results are in agreement with other panbiogeographical studies of South American crustaceans and insects. Possible factors responsible for generating this pattern are the dispersal and colonization potential of zooplanktonic crustaceans and the marked endemism of the malacostracans.

Los copépodos intermareales chilenos han sido un grupo poco estudiado, existiendo reportes aislados para el litoral de Chile central y para territorios insulares. El objetivo del presente estudio fue analizar los ensambles de especies de copépodos intermareales en territorios insulares chilenos (islas de Pascua, San Félix, Alejandro Selkirk y Robinson Crusoe) y compararlas respecto a una zona del continente (Montemar, Valparaíso), por medio de un análisis de modelo nulo de co-ocurrencia de especies y un análisis de conglomerados. Los resultados del modelo nulo indicaron, para una simulación, que hay factores reguladores, mientras que en dos simulaciones no hay factores reguladores, lo que se debería al bajo número de especies reportadas. Por otro lado, el análisis de conglomerados reportó la existencia de un grupo principal conformado por las islas Alejandro Selkirk, San Félix y Robinson Crusoe, seguido después por la isla de Pascua y finalmente por Montemar. Se analizaron tópicos ecológicos, principalmente relacionados con los patrones de regulación de la riqueza de especies, como posibles explicaciones de los resultados observados.

The increased activity of aquaculture in Chile involves cultivation of salmonids, oysters mussels and other species such, and to a lesser extent species such as red abalone (Haliotis rufescens) and Japanese abalone (Haliotis discus hannai). The aim of this study was to evaluate the growth rate of Haliotis rufescens and Haliotis discus hannai fed with different pellet based diets with Macrocystis sp. and Ulva sp., grown in ponds for 13 months. The results for both species denoted that there was an increase in length and biomass during experimental period, existing low growth rates during the austral winter (July-September) and increase during the austral summer (December-January). Results are consistent with descriptions of literature that there is high rate of growth during the summer and using diet of brown algae. From the economic standpoint abalone farming would be an economically viable activity for local aquaculture, considering the water quality and food requirements.

Chilean inland-water ecosystems are characterized by their low species-level biodiversity. This study analyses available data on surface area, maximum depth, conductivity, chlorophyll-α concentration, and zooplankton crustacean species number in lakes and ponds between 23° and 51°S. The study uses multiple regression analysis to identify the potential factors affecting the species number. The partial correlation analysis indicated a direct significant correlation between chlorophyll-α concentration and species number, whereas the multiple regression analysis indicated a direct significant response of species number to latitude and chlorophyll-α concentration. These results agree with findings from comparable ecosystems in Argentina and New Zealand.

Se realiza una revisión de las especies de anfípodos del género Hyalella en aguas continentales de la Patagonia, isla Tierra del Fuego, Reserva de la Biosfera de Cabo de Hornos e islas adyacentes (38-54°S). Esta zona austral presenta numerosos tipos de ambientes acuáticos continentales como lagos, humedales y arroyos, y las principales especies en ambientes bentónicos corresponden a anfípodos del género Hyalella. La bibliografía menciona la presencia de H. costera, H. chiloensis, H. falklandensis, H. franciscae, H. neonoma, H. patagónica, H. rionegrina y H. simplex. La distribución de estas especies concuerda con estudios biogeográficos sobre la presencia de especies endémicas y de amplia distribución en el sur de la Patagonia y zona subantárticas. A pesar de la presencia de especies depredadoras introducidas, sobre la base de la literatura, los anfípodos serían más abundantes debido a la presencia de materia orgánica particulada.This study reviews the amphipod species of the genus Hyalella in the inland waters of Patagonia, Tierra del Fuego Island, Cape Horn Biosphere Reserve, and adjacent islands (38-54°S). This southern zone has numerous kinds of continental water bodies such as lakes, wetlands, and streams, and the main species in benthic assemblages are amphipods of the genus Hyalella. The literature mentions the presence of H. costera, H. chiloensis, H. falklaidensis, H. franciscae, H. neonoma, H. patagonica, H. rionegrina, and H. simplex. The distribution of these species agrees with biogeographical studies about the presence of widespread, endemic species in southern Patagonia and the sub-Antarctic zone. In spite of the presence of introduced predatory species, the literature indicates that the amphipods are more abundant due to the presence of particulated organic matter.

Chilean Patagonia has protected mountainous areas with evergreen native forests; in which the lakes and rivers, of volcanic or glacial origin, are oligotrophic. In Bulgaria, there are mountainous zones with native forests and associated lakes of volcanic origin. The aim of the present study is to carry out a preliminary comparison of zooplanktonic crustaceans in lake ecosystems associated with native forests of Chilean Patagonia and of Bulgarian mountains. The study revealed that the lakes studied in Chilean Patagonia are associated mainly with Nothofagus forests; they are oligotrophic, with a low number of zooplanktonic crustacean species. Similar results were observed for Bulgarian mountain lakes associated with Fagus forests. A null model analysis of species co-occurrence was applied to the two groups of lakes, and the result revealed the absence of regulatory factors in species associations. These studies agree with similar descriptions of lakes in Andean Patagonia and New Zealand. They highlight the important role of native Nothofagus forests in Argentina and Chile, and of Fagus forests with associated soil properties in Bulgaria, in the oligotrophy of the lakes studied.La Patagonia de Chile tiene una serie de áreas protegidas con bosques nativos perennes asociados a lagos y ríos oligotróficos y de origen glacial. Por otro lado en Bulgaria hay una serie de zonas montañosas con lagos asociados de origen volcánico o glacial. El objetivo del presente trabajo es realizar una primera descripción de especies de crustáceos zooplanctónicos en ecosistemas lacustres asociados a bosques nativos en la Patagonia de Chile y en las montañas de Bulgaria. Los estudios indican que los lagos de la Patagonia de Chile están asociados principalmente con bosques de Nothofagus, mientras que similares resultados fueron observados en lagos de Bulgaria con bosques de Fagus. La regresión lineal entre concentración de clorofila y número de especies para lagos chilenos, fue significativa mientras que en lagos de Bulgaria el análisis de regresión no indicó diferencias significativas. Se aplicó un análisis de co-ocurrencia de especies para ambos grupos de lagos y los resultados indicaron la ausencia de factores reguladores en las asociaciones de especies. Estos estudios concuerdan con descripciones similares para lagos de la Patagonia andina y Nueva Zelanda, y remarcan el rol de los bosques nativos de Nothofagus en Argentina y Chile, así como la presencia de bosques de Fagus y las propiedades del suelo en Bulgaria, como regulador importante de la oligotrofía asociada a los lagos analizados.

Distributional patterns of the South American species of the freshwater amphipod genus Hyalella were analysed using a panbiogeographic approach. Five generalized tracks were found: (1) northern Andes to Lake Titicaca (H. dielaii, H. meinerti, H. dybowskii, H.jelskii, H. lubominsky, and H. pauperocavae; (2) lake Titicaca (H. armata, H. cuprea, H. latinamus, H. lucifugax, H. montforti, H. neveulemairei, H. robusta, H. tiwanaku, H. simplex simplex, and H. solida); (3) central Andes (H. fossamancinii and H. kochi); (4) Pampas (H. bonariensis, H. caeca, H. castroi, H. longispina, H. montenegrinae, H. pampeana, H. pernix, H. pseudoazteca, and H. warmingii); and (5) Subantarctic (H. patagonica H. costera, H. curvispina, H. chiloensis, H. falklandensis, H. franciscae, H. neonoma, H. patagonica, and H. simplex). One node was found at lake Titicaca (intersection of generalized tracks 1, 2, and 3).Se estudió el patrón de distribución de especies Sudamericanas del género de anfípodo de agua dulce Hyalella mediante una aproximación panbiogeográfica. Se encontraron cinco trazos (1) Norte de los Andes al Lago Titicaca (H. dielaii, H. meinerti, H. dybowskii, H.jelskii, H. lubominsky, y H. pauperocavae; (2) Lago Titicaca (H. armata, H. cuprea, H. latinamus, H. lucifugax, H. montforti, H. neveulemairei, H. robusta, H. tiwanaku, H. simplex simplex, y H. solida); (3) Andes centrales (H. fossamancinii y H. kochi); (4) Pampas (H. bonariensis, H. caeca, H. castroi, H. longispina, H. montenegrinae, H. pampeana, H. pernix, H. pseudoazteca, y H. warmingii); y b (5) Subantártico (H. araucana, H. costera, H. curvispina, H. chiloensis, H. falklandensis, H. franciscae, H. neonoma, H. patagonica, y H. simplex). Se encontró un nodo en el lago Titicaca que correspondió a la intersección de los trazos 1; 2 y 3.

The lakes studied (Tinquilco, Verde, Toro, Chico) are located in the Huerquehue National Park (39°08'S, 71°40'W), Chile. An inventory of the aquatic and riparian species was performed between December 2005 and March 2006. A null model analysis was done to determine the existence of regulatory factors of species associations, and the Jaccard index was applied to determine floristic similarities. Seventy-five species were identified. The greatest number (54) and highest percentage of introduced species (37%) occurred at Tinquilco Lake, placing it in the category of "high human disturbance". Verde Lake, on the other hand, presented the lowest number of species (21), and the percentage of introduced species did not exceed 20% in the other three lakes, which are considered to have "low human disturbance". The analysis of the null model revealed the presence of regulatory factors in one of the three simulations. However, in the other two simulations, the species associations appeared to be random, presumably because many species were repeated at the study sites. According to the Jaccard index, Tinquilco Lake is noticeably different from the other lakes, probably due to its transition from oligotrophy to mesotrophy.Los lagos estudiados (Tinquilco, Verde, Toro, Chico) se localizan en el Parque Nacional Huerquehue (39°08'S, 71°40'W). Entre diciembre de 2005 y marzo de 2006, se inventarió su flora acuática y ribereña. Para determinar la influencia de factores reguladores en las asociaciones de especies se aplicó un análisis de modelo nulo y para determinar similitudes florísticas se aplicó el índice de Jaccard. Se identificaron 75 especies, donde el mayor número (54) y el mayor porcentaje de especies introducidas (37%) se registró en el lago Tinquilco, por lo que se incluye en la categoría de "altamente intervenido"; mientras que el menor número de especies se registró en el lago Verde con 21, y el porcentaje de especies introducidas no superó el 20% en los otros tres lagos, por lo cual se consideran como "poco intervenidos". Los análisis del modelo nulo muestran la presencia de factores reguladores en una de las tres simulaciones, mientras que en las dos restantes se sugiere una asociación aleatoria de las especies, supuestamente explicada por la presencia repetida en los sitios. El índice Jaccard reveló que el Tinquilco es notablemente diferente a los otros lagos, cuya probable causa se relacionaría con la transición de oligotrofía a mesotrofía.

The brine shrimp Artemia is important for aquaculture since it is bighly nutritious. It is also used widely in biological studies because it is easy to culture. The aim of the present study is to review the literature on the taxonomical nomenclature of Artemia. The present study indicates the existence of seven species: three living in the Americas, one in Europe, and three in Asia.El camarón de salmuera Artemia es importante para la acuicultura por su alta calidad nutricional y es muy utilizado para estudios biológicos por ser de fácil cultivo. El objetivo del presente estudio es revisar la literatura sobre la nomenclatura taxonómica de Artemia. Se determina la existencia de siete especies; tres de ellas viven en América, una en Europa y tres en Asia.

The crustacean zooplankton of Chilean inland waters are characterized by abundant calanoid copepods, mainly from the gemís Boeckella. The present study aims to update the distribution of Boeckella gracilis in the inland waters of the Araucania region (38-39°S) and to use null model analysis to understand the B. gracilis species associations. In the literature for Chile, this species is reported to be found in one northern lake and in three lakes of northern Patagonia. These fmdings are complemented by reports of this species for coastal and mountain ponds and mountain lakes of the Araucania region. These results agree with descriptions of this species for South American inland waters. The results of the null model analysis reveal factors regulating the species associations, whether comparing all the inhabitats or the guild structure, although some simulations show the opposite situation due to the presence of repeated species at many sites.Los crustáceos zooplanctónicos en aguas continentales chilenas están caracterizados por la abundancia de copépodos calanoideos, principalmente del género Boeckella. El objetivo del presente trabajo es actualizar la distribución de esta especie en aguas continentales de la región de la Araucania (38-39°S), y el uso de modelos nulos para comprender sus especies asociadas. Las descripciones de la literatura indican que en Chile esta especie está en un lago del norte, y tres lagos en el norte de la Patagonia. Estos resultados están complementados con reportes de esta especie en pozas costeras, pozas y lagos de montaña en la región de la Araucania. Estos resultados concuerdan con las descripciones de esta especie para aguas continentales Sudamericanas. Los resultados del análisis de modelos nulos revelan que las asociaciones de especies tuvieron factores reguladores, ya sea comparando todos los habitantes y como estructura de gremios, aunque en algunas simulaciones se observó una situación opuesta, esto se debió a la presencia de especies repetidas en muchos sitios.

Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.Nematóides do gênero Anisakis têm nos peixes marinhos seus hospedeiros intermediários. Um desses hospedeiros é Thyrsites atun, um importante recurso pesqueiro no Chile entre 38 e 41° S. Este artigo descreve a freqüência e o número de nematóides Anisakis nos órgãos internos de Thyrsites atun. Uma análise baseada em modelos de distribuição espacial demonstrou que os parasitos tendem a ficar agrupados. A variação numérica de parasitas por hospedeiro pôde ser descrita por distribuição binomial negativa. O número máximo observado de parasitas por hospedeiro foi nove. Os aspectos ambientais e zoonóticos desse estudo também serão discutidos.

El zooplancton tiene una importante función en las cadenas tróficas de los ecosistemas lénticos, transfiriendo la energía de los productores primarios fotosintéticos hacia los niveles tróficos superiores. Las comunidades animales muestran un patrón de asociación, regulado por factores ambientales bióticos y/o abióticos, en el que las especies de encuentran organizadas en gremios, que utilizan un mismo tipo de recurso de manera similar, y a la vez enfrentando diversos gradientes bióticos y abióticos que afectan su comportamiento y adecuación biológica. Buscamos determinar la existencia de algún patrón regulador espacial o de aleatorización en la distribución espacial de los crustáceos zooplanctónicos de aguas continentales chilenas, cuya diversidad ambiental se ve reflejada en la composición de especies de crustáceos zooplanctónicos. Estudiamos 85 sitios, aplicando un modelo nulo para asociaciones de especies. La distribución espacial de estos crustáceos zooplanctónicos se encuentra establecida por patrones reguladores, lo cual concuerda con la literatura indicando un papel importante de las condiciones tróficas y de la conductividad como reguladores de la composición de especies. Estos resultados concuerdan con descripciones para lagos de Argentina y Nueva Zelanda. PALABRAS CLAVE Zooplancton, oligotrofía, lagos, Patagonia, asociaciones de especies

The Chilean Patagonia has numerous kinds of inland water ecosystems such as lakes, ponds, wetlands and rivers that have been poorly studied due to access difficulties. This study was carried out in Aysen region, in southern Chile, and it included different kinds of water bodies such as rivers, streams, ponds, lagoons and lakes distributed along an altitudinal gradient at 46° S. It was found a low species number, essentially cladocerans, copepods and amphipods. A null model was applied in order to determine the existence of regulator factors of species associations, and the results revealed that they are not random. The patterns would be influenced by geographical and limnological characteristics of the studied sites. Our results would agree with regional studies on habitat heterogeneity such as in Torres del Paine National Park and other zones in Tierra del Fuego island.

This paper describes the frequency and number of Sphyrion laevigatum in the skin of Genypterus blacodes, an important economic resource in Chile. The analysis of a spatial distribution model indicated that the parasites tended to cluster. Variations in the number of parasites per host could be described by a negative binomial distribution. The maximum number of parasites observed per host was two.

ABSTRACT The benthic fauna in northern Patagonian streams is characterized by presence of water quality indicator species. The aim of the present study was characterized the benthic communities in streams associated to sites with presence of Nothofagus forests and with human intervention without Nothofagus forests using null models in ecology, unified neutral theory of biodiversity (UNTB) and unweighted pair group method with arithmetic mean (UPGMA). The results of species co-occurrence null model revealed that species associations are random, whereas the results of niche overlap null models revealed the presence of niche overlap. The UNTB results revealed low species number. The results of UPGMA revealed that species composition is specific for each site existing marked differences. The exposed results agree with results observed for central and northern Patagonian Chilean rivers, where the species composition is variable in according to surrounding basin properties and seasonal conditions.

The invertebrate communities of the northern Chilean rivers are characterised by their marked endemism andspecificity of their community structure in different basins. The river systems located in the Atacama Desert are endorheicand are affected by the rainy period of January-February commonly known as the “Bolivian winter“. The present study isthe first report on the observations of arthropods in the ephemeral Atacama River during a period of the “Bolivian winter“.The Atacama River is characterised by species with poor invertebrate assemblage dominated by diapausing crustaceans(cladocera, copepod, ostracoda) and dispersing aquatic insects (ephemeroptera and diptera larvae).