We describe the change in the fish community of the Porce River in Magdalena River Basin, Colombia, following the construction of the Porce III hydropower reservoir based on 13 years of monitoring data. The results show a clear reduction of the number of native species, which have been supplanted by colonizing non-native species, especially in the reservoir. Four native species detected prior to dam construction have apparently disappeared, but 12 new species were registered post-construction. We analyzed spatial changes in beta diversity in the aquatic environments surrounding the dam. The new environment generated by the reservoir presents a unique species composition and contributes significantly to the total beta diversity of the system. Altogether three distinct new fish assemblages emerged following reservoir formation and there are now six assemblages where there had previously been three. This dramatic change, already visible within a decade of construction, highlights just how strong of an impact dam construction has on habitats and how rapidly fish communities react in this hotspot for endemic fish diversity. Our findings demonstrate the importance of monitoring fish communities for revealing the impact of damming on river ecosystems and informs potential complementary fish diversity inventories elsewhere in the Magdalena River basin.

A ndrés Galeano -a Spaniard by birth and Berliner by residence -is a visual artist and philosopher. Performance, photography, and video are his main media of expression. He works solo and collaboratively with other artists and also curates performance art shows. In his early performances he worked with everyday objects and predominantly in public settings, dealing with historical, social, and ethical issues. Several of his performances have investigated the audience's role in performance art, and he has challenged spectators to take some responsibility for the outcome of his performances. Galeano has also been interested in birds and flying, and his live performances have grown more complex by the addition of found photography, photo projections, and various audio and video presentations. He based the structure of some of his performances on the rhythms of birdsong. In his newer projects he not only uses photographs and slide projections but has begun to investigate the indexical and documentary nature of photography. His most recent series, entitled iPerf, consists of performances that incorporate found photography alongside photos and video materials from his preceding performances. It is, to use Galeano's words, a digital performance during which the artist uses audiovisual materials and the internet, focusing on the iconography and usage of a pointing index finger and web-based communication channels. This interview was taped in the Theatre Centre, in Toronto, Canada after Galeano's performance iPerf 1.0.1, on

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En la cuenca del río Magdalena, las actividades de rescate de peces son una medida de manejo ambiental utilizada para reducir su mortalidad en el área próxima a los embalses. Cuando se realiza la apertura y posterior cierre de compuertas del vertedero, producto de la operación de la central hidroeléctrica Porce III, aguas abajo de la presa se crean hábitats acuáticos temporales en forma de pozas marginales de lecho rocoso, en donde se presentan atrapamientos de peces. El objetivo del rescate es reubicarlos al canal principal del río para reducir su mortalidad. Entre los años 2013 y 2020 se capturaron 4927 individuos, representantes de 28 especies, 12 familias y cinco órdenes. Reubicamos a 4704 individuos nuevamente en el río Porce, siendo las especies de los géneros Chaetostoma, Andinoacara, Astyanax y Rhamdia los de mayor captura. También se capturaron especies potamodromas de la familia Pochilodontidae, cuya presencia próxima a la presa se debe posiblemente a migraciones que realizan para llevar a cabo su reproducción. Estas acciones de rescate y reubicación, producto de la operación de las centrales hidroeléctricas, deben ser replicadas en la cuenca como estrategia para mitigar los impactos ambientales ocasionados por la fragmentación del hábitat.

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