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URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1401
Centro Nacional de Pesquisa e Conservação de Répteis e Anfíbios
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Resultados da Pesquisa
Item Growth of Caiman crocodilus yacare in the Brazilian Pantanal.(Plos One, 2014-02-28) Campos, Zilca; Moura, Guilherme; Coutinho, Marcos; Magnusson, William E.; Sean Rogers, University of Calgary, Canada2013.We recaptured 647 of 7769 C. c. yacare initially marked in an area of 50 km2, in two ranches. We were able to determine size at age accurately for 24 male and17 female caimans that had been marked at hatching or less than 1 year old, and recaptured over periods of 5 to 24 years. The other 606 caimans were used to evaluate short-term growth rates. Age-size relationships were estimated using growth models from the Richards family of curves (full model, von Bertalanffy and monomolecular). The form of the relationships differed between analyses based on caimans of known age and analyses based on integration of growth rate on size relationships for caimans whose ages were not known. Individuals showed large variation in short-term growth rates, but data on known-age animals indicated little between-individual variability in long term growth rates. There was evidence of a small effect of rainfall, but not temperature, on short-term growth of small caimans, but most variation in growth rates was unexplained by variables other than age and sex. Data on known-age individuals indicated that female C. c. yacare generally reach sexual maturity between 10 and 15 years of age. Because of the asymptotic relationship between age and size, deviations of observations from the model for age are larger than for size, and estimates of age at a given size have greater errors than estimates of size at a given age. Integration of growth rate on size relationships may be adequate for estimating size from age in many cases, but accurate estimates of age from size require data on known-age individuals over the size range of the species.Item Spatial and temporal variation in reproduction of a generalist crocodilian, Caiman crocodilus yacare, in a seasonally flooded wetland.(2015) Campos, Zilca; Mourão, Guilherme; Coutinho, Marcos; Magnusson, William E.; Soriano, Balbina M. A.We monitored the number of caiman (Caiman crocodilus yacare) nests in two ranches in the Brazilian Pantanal that cover an area of about 50.000 ha for 28 years (1987?2014). The number of nests was related to combinations of rainfall, water level, and number of days with temperature below 20°C, depending on the area. Most of the variation in number of nests could not be predicted by the environmental variables, but could be represented mathematically by a sine wave. We were not able to identify any external driver and suspect that the regular fluctuations may have resulted from an intrinsic population process. Presently, ranches are used as management units under the legislation for ranching Pantanal caimans. However, although some breeding females were recaptured in the area after periods of up to 21 years, most were not recaptured near nests or in general surveys of the area, suggesting that females are not strongly philopatric and that ranches do not represent isolated demographic units.Item Dia dos Crocodilianos é comemorado em 17 de junho.(Rede/ICMBio, 2021-06-17) Coutinho, Marcos; Comunicação ICMBio