Caracterização de habitat e aspectos reprodutivos da ariranha (Pteronura brasiliensis, Zimmermann, 1780) no lago da Usina Hidrelétrica de Balbina, Amazonas, Brasil
The giant otter (Pteronura brasiliensis) is a social animal that lives in cohesive family groups and uses dens which are dug on the banks of rivers, lakes and streams, to sleep at night and care for their cubs. Between September/2001 and May/2010, 54 field trips were carried out in order to characte...
| Autor principal: | Bozzetti, Bruno Freitas |
|---|---|
| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
|
| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/11315 http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4292154D1 |
| Resumo: |
|---|
|
The giant otter (Pteronura brasiliensis) is a social animal that lives in cohesive family groups and uses dens which are dug on the banks of rivers, lakes and streams, to sleep at night and care for their cubs. Between September/2001 and May/2010, 54 field trips were carried out in order to characterize and describe the areas used for dens construction and to better know the reproductive aspects of the species in Balbina Lake. During this field work, a total of 164 dens were analyzed. The dens were classified by the number of visits and divided into frequencies of ≥ 40% (n =30) and < 40% (n =134) of use. Soil samples were collected in front of the dens, as well as vegetation of the area surrounding the dens holes, slope angles of the river banks, height measurements of the dens entrance to the water level, water transparency, dens entrance size and orientation, and information regarding the reproductive period, litter size and the offsprings biometrics data. The data showed no significant difference (p> 0.05) regarding the frequency of den use by giant otters, except for the dens inclination angle (p=0.0462, t=-2.0083, d.f=162). and height of the opening holes at water level during periods of drought and flood (p=0.027, t=-2.4814, df=135). Soil analysis revealed that clay was the dominant portion in 50% of the analyzed soils. The azimuth angle of the dens openings varied between 4º and 360º, covering all quadrants from N to NW. The average height of the dens entrances to the water level was 1.98 m and average slope at the interface water / land in front of the dens was 53º (min. 12º and max. 88º). The average water transparency in front of the dens ranged from 1.33 m to 1.69 m, and mean heights and lengths of the openings of the holes was 32 cm and 61 cm, respectively, being built mostly (73% ) among the roots or trunks vegetation associated with the margins of watercourses. About 80% (n=28) of births records occurred between September and December, characterized by receding water and beginning of dry season. The number of cubs ranged from 1 to 3 animals with weight and average length of 553 g and 36 cm, respectively. The results regarding the characterization of the environments used by P. brasiliensis in Balbina reservoir allow a better view of the scenario where the species occurs, showing that otters use a diverse combination of aquatic and terrestrial environments, using banks with different slopes, digging dens at different water heights, with various opening sizes, internal sizes and shapes, different soil types, with various levels of vegetation cover and water clarity, and without apparent prevalence regarding dens mouth azimuth angles. Furthermore, the data showed that a certain prevailing reproductive period in the Amazon region, regardless of the type of habitat or human interference. It is worth noting that the results presented here are not mandatory requirements for the occurrence of P. brasiliensis, given its large tolerance capacity for different environmental parameters, but contribute to the characterization of the environments used by giant otters in the construction of their dens and breeding biology, analyzing characteristics and use patterns that allow to identify potential areas in dammed areas, and when compared to natural environments, will assist in better understanding the interaction of the species with its environment. |