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1.
Bioikos (Campinas, Online) ; 29(2): 11-18, 2015. map, tab
Artigo em Português | VETINDEX | ID: biblio-1464014

Resumo

A perda de habitat causa um declínio nas populações de plantas e animais, afetando suas interações, como a polinização. Em áreas urbanas, a deficiência de polinizadores é a principal causa para redução do sucesso reprodutivo nas plantas. A presença de fragmentos de mata pode auxiliar na conservação de visitantes florais, auxiliando na produção de sementes. Para testar essa hipótese, foram feitos testes reprodutivos e coletas ativas dos visitantes florais em árvores de araçá em área urbana e fragmento de mata. Os visitantes mais abundantes em ambas as áreas foram as abelhas. Os valores de abundância das abelhas não variaram entre si mais que o acaso, porém a diversidade foi maior na área com fragmento. A produção de frutos por autopolinização supera a de polinização natural, devido, provavelmente, ao fato de que muitos dos visitantes florais atuam como pilhadores de pólen, o que diminui a quantidade deste que é disponível para a polinização. Apesar da maior diversidade de visitantes na área de fragmento de mata, da autocompatibilidade e do comportamento de pilhador dos visitantes, esses fatores não influenciam no sucesso reprodutivo da espécie estudada. Palavras-chave: Antropização. Autocompatibilidade. Pilhadores de pólen. Sucesso reprodutivo.


Habitat loss causes a decline in plant and animal populations, negatively affecting plant-pollinator interactions, such as pollination. In urban areas pollinator deficit is the main cause of plants low reproductive success. The presence of forest fragments in urban areas may help to preserve floral visitors, increasing seed production. This hypothesis was tested by conducting reproduction tests of strawberry guava trees in an urban area and at a forest fragment within an urban area and by actively collecting its floral visitors. Bees were the most abundant flower visitors in both areas. Bees abundance was strictly casual, but diversity was higher in areas with fragment. Fruit production by selfing exceeds that of natural pollination probably because many floral visitors act as pollen thieves, decreasing the amount of pollen available for pollination. Despite the greater diversity of visitors in the forest fragment area, self-compatibility, and the robbing behavior of visitors, these factors do not influence the reproductive success of the study species.


Assuntos
Animais , Biodiversidade , Flores , Psidium , Área Urbana
2.
Bioikos ; 29(2): 11-18, 2015. mapas, tab
Artigo em Português | VETINDEX | ID: vti-15659

Resumo

A perda de habitat causa um declínio nas populações de plantas e animais, afetando suas interações, como a polinização. Em áreas urbanas, a deficiência de polinizadores é a principal causa para redução do sucesso reprodutivo nas plantas. A presença de fragmentos de mata pode auxiliar na conservação de visitantes florais, auxiliando na produção de sementes. Para testar essa hipótese, foram feitos testes reprodutivos e coletas ativas dos visitantes florais em árvores de araçá em área urbana e fragmento de mata. Os visitantes mais abundantes em ambas as áreas foram as abelhas. Os valores de abundância das abelhas não variaram entre si mais que o acaso, porém a diversidade foi maior na área com fragmento. A produção de frutos por autopolinização supera a de polinização natural, devido, provavelmente, ao fato de que muitos dos visitantes florais atuam como pilhadores de pólen, o que diminui a quantidade deste que é disponível para a polinização. Apesar da maior diversidade de visitantes na área de fragmento de mata, da autocompatibilidade e do comportamento de pilhador dos visitantes, esses fatores não influenciam no sucesso reprodutivo da espécie estudada. Palavras-chave: Antropização. Autocompatibilidade. Pilhadores de pólen. Sucesso reprodutivo.


Habitat loss causes a decline in plant and animal populations, negatively affecting plant-pollinator interactions, such as pollination. In urban areas pollinator deficit is the main cause of plants low reproductive success. The presence of forest fragments in urban areas may help to preserve floral visitors, increasing seed production. This hypothesis was tested by conducting reproduction tests of strawberry guava trees in an urban area and at a forest fragment within an urban area and by actively collecting its floral visitors. Bees were the most abundant flower visitors in both areas. Bees abundance was strictly casual, but diversity was higher in areas with fragment. Fruit production by selfing exceeds that of natural pollination probably because many floral visitors act as pollen thieves, decreasing the amount of pollen available for pollination. Despite the greater diversity of visitors in the forest fragment area, self-compatibility, and the robbing behavior of visitors, these factors do not influence the reproductive success of the study species. (AU)


Assuntos
Animais , Biodiversidade , Flores , Psidium , Área Urbana
3.
Bioikos ; 27(1)2013.
Artigo em Português | VETINDEX | ID: vti-714413

Resumo

Oligochaetes are important components of energy flow in freshwater ecosystems. Even though of ecological significance, few studies are available about this group. Therefore, this study analyzed the diversity of Oligochaeta in three anthropic lakes and investigated their distribution over a seasonal cycle in a forest fragment at Porto União, Santa Catarina, Brazil. Sediment samples were obtained using na Ekman-Birge (15x15cm) grab in October (spring) and January 2011 (summer), March (autumm), and July (winter) 2012. We collected 305 individuals, belonging to 4 species, and 5 genera from the Tubificinae and Naidinae families. The highest density was in autumm, a period with greater climatic stability. Limnodrilus hoffmeisteri (Claparede, 1862) was the most abundant species, present in all sampling periods. Our results increase the knowledge on oligochaeta in Southern Brazil and provide the first record limnic oligochaetes to Porto União, Santa Catarina.Key words: Atlantic Forest. Autumm. Diversity. Seasonality.

4.
Bioikos ; 27(1)2013.
Artigo em Inglês | VETINDEX | ID: vti-714334

Resumo

Benthic invertebrates are a key link between primary producers and higher trophic levels in aquatic systems. Feeding interactions between species in food webs may provide information about biodiversity and the organization of aquatic ecosystems in different seasonal periods. We evaluated the influence of seasonal variation on the structure of food webs in the Rio Claro Mallet, Paraná, Southern Brazil. Two samplings were performed in the dry (October and November 2010) and wet (December 2010 and February 2011) seasons in three sites along the river. We conducted food web modeling and also calculated measures of benthic community structure regarding seasonal periods. Our results suggest that the invertebrate community changes depending on flooding. However, particular trophic groups may be more resilient after disturbances.Key words: Benthic macroinvertebrates. Food webs. Lotic ecosystems. Resilience.


Benthic invertebrates are a key link between primary producers and higher trophic levels in aquatic systems. Feeding interactions between species in food webs may provide information about biodiversity and the organization of aquatic ecosystems in different seasonal periods. We evaluated the influence of seasonal variation on the structure of food webs in the Rio Claro Mallet, Paraná, Southern Brazil. Two samplings were performed in the dry (October and November 2010) and wet (December 2010 and February 2011) seasons in three sites along the river. We conducted food web modeling and also calculated measures of benthic community structure regarding seasonal periods. Our results suggest that the invertebrate community changes depending on flooding. However, particular trophic groups may be more resilient after disturbances.Key words: Benthic macroinvertebrates. Food webs. Lotic ecosystems. Resilience.

5.
Bioikos ; 27(1)2013.
Artigo em Português | VETINDEX | ID: vti-714311

Resumo

Benthic invertebrates are a key link between primary producers and higher trophic levels in aquatic systems. Feeding interactions between species in food webs may provide information about biodiversity and the organization of aquatic ecosystems in different seasonal periods. We evaluated the influence of seasonal variation on the structure of food webs in the Rio Claro Mallet, Paraná, Southern Brazil. Two samplings were performed in the dry (October and November 2010) and wet (December 2010 and February 2011) seasons in three sites along the river. We conducted food web modeling and also calculated measures of benthic community structure regarding seasonal periods. Our results suggest that the invertebrate community changes depending on flooding. However, particular trophic groups may be more resilient after disturbances.Key words: Benthic macroinvertebrates. Food webs. Lotic ecosystems. Resilience.

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