Long-Term Effects of Environmental Changes on Alpha and Beta of Fish Species, Functional, and Phylogenetic Diversity in the Minjiang Estuary

Abstract

Species, functional, and phylogenetic diversities are the three main dimensions of biodiversity. In the context of the current biodiversity crisis, a key question is how these diversities and their determinants change over time. Previous studies on the three diversities of fish have mainly focused on freshwater ecosystems, with little research conducted in estuarine ecosystems. Here, we evaluated the temporal changes of species, functional, and phylogenetic α- and β-diversity for fish in the Minjiang Estuary, and identified the environmental factors that shape these patterns based on fishery survey data in the Minjiang Estuary during 2006 and 2016. Results showed that species richness (SR) and functional richness (FRic) markedly declined. Meanwhile, functional β-diversity (FD-β) and functional turnover (FD-tu) showed opposite trends between the two study periods. The turnover of species, functional traits, and mitochondrial gene were mainly contributed to their corresponding β-diversity, while differences in species and phylogenetic richness are also important for their β-diversity. Principal coordinate analysis results indicated that the environmental condition in 2016 differed from that in 2006. The changes in environmental variables have a greater influence on β-diversity compared with α-diversity. Specifically, the temporal changes of β-diversity were primarily driven by temperature, while depth and precipitation had a minimal effect. The species, functional, and phylogenetic diversities are the complementary aspects of fish diversity rather than surrogates, and they should be simultaneously considered in biodiversity studies. Majority of the aspects of biodiversity changed from weakly to strongly affected by changes of the different environmental variables.

Keywords: Alpha and beta diversity, Functional differentiation, mitochondrial gene composition, Standardised effect size, Environmental driver