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1.
Artigo em Inglês | VETINDEX | ID: vti-690446

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

2.
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1504158

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

3.
Artigo em Inglês | VETINDEX | ID: vti-441406

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

4.
Artigo em Inglês | VETINDEX | ID: vti-690166

Resumo

Grazing and fire, used in pasture regeneration practices, are inter-related activities in livestock management. Both activities affect habitat characteristics by changing the structure of the herbaceous and shrubby vegetation, reducing their biomass and litter cover. This study evaluated the effect of fire and livestock grazing on the assemblage of non-flying small mammals in grassland-Araucaria forest ecotones in southern Brazil. We compared four areas frequently affected by livestock management with four protected areas. Surveys were carried out in four sampling periods, one in each season of 2004. We captured a total of 325 individuals from 12 species of rodents - Akodon montensis Thomas, 1913, Akodon paranaensis Christoff, Fagundes, Sbalqueiro, Mattevi e Yonenaga-Yassuda, 2000, Akodon sp. 1, Akodon sp. 2 (2n = 34), Brucepattersonius iheringi (Thomas, 1896), Delomys dorsalis (Hensel, 1872), Oligoryzomys flavescens (Waterhouse, 1837), Oligoryzomys nigripes (Olfers, 1818), Oxymycterus nasutus (Waterhouse, 1837), Scapteromys sp. (2n = 34), Sooretamys angouya (Fischer, 1814) and Thaptomys nigrita (Lichtenstein, 1829) - and two species of marsupials - Monodelphis dimidiata (Wagner, 1847) and Philander frenatus (Olfers, 1818) -, in a total effective effort of 5254 traps.day-1. The abundance, biomass and diversity of non-flying small mammals were significantly higher in the protected areas than in those affected by fire and livestock grazing. Species strictly associated with grassland habitats were not found in the impacted area. These results indicate that the presence of herds of domestic ungulates negatively affect the assemblage of non-flying small mammals in grassland and Araucaria forest areas in southern Brazil.

5.
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1503867

Resumo

Grazing and fire, used in pasture regeneration practices, are inter-related activities in livestock management. Both activities affect habitat characteristics by changing the structure of the herbaceous and shrubby vegetation, reducing their biomass and litter cover. This study evaluated the effect of fire and livestock grazing on the assemblage of non-flying small mammals in grassland-Araucaria forest ecotones in southern Brazil. We compared four areas frequently affected by livestock management with four protected areas. Surveys were carried out in four sampling periods, one in each season of 2004. We captured a total of 325 individuals from 12 species of rodents - Akodon montensis Thomas, 1913, Akodon paranaensis Christoff, Fagundes, Sbalqueiro, Mattevi e Yonenaga-Yassuda, 2000, Akodon sp. 1, Akodon sp. 2 (2n = 34), Brucepattersonius iheringi (Thomas, 1896), Delomys dorsalis (Hensel, 1872), Oligoryzomys flavescens (Waterhouse, 1837), Oligoryzomys nigripes (Olfers, 1818), Oxymycterus nasutus (Waterhouse, 1837), Scapteromys sp. (2n = 34), Sooretamys angouya (Fischer, 1814) and Thaptomys nigrita (Lichtenstein, 1829) - and two species of marsupials - Monodelphis dimidiata (Wagner, 1847) and Philander frenatus (Olfers, 1818) -, in a total effective effort of 5254 traps.day-1. The abundance, biomass and diversity of non-flying small mammals were significantly higher in the protected areas than in those affected by fire and livestock grazing. Species strictly associated with grassland habitats were not found in the impacted area. These results indicate that the presence of herds of domestic ungulates negatively affect the assemblage of non-flying small mammals in grassland and Araucaria forest areas in southern Brazil.

6.
Artigo em Inglês | VETINDEX | ID: vti-441158

Resumo

Grazing and fire, used in pasture regeneration practices, are inter-related activities in livestock management. Both activities affect habitat characteristics by changing the structure of the herbaceous and shrubby vegetation, reducing their biomass and litter cover. This study evaluated the effect of fire and livestock grazing on the assemblage of non-flying small mammals in grassland-Araucaria forest ecotones in southern Brazil. We compared four areas frequently affected by livestock management with four protected areas. Surveys were carried out in four sampling periods, one in each season of 2004. We captured a total of 325 individuals from 12 species of rodents - Akodon montensis Thomas, 1913, Akodon paranaensis Christoff, Fagundes, Sbalqueiro, Mattevi e Yonenaga-Yassuda, 2000, Akodon sp. 1, Akodon sp. 2 (2n = 34), Brucepattersonius iheringi (Thomas, 1896), Delomys dorsalis (Hensel, 1872), Oligoryzomys flavescens (Waterhouse, 1837), Oligoryzomys nigripes (Olfers, 1818), Oxymycterus nasutus (Waterhouse, 1837), Scapteromys sp. (2n = 34), Sooretamys angouya (Fischer, 1814) and Thaptomys nigrita (Lichtenstein, 1829) - and two species of marsupials - Monodelphis dimidiata (Wagner, 1847) and Philander frenatus (Olfers, 1818) -, in a total effective effort of 5254 traps.day-1. The abundance, biomass and diversity of non-flying small mammals were significantly higher in the protected areas than in those affected by fire and livestock grazing. Species strictly associated with grassland habitats were not found in the impacted area. These results indicate that the presence of herds of domestic ungulates negatively affect the assemblage of non-flying small mammals in grassland and Araucaria forest areas in southern Brazil.

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