Análise dos padrões de paleoendemismo e neo-endemismo da comunidade de peixes das bacias da América do Sul.

Abstract

The Neotropical region has the largest ichthyofaunal community in the world, with more than 6,200 species, most of which are found in the Amazon and La Plata basins. This diversity is linked to numerous geological and dispersal events, which, combined with refuge areas, have led to the occurrence of freshwater fish endemism. From a phylogenetic perspective, locations can be classified as paleo-endemic, neo-endemic, mixed-endemic, or super-endemic centers. Recognizing that endemism patterns are directly related to the scale used, we conducted an analysis with three approaches: one for South America and two for the most species richness basin complexes, the Amazon Complex and the La Plata Basin. Using fish species occurrence data for South American sub-basins and a temporally calibrated phylogeny, we applied the CANAPE methodology to identify the occurrence of endemism centers in these three approaches. The results indicated that about 22% of South American sub-basins are configured as endemism centers. Among these, the number of super-endemic centers was the highest, mainly located in the western portion of the Amazon basin for both South America and the Amazon Complex. Neo-endemic centers occurred in the southeastern region of South America and in the La Plata Basin, while few centers were classified as paleo-endemic, occupying the northwestern and/or northern portion of South America. The analysis of mean phylogenetic beta diversity demonstrated that phylogenetic turnover processes were more impactful in the formation of mixed-endemic and super-endemic centers and less impactful in the formation of neo-endemic centers. The effectiveness of protected areas (PAS) was assessed using data from the International Union for Conservation of Nature (IUCN) regarding strictly protected areas and sustainable use areas. The results showed that mixed-endemic and super-endemic centers have moderate protection compared to existing protected areas, whereas neo-endemic centers generally receive poor protection from these areas, particularly in the South American and La Plata Basin approaches. Considering that aquatic communities are frequently overlooked in biodiversity conservation initiatives, the data collected are crucial for their inclusion in conservation strategies. Thus, it is imperative to establish comprehensive guidelines and public policies to mitigate anthropogenic impacts on basins within neo-endemic centers, as the current minimal protection in these regions may result in irreversible and unparalleled losses for the South American freshwater fish assemblage.