Concern has grown in Chile to protect and conserve aquatic ecosystems taking into account the high degree of habitat degradation. As a fi rst step towards the development of conservation plans, it is necessary to classify these ecosystems in order to learn about them and understand their different types and functions. Considering that hydrological regime is the main factor in the composition of river ecosystems, an Eco-Hydrological Classifi cation of Chilean Rivers (REC-Chile) has been developed. REC-Chile is based on the hierarchical superposition of the controlling factors of the hydrological pattern in Chile. REC-Chile is a multi-scale classifi cation system, allowing to represent different river patterns at different spatial scales according to the selected controlling factors. The typology of the river segment is represented as a 6-digit code, in which the position of the digit represents the controlling factor and the digit value represents the factor category. This hierarchical confi guration and the assignment of geography-independent classes makes REC-Chile an easy way of interpreting the hydrological classes. Given the fl exibility provided by the multi-scale nature of REC-Chile, and the simplicity in the interpretation of the classes, it is expected that REC-Chile will become a very useful and suitable tool for developing conservation plans for aquatic ecosystems. KEYWORDS:Hierarchical classifi cation, controlling factors, hydrological pattern, rivers, Chile. RESUMENEn Chile existe un aumento en la preocupación por proteger y conservar los ecosistemas acuáticos debido al elevado estado de deterioro del hábitat. Como un primer paso para desarrollar planes de conservación, se hace necesario realizar una clasifi cación de estos ecosistemas para conocer y entender los distintos tipos y su funcionamiento. Entendiendo que el caudal es el principal factor en la composición de ecosistemas fl uviales, se ha desarrollado una clasifi cación EcoHidrológica de los ríos de Chile (REC-Chile) basada en una superposición jerárquica de factores controladores del patrón hidrológico en Chile. REC-Chile es multiescalar, permitiendo según los factores controladores seleccionados representar distintos patrones fl uviales a diversas escalas espaciales. La tipología del tramo de río se representa como un código de 6 dígitos, en donde la posición del dígito representa el factor controlador y el valor a la categoría de éste. Esta confi guración jerárquica, así como la asignación geográfi camente independiente de sus clases, dota a la REC-Chile de facilidad en la interpretación hidrológica de las clases. Debido a la ductilidad y fl exibilidad, entregada por la multiescalaridad y por la sencilla interpretación de sus clases, se espera que la REC-Chile se convierta en una herramienta para desarrollar planes de conservación de los ecosistemas acuáticos.
How to cite this paper: Parodi, J., Olivares, P., Chavez, V. and Peredo-Parada, M. (2015) Laboratory Handling of Didymosphenia geminata (Lyngbye) Schmidt and the Effect of Control Efforts on Viability. Advances in Bioscience and Biotechnology, 6, 508-516. http://dx. AbstractDidymosphenia geminata (Lyngbye) Schmidt is a type of diatom that exists in Chile as an introduced species, invading the country and its rivers. We collected samples of D. geminata from two sampling points in Chile, assessing their viability and response to control agents. Fresh D. geminata showed more than 90% of viable granular forms (containing granules in their cytoplasm); however, the dry form presents near 50% viability. By creating dry D. geminata through exposure to 38˚C temperatures for 7 days, viability values of the granular form decreased to 20%. D. geminata kept at room temperature for more than 4 weeks reported values of granular forms at 50%, while samples that were refrigerated at 4˚C maintained values of granular forms at 90% for 4 weeks. Previous studies suggest that high salt concentration affects the viability of D. geminata. When taking wet D. geminata samples and exposing them to a solution of 10% NaCl for 10 minutes, we observed no differences compared to the control samples, finding granular forms at 90%. When the D. geminata was exposed to a 5% soap solution, reductions of over 90% of the granular forms were observed. Our results suggest that the viability of D. geminata is associated with the granular content within their cytoplasm, and that it is possible to alter laboratory conditions for their study. These early studies are important in order to better manipulate the model in the laboratory, allowing us to obtain new evidence regarding the microalgae's biology through in vitro studies. * Both authors collaborate in equal way. J. Parodi et al. 509
RESUMENEl conocimiento de las especies nativas de Chile se caracteriza por ser insuficiente, incompleto, fragmentado y poco actualizado, lo cual constituye una de las principales limitantes para desarrollar estrategias de conservación de especies o planes de conservación y recuperación de sistemas acuáticos. Lo anterior cobra mayor importancia dada la mayor presión que tienen actualmente estos ecosistemas en el país. Para paliar este vacío se ha confeccionado una Base de Datos Eco-Hidrológica de los ríos de Chile. Esta base de datos cuenta con información hidrológica, fisicoquímica de las aguas, sedimentológicas e información íctica. Esta última información se ha basado en recopilación bibliográfica de literatura referente a distribución de peces, dividida en tres niveles (I, II y III) de acuerdo al detalle y escala espacial de la información (macroescala, mesoescala y microescala, respectivamente). La Base de Datos Eco-Hidrológica confeccionada la conforman 393 estaciones fluviométricas, 361 estaciones de calidad del agua, 92 estaciones sedimentológicas y un total de 1580 registros de peces distribuidos a lo largo de todo Chile. Esta base de datos se ha integrado en la plataforma de gestión "Clasificación Eco-hidrológica de los ríos de Chile" (REC-Chile), la cual se construyó basándose en los factores medioambientales que controlan el régimen hídrico de un río. La utilización conjunta de la base de datos junto con REC-Chile permitirá desarrollar una mejor planificación y gestión de los ecosistemas acuáticos en Chile.PALABRAS CLAVES: Chile, REC-Chile, base de datos eco-hidrológica, gestión ecosistemas acuáticos, peces nativos chilenos. ABSTRACTThe limited knowledge of Chilean native species is one of the main constraints to develop conservation strategies for species or conservation planning and rehabilitation of aquatic ecosystems. To fill this gap it was developed an EcoHydrological Database of the Chilean rivers. This database contains information about hydrology, water quality, substrate and fish information. The latter information was based on literature collection concerning on fish distribution, divided into three levels (I, II and III) according to detail and spatial scale of the information (macro, meso and microscale, respectively). The database has 393 hydrological stations, 361 water quality stations, 92 substrate stations and a total of 1580 fish records distributed throughout Chile. This database has been integrated into the management platform «River Environmental Classification of Chilean Rivers» (REC-Chile), which was built based on environmental factors which control the hydrological pattern of a river. The joint use of the database along with REC-Chile will further develop planning and management of aquatic ecosystems in Chile.
Despite its theoretical relationship, the effect of body size on the performance of species distribution models (SDM) has only been assessed in a few studies, and to date, the evidence shows unclear results. In this context, Chilean fishes provide an ideal case to evaluate this relationship due to their short size (fishes between 5 cm and 40 cm) and conservation status, providing evidence for species at the lower end of the worldwide fish size distribution and representing a relevant management tool for species conservation. We assessed the effect of body size on the performance of SDM in nine Chilean river fishes, considering the number of records, performance metrics, and predictor importance. The study was developed in the Bueno and Valdivia basins of southern Chile. We used a neural network modeling algorithm, training models with a cross-validation scheme. The effect of fish size on selected metrics was assessed using linear models and beta regressions. While no relationship between fish size and the number of presences was found, our results indicate that the model specificity increases with fish size. Additionally, the predictive importance of Riparian Vegetation and Within-Channel Structures variables decreases for larger species. Our results suggest that the relationship between the grain of the dataset and the home range of the species could bias SDM, leading in our case, to overprediction of absences. We also suggest that evolutionary adaptation to low slopes among Chilean fishes increases the relevance of riparian vegetation in the SDMs of smaller species. This study provides evidence on how species size may bias SDM, which could potentially be corrected by adjusting the model grain.
Mesohabitat heterogeneity in four mediterranean streams of the Jucar river basin (Eastern Spain)The hydromorphological units or mesohabitats of the headwaters of four Mediterranean streams were studied by classifying them according to their length, width, average and maximum depth, percentage of substrate and water volume. These characteristics of the streams were assessed over four consecutive years (2003)(2004)(2005)(2006). The main objective of the study was to analyse the spatial and temporal pattern of the physical attributes of the mesohabitats. Classification strength and dendrograms were examined for each stream, mesohabitat type, and combination of stream and mesohabitat type and for stream mesohabitat type and year, whereas Nonmetric Multidimensional Scaling ordination (NMDS) was used to analyse classification patterns. The Villahermosa and Ebrón streams were more homogeneous than the Palancia and Vallanca streams, whereas riffles and glides were more homogeneous than pools and rapids. The NMDS indicated that the slow water-velocity (pools, glides) and fast (riffles, rapids) mesohabitats tended to group together. Temporally, the Ebrón stream pools were homogeneous and very stable over the four years, whereas the Vallanca and Villahermosa pools showed a certain degree of variability. The Palancia pools were the most variable and heterogeneous during the study period. These results underscored the importance of separating different types of deep, slow-velocity habitats in mesohabitat inventories and the importance of evaluating habitat classifications in eco-hydromorphological and hydrobiological studies, especially in Mediterranean streams and rivers.
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