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URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/1481
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Item Density matters(ResearchGate, 2024) Moinet, Marie; Abrahão, Carlos R.; Gasparotto, Vinícius P. O.; Wilkinson, David A.; Vallée, Emilie; Benschop, Jackie; Russell, James C.Rodents are maintenance hosts of numerous pathogens, and both their density and the pathogen prevalence determine the risk they pose to other animals or humans. However, density is often overlooked. We investigated a capture-mark-recapture-sampling strategy to study introduced mice (Mus musculus) and Leptospira as a model and demonstrate the advantages of a combined approach. We estimated population density and Leptospira prevalence in mice in a replicated longitudinal survey conducted between 2016 and 2018. Capture-mark-recapture sessions were undertaken at two sites in Spring and Autumn and blood and kidney samples were collected at the end of each session. Mouse density and areas of activity were estimated using spatially explicit capture–recapture (SECR) models and both were compared between Leptospira positive and negative mice. Leptospira exposure and shedding status were estimated using Microscopic Agglutination Test, and a combination of culture and lipL32 PCR on kidneys. Leptospira prevalence was higher in spring (83%–86%) than in autumn (31%–37%) and mouse densities simultaneously varied from 3.6 to 55.9/ha. However, despite these variations in prevalence and density, the density of infected animals remained relatively constant over time (3–8/ha). Shedding or being seropositive was also associated with the activity of mice. Shedding or seropositive mice had a larger activity area, and seropositive mice were trapped on average 1 day earlier than seronegative mice. Synthesis and applications: Our results show how understanding the population dynamics of pathogen-carrying rodents is critical in epidemiology. The wider movement patterns and easier encounters of positive mice highlight the possibility of biases in classical prevalence surveys and have implications for disease transmission within and between species. Importantly, and quite counter-intuitively, Leptospira prevalence was negatively associated with mouse density, resulting in a constant density of shedders that contradicts the conventional view of higher exposure risk at high rodent density. More broadly, such sampling designs can improve animal and disease control policies and better inform modelling studies by providing more parameter estimates than classical prevalence surveys.Item USE OF KNOWN INDIVIDUAL MARKING IN RESEARCH AND MONITORING OF FRESHWATER TURTLE POPULATIONS(ResearchGate, 2024) Cunha, Fabio; Ândrade, MarceloThe marking or tagging of turtles is a widely used to facilitate the monitoring of population demography, structure, and conservation of species. Even though they are used in many studies of turtle demography, the available methods are not very efficient, except for microchips (Passive Intergraded Transponder/PIT tags); however, the latter is too expensive to be used on a large scale. Here we present a viable, cost-effective tagging alternative that uses a durable plastic cattle tag and pin. Turtles in the genus Podocnemis were tagged in the Lower-Amazon region, west of the state of Pará, Amazon, Brazil. This method is highly recommended for future work on monitoring and population structure of large species of freshwater turtles. In addition to feasibility, it can be used in the form of citizen science, as the information can be obtained by laypeople and taken to researchers and conservationists. Resumen El marcado o marcaje de tortugas es un método ampliamente utilizado para facilitar el seguimiento de la demografía y estructura de las poblaciones y la conservación de las especies. Aunque se utilizan en muchos estudios de demografía de tortugas, los métodos disponibles no son muy eficaces, excepto los microchips (Passive Intergraded Transponder/PIT tags); sin embargo, estos últimos son demasiado caros para ser utilizados a gran escala. Aquí presentamos una alternativa de marcado viable y rentable que utiliza una marca de plástico duradera para ganado y un alfiler. Se marcaron tortugas del género Podocnemis en la región del Bajo Amazonas, al oeste del estado de Pará, Amazonas, Brasil. Este método es muy recomendable para futuros trabajos de seguimiento y estructura poblacional de grandes especies de tortugas dulceacuícolas. Además de su viabilidad, puede utilizarse en forma de ciencia ciudadana, ya que la información puede ser obtenida por profanos y llevada a investigadores y conservacionistas.