Browsing by Author "Valdivia, Catalina"

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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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    Bioclimatic and anthropogenic variables shape the occurrence of Batrachochytrium dendrobatidis over a large latitudinal gradient
    (NATURE PORTFOLIO, 2021) Alvarado Rybak, Mario; Lepe Lopez, Manuel; Penafiel Ricaurte, Alexandra; Valenzuela Sanchez, Andres; Valdivia, Catalina; Mardones, Fernando O.; Bacigalupe, Leonardo D.; Puschendorf, Robert; Cunningham, Andrew A.; Azat, Claudio
    Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has caused the greatest known loss of biodiversity due to an infectious disease. We used Bd infection data from quantitative real-time PCR (qPCR) assays of amphibian skin swabs collected across Chile during 2008-2018 to model Bd occurrence with the aim to determine bioclimatic and anthropogenic variables associated with Bd infection. Also, we used Bd presence/absence records to identify geographical Bd high-risk areas and compare Bd prevalence and infection loads between amphibian families, ecoregions, and host ecology. Data comprised 4155 Bd-specific qPCR assays from 162 locations across a latitudinal gradient of 3700 km (18 degrees to 51 degrees S). Results showed a significant clustering of Bd associated with urban centres and anthropogenically highly disturbed ecosystems in central-south Chile. Both Bd prevalence and Bd infection loads were higher in aquatic than terrestrial amphibian species. Our model indicated positive associations of Bd prevalence with altitude, temperature, precipitation and human-modified landscapes. Also, we found that macroscale drivers, such as land use change and climate, shape the occurrence of Bd at the landscape level. Our study provides with new evidence that can improve the effectiveness of strategies to mitigate biodiversity loss due to amphibian chytridiomycosis.
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    Effects of trial and error and social learning on flavour palatability in nursery pigs
    (2021) Figueroa, Jaime; Luna, Daniela; Salazar, Laura C.; Morales, Pia; Valdivia, Catalina; Mueller, Maximiliano; Dwyer, Dominic
    The acquisition of behaviours that enhance the acceptability of new feeds could improve the performance and animal welfare in the pig industry. Pigs may learn individually by trial and error and/or by social learning to consume and prefer new flavoured feeds. However, there is little information regarding the effects of learning on the palatability of those flavours. This study aimed to investigate possible changes in pigs? hedonic responses, estimated by the mean consumption time per approach (CT/A), for flavours previously learnt through individual experiences (Experiment 1) and socially by a brief interaction with an experienced conspecific (Experiment 2). A total of 96 nursery pigs were used to study their preference, acceptability and palatability for flavours previously learnt about. Flavours were associated with 4% sucrose (Experiment 1) or with a demonstrator that recently consumed the flavour (Experiment 2). Those flavours or positive conditioned stimulus (CS+) were compared with control flavours that were not positively conditioned (CS-). In experiment 1, pigs preferred (P = 0.010) and tended to accept more (P = 0.069) of the CS + than CS- in water solutions. Nevertheless, no palatability differences were found (P = 0.875). In experiment 2, observer animals had a higher intake of CS + following interaction with demonstrators that consumed the same flavoured feed (P = 0.041). Snout to snout interaction time between those demonstrators and observers tended to present a positive correlation with CT/A (r = 0.497, P = 0.1). Thus both individual trial and error learning, and social learning, increased pigs acceptance of, and preference for, food flavours. However, only social learning modified the pattern of consumption with the observation of a correlation between changes in the CT/A ratio and the degree of snout to snout contact time between demonstrators and observers. Thus the mechanisms and effects of social and individual learning appear to differ at least partially. Regardless of mechanism, the fact that associative learning can increase food flavour consumption suggests that interventions based on associative learning may be beneficial for addressing welfare problems in pig production linked to low consumption, in particular with respect to weaning where the low consumption may relate to the inexperience of the animals.