Résumé
The interplay of evolutionary, ecological, and anthropogenic processes is
critical in shaping species distributions and biodiversity patterns.
Recent studies highlight the importance of examining functional and
phylogenetic traits to gain a more comprehensive understanding of these
patterns. However, significant knowledge gaps remain regarding functional
and phylogenetic diversity patterns among freshwater fish, particularly in
the context of large-scale hydrological alterations such as the
South-to-North Water Diversion Project (SNWDP). In this study, we
investigated the spatial patterns of fish taxonomic, functional, and
phylogenetic diversities and community assemblage, alongside their
environmental drivers, within five impounded lakes of SNWDP. Our analysis
sought to identify relationships between different aspects of diversity,
assessing patterns of mismatch or congruence, and evaluating the efficacy
of using one aspect as a proxy for another. Our results revealed that: 1)
fish diversity and community assembly showed no longitudinal gradient,
with spatial mismatches across diversity dimensions; 2) functional
diversity was negatively correlated with both taxonomic and phylogenetic
diversities, while the latter two showed no correlation; and 3) the SNWDP
primarily affected taxonomic and functional diversities by altering water
depth, nutrient status and promoting non-native species invasion, while
phylogenetic diversity was mainly influenced by changes in water
temperature and dissolved oxygen. These findings underscore the distinct
contributions of various diversity measures and emphasize that no single
measure can reliably predict another, highlighting the necessity of
selecting diversity measures tailored to specific questions (e.g., for
conservation or fisheries management).