First case of chytridiomycosis in an adult specimen of a native anuran from Uruguay

En Uruguay la infección causada por Batrachochytrium dendrobatidis (Bd) había sido detectada en Lithobates catesbeianus de criaderos comerciales y en larvas silvestres de especies autóctonas, pero no había sido confirmada aún en ejemplares adultos de ninguna especie nativa. En junio de 2009 se colectaron dos machos adultos silvestres de Pleurodema bibroni en el Cerro Verde (33.935°S, 53.5070556°W, Rocha, Uruguay), se les tomaron muestras para análisis de ADN (qPCR) para detectar Bd. Uno de ellos resultó positivo y el análisis histológico de la piel del ejemplar también confirmó la infección. Por tanto se diagnostica por primera vez la infección por Bd en adultos silvestres de esta especie en Uruguay, que además está considerada como Amenazada a nivel nacional y Near Threatened para la IUCN.Fil: Bardier, Cecilia. Universidad de la República; UruguayFil: Ghirardi, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Levy, Michael. University of North Carolina; Estados UnidosFil: Maneyro, Raúl. Universidad de la República; Urugua

Quantitative determination of the minimum body size for photo-identification of Melanophryniscus montevidensis (Bufonidae)

Toads of the genus Melanophryniscus possess unique color patterns on the belly, which allows for individual recognition. Photo-identification has proven to be an efficient non-invasive technique to identify individuals for this genus. However, such color patterns are absent in newly metamorphosed individuals. We studied the development of the ventral coloration pattern and evaluated its persistence in Melanophryniscus montevidensis to determine the minimum size and age at which use of the color pattern is a trustworthy (i.e., as stable as in adults) identification method for this species. From spawns raised in the field, we obtained eight metamorphs and maintained them in semi-natural conditions to photograph their bellies. We visually analyzed the images to establish the stabilization point of the color pattern. Using the software Wild-ID, we calculated the similarity score between the images from the stabilization point with sets of images before and after stabilization. Similarity scores of adults from previous studies did not differ significantly from the scores of juveniles after the pattern stabilized, but they did differ significantly from the scores of juveniles compared to themselves at least 70 d before stabilization. The color pattern developed progressively and stabilized at a median of 220 d after metamorphosis, with a maximum snout-vent length of 13.2 mm, which we considered the minimum size for photo-identification purposes. Although we observed ontogenetic and individual variation, the pattern remained unchanged since just before the first year of age. Taking into account the threshold size we determined, photo-identification is a suitable method for ecological studies of this species

Inventory and conservation priorities for amphibian species from Cerro Verde (Rocha, Uruguay) and surroundings

Cerro Verde Protected Area, on the coast of Uruguay, serves mainly to protect the marine fauna, which has charismatic species including marine turtles and dolphins. However, the terrestrial portion of this area has the conditions for hosting a great diversity of amphibians. The aims of this study were to build the inventory of amphibians from Cerro Verde, to assess its completeness and to compare it with the inventory constructed from historical records. Acoustic surveys were conducted monthly from 2007 to 2009 at 16 water bodies of the area. Nineteen species were found during this sampling period; the accumulation curve of richness showed an asymptotic pattern, indicating the completeness of the inventory. However, species previously collected in the area were not found during this study, suggesting a loss of diversity in the last decades

Inventory and conservation priorities for amphibian species from Cerro Verde (Rocha, Uruguay) and surroundings

Cerro Verde Protected Area, on the coast of Uruguay, serves mainly to protect the marine fauna, which has charismatic species including marine turtles and dolphins. However, the terrestrial portion of this area has the conditions for hosting a great diversity of amphibians. The aims of this study were to build the inventory of amphibians from Cerro Verde, to assess its completeness and to compare it with the inventory constructed from historical records. Acoustic surveys were conducted monthly from 2007 to 2009 at 16 water bodies of the area. Nineteen species were found during this sampling period; the accumulation curve of richness showed an asymptotic pattern, indicating the completeness of the inventory. However, species previously collected in the area were not found during this study, suggesting a loss of diversity in the last decades

Historia natural y conservación de los anfibios de Cerro Verde (Rocha, Uruguay)

Tribunal: Dr. Alejandro Brazeiro, Dr. Martín Bolazzi, Dr. Gabriel Francescoli.Orientador: Dr. Raúl Maneyro

To tag ornot to tag: comparative performance of tagging and photo-identification in a long-term mark-recapture of Juvenile Green Turtles (Chelonia mydas)

Capture-mark-recapture (CMR) methods are widely used to estimate population parameters and to collect data on animal demography, migration, and life history. Sea turtle research programs generally use artificial tags, an invasive method. Photo-identification (PID) methods have become an important tool for animal identification. Herein, we assessed the effectiveness of a PID method for marking green turtles (Chelonia mydas) compared to traditional methods (artificial tags). As a part of a long-term CMR study, green turtles have been tagged and photographed since 2001. We analyzed 1917 captures with left and right side photographs of tagged turtles using Wild-ID software, these results were compared with tag-recapture data to assess error rates (false positives and negatives), and different effectiveness metrics. A combination of PID and tags (a match from either method was considered a recapture) was the most error-free and efficient criterion for identification of recaptures; however, it was the most time consuming and invasive criterion as well. We also assessed the effect of image quality indicators on the error rates of PID. We found that turtle cleanliness increases the similarity of images (indirectly related to false negatives), but we found no effect of sharpness, angle, light condition, or width and height in pixels of images on error rates. We could conclude that if image quality is improved, tags could be substituted by PID. However, we strongly recommend researchers to consider local situations (occurrence of by-catch or stranded dead turtles, for which tags are still necessary) before deciding to apply only PID.Fil: Buteler, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Bardier, Cecilia. Universidad de la Republica. Facultad de Agricultura; UruguayFil: Cabrera, Mario Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Gonzalez Bengoechea, Yaco. Karumbe NGO; UruguayFil: Vélez Rubio, Gabriela Manuela. Universidad de la Republica; Uruguay. Karumbé Ngo; Urugua

Un criterio para foto-identificación mediante información de imágenes bilaterales en tortugas verdes (Chelonia mydas) juveniles

La identificación de individuos es esencial para entender la dinámica de las poblaciones y optimizar esfuerzos de conservación. Los programas de investigación en tortugas marinas utilizan marcas artificiales para su identificación, pero es un método invasivo con alto porcentaje de pérdida. Con el avance de la tecnología, la foto-identificación se ha convertido en una herramienta importante en ecología. El objetivo de este estudio es establecer criterios que permitan identificar individuos juveniles de tortuga verde mediante foto-identificación. Se utilizó el número de marcas metálicas y fotos bilaterales de tortugas recolectadas entre 2001 y 2020 (ONG Karumbé). Cada conjunto de fotos (perfil izquierdo y derecho) se analizó con el software Wild-ID y se generó un registro de coincidencias izquierdo, derecho y bilateral (PID). Posteriormente se evaluó la precisión de los tres métodos (izquierda, derecha, PID) comparándolos con la “verdadera” coincidencia (consenso entre registro de coincidencias entre perfiles derechos + izquierdos + marcas + comparación visual posterior). Se analizó una muestra que contenía 1917 pares de fotos, resultando coincidentes 81, 83 y 92 fotos; los falsos negativos fueron 18, 16 y 7, y los falsos positivos fueron 0, 3 y 0 para el lado izquierdo, derecho y PID respectivamente. Esto resultó en FFR (tasa de falso rechazo) de 0.18, 0.16 y 0.07 y de FAR (tasa de falsa aceptación) 0, 1.6x10-6 y 0. Según la coincidencia “verdadera“ se reportaron 1818 tortugas, pero según el PID se reportaron 1817 tortugas. Este es el primer estudio, en nuestro conocimiento, que evalúa el uso del software Wild-ID para foto-identificación de juveniles de C. mydas. Si bien existen errores asociados al uso de las fotos, se comprobó que complementando información bilateral se reducen errores de identificación. Los resultados indican que este software, utilizando información bilateral es eficaz para la identificación individual de esta especie.Fil: Buteler, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Bardier, Cecilia. Universidad de la Republica. Facultad de Agricultura; UruguayFil: Gonzales, Yaco. Ong Karumbe; UruguayFil: Fallabrino, Alejandro. Ong Karumbe; UruguayFil: Velez Rubio, Gabriela. Ong Karumbe; Uruguay. Universidad de la República; UruguayFil: Cabrera, Mario Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaXXI Congreso Argentino de HerpetologíaCórdobaArgentinaAsociación Herpetológica Argentin

Performance of visual vs. software-assisted photo-identification in mark-recapture studies: A case study examining different life stages of the pacific horned frog (Ceratophrys stolzmanni)

peer reviewedThe use of individual phenotypic features as non-invasive marks through photo-identification (photo-ID) has many advantages for individual-based field studies. However, since error rates vary between species, matching techniques, and image qualities, it is important to assess error rates to evaluate the reliability of photo-ID. We tested the performance of this method in the Pacific Horned Frog, Ceratophrys stolzmanni, a threatened anuran with a variable dorsal coloration. We compared the effectiveness of visual (i.e. human recognition) versus software-assisted recognition techniques (Wild-ID and APHIS), and assessed the potential applicability of these techniques to identify post-metamorphic individuals (froglets). The three techniques differed in their performance. The visual technique was the only one to produce type I errors between pairs of images (i.e. matching images which are not true matching pairs), however it also produced fewer type II errors (i.e. not identifying true matching pairs of images) than the software-assisted techniques. For froglets, we found that similarity scores calculated by photo-ID software did not differ significantly between groups of froglets and older individuals, supporting the idea that colour patterns in this species remain stable after metamorphosis. The lack of type I errors and the substantial reduction in required time achieved through the use of software, make software-assisted techniques (particularly Wild-ID) a valid and convenient matching technique for C. stolzmanni. We propose that photo-ID can also be applied to froglets of this species, since the pattern at this stage appears to be as variable as in adults and maintained through life

Performance of visual vs. software-assisted photo-identification in mark-recapture studies: a case study examining different life stages of the Pacific Horned Frog (Ceratophrys stolzmanni)

The use of individual phenotypic features as non-invasive marks through photo-identification (photo-ID) has many advantages for individual-based field studies. However, since error rates vary between species, matching techniques, and image qualities, it is important to assess error rates to evaluate the reliability of photo-ID. We tested the performance of this method in the Pacific Horned Frog, Ceratophrys stolzmanni, a threatened anuran with a variable dorsal coloration. We compared the effectiveness of visual (i.e. human recognition) versus software-assisted recognition techniques (Wild-ID and APHIS), and assessed the potential applicability of these techniques to identify post-metamorphic individuals (froglets). The three techniques differed in their performance. The visual technique was the only one to produce type I errors between pairs of images (i.e. matching images which are not true matching pairs), however it also produced fewer type II errors (i.e. not identifying true matching pairs of images) than the software-assisted techniques. For froglets, we found that similarity scores calculated by photo-ID software did not differ significantly between groups of froglets and older individuals, supporting the idea that colour patterns in this species remain stable after metamorphosis. The lack of type I errors and the substantial reduction in required time achieved through the use of software, make software-assisted techniques (particularly Wild-ID) a valid and convenient matching technique for C. stolzmanni. We propose that photo-ID can also be applied to froglets of this species, since the pattern at this stage appears to be as variable as in adults and maintained through life