Robustez em redes mutualísticas entre aves frugívoras e plantas: efeitos ecológicos, morfológicos e taxonômicos

Abstract

Frugivory and seed dispersal are fundamental ecological processes for maintenance and conservation of tropical forest areas and ecosystems resilience. Based on literature data and fecal samples of birds collected after mist netting procedures, we investigate factors that can affect the relationship between frugivorous birds and fruit consumption, such as body mass, niche relationships and species taxonomic groups and how they can affect robustness of mutualistic bird x plant interaction networks. Using Horn-Morisita niche overlap, body mass coefficient of variation, and variation in taxonomic distinctness index (varDT) as explanatory variables, we applied multiple linear regression to test the hypotheses that increased robustness in bird x plant frugivory networks occurs where birds have larger trophic niche overlaps and lower body mass variations, and decreased robustness where they are more taxonomically diverse, in response to less functional redundancy. Bird body mass and niche overlap did not explain the variation in robustness in seed dispersal networks. On the other hand, the results showed an effect by varTD, suggesting that the larger the taxonomic distinction of birds in a frugivore assemblage, the larger the robustness of the networks. Some hypotheses are suggested to explain this effect. Whatever the factors that lead varTD to favor the robustness of mutualistic bird-plant networks, the results demonstrate that conserving diversity above the species level, and not just species limited to a few taxonomic groups can be an important strategy for ecosystems conservation throughout the time.