Efeito de plantas exóticas sobre a fidelidade de polinizadores e a qualidade do serviço de polinização

• Autor(a) principal: Valente, Cristiele Barbosa
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/7889
• topic: Plantas exóticas; Polinização; Polinizadores; Visitantes florais; Exotic plants; Pollination; Pollinators; Floral visitors; CIENCIAS BIOLOGICAS::ECOLOGIA

The invasion of terrestrial habitats by exotic plants often has negative effects on growth and fitness of native plants. Exotic plants may change the foraging behavior of pollinators and dynamics of interactions of local assemblages. Due to the lack of shared evolutionary history between exotic plants and native pollinators, it is likely that the morphological and phenological mismatches are especially important in determining the interactions involving exotic plants and specialist native pollinators. In addition, exotic plant species are expected to be pollinated by abundant generalist pollinators whose interactions are phylogenetically constrained compared to specialists pollinators. To evaluate these issues, we compiled 28 plant-pollinator networks with 778 plant species (10% alien) and 3019 pollinator species, comprising 7919 interactions. We expected that: (a) exotic plants tend to be visited by more generalist pollinator species compared to the co-occurring native plant species; (b) an increase in the proportion of exotic plants in the plant-pollinator networks promotesan increase in the global connectivity and nestednessof the interactions. If these predictions are correct, then the introduction of plants should also promote an increase in the risk of heterospecific pollen deposition on native plants. We found that exotic and native plants did not differ in the average degree of specialization of their pollinators. Moreover, an increase in the proportion of alien plants did not affecteither structure or the connectivity of networks. On the other hand, there was an increase in the risk of heterospecific pollen deposition on native plant stigmas when the proportion of exotic plants increases to about 1/3 of the flora pollinated by animals.However, above this percentage the relationship is reversed. This result may be a consequence of progressive decrease in pollinator fidelity of native plants in habitats with low-levels of invasion by exotic species, reducing the amount of shared pollen due to the impoverished pollinator fauna.