ABSTRACT Freshwaters of northern Chilean Andes include many bogs referred to as "bofedales". streams of snowmelt origin feed these endor-heic water bodies at high altitudes in the arid mountain zone. Our knowledge of biota inhabiting these ecosystems is rudimentary due to their marked geographical isolation. The present study aimed to do a first characterization of invertebrate fauna in Lauca bogs (18° S, Chile) using species co-occurrence and niche sharing null models. The results revealed the presence of non-structured patterns in co-occurrence considering each site as well as all sites that is most probably an effect of the presence of many repeated species in the studied sites. In contrast, niche sharing results revealed the existence of niche sharing due to interspecific competition at each site and among all sites. The results agree with similar observations for Chilean inland waters at lower altitudes. The present study contributes to understanding the invertebrate community patterns of Lauca bogs and gives the basis for more complex ecological studies.

RESUMEN Las aguas dulces del norte de los Andes chilenos incluyen muchos pantanos llamados "bojedales". Estos cuerpos de agua endo-rreicos son alimentados por corrientes de origen de deshielo a gran altura en zonas áridas de montaña. Nuestro conocimiento de la biota que habita en estos ecosistemas es rudimentario debido a su marcado aislamiento geográfico. El objetivo del presente estudio jue hacer una primera caracterización de la jauna de invertebrados en los pantanos de Lauca (18 ° S, Chile) utilizando modelos de nulo de coexistencia de especies y nichos compartidos. Los resultados revelaron la presencia de patrones no estructurados en co-ocurrencia considerando cada sitio, así como todos los sitios, lo que probablemente sea un efecto de la presencia de muchas especies repetidas en los sitios estudiados. Mientras que los resultados de compartir nicho revelaron la existencia de compartir nicho debido a la competencia interespecífica en cada sitio y entre todos los sitios. Los resultados concuerdan con observaciones similares para las aguas continentales chilenas en altitudes más bajas. El presente estudio contribuye a la comprensión de los patrones comunitarios de invertebrados de los pantanos de Lauca y proporciona la base para estudios ecológicos más complejos.

ABSTRACT The ancient catfish family Diplomystidae, with seven species endemic to rivers of southern South America, represents one of the oldest branches of the diverse order Siluriformes. With most species endangered, new reports of these species become extremely valuable for conservation. Currently, it is assumed that Diplomystes species inhabit only Andean (large) basins, and that they are extinct from coastal (small) basins from which their presence have not been recorded since 1919. Here, we document new records of the family Diplomystidae in the Laraquete and Carampangue basins, two coastal basins from the Nahuelbuta Coast Range, Chile, with no previous reports. This finding represents the rediscovery of the genus in coastal basins in more than a Century. Based on analysis of mitochondrial DNA sequences, the collected specimens were found to be closely related to Diplomystes nahuelbutaensis from the Andean Biobío Basin, but sufficiently differentiated to suggest that coastal basin populations are a different management unit. These populations are important because, contrary to previous thoughts, they prove these catfish can survive in small river networks, providing unique opportunities for research and conservation. The conservation category of Critically Endangered (CE) is recommended for the populations from the Laraquete and Carampangue basins.

RESUMEN La familia de bagres Diplomystidae, con siete especies endémicas de ríos del sur de Sudamérica, es uno de los linajes mas antiguos del diverso orden Siluriformes. Al estar la mayoría de las especies amenazadas, nuevos registros de éstas son extremadamente valiosos para su conservación. Actualmente, se ha asumido que los Diplomystidos se distribuyen solo en cuencas Andinas (más grandes), y que sus especies estarían extintas en cuencas de menor tamaño como las costeras, sin registros desde 1919. En este trabajo documentamos la familia Diplomistidae en las cuencas de Carampangue y Laraquete, dos cuencas costeras de la Cordillera de Nahuelbuta, Chile, lo que representa el primer registro de esta familia en estas cuencas costeras. Además, este hallazgo representa el re-descubrimiento de la familia en cuencas costeras después de un siglo. Sobre la base de análisis de ADN mitocondrial, los especímenes colectados se relacionaron más cercanamente con poblaciones de la especie Diplomystes nahuelbutaensis presente en la cuenca del Biobío. Sin embargo, existen diferencias genéticas suficientes entre las poblaciones costeras y las del Biobío para justificar su separación como unidad de manejo distinta. Estas poblaciones costeras son importantes porque demuestran que los Diplomístidos pueden sobrevivir en cuencas de pequeño tamaño, ofreciendo oportunidades únicas para su investigación y conservación. Se recomienda la categoría de conservación En Peligro Critico de Extinción (CR) para las poblaciones de las cuencas Laraquete y Carampangue.

Abstract Galaxias maculatus is an abundant freshwater fish species in Chilean continental waters where it plays important ecological functions, yet few parasitological records of this species exist in Chile and all of them cover a very limited geographic range. The objective of this study was to assess large scale geographic variation in composition of parasite infracommunities of Galaxias maculatus. Specifically, parasite infracommunities of this species were compared among 11 locations across 9 degrees of latitude and 3 ecosystem types (lake, river and estuary). Most taxa found had been previously reported in Chile and Argentina. However, this is the first report for Tylodelphys sp. in this host in Chile. Furthermore, the cranial parasite Tylodelphys sp. had the highest overall prevalence and abundance compared to other parasite species. Despite the fact that the abundance of Tylodelphys sp. was not significantly correlated with Fulton's condition factor of fish, infected fish seem to have a better body condition compared to uninfected ones. The most important source of variation in composition of infracommunities was the sampling location. Furthermore, fish from lakes have a different composition of parasite infracommunities mainly due to higher abundances of Tylodelphys sp.

ABSTRACT Chungungo Lontra felina (Molina, 1782), is a marine mustelid. Its distribution extends from Peru to Cape Horn. This species is considered endangered throughout its entire range of distribution. The main threats to its populations are illegal hunting, coastal pollution and exploitation of their food resources. It has been reported that chungungo feeds mainly on crustaceans, fish and shellfish. Previous studies have compared feeding ecology of L. felina in some locations of Chile. There are, however, no reports that determine and compare feeding ecology of L. felina in the Biobío Region. Non-invasive methods such as fecal analyses allow to determine some properties of the diet by analyses of indigested prey or their parts. Present study was conducted in two locations in the Biobío Region: Caleta Chome and San Vicente and a total of 131 fecal remains was collected (65 in Caleta Chome and 66 in San Vicente). Fecal specimens were sieved and the remains of undigested prey were identified and categorised as crustaceans, fish or shellfish and counted. Furthermore, they were identified to the lowest possible taxonomic level using magnifying glass and identification keys available in literature. Low diversity of prey was found in both locations and the diet of chungungo consisted mainly of crustaceans, followed by fish and shellfish. Furthermore, greater variability and diversity of prey consumed by chungungo was found in Caleta Chome compared to San Vicente.

RESUMEN Chungungo Lontra felina (Molina, 1782) es un mustélido que presenta conducta exclusivamente marina con distribución desde Perú hasta Cabo de Hornos. Esta especie se encuentra categorizada En Peligro según UICN. Esto se debe principalmente a la caza ilegal, contaminación de las costas y explotación de sus recursos tróficos. De acuerdo a registros previos en distintas localidades de Chile, L. felina en sus hábitos alimenticios es una especie generalista, se alimenta principalmente de crustáceos, peces y moluscos según la oferta de cada localidad en que se encuentre. No obstante, no hay un estudio que determine y compare la alimentación de L. felina en localidades de la Región del Biobío. A través de métodos no invasivos, como el análisis fecal, es posible realizar una aproximación de la dieta, mediante presas no digeridas. De esta forma, con la finalidad de conocer la composición trófica del chungungo en la costa de la Región del Biobío se realizó un estudio de análisis fecal en dos localidades; Caleta Chome y San Vicente las cuales presentan características geográficas, antropogénicas y de contaminación distintas. En total se colectaron 131 restos fecales, 65 en Caleta Chome y 66 en San Vicente. En ambas localidades se encontró una baja diversidad de presas consumidas en comparación a estudios realizados en otras localidades de Chile, sin embargo, entre estas dos localidades se encontró una mayor diversidad de presas consumidas por L. felina en Caleta Chome que en San Vicente. La dieta de ambas localidades fue principalmente de crustáceos, seguido de peces y por último moluscos.

Abstract Background: Fragmentation (establishment of barriers e.g., hydropower dams, reservoirs for irrigation) is considered one of the greatest threats to conservation of river systems worldwide. In this paper we determine the fragmentation status of central Chilean river networks using two indices, namely Fragmentation Index (FI) and Longest Fragment (LF). These are based on the number of barriers and their placement as well as river length available for fish movement. FI and LF were applied to eight Andean river basins of central Chile in order to assess their natural, current (2018) and future (2050) fragmentation at the doorstep of a hydropower boom. Subsequently, we exemplify the use of these indices to evaluate different placement scenarios of new hydropower dams in order to maximize hydropower use and at the same time minimize impact on fish communities. Results: In the natural scenario 4 barriers (waterfalls) were present. To these 4 barriers, 80 new ones of anthropogenic origin were added in the current (2018) scenario, whereas 377 new barriers are expected in near future (2050). Therefore, compared to the ‘natural’ scenario, in 2050 we expect 115-fold increase in fragmentation in analysed river systems, which is clearly reflected by the increase of the FI values in time. At the same time, the LF diminished by 12% on average in the future scenario. The fastest increase of fragmentation will occur in small and medium rivers that correspond to 1st, 2nd and 3rd Strahler orders. Finally, case study on configuration of potential hydropower plants in the Biobio basin showed that hydropower output would be maximized and negative effects on fish communities minimised if new hydropower plants would be located in tributaries of the upper basin. Conclusions: Fragmentation of Chilean Andean river systems is expected to severely increase in near future, affecting their connectivity and ecological function as well as resilience to other anthropogenic stressors. Indices proposed here allowed quantification of this fragmentation and evaluation of different planning scenarios. Our results suggest that in order to minimise their environmental impact, new barriers should be placed in tributaries in the upper basin and river reaches above existing barriers.

Resumo Objetivo Os sistemas fluviais do Chile central são curtos, íngremes e fluem rapidamente. Eles são caracterizados por regimes de descarga dominados por chuvas e neve derretida. A fauna de invertebrados desses sistemas fluviais é altamente endêmica. O objetivo do presente estudo foi descrever a estrutura da comunidade de invertebrados em oito sistemas fluviais na região central do Chile (33-39°S), utilizando co-ocorrência de espécies e modelos nulos de compartilhamento de nichos. Métodos Amostras de invertebrados foram coletadas de rios chilenos centrais (33-39 ° S), os dados foram analisados com as espécies de coocorrência e os modelos nulos de compartilhamento de nichos para determinar potenciais padrões de estruturação. Resultados Os resultados revelaram a presença de padrões não estruturados em coocorrência, considerando cada local, bem como todos os locais, que é mais provavelmente um efeito da presença de muitas espécies repetidas nos locais estudados. A sobreposição de nicho revelou a existência de competição interespecífica em cada local e entre locais Os resultados obtidos para estes sistemas fluviais corroboram observações dos rios patagônicos chilenos. Conclusão O presente estudo contribui para a compreensão dos padrões biogeográficos e ecológicos das comunidades de invertebrados nos rios da região central do Chile e, como tal, constitui a base para estudos ecológicos mais complexos.

Abstract Aim River systems of Central Chile are short, steep and fast flowing. They are characterized by discharge regimes dominated by rainfall and snowmelt. Invertebrate fauna is highly endemic. This study aimed to describe the community structure of invertebrate in eight river systems in Central Chile (33-39°S) using species co-occurrence and niche sharing null models. Methods Invertebrate samples were collected from Central Chilean rivers (33-39°S), data were analyzed co-occurrence species and niche sharing null models for determine potential structuring patterns. Results The results revealed the presence of non-structured patterns in co-occurrence considering each site as well as all sites, that is most probably an effect of presence of many repeated species in the studied sites. Furthermore, we found the existence of niche overlap due to interspecific competition at each site and among all sites. The results obtained from these river systems corroborate observations from Chilean Patagonian Rivers. Conclusion This study contributes to understanding of biogeographical and ecological patterns of invertebrate communities in central Chilean Rivers and provide foundations for more complex ecological studies.