Comunidade aquática associada a bromélias: dispersão, colonização e a aplicabilidade da Teoria de Biogeografia de Ilhas

Abstract

Aquatic organisms have different dispersive capacities to colonize isolated water bodies. Passive dispersers, use external vectors like wind, rain or animals to transport propagules, while active dispersers select humid habitats as a refuge, forage, and oviposition site. Isolated aquatic habitat, like bromeliads tanks, have associated communities connected by dispersion and can be studied from the perspective of the metacommunity theory. These natural models allow us to investigate the spatial and temporal dynamics of diversity and how it responds to the species' dispersal modes. The spatial organization of bromeliads also allows them to be studied under the Island Biogeography Theory (TBI), which proposes that the richness is positively correlated to the area and negatively correlated to the isolation. However, the theory's extensions suggest that species with different body size and trophic levels respond specifically to area and isolation. In this sense, we investigated the contribution of different passive dispersers vectors to the bromeliads community, testing whether the exclusion of the vectors affects the community structure and diversity (chapter 1). Then, we investigate whether the pattern of species distribution with passive and active dispersers corroborates with TBI predictions its extensions (chapter 2). In the first article, we observed that bromeliads under the influence of high dispersion flow and more vectors have more diverse communities, while microcosms under exclusion have lower diversity. However, besides dispersion, we believe that the indirect effect of predator colonization was also decisive for the community structure. In the second article, we observed that area and isolation affect the richness and abundance of passive and active dispersers in different ways. For those with passive atmospheric dispersion, with smaller body size, the area determines the patterns of richness, while isolation determines the patterns of abundance. However, active dispersers and phoresy dispersers have a positive relationship with area and isolation as predicted by the allometric and trophic theory of island biogeography. These results show that environments under the influence of different dispersion sources have complex communities and provide novels insights into how the diversity of passive and active dispersers is affected by the spatial context in isolated aquatic environments.