Browsing by Author "Valenzuela-Sanchez, Andres"

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    A flagship for Austral temperate forest conservation: an action plan for Darwin's frogs brings key stakeholders together
    (2021) Azat, Claudio; Valenzuela-Sanchez, Andres; Delgado, Soledad; Cunningham, Andrew A.; Alvarado-Rybak, Mario; Bourke, Johara; Briones, Raul; Cabeza, Osvaldo; Castro-Carrasco, Camila; Charrier, Andres; Correa, Claudio; Crump, Martha L.; Cuevas, Cesar C.; de la Maza, Mariano; Diaz-Vidal, Sandra; Flores, Edgardo; Harding, Gemma; Lavilla, Esteban O.; Mendez, Marco A.; Oberwemmer, Frank; Carlos Ortiz, Juan; Pastore, Hernan; Penafiel-Ricaurte, Alexandra; Rojas-Salinas, Leonora; Manuel Serrano, Jose; Sepulveda, Maximiliano A.; Toledo, Veronica; Ubeda, Carmen; Uribe-Rivera, David E.; Valdivia, Catalina; Wren, Sally; Angulo, Ariadne
    Darwin's frogs Rhinoderma darwinii and Rhinoderma rufum are the only known species of amphibians in which males brood their offspring in their vocal sacs. We propose these frogs as flagship species for the conservation of the Austral temperate forests of Chile and Argentina. This recommendation forms part of the vision of the Binational Conservation Strategy for Darwin's Frogs, which was launched in 2018. The strategy is a conservation initiative led by the IUCN SSC Amphibian Specialist Group, which in 2017 convened 30 governmental, non-profit and private organizations from Chile, Argentina and elsewhere. Darwin's frogs are iconic examples of the global amphibian conservation crisis: R. rufum is categorized as Critically Endangered (Possibly Extinct) on the IUCN Red List, and R. darwinii as Endangered. Here we articulate the conservation planning process that led to the development of the conservation strategy for these species and present its main findings and recommendations. Using an evidence-based approach, the Binational Conservation Strategy for Darwin's Frogs contains a comprehensive status review of Rhinoderma spp., including critical threat analyses, and proposes 39 prioritized conservation actions. Its goal is that by 2028, key information gaps on Rhinoderma spp. will be filled, the main threats to these species will be reduced, and financial, legal and societal support will have been achieved. The strategy is a multi-disciplinary, transnational endeavour aimed at ensuring the long-term viability of these unique frogs and their particular habitat.
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    Towards understanding the effects of oceanic plastic pollution on population growth for a South American fur seal (Arctocephalus australis australis) colony in Chile
    (2021) Joaquin Perez-Venegas, Diego; Valenzuela-Sanchez, Andres; Montalva, Felipe; Paves, Hector; Seguel, Mauricio; Wilcox, Chris; Galban-Malagon, Cristobal
    Entanglement of pinnipeds with plastic debris is an emerging conservation and animal welfare issue worldwide. However, the origins and long-term population level consequences of these entanglements are usually unknown. Plastic entanglement could produce a combination of wounds, asphyxiation, or inability to feed that results in the death of a certain percentage of individuals from the total population. In this research, we report on the consequent effect of plastic entanglement on population growth de-mographics in a South American fur seal (Arctocephalus australis australis) colony on Guafo Island, southern Chile. Using a stochastic matrix population model structured according to age and sex, and assuming an otherwise stable population, we explored population growth rates under five scenarios with differing rates of entanglement: A) a zero rate of plastic entanglement, B) entanglement rates (number of entangled individuals as a proportion of the total number of individuals) as observed in our study population (overall entanglement ratio of 1.2 x 10(-3)); and for the other scenarios, entanglement ratios as reported in the literature for other pinniped colonies around the world: C) 3.04 x 10(-3), D) 4.42 x 10(-2), and E) 8.39 x 10(-2). Over the 30 years forecasting period and starting with a population size of similar to 2950 individuals, the population growth rate was lower under all scenarios with rates of entanglement greater than zero (scenarios B-E). In comparison with scenario A, at the end of the 30-year period forecasted, we calculated a projected decrease in population size of between 20.34% (scenario B) and 91.38% (scenario E). These results suggest that even the lowest levels of entanglement in pinnipeds as reported in the literature might have significant effects over time on population-level dynamics. Our research offers potential insight when devising policy for the management and limitation of plastic pollution in the oceans, and indeed for the conservation and management policy of affected marine species. Furthermore, whilst there are some limitations to our methodology, it offers a straightforward and potentially useful approach for the standardized prediction of impacts at a population level of different rates of plastic pollution and entanglement and could be applied in distinct populations of the same species around the world. (C) 2021 Elsevier Ltd. All rights reserved.