O papel de interações bióticas e fatores abióticos na estruturação de comunidades de formigas na Amazônia Central
One of the main goals in ecology is to determine which factors govern species cooccurence in local assemblages. This doctoral thesis documented the patterns of ant diversity across different forests and scales in Central Amazonia, and explored the possible mechanisms leading to these patterns. The...
| Autor principal: | Baccaro, Fabricio Beggiato |
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| Grau: | Tese |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/12222 http://lattes.cnpq.br/2034428391439802 |
| Resumo: |
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One of the main goals in ecology is to determine which factors govern species cooccurence in local assemblages. This doctoral thesis documented the patterns of ant diversity
across different forests and scales in Central Amazonia, and explored the possible mechanisms leading to these patterns. The role of antagonistic species interactions and
environmental constraints on ant co-occurrence patterns were investigated through correlative studies based on field sampling at four sites. The sites cover a latitudinal gradient in
Amazonian forests and encompass wide environmental heterogeneity, including areas of open and closed savannas, dense forests, and areas subject to different degrees soil water availability. The ant abundance, richness and composition also showed a marked variation between sites. Interference competition models tended to be more frequent in smaller sample units or in assemblages sampled with interactive methods, such as baits. The distance traveled
between bait and nest entrance, including the dominant species, was relatively small. Both results suggests that competition from ecologically dominant species may reduce species richness in small areas especially when artificial baits are used, but appears to be less important than environmental constraints in determining ant species richness across scales of hectares and greater. The role of highly specialized parasites, which alter the behavior of their
hosts to increase their own transmission, in structuring ant communities also appears to be small. There is a mismatch between infected and non-infected species distribution patterns suggesting that the number of host species suitable for behavioral manipulation is limited. These results, associated with small number of infected individuals around the colonies, probably limit the effect of these parasites regionally. The structures of ant assemblages studied were more strongly related to environmental restrictions than antagonistic interactions, such as inter-specific competition and parasitism. Regionally, fewer ant species were found in areas with lower average rainfall compared with areas with more water availability. Locally, the soil water availability, estimated by the water-table depth along one year, was also strong correlated with changes in ant assemblage structure. More ant species were found in areas with relative shallow water table. However, changes in number of species were mainly a result of an increase in generalist species associated with a decrease in the number of specialist predators and small hypogaeic generalist foragers. Although disturbance
by the water-table may increase ant diversity at site scale, it reduces the ant assemblage functional diversity locally. |