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Studying beta-diversity patterns of biological communities and how species are organized in space is central to understanding the processes that maintain species diversity. Furthermore, knowledge on beta-diversity patterns is key for the protection and conservation planning of regional diversity. Insects represent the terrestrial animal group with the largest global biomass and a great body of information about spatial diversity patterns of megadiverse orders such as hymenopterans, lepidopterans, and coleopterans is available. However, studies dedicated to understanding these patterns in dipterans are scarce. Here, we aim to characterize the spatial variation of the assemblage of phytosaprophytic flies in the Amazon forest by investigating its distribution across hierarchies of spatial scales and the effect of geographical distance. The study site is located in the Direct Influence Area of the Belo Monte hydroelectric dam, Para state, Brazil. Sampling followed the Rapid Assessments for Long Term Ecological Research experimental design. Fly assemblages were not uniform across most of the spatial scales investigated. The larger scale (from 10 to 100 km) contributed more to the gamma diversity of the region than the smaller ones (approximately 1 km). The beta diversity with a Shannon index of over 60 % of γ taxonomic diversity was influenced by the diversity within transects (α-diversity). Pairwise dissimilarity showed no significant relationship between geographical distance and Sorensen dissimilarity, turnover, nestedness, balanced variation in species abundances, or abundance gradient components. The absence of stochastic processes in the formation of the assemblages of phytosaprophytic flies indicates that environmental filters are more important to its structuring than neutral processes. Thus, studies on larger scales can provide more robust evidence on the assemblages distribution, both in preserved and highly impacted environments. Our study considered this wide-scale and our finding revealed some patterns in the assembly rules of the flies community Amazon. |
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